The Universe: ALIEN PLANETS and the Great Unknown *3 Hour Marathon*

are there planets beyond our solar system it's a question few had dared to probe the origin of hunting for planets started really from The Lunatic Fringe of Science Now hundreds of these exotic worlds have been found could any of them be home to alien life right now the S plants we're discovering are kind of monsters you would be incinerated immediately uh before you had a chance to really sort of groove on your surroundings but some planets hold more promise I'm so excited about gisa 436 I'm almost jumping out of my clothes could we be on the verge of finding another Earth we still don't know whether our Earth is a commonly occurring planet or a one in a billion freak Cutting Edge science strange worlds and wild weather as we travel the universe in search of alien planet [Music] lurking in the constellation Pegasus 50 light years from Earth is a monstrous Planet a superheated gas giant almost as massive as Jupiter whipping around its star in a little over 4 days it's called 51 pegas B and in 1995 it became the first planet detected orbiting an alien Sun it was a landmark Discovery but just a stepping stone on an even greater quest to find a planet that looks more like our own the ultimate but elusive goal for astronomers is to find another Earth what we're after is the appreci a of where our Earth fits in in the grand context of our universe and we'd love to be able to find other Earths but Earths are so undetectable little chunks of rock that don't emit much light how common might earthlike planets be in the universe even if only 1% of all stars were circled by a planet like our own that would still mean there are billions of other Earths waiting to be discovered we are almost sure that rocky earthlike planets exist in abundance out there but how earthlike there are still open questions about the uniqueness of our Earth and we don't know whether our Earth is unusual or not it's an extremely profound and I think disturbing question in the realm of alien planets there's a wide range of imaginable worlds we might find Ocean worlds completely covered in water frigid ice planets mars-like worlds but perhaps with thick atmospheres fed by Massive active volcanoes and even planets with two suns in their Skies there may be planets that humans would find hospitable and others on which humans wouldn't dare tread that could still be home to other types of creatures perhaps the major lesson we've learned so far from looking for plants around other stars is that nature can make a lot more plants than we can dream of finding just one other truly earthlike Planet would hint that Earths are common in the universe and if Earths are common then perhaps life too is widespread but of the over 200 alien planets detected so far most of them seem utterly hostile to Life as we know it so far we found sort of three kinds of worlds one kind are the the planets that are really close to the star that they orbit and they're totally baked to death then there are the ones that are quite far away and they're pretty cold and then there are the ones in the highly eccentric orbits which sometimes get close to the star and sometimes far away so they're alternately very hot and cold so far we definitely haven't found any worlds with jungles and forests indeed we haven't found any worlds that are square smack in the habitable zone where there's liquid water on the surface and other nice conditions our frame of reference for what we consider to be a nice planet is this one we like it quite a bit um we've got breathable air it's a pleasant temperature and there's water and even in in our own solar system we don't see a lot of planets like that and right now the sort of plants we're discovering are kind of monsters in other words they're extremes so is the Earth with its Rocky surface oceans and Abundant Life just a planetary Wonder with no close kin in the cosmos the early discoveries of alien planets have yet to answer that question but they have brought legitimacy to what once seemed like a feudal Quest while many believed there had to be other worlds out there in the vastness of the universe locating them was widely considered beyond the reach of modern science only a few decades ago an astronomer hunting for these so-called extra solar planets was taken about as seriously as someone searching for UFOs the search for planets as it started in the 1980s and 1990s was considered uh off of the Beaten Track of standard science in the early 80s astronomer Jeff Marcy's career was going nowhere his research into the magnetic fields of stars had reached a dead end and he was beginning to question his own abilities as a scientist when I first began thinking about looking for planets it was in a time in my career when I thought it was over I thought there were there was no hope for me as a scientist and I thought the best shot I had going out in Flames was to try an experiment that everybody thought would never work namely looking for planets around other stars and um most people thought we would never find any planets before Jeff Marcy his collaborator Paul Butler and a handful of pioneering astronomers around the globe could begin the search for alien planets they had to First perfect methods for finding them stars are easy to locate using conventional telescopes but to find a Planet take some Ingenuity and patience unlike the Stars they orbit planets are small and emit very little light even the giant of our Solar System Jupiter is a thousand times less massive than the Sun and 10 billion times fainter I hear difficulty in taking a picture of a planet around a star is that the planet is extremely extremely faint compared to the star the star is so bright it almost completely obscures the much much dimmer Planet Blinded By Starlight Planet Hunters realized that even if they couldn't see a planet directly they should still be able to detect its gravitational effect on the star at orbits a star with no planets should drift smoothly through the sky while one with planets should exhibit a Telltale gravitational wobble we often say that planets orbit the Sun or other stars but that's not exactly true the planets and the stars orbit their Common Center of mass or center of gravity and this Center of Mass isn't halfway between them just like on a seesaw the more massive object must be closer to the center of Mass to bring balance to the system so consider the Sun and Jupiter the sun is about a thousand times more massive than Jupiter so the sun is here the fil fulcrum or balancing point is there and Jupiter is way out here A Thousand Times farther away in space this means that planets Trace out large orbits around the center of mass while stars make much smaller but still detectable orbits here's a hypothetical Planet orbiting a star in fact they're orbiting their Common Center of mass so the planet moves in a relatively large orbit but the star also moves but in a much smaller orbit so the star moves only a little bit and the planet moves a lot I have a somewhat unusual hobby for an astronomer I'm a belly dancer and fire performer but it turns out that spinning fire is a great way of simulating the motion of a planet and the centripetal motion of your fire on the chain is very similar to the motion of a planet under Gravity the light on my wrist represents the star and the spinning ball of fire around that is a planet and as you can see the ball of fire draws out a large Circle and my wrist is drawing out a smaller circle inside it it's this tiny wobble of Starlight that scientists use to find extra solar planets but even this wobble would be undetectable if it wasn't for the Doppler effect the fact that wavelengths get shorter as the object emitting them moves toward you and longer as it moves away from you the Doppler effect is very familiar if you've ever heard a train going by blowing its [Applause] whistle so when the train is coming toward you you hear high pitched whistle and as the train recedes into the distance away from you you hear the pitch of the whistle get lower and lower in frequency just like sound waves light waves appear to shift in frequency as the object emitting them comes toward W or away from you light from an object moving toward you will look slightly Bluer light from an object moving away from you will look slightly redder when the light waves shift their wavelength toward the blue and toward the red and back toward the blue again as the star wobbles around the shift is excruciatingly tiny but it's that difference in the wavelength of the light waves coming at you that is what we measure and it's what allows us to detect planets around other stars using this Doppler technique Marcy and Butler spent over a decade patiently studying 12 120 nearby stars for any sign of a wobble I went 11 years without finding a single planet nothing and no one was surprised by that it it seemed logical to everybody else that it was a fruitless uh frivolous maybe even lunatic exercise to look for planet of any sort but then in 1995 came the surprise announcement from Swiss astronomers Michelle mayor and edlo that they had discovered a gas giant planet circling the star 51 pegasi Marcy and Butler rushed up to Lick Observatory on Northern California's Mount Hamilton to aim their own telescope at the star and see if they could confirm the Swiss team's results yeah there it is looks beautiful Paul Butler and I were shocked to see that the wobble of the star was precisely as the Swiss had said it was and I remember driving off Mount Hamilton from Lick Observatory in complete silence Paul Butler next to me we knew that the first extrasolar planet had been discovered it was it was a very moving you know personally moving moment despite the Monumental nature of the discovery this like all future extrasolar planets wouldn't get the name of a Greek or Roman god it would take the astronomical catalog name of its parent star 51 pegy and add to it a lowercase b in this standard nomenclature if a second planet was found around the same star it would get a lowercase C and so on through the alphabet its name was the only thing un assuming about 51 pegas B the discovery shook the foundations of our understanding of planets in 1995 astrophysicist Alan boss was asked to review a paper announcing the discovery by two Swiss astronomers of the first planet orbiting an alien Sun reviewing this paper caused me a fair number number of sleepless nights because it was pretty stunning what they had found stunning because the Swiss claim to have found a jupiter-like planet but where Jupiter orbits the Sun in 12 years this planet zipped around its star in only 4 days and that also meant that the planet had to be much much closer to its Central Star roughly roughly 100 times closer than than Jupiter is and that just was hard to understand Jupiter orbits the Sun at a comfort able distance of around half a billion miles 51 pegas B is more like 5 million miles from its star if it were dropped into our own solar system this Alien Planet would orbit much closer to the Sun than Mercury our innermost Planet being so close to the star means that the planet is being literally fried the radiation from the star is incredible compared to what we experience here on Earth relatively far from our sun so this was a completely unexpected Discovery it was a planet that could not have formed there astronomers knew it didn't belong there in the same way that if we found a giant Redwood in the middle of Central Park we would know that it didn't belong there you'd have to ask yourself how did it get there and that's what astronomers were asking themselves about these giant planets that they were finding 51 pegas B wasn't just a freak of nature it was the first of dozens of so-called Roasters or hot Jupiters to be discovered in seemingly impossible close-in orbits impossible because the accepted theory for how gas planets form suggests that rock and ice in a disc surrounding a young star coalesces into a solid core that then accretes gas growing larger and larger until it is cleared out all the planet forming material in its area this process can only occur at a distance Far Enough From the Star where it's cold enough for ice to exist you can't form something that massive that close in to a star it needs to form past the snow line where ice can form and in our solar system that's about where Jupiter is about five times further out from the Sun than the Earth so how could a gas giant planet like 51 pegy B form so scorchingly close to its star it was one of these things where uh woke up in the middle of the night and one night I said to myself maybe what this means is that this object had to have migrated inwards from where it originally formed we now I think have an understanding that planet formation is an almost chaotic process a sort of roll of the dice with many planetesimals Wann toe planets forming building up and a competition a sort of gravitational musical chairs takes place in which the planets compete for their own space in this competition some planets are flung out of the solar system and some are tossed toward the center it's believed some planets crash and burn on their parents star While others survive in a close but stable orbit these survivors are the hot Jupiters yeah I think the discovery of the hot Jupiter circling 51 pegasi sent Planet Hunters Jeff Marcy and Paul Butler back to analyze the data they'd been collecting for the past decade their team had been looking for the expected long-term wobbles caused by a giant planet we ourselves suddenly realized Iz we should analyze our data in a slightly different way look for the shorter period planets not just planets that take a long time to go around their star and that led us to discover within existing data all of these planets that had been buried there for years I remember the day like it was yesterday December 30th 1995 and at 8:00 a.m. the phone rings I pick it up it's Paul Butler my Ace collaborator for 20 years now and Paul just said Jeff come over [Music] here so of course I immediately got in my car I drove right to this very office right here where I'm sitting now in Campbell Hall at UC Berkeley and he showed me his computer screen and there on that screen was the unmistakable graph of the wobble of the star 70 virgines going up and down and up and down the star wobbling to and fro exactly as we had imagined a planet signature would look in our data so that was the moment with both of our eyes open this wide that we knew we had discovered our first planet the second planet ever discovered 70 virgines B is 59 light years from Earth in the constellation Virgo with a mass at least seven times larger than Jupiter this world immediately claimed the title as the planetary heavyweight of the known universe here right before our eyes essentially is a planet seven maybe 10 times bigger than our own Jupiter telling us immediately that yes nature does make planets even bigger than the largest ones we have here in the solar system rather than a hot Jupiter this planet was the first of a new class of alien worlds called eccentric Giants because of their eccentric or elongated orbits 70 virgines B swings out as far as 63 million miles from its star and passes as close as 27 million miles the frightening aspect of the planet around 70 virgines is that we all grew up in kindergarten learning that planets go around the Sun in nearly circular orbits so what in the world is a planet doing going around its star in one of these elongated wacky orbits already the first two planets discovered around alien suns were challenging our view of how planets should behave further discoveries over the next decade would show that eccentric orbits are common in the universe while the circular orbits of our solar system seem to be rare it's embarrassing frankly when you think about how we humans imagined planets would orbit other stars how common they would be what properties they would have guess what we imagined that those planets would look just like the planets that orbit our sun extraordinarily nearsighted in retrospect and for a scientist I find it embarrassing that I was a party to this but in fact what we've learned is that planets around other stars are remarkably different from the representatives we have around our sun the planet hunting Revolution that began in the 1990s has also obliterated ated any notion that planets are rare in the universe with an Ever growing catalog of alien planets astronomers are now trying to learn all they can about the more than 200 worlds they've already discovered the Doppler technique used by Jeff Marcy and other astronomers tells them the mass of the planet they found but it doesn't tell them the size to figure out just how how big an alien planet is requires a bit of good luck the orbit of the planet has to be aligned in such a way that from Earth we can see it pass directly in front of its star this is called transiting by measuring how much the Starlight dims during this Transit astronomers can actually determine the size of the planet in the fall of 2007 astronomers were watching when a hot Jupiter called race 4 transited its star the planet was about the same mass as Jupiter and therefore should have been roughly the same size but astronomers were in for a surprise Trace 4 turned out to be almost twice as big as Jupiter it was in fact the largest planet ever discovered sort of a Jupiter on steroids some of these extra solar planets are really fluffy they're really uh expanded in size and we think that the reason why that's happening is because they have an internal source of heat which is raising the pressure inside the planet causing it to expand that's very similar to uh a steam boiler on a steam [Music] train in a steam boiler you have water which is being heated by a heat source that water is turning to steam the pressure is increasing and that's causing the Piston of the boiler to move out to expand [Music] if you didn't have the gas's ability to expand the planets wouldn't inflate steam trains wouldn't work we wouldn't be climbing up this mountain while internal heating is the likely cause of the so-called fluffy Jupiters something much stranger is happening on this alien world in the field of extra solar planets it seems each new discovery creates a brand new world of scientific Intrigue at the University of Arizona planetary scientist Adam shman P the weather on other planets recently showman helped generate the first ever forecast for a planet beyond our solar system and what he found was weather truly befitting an alien world we think that the winds are probably about 6,000 mph possibly even more this is huge compared to the wind speed on any planet in our solar system this is hd189733b it's a hot juper more than 60 light years from Earth that races around its sunlike star in a little over 2 days at a distance of only 3 million miles how is it possible to Divine the weather on a planet 370 trillion miles away first you have to take the planet's temperature scientists knew that since the planet orbits so close to its star it would be tily locked a gravit ational effect that would cause it to show the same face to the star at all times one side would always be bathed in the burning hot light of the alien sun while the other would be cloaked in Perpetual Darkness if there was no wind on these planets then that would mean that the day side would then be very very hot and the night side would be very very cold in the spring of 2007 scientists used the Spitzer Space Telescope which sees in infrared wavelengths associated with heat to generate a crude map of the temperature on both the day and night side of the planet you are actually looking at the first map of any kind made of an alien world what the map shows is that the day side of the planet is roasting at an otherworldly 1500° Fahrenheit No Surprise given how close the planet orbits to its star what was surprising was how hot the night side of the planet turned out to be despite being in total darkness it swelters at around 1,000° clearly something was Distributing heat throughout the planet's atmosphere carrying thermal energy from the day side clear around the other side of the planet from his knowledge of weather and our own solar system showman knew what the culprit was he ran the numbers and that's when he figured out that this alien world had jet streams of unprecedented magnitude their 6,000 mph winds dwarf anything in our own solar system earth actually has the slowest speeds of any planet in our solar system with a typical speed of about 20 mph the gas giants in our solar system actually have somewhat faster winds than the earth simply because there's no surface to have friction to slow down the winds on Jupiter and Saturn for example the winds are a few hundred miles hour so there still about almost a factor of 10 lower than on these hot Jupiters the weather on hot Jupiters may be extreme but the forecast for another class of alien planets The Eccentric Giants is tailor made for a disaster movie this is HD 80606b a gas giant planet located roughly 200 light years from Earth orbiting a star in the constellation Ursa Major a year on this bizarre world lasts 111 days and it has the most eccentric orbit of any known planet with its nearly circular orbit Earth's distance from the Sun changes relatively little throughout the year varying by only about 4 million miles but during its year HD 80606b comes as close as 3 million mil to its sun and as far as 78 million a difference of 75 million miles this crazy uh orbit leads to completely crazy weather uh the planet heats up by hundreds and hundreds of degrees in a matter of a few hours and that drives just absolutely tremendous storms as the planet swings in close to its star the alien Sun looms ever larger in the sky and so you get a huge amount of heating on one side of the planet the other side of the planet is in the night what that does is it drives an intense storm it's basically a shock wave around both sides of the planet that is moving roughly at the speed of the supersonic jet this fiery hurricane rips around the planet in only 12 hours as the shock wave slowly dies down the superheated atmosphere turns into a giant Vortex that engulfs an entire hemisphere a sort of Greater red spot as the planet moves away from the heat of its star the storm gradually loses energy and intensity but on this eccentric giant the C never lasts for long every 111 days the shock wave is reignited as and the violent cycle begins a new it's much Stranger than anything that we have in our own solar system if you were there you would you would be incinerated immediately uh before you had a chance to really sort of groove on your surroundings the universe seems Adept at creating strange worlds even in the most unlike of places this is a pulsar a rapidly spinning variety of an exotic Stellar object called a neutron star neutron stars are the remnants Left Behind after a massive star explodes in a supernova no one expected to find planet circling in such a treacherous Cosmic neighborhood never in my wildest dreams did I think we would ever find planets orbiting a neutron star a pulsar I mean after all neutron stars are formed as a result of supernova explosions where the star just blows up so certainly any planets that might have been there to begin with would have been blown away and yet in the early 1990s astronomers CED two rocky planets around a pulsar 7,000 trillion miles from Earth their Discovery in fact predates 51 pegas B making them technically the first alien worlds ever detected but since they orbit such strange Stars many astronomers consider Pulsar planets to be in a category of their own the Pulsar planets were very interesting they're they're actually very low in Mass and uh more similar to to the Earth's mass they form an interesting exotic classification or family of planets but it's by no means the mainstream While most planets are believed to have formed out of the same dis of gas and dust as their parent Stars clearly these Pulsar planets formed a different way the planets that have been found must have formed after the supernova explosion and that's really bizarre because we would think that all of the material was blown away but apparently some of that debris must have somehow been in a disc and parts of that dis coales into planets but that's extremely surprising I don't know that anyone really understands that process yet although the Pulsar planets are believed to have rocky surfaces it's unlikely they would be a platform for life and any visit by humans would be shortlived as the Pulsar rotates it emits well focused beams of charged particles from its poles creating a rotating Spotlight of horrific radiation standing on a pulsar Planet would be a very dangerous proposition there would be high energy radiation all around you just an onslaught of particles and and waves and the radiation field would be so strong that it would probably destroy your living tissue and it would certainly cause cancer and mutations very quickly but it would probably kill you if you were really unlucky or lucky I suppose if you're going to die anyway might as well die in a spectacular way you would be in the beam of the Pulsar so every rotation the beam would flash past you and you would see this incredibly bright Beacon like a lighthouse really close to you just flashing in your face it would not be a very hospitable environment no way well the Pulsar planets might not be nice places to visit they have taught us something fundamental about planet formation in the universe these planets weird planets around a neutron star have taught us that planetary formation appears to be relatively easy gravity appears to like to pull stuff together when there's enough stuff in a in a given region if nature is so good at making planets even under difficult circumstances then the odds are fairly high that the universe is full of planets and that somewhere out there in the cosmos other Earths are waiting to be discovered but if that's the case then where are the Earths why haven't we found them yet the first planets that were found in the late 1990s were massive planets 300 times the mass of our Earth and it's really not a surprise that we found the most massive ones first like the giant redwood trees behind me they were the easiest to see from the enormous distances that we were looking so when we find Stars where we say ah there's just one single massive Planet one giant Redwood um that's almost certain to not be true there's almost certainly a forest of planets and asteroids and comets also orbiting that star as astronomers continue to scrutinize alien solar systems they are edging ever closer to finding earthlike planets this is glea 436b It's a world roughly 20 times the mass of Earth similar in mass and size to Neptune it orbits a star 30 light years away in the constellation Leo I'm so excited about gisa 436 I'm almost jumping out of my clothes it's the most important Discovery uh since 51 pegasi maybe even more important what has Jeff Marcy so excited is that this planet was found to have a density of 2.1 g per cubic cm what does that mean it's a spectacular number because every school child knows that the density of water is 1 G per cubic cm and we also know that rocks that you pick up on the street the density of our Earth for example as a rock is about 5 gr per cubic cm and therefore this planet around 436 is composed of a mixture of rock and water a planet made of rock and water sounds tantalizingly earthlike but glea 436b has so much water there would be no land masses exposed at all and you wouldn't want to take a swim in the oceans of this watery alien world there may be a layer of liquid water on the surface but below that things begin to get a little weird there's so much water that the sheer gravitational force of the water molecules pressing down toward the center will crush the water so tight that the water molecules are almost touching each other it's a very odd type of water in fact we call it ice even though it's not cold because the water molecules would be arranged in a a structure like ice but only due to its high pressure clearly glea 436b isn't quite an earthlike Planet but what about this alien world what would make an alien Planet truly earthlike it should be made primarily of Rock with enough water for oceans but not so much water that the land masses are completely submerged it would also have to be in its Stars habitable zone the typical idea for a habitable zone is the range of distances from a star where an earthlike Planet could have liquid water at its surface the idea would be that if you took Earth and pushed it in too far the oceans would all boil away and that's bad for life or if you took the Earth and pushed it out too far the oceans would all freeze and that's bad for life in our own solar system the habitable zone ranges from Mars's orbit into as close as where Venus orbits but the habitable zone in Alien solar systems varies depending on how hot the star is currently our best hope for finding habitable earthlike planets is is to look around cool dim Stars called red dwarfs or M dwarfs the M dwarfs themselves are very special Stars so our sun might be a 100 watt light bulb an M dwarf is perhaps a 10 watt light bulb and so what that means is that to stay warm enough so that you have liquid water not ice uh but still not too hot you move the planet in much closer and those close planets are easier for us to detect with our technique because they tug on the star [Music] more one of these M dwarfs called glea 876 has been found to have at least three planets orbiting it two of them are gas giants but the third gisa 876 D is one of the smallest planets discovered so far at roughly six or seven times the mass of the Earth it's also just on the edge of its Stars habitable zone the planet orbits in just one 1.9 days around its host star but because the host star is so low in Luminosity it puts it on the edge of what you might imagine the habitable zone to be there could be some region a ring around the planet towards the backside where the temperature is actually just right for liquid water to exist when it was first discovered scientists hailed this planet as the first of the super Earths seven times the mass of the Earth sounds so close to the to the size of our Earth that you wonder whether or not it's a rocky planet maybe with a thick atmosphere but today the experts are unsure whether this is a large rocky planet at all like Leisa 436b it may be completely covered in an ocean of super dense water so to call it a super Earth is to suggest that we found a planet that's a close cousin of our Earth I would now rather think of it as a distant cousin not unrelated to our Earth but far enough away indeed more like Neptune in our own solar system that has a big Rocky core but surrounded by a big envelope of water so the race continues to discover the first truly earthlike Planet at the University of Arizona astronomer laired close is hoping to capture the first picture of an alien Earth but to do that we'll take a giant leap in telescope technology here at the steward Observatory mirror lab in a cavernous space underneath the bleachers of the University's football stadium Engineers are working on the next generation of super [Music] telescopes this is the largest mirror that's ever been made this mirror is 8.4 m M across but it's just 17th of the size that's needed for the giant mellin telescope and together when combined with seven other mirrors like it with the giant mellin telescope we will be able to actually directly image extrasolar planets and maybe even earthlike planets around alien Suns scheduled for completion in 2016 this telescope will be able to make images up to 10 times sharper than the Hubble Space telescope NASA and the European Space Agency are also developing several missions that will use space based telescopes to search the stars for our planetary kin this will be incredibly exciting for humankind to know whether or not around those little points of light that we see in the night sky whether there's earthlike planets tight end and orbit around those [Music] Stars as technology improves we're going to be able to find planets that look much more like the Earth uh planets that perhaps have life on them and maybe even planets that have forests and steam trains the astronomers who have dedicated their lives to this Quest all believe it's only a matter of time before we find the first truly earthlike Planet the most exciting thing I can tell you is that we are now routinely discovering commonly discovering planets that are a mere five or 10 times the mass of our Earth um we're not quite to the point where we're finding Earths and that's where we really want to be but we're finding planets that are ever so close to our home planet so when we actually do cross that final threshold and do find evidence that there's a habitable planet out there this is going to be quite an epical event for Humanity people should not worry too much yet that we haven't found any earthlike planets because well a lot of effort is going into it right now and I think it will be done in the next 10 years yeah stay tuned our closest neighbor mysterious as it is tied to our very survival its luminance has captivated us since the beginning of humanity but a closer look reveals an everpresent source of myth controversy and mystery an unseen force that pulls at the Earth every second of the day a source of Illusion and wonder a Celestial body so close to home that it may impact the way we behave and the way our body [Music] functions and without it some argue the planet Earth as we know it may never have [Music] evolved almost 240,000 M from Earth our moon outshines every other Celestial body in the night sky the moon when it's up and when it's bright makes us dream and wonder our enigmatic neighbor is also the source of countless Unsolved Mysteries and age-old myths the Moon is a spooky place it's a mysterious Place uh from the human perspective the Moon is a beautiful and a really obvious thing to see it's hard to miss a big shining moon in the sky so I think all people from all times have had some need to understand it some need to relate to it science May cast an empirical light on some things about the universe but lunar experts are the first to admit they don't have all the answers when it comes to our moon science is about process we're never sure about explanations we know so little about the moon because we've only been observing it close up for a few hundred years and it's been there for over 4 and A2 billion years our moon teamed with volcanic activity 3 to 4 billion years ago today most believe it's an inactive dead world floating through space but is it July 20th 1969 Neil Armstrong took his historic small step during that first visit to the lunar surface that's one small step for man one while on the moon Armstrong reported seeing what he called an area that is considerably more illuminated than the surrounding area and that the area seems to have a slight amount of fluoresence to it what could it [Music] mean today almost 40 years later no one knows exactly what that light source was but scientists have witnessed similar occurrences there have been a whole class of changes on the moon that have involved brightenings color changes and even gasas emissions these events have left some like NASA astronomer Bonnie barate perplexed by what they call lunar transient phenomena or ltps lunar transient phenomena our controversial scientists are very skeptical about them the problem is there's no observations true and firm on these events but ever since the Middle Ages lunar observers have reported seeing these mysterious lights they're usually witnessed in the dark shadowy areas of the Moon where the contrast is greater they last anywhere from a few seconds to a few hours and that's why they've been so hard to confirm convinced that these ethereal displays are a real phenomenon but unsure as to what's causing them experts have honed in on several possible explanations there have been number of theories that have surfaced for lunar transient phenomena Ever Changing views from Earth may be causing the appearance of bright flashes or Surface changes on the moon some of the events that that I've seen are clearly just due to turbulence in the Earth's atmosphere these cause movement and change on the moon but barate thinks that not all ltps can be explained by atmospheric turbulence the anomalies that Neil Armstrong reported were seen from the lunar surface so atmospheric turbulence couldn't be causing them many astronomers like Laura Danley of the Griffith Observatory believe that the high velocity impact of meteors and asteroids accounts for much of this activity being observed from Earth they're traveling very fast so when they smash into the Moon there's a big uh bright explosion really these impact explosions known as Fireballs may be one source of the activity but that premise has a gaping hole in it even though we've seen these flashes on the Dark Side of the Moon we haven't identified a crater associated with any of them and that's where we get into the controversy there hasn't been any large event that has been unequivocally observed another possible explanation is that when a meteor hits the moon and creates a massive crater landslides around the Crater Rim kick up mountains of lunar dust the fine dust could absorb and scatter light rays or make it appear as if the moon has somehow changed its surface features it's possible that if a landslide occurred on the moon you would see something from the earth the edge of a crater being obscured a cloudlike feature forming in other words we would see a crater wall an ltp and then a collapsed crater wall we've never seen that yet Perhaps the most controversial theory behind these lunar anomalies could alter our view of the Moon entirely it would challenge the belief that the moon has been geologically inactive for Millennia one of the most intriguing explanations for lunar transient phenomena is active volcanoes on the moon this is the most scientifically important because it would tell us that the moon is still geologically active photographs taken during the Apollo space missions revealed a rocky formation on the lunar surface called the AA structure with this data scientists speculated that the moon could have experienced volcanic activity in the last million [Music] years the information was groundbreaking and it meant that volcanic activity could be the primary source of ltp but most scientists are yet to be convinced the thing about science is whenever you have a theory or a model you have to be able to get data of an event over and over again in terms of these more mysterious brightenings or things that could be volcanic events we've never actually had two independent observers obtain incontrovertible data at the same time even if the moon isn't geologically active some astronomers believe there may be gases left over from a time when the volcanic activity was prevalent if residual gases reached the surface the sun's Rays would scatter colored Hues of red and blue from the gas particles the moon could still be experiencing outgassing without having actual activity in the interior there are minerals in the Moon that produce gases and they seep up to the surface in the moon and come out with so many lunar transient phenomena theories out there which is the most plausible Dr barate doesn't point to one explanation for the phenomenon I think the reasons for ltp are probably Myriad I think there's more than one explanation it's not just one phenomenon it's many different types of activities for now the cause of The elusive lunar transient phenomena May remain hidden On the Dark Side of the Moon but the cause of Full Moon fever here on Earth may be even tougher to diagnose what role if any does the full moon have on our bodies and our minds when it comes to exploring the mysteries of the Moon perhaps the most celebrated and controversial is whether our satellite has any influence on the mind and body we know that there's some relationship between the Earth and the moon and so it's perhaps not such a great leap to imagine that the different ch changes the full moon might have some influence on on people there are lots and lots of mysteries physical and psychological one of the words for Badness lunacy comes from the Latin word for Moon Luna so I think throughout history people have Associated the moon with human psychology a lot of people really believe that the full moon affects their behavior affects maybe their biochemistry or something like that there is a widely held belief among many people including clinicians that during the full moon there are changes palpable changes in emergency room visits in pregnancy rates in birth rates there is a mythology of about Behavior which changes consistently with the phases of the moon anecdotal evidence abounds but does science support the belief that a full moon has a measurable effect on the Earth's occupants people have long tried to associate the moon and the gravitational effects of the Moon with behavior in people and and animals fact the moon stirs up the oceans which make up 70% of our planet so if the human body is made up of 70% water wouldn't that mean the moon has just as much pull on human beings some respected members of the medical community have reported changes in human behavior and Physiology during full moons we must be open-minded and as careful observers continue to posit some relationship between changes in the lunar cycle and the way in which we behave the way in which our health and and and disease patterns move ahead through time then we probably need to ask in creative and and critical and rigorous fashion the question is this [Music] possible there are some in law enforcement who believe that crime rates increase when the moon is full but others Manning the front lines aren't so sure the way I see it personally I see it as a myth at the start of a full moon shift Deputy Jose Castro with the West Hollywood Sheriff's Department scoffed at the idea that a LUN pull has any effect on people but in his first 20 minutes on duty three calls had already come in right now we're responding to a 488 which is a theft that had just occurred the call indicates that a male Hispanic approximately 32 years of age wearing an orange jail jumpsuit no pants wearing blue underwear stole book right now we're responding to a call of a 2735 which is a domestic violence now that is happening this is the first domestic violence we've had in a while and it just so happens there is a full moon right now we are in route to a certain celebrity that lives within our area um the call states that a neighbor at this celebrity's residence is throwing bottles at the informant front yard by the end of his busiest Tuesday night of the year Deputy Castro skepticism was beginning to wne I I'll tell you what U at the beginning of the shift I wasn't a big believer but uh but I'm becoming a Believer now a lot of this is tied to the idea that the moon causes tides on Earth so maybe it causes tides within people but that just can't happen the moon does not have a tidal effect on our bodies my chest doesn't get bigger because the moon's pulling on it Dr Peter prman a medical doctor at Cedar Sinai Hospital in Los Angeles acknowledged that some of his peers believe that the moon influences human [Music] behavior Physicians who believe that uh the moon does affect our bodies and our Behavior come to that conclusion on the basis of their observations now those observations may be very skewed they may be very situational and they may not mean a thing except that that's what somebody has observed but prman suspects the claims may contain a bias that's based on personal experiences if you look at the evidence you find that there really is no clear mechanism for the influence of the Moon with health and disease in human beings nevertheless there continue to be astute clinicians and careful observers who insist that they do see relationships people's behavior is driven by what they believe and if you believe there is something U magical about the moon and it holds a spell over you then perhaps you will change your behavior whether the full moon has any measurable impact on body and mind will continue to be a source of debate and part of the mythology of our moon and there are other mythological Legends surrounding our closest neighbor even then not everyone can see the man in the moon the man on the moon in these giant uh dark areas that create what some people think looks like eyeballs and a nose and a smiley [Music] face let me Begin by saying that I have never seen seen the man on the moon and how anyone can see it um is a matter of subjective creativity the Moon is long been the object of lore and myth but what we think we see is all in the eye of the [Music] beholder most culturs actually don't see a man on the moon they the rabbit is a big favorite of among many and there are [Music] others but everyone who looks up at the Moon can see light and dark areas on the lunar surface and these are not an illusion but very real mountains and valleys the light areas are rugged cratered Highlands known as teray Latin for lands the highlands are part of the moon's original crust that was shattered by the impact of meteoroids asteroids and comets the darker areas on the moon are known as Maria Mari is a a word meaning C they are ancient Lava Beds that were at one time flowing but are now solid formed from Impact cratering over billions of years the Maria account for 16% of the moon's surface and look like bodies of water the latest thinking is that uh giant asteroids hit the other side of the moon and rocked the moon so significantly that lava oozed out of the side that we see and created these big dark expanses of lava that of course solidified over time the ancient volcanic activity that for from the contrasts of dark and Light have inadvertently created what some see as the features of a human [Music] face the eyeballs are actually the mar embrium sea of rains and the Mari serenus which means sea of Serenity the nose is the sinuses tum which means Bay of Billows and the open mouth is the mar nubium the sea of clouds and the mar cognitum or sea of knowledge for humans to see a man on the moon may be our way of trying to understand the lunar mystery and how we're inextricably connected to it many Mysteries of the Moon have influenced our civilization in dramatic ways Ancient Man based his calendar agriculture mathematics and astronomy on the changing but consistent phases of the moon every month the moon appears to change its shape during an 8-phase spin cycle why does the moon have phases the phases of the moon occur because as the moon orbits around the earth we see more or less of its lit SI the light we see being reflected from the Moon is actually coming from the Sun imagine the sun is over there and and this is the Earth and this is the the moon when when the moon is fully lit by the Sun and we can see that Lit side it's a full moon as the moon goes around the earth we see less and less of the lit side and more and more of the dark side the full Moon occurs when the moon is on the opposite side of the earth from the sun and the lunar surface facing us is fully lit the shapes of the phases of the moon are due to our perspective on Earth seeing more or less of the lit side of the moon it's not a case of for example the Earth blocking some of the light that would have otherwise struck the Moon that does occur however during an eclipse and that terrestrial perspective can sometimes play tricks on us when it comes to the moon size looks can be deceiving some of the moon's Mysteries are difficult to comprehend when our eyes tell us one thing and science another we just need a different perspective on the problem sometimes when the full moon rises in the sky it appears much larger near the Horizon than it does when it's positioned higher in the sky some observers judge the moon to be as much as 50 to 75% larger when it first appears but is the full moon really larger when it's near the Horizon my friends all think that the Moon is bigger when it's on the horizon I I think that the Moon is bigger when it's on the horizon so what could be causing it to look so different the moon doesn't really change its apparent size uh from The Horizon to overhead but our perception is that it's larger one theory is that our mind judges the moon's size in relation to other objects it looks much larger at the Horizon because there things we can compare it to whereas at the top of the sky it's out there by its its little old self in other words if we see a large object such as a House dwarfed by the moon our mind tells us that the moon must be enormous but when the moon is out by itself our mind doesn't make that assumption we see the moon as small another possible cause of this is the ponzo illusion named after Mario ponzo who suggested that the Mind judges the size of an object based on its best background ponzo drew two identical bars across a picture of railroad tracks as they recede in the distance the upper bars look wider because they appear to span the rails compared to the lower bars which fits between the rails but in fact the lines overlaid on the tracks are the same size at both ends go out and take a pencil and when the moon's Rising put the pencil out at arms length and see how big the Moon is compared to the Eraser on the pencil and then go out a couple hours later and do the same thing when the moon is higher in the sky and you'll see that the Moon is exactly the same size in relation to the pencil eraser at both times the moon May play tricks with us when it comes to judging its size but there's nothing imaginary about its effects on our Earth of all the hidden lunar Mysteries there's one that can be observed right here on Earth it may be the most influential phenomena that can be attributed to the Moon from our place on Earth Tides just appear to be the times of day when the sea Rises and Falls but that's an interaction a gravitational interaction between the Moon and the Earth so when the moon is passing by it pulls on the oceans and pulls it up higher and we see it as a high tide the ocean tides are caused by the gravitational pull of the Sun and our moon the Sun and and the moon both pull on the earth and contribute to Tides but the Moon is much closer so its pull of gravity is felt more strongly than the sun's oceanographer Tana Ross says the moon's constant tug on the earth is formidable the reason that the moon's influence is so visible in the form of Tides is because water can run it can it can move it's it's malleable in a remote Bay in Canada one Community has learned to live with mysterious and extreme ocean tides that are found nowhere else on Earth while normal Tides Rise by an average of 3 ft the waters along the Bay of fundi between Nova Scotia and New Brunswick swell up to 50 ft twice every day one of the reasons the Bay of fundi has such large Tides is because of the shape of the land form underneath the bay kind of a funnel shaped and so as the water level rises it really Rises rapidly at high tide 100 billion tons of water soses into the bay in a matter of hours then during low tide most of it drains out like a bathtub the bay is is shaped just so so that the the first tide comes in like a wave and it moves along Flex off the back and it comes out to the mouth just at the same time as the next tide has built up and so they they add up in a Thing Called resonance title resonance is uh just getting the the rise of the high tides to coincide certain wavelengths are reflected in a way that they reinforce each other and amplify each other and the tide is therefore Amplified the unique funnel shape of the Bay of funi contributes to this resonance and the height of its Tides the bay gradually splits into a series of basins and River Junctions that restricts the tidal flow and contributes to the extraordinary Tides Tides one more way our planet is forever tied to the moon but it doesn't end there we know that the moon's gravity is constantly pulling up on the Earth's oceans while the Earth's gravity pulls down on the moon everything in space is tugging on everything else so the Earth is tugging on the moon and the Moon is tugging on the earth the moon's gravitational pull on our oceans is so powerful that it creates what's called a tidal bulge on both sides of the planet the moon pulls on the earth gravitationally and uh when it does so it also pulls on the oceans that are sort of stretched up a little bit toward it it pulls preferentially on the front side of the Earth Earth pushes pulls the ocean toward it then pulls the earth a little bit less and on the back side the ocean is not pulled quite as far toward the moon so that's why there are two bulges they're called tidle bulges on the earth tidal bulges on our vast oceans actually impact the Earth's rotation this tidal bulge that's created by the moon it's moving out ahead of the Moon a little a little bit and the Moon is actually pulling back on this tidal bulge now when the moon pulls back on this tidal bulge that slows the Earth down without our moon the Earth would spin much faster and our days would be much shorter and this would affect how life has evolved on this planet but these tidal forces which tie the Earth to the Moon travel a two-way street our Earth also has an undeniable effect on the moon so if the moon had water on it with the Earth's gravitational pole cause similar tides on lunar oceans the answer is yes in fact billions of years ago the moon was almost entirely made up of liquid but not water when the moon was first formed and very young it was entirely liquid rock magma the moon would have been like a blazing Inferno in the [Music] sky and because the rock was Liquid even though it was Rock the gravitational pull of the earth and the orbit of the moon caused the liquid rock to have Tides just like the water on the Earth today over time the moon and its lava Tides cooled into a solid desolate landscape but the gravitational relationship between the Earth and the moon has never ceased but imagine if there was no moon making an appearance each night how different a world would it [Music] be we are always tied to this mysterious orb we call the moon but what would have happened to Earth if there were no moon the fact that we exist today is in part due to the Moon allowing the Earth to create the uh environment the early oceans full of minerals that allow us to exist if there had never been a Moon Earth would be a different place today because the moon creates tides on Earth that shape our shorelines and shape the landscape here's how the moon impacted our Evolution about 4 and 1/2 billion years ago the gravitational forces between the Moon and Earth were much stronger when the moon was formed it was much much closer to us than it is today took only 5 hours for it to orbit the earth and it was huge in the sky because it was so much closer and more gravity exerted onto the Earth from a closer Moon meant the world to Our Fate as a species When Oceans first washed our planet under a closer Moon the tides were a thousand times greater than they are today you could imagine that instead of having a 10 foot tide like we have today you'd have a 10,000 fot tide so you would have 10,000 foot Tides rushing Inland these intense Tides help help create the right conditions in the oceans for life to develop tide rip the outer layers of the crust off of the earth and put them into the ocean and that mineral Rich soup the primordial soup uh was capable of developing and evolving life and some scientists believe that tital pools would have been an ideal setting for life to evolve and adapt to a terrestrial environment that would have been a great place for example for the first creatures from the sea to get their legs they could have come into a tidal pool where it's wet half the day and dry half the day and it would have been a great place to grow your legs and eventually move on to land according to to astronomer Neil cumins we can't underestimate the moon's influence on our development as a species without the moon I don't think that that process would have occurred nearly as quickly um we have evolved so that our biological clocks are based on around 23 24hour time uh if the moon had never existed the day would be 6 hours long and we as the creatures we are today couldn't exist as the moon slowed Earth's orbit it stabilized our rotation and affected our climate and ocean tides and the moon greatly influenced the development of mammals so dependent on moonlit nights for their survival has the moon had a major impact on our existence I think absolutely every time the moon is full the lunar image is exactly the [Music] same there's a puzzling mystery to this it makes many wonder why we never see another side of the moon after 4 5 billion years of evolving the Earth Moon system has arrived at a point where the Moon shows us the same face all the time billions of years ago the friction created by volcanic tides caused the moon to slow its rotation and become tidy locked to Earth this doesn't mean our moon isn't spinning but it has slowed down considerably over billions of years and the secret of the moon's hidden Far Side has to do with synchronicity if this is the Earth and if this is the side of the moon that we see if the moon were not rotating then eventually we would see the other side of the moon because the Moon is rotating at the same rate that it orbits the earth synchronous rotation we always see the same side The Far Side of the Moon is not always dark if you were out in space you would be able to see that the Sun hits all sides of the Moon as the moon makes its month-long orbit around the Earth but from where we sit we can only see one side gravity is in firm control of the Earth Moon relationship [Music] or is [Music] it the gravity that has held the moon in our orbit is slowly losing its grip and the consequences of that are enough to make one look at the Moon in a whole new light gravity is a force that holds the moon to the earth just as this athlete is bound to the Hammer that is orbiting about his body so gravity binds the moon in the earth If gravity all of a sudden went away the Moon would fly off into space just as this Hammer flies off over the field of course gravity never stops working but could the moon somehow slip loose of its grip the truth is the moon has always been slowly slipping away from us the moon has been moving away and it's still moving away in fact the moon moves away from us a couple of inches every year and eventually the moon's going to be so far away that it won't even seem like our moon anymore ever since the Moon and Earth became intertwined the energy from the Earth's gravitational tug has been causing the Moon to spiral away from our planet it's currently moving away from us at a rate of 1 to 2 in each year the key to this unexpected effect are the tidal bulges created on the Earth by the moon the tides on Earth actually act to propel the moon outward spiraling out further from the Earth every orbit the reason is because the Earth spins faster than the moon orbits us so after the Moon is pulled up a tidal bulge rais the high tide the Earth turns and pulls slightly ahead of it so there's just a little bit of a forward force or we call it a torque a little bit of an extra kick that speeds it up ever so slightly but over time that speeding up makes it go faster and faster which in orbit means it's going spiraling further and further away over time the moon will expand its orbit until someday it will finally be beyond our Earth's gravity but scientists say there's no no cause for panic quite a bit of time will pass before the moon is out of sight and out of orbit estimated time of total departure about 50 billion years and our sun will flame out in less than 10 billion years throughout history the moon has delighted surprised and sometimes terrified us and the movement of our Earth may be the cause of this mystery another secret of the moon has been documented in ancient text and continues to a maze it usually appears every few years during a total lunar eclipse the full moon dramatically changes colors what causes this a lunar eclipse is very simple it just occurs when the earth gets between the Sun and the Moon so when Earth gets in the way Earth casts a Giant Shadow that blocks the sunlight from reaching the moon at the peak of this eclipse the moon passes completely into Earth's Shadow or Umbra and transforms not to black as one might expect but to a blood red what happens is some of the sunlight that's being blocked by the Earth actually slips through the atmosphere and the red light gets through the best as the sun's rayss pass through the Earth's atmosphere they're bent a little bit and the red rays are are bent in such a way that they make it over the over the surface of the Earth and illuminate the moon and when only red or orange Light reaches the lunar surface the moon appears red another Optical phenomenon that adds to the moon's mystique and part of that Mystique can be attributed to the dramatic presence of the Moon above us it outshines every other Celestial body in the night sky there's a special magic to the Moon uh its changing phases its brightness in the otherwise dark sky but we also see the moon during the daytime why is this it's actually very easy to understand why we can see the the moon during the daylight you can do this demonstration at home all you need is a bright light to act as the sun and a piece of fruit to act as the moon my face is acting as the Earth the lit up side is the daylight side and the par in Shadow is the nighttime side now the moon of course orbits the earth and at some of the times during the month in its orbit it's on the daylight side of the moon so I'm able to see it in full daylight actually many planets and stars are just above us during the daytime but the light from the sun is just so bright that it obscures nearly all of them only the moon which is 100,000 times brighter than the nearest star shines through we don't always see the moon during the day because it's constantly moving around our Earth and it's not in the same position at the same time every day but somewhere on the planet it's always visible but as we've learned not everything about the Moon is easy to explain or understand there are still plenty of questions left unanswered it's been part of the moon's Mystique since history was first recorded We Are Forever tied to our neighbor but we know so little about that dependence there could be other things that are happening that we just don't know about [Music] yet over the next Century or so I think that uh science is going to take us further into understanding its Mysteries whether we will fully understand it I doubt it I certainly don't think we know everything there is to know about the moon there is a tremendous amount to learn but fortunately it's within reach and we will go exploring it further and learn a lot more about it until we rekindle our efforts to explore the lunar World more thoroughly we may never know all the secrets or hope to solve the hidden mysteries of the Moon our infinite universe is brimming with strange violent and potentially life transporting phenomena imagine Cosmic portals where objects could disappear be ejected or escape to some other place in space or time they are tickets to Oblivion for the most part either you get shredded in a black hole you get transported to another part of the universe and a wormhole or you get obliterated by the gusher of a white hole blast off to the warp side of the universe as scientists search for black holes white holes and worm holes are they frivolous fantasies or a science [Music] fact the universe is a cosmic Cornucopia of Endless Possibilities imagine a shuttle service to anywhere in the cosmos it's not aboard a futuristic spaceship it's a galactic ride through a wormhole a theoretical tunnel providing shortcuts through space and time wormholes a little bit like a subway system that you might use in the city where you you're going into a hole you go through a tunnel and then you come out at the other end through another hole and then you've traveled through the city same thing would be possible in a wormhole to travel between different points in the universe physicist Clifford Johnson has contemplated the possibility of wormholes the difference between uh Wormhole and uh subway system system is that you're using the Wormhole to travel a greater distance than you would if you were traveling in ordinary space in theory a wormhole has a throat connected to an entrance and exit called mouths located in different parts of space a wormhole is appealing because we're limited by the speed of light we can't get to the Andromeda galaxy in less than and uh something like 600,000 years even moving at the speed of light I keep wondering if the really next big Discovery in astronomy could be a wormhole not just because they're fun for people like me but because they could take us to someplace that we can't plausibly ever get any other way Gregory Benford has pondered the science and fiction of outer space as both a physicist and author of over 30 sci-fi novels Benford has witnessed Fantastical theories become a reality a lot of us would like to know if wormholes really exist or whether they're just another mathematical construct thought up by Einstein the genius Albert Einstein's general relativity laws allow for the existence of wormholes in 1930 Einstein and his his colleague Nathan Rosen calculated the mathematics of one of these Intergalactic pipelines it became known as the Einstein Rosen Bridge the wormhill is a solution of Einstein's equations for general relativity telling us how gravity Works they're hypothetical and what they do is they connect different parts of space and time the Einstein Rosen mathematical Wormhole arose from studying black holes a black hole is a region in space of extremely strong Gravity the gravity is so strong that there is no way for objects that get too near to break away from its gravitational pull nothing can escape a close encounter with a black hole not even light this inverted Fountain serves as a visual analogy to what's going on around a black hole at the bottom is the uh area inside The Event Horizon and the water falling into it is analogous to gas that might fall into a black hole imagine yourself being a fish swimming around this region once you get down inside this central portion you're past the point of no return but Einstein never intended his Wormhole as a tool for space travel his Wormhole is theoretically created at some moment of time it opens up briefly then pinches off anything that tries to pass through it will get crushed when it squeezes apart the typical Wormhole that you write down in your equations and study is unstable it'll vanish in an incredibly short time so what you need is some means of holding it open after Einstein's Wormhole was determined unstable in the 1960s little research was done on the concept then the sci-fi film contact was released in the late 1990s based on the book by renowned astronomer Carl Sean it proposed that a wormhole could be used for space travel the book contact and then subsequently the movie was a nice place in fiction that was accessible to everyone where you could see the idea of a wormhole so it was a nice way of getting people interested in that idea all over again this was kind of a very far-fetched idea that wasn't even considered very seriously by many physicists until Carl Sean decided to write this book and try to make it as realistic as possible and since that time theoretical physicists studying Einstein's general theory of relativity have considered travel through wormholes scientists began to investigate whether there might be a type of Wormhole different from Einstein's that is traversable but traversible wormholes needed something to prevent them from pinching off you want to stabilize the Wormhole you don't want the Wormhole to collapse keep the Wormhole open that requires something new called negative matter or exotic matter we've never seen negative matter before it would have anti-gravitational properties but one day if we ever find negative matter perhaps that's the key to stabilize the Wormhole the idea of a traversible wormhole captivated science fiction enthusiasts it also reinvigorated the serious study of wormholes within the science Community this transversal Wormhole created quite a sensation cuz Perhaps it is physically possible to one day build a subway system to another galaxy the term Wormhole came from an analogy with an apple you want to get from one part of the Apple to another part if you're a worm you can eat your way down into the body of the apple and make a little tunnel and come out the other way and it's shorter but unlike a worm moving here on this Apple for a wormhole in our universe we might not know what danger lie at the other end of the Wormhole the other end of a wormhole could be connected to a very dangerous part of the universe with all sorts of exotic phenomena it might even be in the core of a star if we ever find a wormhole and if it's close enough for us to reach almost certainly we'll first send automated probes through and direct them to come back back maybe even put them on a cable in case something nasty happens to them and they can't return physicists do not know of any way that a wormhole might arise naturally in our universe but can they be made artificially one possibility that physicists have speculated about that might allow you to construct wormholes would be to blow them up from what's considered to be the fabric of SpaceTime that might actually contain tiny wormholes seething in and out of existence due to the laws of quantum mechanics scientists proposed that perhaps traversible wormholes could be sculpted out of quantum foam a subatomic bubble like structure that might exist everywhere in the universe on length scales a billion trillion times smaller than the nucleus of an atom that's how you do it in principle it's completely unfeasible using any technology that we know of but it's at least something you might consider if one could be engineered or located in space scientists contemplated other possibilities for a wormhole could it transport Galactic vacationers to different points in time as well as different places in space to actually create a time machine or a wormhole machine that would take us to a distant Galaxy you would have to have the physics of an advanced civilization a civilization perhaps millions of years Beyond ours time machines have mystified movie audiences for over 50 years gentlemen I am talking about traveling through time in a machine constructed for that very purpose but could a wormhole be used for such travel the Wormhole may lead to things like being able to go to another galaxy by walking 5T through a wormhole or even going to another time but wormholes as time machines pose unsettling questions in the distant future will earthlings be able to travel to the Past past and perhaps change [Music] history scientific ideas considered far-fetched today could One Day become as acceptable as the fact that the Earth is round the laws of physics may allow for the existence of wormholes tunnels providing shortcuts through space as well as time so could these Cosmic Subway systems theoretically be engineered into time [Music] machines Einstein's general relativity laws reveal that time travel into the future is possible they show that time is perceived differently depending on where one is in the universe and how one moves objects moving at close to the speed of light age slower than static objects and objects near a gravitating body age more slowly than objects farther away clocks run at different rates in different gravitational fields the stronger the gravitational field the more slowly time passes relative to someone out in space where there's no gravitational field on Earth here on the surface our clocks run slightly more slowly than clocks high up in the sky so an example of this is that the clocks in the GPS system of satellites run a little bit more quickly than the clocks here on Earth because they're in a weaker gravitational field and the scientists and Engineers developing the GPS system had to take into account the different rate at which clocks run if they hadn't done that correctly then your GPS system wouldn't work if you were taking a trip from Los Angeles to New York you'd end up somewhere in Massachusetts forward time travel has been tested Ed using highly precise atomic clocks scientists have placed one clock on the ground and another in a rocket flying high above the Earth the two were compared using radio signals between rocket and ground the clock on the rocket ticked faster here on Earth my clock is running more slowly compared to someone in rocket ship somewhere further away from Earth so their clock is moving more quickly they're going to the Future faster physicists have studied whether wormholes could provide travel not only to the future but also to the past if there was a wormhole with one mouth near Earth and the other in the center of our galaxy the rate of flow of time was will be different at the one mouth than at the other when compared through the external universe but when looking directly Through the Wormhole the rate of flow of time appears to be the same this difference in their relative ticking rates as viewed externally versus viewed Through the Wormhole would convert the Wormhole into a time machine what that means is that by entering a wormhole you could leave here today and come out the other end of the Wormhole hundreds or thousands of years earlier the Wormhole may lead to things like being able to go to another galaxy or even going to another time it's possible you can use a wormhole of a certain kind to actually transport information backward in time or people backward in time but backward time travel raises disturbing paradoxes could one actually Voyage to the past and change [Applause] history one of the problems with traveling backwards in time is that it produces various paradoxes the most famous of this is the grandfather Paradox this says that if I have a time machine I could go back in time and I could kill my grandfather who would then never have had my father who would never have had me I would never have been born so that means you would never have been able to go back into the past in the first place or let's say you go backwards in time and meet your teenage mother before you're born and then your teenage te mother falls in love with you then how can you be born if your teenage mother spurned your father and fell in love with you instead the Practical problems are enormous but one day if somebody knocks on your door and claims to be your great great great great great great great granddaughter someone from the future going backwards in time to meet her illustrious ancestor don't slam the door perhaps in the future our descendants will have the possibility of time travel and perhaps one day they may come knocking on your door backward time travel has ignited a myriad of Science Fiction scenarios if that machine can do what you see it can destroy it George before it destroys you if the laws of physics permit wormholes then how can those laws deal with the danger of changing history one possibility is that the laws of physics allow you to do backward time travel as long as it leads to a self-consistent universe that in some sense the history is not changeable you can't go backwards and change things which would stop you from having been created in the first place for example in the grandfather Paradox for now forward or backward time travel through a wormhole remains in question and some scientists think that any attempt to create a wormhole time machine May destroy the Wormhole what actually happens when you try and make that Wormhole into a time machine is that as soon as it starts connecting different times you get a pile up of radiation so intense that it destroys the entire Wormhole that's stopping you from making that Wormhole into a time machine this seems to be a sign that maybe this is the way nature protects itself using the laws of physics from ever producing paradox boxes and strange things that time machines seem to suggest Wormhole travel is really iffy because you have to know a lot about the Wormhole so that it doesn't do unpleasant things like for example turn you into a big ball of gas all of a sudden because the gravitational stresses that support the Wormhole are plausibly quite strong the idea of a wormhole is not something that we can point to and say that's impossible it would be absurd to say we can't do that ever because we're dealing with powers energies and knowledge that are outside of our current domain like a wormhole there's another phenomenon that has never been discovered but Einstein's general relativity laws allow for its existence it's called called a white hole while a black hole is an object into which things are falling and disappearing rather like a sinkhole a white hole is doing the opposite things are coming out things are coming out rather like a fountain a white hole is like the Unicorn an exotic animal that's never been seen before a white hole is very similar to a black hole except it runs backwards think of running the videotape backwards instead of matter falling into the Event Horizon never to come out matter falls out of a black hole so it's the opposite a Time reverse black hole black holes as we know have now been understood to be out there in our universe and so you might wonder whether the same thing is true about white holes as well for example quazars when they were first discovered were thought to be maybe white holes why because they seem to be producing a huge amount of energy we now know that that's not the case quazar are actually powered by black holes there's a school of thought that says that anything that can exist must exist somewhere and if one adopts that school of thought then at the moment we have to admit that white holes might be out there somewhere if nature uses white holes physicists speculate that they could have been an important element in the earliest stages of the universe maybe even in the formation of the universe itself when trying to decode some of the Mysteries of the universe the answers May truly be black and white the universe began with a big bang an expanding Fireball of matter and energy energy that started compressed as a tiny subatomic Point called a singularity a singularity is a region where gravity is immensely strong the Big Bang Singularity gave rise to the entire universe which includes space time and all the matter that fills it a similar type of Singularity is a white hole a theoretical object that arises in Einstein's theory of gravity it's essentially a black hole in reverse a point of Singularity where matter is ejected consequently some scientists have wondered if the universe could have been created from a white hole one idea to describe the entire un Universe has been that it's one big white hole in which there's an emergence from some initial Singularity that creative thought is one amongst many for How the Universe was seated and how it began and how the big bang emerged think about it a white hole emits matter it doesn't gobble up matter but isn't the Big Bang the same thing a small little quantum dot that expand and spews out matter so perhaps the white hole could be the story of our Universe NASA's Wilkinson microwave anisotrophy probe known as W map has measured the radiation left over from the very early Universe studies of this Cosmic microwave background have confirmed that the Universe began with a brief but colossal growth birth called inflation that preceded its regular phase of expansion so some scientists speculate whether a white hole could have been the instigator of this growth birth the evidence coming from our space satellites like the W map orbiting the Earth right now is consistent with the idea of a Multiverse a Multiverse consists of many universes like soap bubbles floating in a bubble bath in a bubble bath we have bubbles popping into existence collap csing back giving birth to baby soap bubbles so in other words Big Bangs could be happening all the time perhaps each Big Bang starts with a white hole that then expands rapidly giving us a baby [Music] Universe it's still unproven whether multiple universes exist and whether white holes may have created them but scientists have shown shown that some types of white holes although possible in theory are highly unstable they would not survive for very long and they simply collapse to form black holes possibly white holes played a role perhaps they formed for a very short time but then being unstable they collapsed but even during that period when they were first formed they may have left some important imprint on the future of the universe we don't know whether that's true but it's a possibility white holes are a nice Act of imagination but uh I don't think they have any substance yet they were entirely theoretical objects but then black holes were that way Once Upon a Time white holes might or might not have existed at the beginning of the universe but one thing certain black holes are no longer science fiction they're science fact scientists agree these whirling vortexes are born out of the Death Rows of massive stars when a sufficiently massive star runs out of fuel it is unable to support itself against its own gravitational pole it then collapses inward to form a black hole black holes are troublemakers in the evolution of the universe they can draw matter in spew it out reform reorganize regions of universe perhaps part of a galaxy take up Residence at the center start running the show they're big muscular things that Lumber around and cannot be stopped black holes are difficult to detect because they're black but they can be observed when they interact with something in space such as is in falling gas which heats up and glows in x-rays years ago black holes were considered to be impossible we have something called the giggle factor in physics people used to giggle whenever we talked about black holes but now we see hundreds thousands of Glorious photographs of black holes there are at least two types of black holes one is called called a stellar Mass black hole which is approximately 3 to 30 times the mass of our sun it speculated that 100 million of these reside in our Milky Way galaxy and similar numbers in other galaxies the other is a super massive black hole that is millions to billions of times the mass of our sun it's believed that this humongous monster lives at the center of most every large Galaxy our own Milky Way galaxy has one yet whether they're Stellar Mass size or super massive all black holes are cosmic cannibals a black hole in some sense is like a cosmic roach motel everything checks in but nothing checks out a trip to a black hole would be fantastic almost psychedelic it's like having a near-death experience as you get even closer to the black hole tidal forces begin to stretch your body apart so that the top of your body and the bottom of your body experience different gravitational forces and you become spaghettified eventually even the atoms of your body become noodles and become ripped apart in the case of of a super massive black hole the process of spaghettification is somewhat different the person jumping in wouldn't be spaghettified until passing through the Event Horizon and the reason for that is because the tidal forces that would stretch him aren't strong enough until you get closer to the singularity so the person jumping in would have a few moments of uh perception that they were inside of a black hole and they could Marvel at that idea before they plunged toward the singularity and then became spaghettified and if one black hole isn't violent enough try two black holes dueling for dominance in the vastness of space black holes occasion Al pair off it may appear as though they're engaging in some sort of cosmic courtship but these unions are anything but harmonious when two black holes get too close they become trapped by each other's Gravity the two orbit around each other like whirling dervishes these binary black holes will eventually Collide and coales it's believed that collisions between black holes would be quite common they would be in orbit around each other and then spiral inwards and at some point they would coales and that coalesence creates a huge disturbance in SpaceTime if you have two objects that are bending space a lot around them and they merge together then you'll get this Ripple this wave going out carrying energy with it typically when black holes Collide they create wild vibrations called gravitational waves which spread across the fabric of space and time these ripples would be just like the ripples you would have say on the surface of a pond if you threw a pebble into a pond it creates a disturbance and then you see the ripples carrying that disturb away to far points of the pond in the past binary black hole collisions were impossible to identify now scientists have developed gravitational wave detectors to track these vibrations and hopefully catch black hole collisions in the ACT ligo is a ground-based Observatory that's currently searching for Gravity waves produced from collisions involving Stellar sized black holes a few times the mass of our sun the system uses lasers to measure the Motions of mirrors that hang by wires from overhead supports when two black holes merge together they'll release these gravitational waves these ripples in the shape of space and as the ripples pass by these giant Contraptions they alter ever so slightly the distances between these detectors and the detectors can actually monitor and see that change in distance and that's the signature of a gravitational wave coming by in the future Lisa a Joint Nasa and European Space Agency Mission will be able to detect waves from collisions involving super massive black holes these impacts occur after two Galaxies have merged and their super massive black holes sink to the center of the newly formed Galaxy and find each other and if collisions involving two super massive black holes isn't chaotic enough try three in January 2007 us and European satellites actually observe black hole triplets 10 billion light years away in the Virgo constellation they're actually three quazars which are luminous objects thought to be powered by super massive black holes located in the centers of galaxies this Trio is en closed proximity to one another they're only about 100,000 to 150,000 light years AP part which is about the width of our Milky Way in all probability the three will eventually engage in a hostile merger if you take three large black holes brought close together because two big spiral or elliptical galaxies have slammed together then it's a real freefor all and two of them could win the game and throw the third one out gravitational interactions between three bodies can lead to the ejection of one of the super massive black holes from the system and then you're just left with a binary super massive pair that will coalesce ultimately the super massive black hole that gets ejected is ejected typically with enough speed that it can't carry stars with it so it becomes a rogue black hole it's off on its own modern science continues to unravel the Mysteries surrounding black holes but for some one enduring question remains the deepest question in all of black hole physics is what lies on the other side of a black hole what happens if you throw the encyclopedia into a black hole is all that information lost we don't know for sure according to Einstein's general relativity laws nothing can ever come out of a black hole but if a black hole is extremely tiny the laws of quantum mechanics merge with the laws of general relativity quantum mechanics governs the world the very small such as electrons neutrons and other subatomic particles general relativity rules the world of the very large where ordinary gravity is dominant like planets stars and galaxies the fact is when you put together quantum theory with black holes you find that they aren't completely inert objects that only suck things in and nothing comes out they actually radiate the black holes that radiate are called mini black holes which are much smaller than their Stellar mass or super massive black hole cousins celebrated physicist Steven Hawking proposed that if many black holes exist they must emit radiation which has been named Hawking radiation It is believed this radiation will cause a tiny black hole to evaporate and potentially disappear Hawking gave m mathematical evidence that when a tiny black hole forms and then evaporates some of the information that went into the black hole never comes back out this startling prediction caused a firestorm among physicists because the laws of quantum theory insist that information can never be completely destroyed essentially the world split into two camps those who believe that Hawking's calculation was really it and the other camp that said well Hawking calculation needs refining string theory and other theories seem to suggest that the information is actually preserved it just comes out very subtly the question of what happens to the information that goes inside a black hole is I think not fully settled the chemical composition of the objects that went into the black hole and other aspects of them their color their temperature etc etc we don't really know what happens to that information it appears unlikely that scientists could Venture inside any black hole and return back home in one piece to report their findings but a worldwide collaboration of scientists may be on the verge of the next best thing manufacturing tiny black holes right here on Earth today scientists are pushing back the boundaries of cosmic research if naturally formed black holes aren't scary enough what about a black hole Factory in Switzerland at the Physics laboratory called CERN scientists have built the Large Hadron Collider the biggest most complex science experiment ever constructed it's a particle accelerator 17 M long and the weight of five jumbo Jets it's capable of crushing subatomic particles together to replicate the energies that existed micros seconds after the big bag this particle collider was designed and built to study important questions in fundamental particle physics but it will cram so much energy together that if physicists are lucky about how nature works at those energies it could also produce tiny black holes we might be able to see microscopic black holes being formed in these high energy collisions and those black holes would then be Iman people to study they would rapidly evaporate we' be able to study their Decay products and understand physics of quantum gravity in the laboratory which is something that we never dreamed to be able to do in our lifetimes but the possibility of manufacturing many black holes has roused suspicion and fear could they escape the Earth's gravity and eventually devour our planet cosmic rays from out of space hit the Earth all the time perhaps with more energy than these mini black holes so these mini black holes are harmless they're not going to eat up the Earth they are not a doomsday device a similar mini black hole scare happened in the United States in Brook Haven New York a smaller collider experiment is already underway the relativistic heavy ion collider better known as Rick is an underground pipeline where gold atoms collide together at 99.9% the speed of light when the experiment began in the year 2000 news spread that these head-on impacts created black holes the laboratory which is very responsible decided it needed to respond to this and and reassure people so it convened a group to look at this and what that group found was that these kinds of collisions had been happening in outer space and that had never caused a problem theoretically we produce conditions in these collisions which should mathematically give some similarity to the the theory that surrounds black holes but in practice we're completely safe there's no way that any black hole that could be a concern could be produced here at uh at RI well Rick certainly is not capable of producing a black hole of any kind there is not enough Mass which is being created here by many orders of magnitude although Rick cannot create many black holes scientists can go through the ashes of these particle collisions to learn about the early moments a few micros after the big bang so we can use this knowledge uh to gain a better understanding of what happened shortly after the uh big ban including uh the possibility of uh uh primordial black hole formation the particle collision experiments in Switzerland and in the US may not produce life-threatening black holes but they could give several important clues about whether information comes back out of a mini black hole and even How the Universe began they do provide a laboratory to see how far we can push Einstein's theory until all Hill breaks loose and the equations collapse and that's why we think that many black holes could be a key to going Beyond Einstein physicists will continue to probe into the mystery still surrounding black holes they will also remain on high alert for any signs of The elusive wormholes and white holes the search for the next Frontier marches on white holes wormholes black holes are tickets to Oblivion for the most part none of these are places that you want to take your summer vacation near and these tickets will cost a lot to even find these objects are hard to observe in the universe and only one of them do we really pretty much know is there the black hole the others may be entirely hypothetical they may be the unicorns of astronomy there are several cases in history of science when an idea or even a solution to an equation just seems like an artifact of our imaginations and actually turned out to be a real thing black holes are such an example maybe white holes and wormholes will have some role in nature which we'll one day discover it's a crucible of creation and destruction the name Milky Way sounds like something kind of comforting and sweet but the Milky Way galaxy is a monster it's just one Galaxy among billions and we're living on the edge just recently we've discovered that there are two small Galaxy colliding with the Milky Way right now it's a tapestry of brilliant Suns and blinding dust it's surprising how little of the light from our rather luminous Milky Way galaxy reaches us it's a place of extremes Where Stars can drift lazily or be flung out at more than a million milph now scientists have pierced the Galaxy's Heart of Darkness to find our way through the Milky Way it's 100,000 light years in diameter has a trillion times more mass than our sun it began about 13 billion years ago and is still under construction it's our galaxy The Milky Way the Milky Way galaxy is an extremely active place it's like a construction project there's things going on all the time and you have old Stars die and get torn down and then that material gets used to build brand new stars in the midst of this work Zone lies our little solar system and a whole lot more I suppose the best way to think of the Milky Way galaxy is our family of stars these are the stars that we travel through the universe with in a clump all orbiting a Common Center within its far-reaching spiral arms lie Clues to where we started and how it will all [Music] end on a clear summer night the stars of the Milky Way unfurl like a shimmering banner across the sky ancient Egyptians saw this River of stars as a pathway to the afterlife but the Greeks were the first to name it the Milky Way comes from the word Galos which is Greek for milk and though we once believed we lived at the center of the universe we now know that we don't even live in the center of our own Galaxy when we look up into the night sky and we see this Milky swath of stars that we call the Milky Way what we're actually seeing is a spiral arm of the Galaxy that's closer to the center of the Galaxy than we are we can't really see the center of the Galaxy from here but what we can see is one of the Spiral arms that's a a few thousand Lighty years closer to the center than we are as we gaze at the Milky Way from our Earthbound position it's like looking at at the edge of a coin we get no sense of the Galaxy's real shape if however you look at a galaxy from the top down it's a disc remember and it looks it's like looking at a frisbee from the top down you can see its full Glory uh even though it's thin you don't see how thin it is but you see it's full structure you can make the analogy of the Milky Way as being very much like a city there's a central region there's big buildings there's a lot of action in the middle and that's certainly true of our galaxy then you move out to the suburbs where life is a little bit more comfortable a little more relaxing it's a better place to raise a family this is where we reside our solar system is among the Milky Ways spiral arms 26,000 light years from the bustling Center our galaxy is so large that it takes Earth more than 200 million years to make one lap the sun is located in what would be just a average neighborhood around the city center but again if you're standing in the middle of this neighborhood you don't really know what the neighborhood on the opposite side of the city looks like because you can't see it directly as we move outward beyond the suburbs the population becomes more sparse and yeah you've even got sort of The Boondocks in our galaxy you got the Halo where you have very old stars in sort of wide orbits around the Galaxy the galactic sprawl doesn't stop at the Milky Ways loose and undefined Halo it reaches far beyond our neighborhood and out to a group of galaxies called the local group if you think of the Milky Way galaxy as a city like Los Angeles then you can think of these as counties all within the state of California and together this local group makes up the entire State besides our huge milky way and the even larger Andromeda galaxy the local group consists of close to 50 smaller galaxies the closest of which are roughly 40,000 light years away they're two relatively nearby dwarf galaxies the large and small clouds of mellin that orbit our Milky Way galaxy and are easily seen in the southern hemisphere they're small little galaxies but our local group has several dozen such galaxies sort of wandering around inside it the big galaxies are the minority one advantage of actually being in the outer edges of our galaxy we have a clear view of uh outside of our Milky Way we're able to see the rest of universe our neighboring galaxies and Galaxy clusters beyond our own local group of galaxies Inside the Milky Ways Halo lie massive globular clusters globular clusters are densely packed regions of stars that are all of similar composition these are like the ethnic neighborhoods of the Milky Way galaxy indeed these globular clusters form when the Galaxy was very young they are among the first stars to have formed some globator clusters are 12 or 13 billion years old they contain 100,000 or even a million stars globular clusters almost as old as the universe itself gave us the first clue to our place in the Galaxy we saw these globular clusters in the sky but their Center was somewhere far away from us and that was one of our first measurements of where the middle of the Galaxy should be it weren't orbiting around us but around an area somewhere about 27,000 light years away we can never get far enough away from our own Galaxy to actually see it but by looking at other galaxies and comparing what we know about our own Galaxy we've got a pretty good picture of the Milky Way the very first time we saw galaxies through telescopes we didn't even know they were galaxies I thought they were just nebula in our own Galaxy and we were just amazed by the beautiful spiral shape so it was sort of natural for astronomers to classify galaxies according to their shape what we see astronomers recognize four basic Galactic shapes elliptical built of old stars and which doesn't spin lenticular consisting of a bulge and a disc and little or no new star formation regular which has no real shape at all like the melenic clouds in our own local group and spiral which includes our Milky Way it's a pin wheel of young and old Stars spinning gracefully through space a long time ago people thought that maybe an elliptical galaxy eventually collapses down into a spiral or maybe eventually spirals all come together and form an elliptical and it was sort of hard to figure out exactly what this sequence is one thing we know is that elliptical galaxies tend to be very large Centaurus a a misshapen elliptical galaxy about 13 million light years away suggests why elliptical galaxies get so big there's a lot of evidence that there's a spiral galaxy in there somewhere that got absorbed by a larger Galaxy so right now it's possible that these really big elliptical galaxies we see maybe the mergers of several Spirals and other types of galaxies our Milky Way isn't in danger of being absorbed anytime soon but the heart of our spiral galaxy has revealed a secret of its own only recently we discovered that the Milky Way is not a classic spiral but a b spiral there's a bar of stars going through the center and the spiral arms sort of attach off from that bar spanning 27,000 light years it's the most popular bar in the Galaxy 30 million stars gravitate to it the bar of our galaxy is a natural result of gravity the mutual gravitational interactions of the individual stars that form the disc of our galaxy and the Bulge of our galaxy causes sometimes the the Stars to sort of bunch up into this bar configuration surrounding the middle of the Milky Way is a huge Central bulge it's mostly composed of stars between 10 and 11 billion years old the size of the Bulge is linked to the Milky Way's most gripping feature of all a super massive black hole though it would easily fit in the space between the Earth and our sun it's 4 million times more massive than our sun now that sounds like a lot but other galaxies have Central black holes which extend up to a billion times the mass of our sun so whereas it's a we call our black hole at the center of our Milky Way a super massive black hole among super massive black holes it's kind of a run black holes can't be seen directly because light can't escape them astronomers have located Galactic Ground Zero through a radio Source in the constellation Sagittarius known as Sagittarius A star it's creating quite a stir the black hole in the middle of our galaxy is spinning and it appears to be spinning at a rate of about one spin per 11 minutes as it spins central region Stars caught in its gravity get swept along for the ride orbiting it at about 3 million mph the black hole affects the central region the most but we can't feel its tug on Earth since we orbit the galaxy far away from the center the Colossal forces at the Galaxy's heart are negated by the Milky Way's unimaginable size to me the name Milky Way sounds like something kind of comforting sweet you know a candy bar that sort of thing but the Milky Way galaxy is a monster it is incredibly huge so when you you think about how vast our solar system is the fact that it takes years for the fastest spacecraft to get out to Saturn or Jupiter if the entire solar system were the size of a CD the Earth would be comparable to the Milky Way that's huge that's absolutely mind-blowing and it never ceases to amaze me and the amazement goes on and on the galaxies bustle and commotion may be concentrated in the center but the spectacular spiral arms have action of Their Own it's here that Stellar neighborhoods are being built and stars are being born this is our galaxy it's a lot to take in and we're just beginning to probe its depths our Suburban location makes it difficult to get the big picture and the hazy clouds of cosmic dust only block our view even the most powerful optical telescope can't Pierce The Darkness so if we want to learn more about the Milky Way We need to look beyond what our eyes can [Music] see for all its fastness and empty space the Milky Way is tremendously active and populated with some astonishing phenomena star clusters nebulas blazing Invaders from other galaxies techn technology is making us rethink old beliefs and is showing us things we've never even considered before and lift off L 15 seconds sending the New Horizon spacecraft on its way to the very edge of our solar system we live on a Dusty planet in a Dusty Galaxy in a Dusty universe empty space isn't so empty optical telescopes can see only as far as the nearest dust cloud which isn't far at all most of our galaxy is invisible to us however and that's because the Galaxy is full of dust dust clouds if you will and these dust clouds block the light from most of the stars in our galaxy it's surprising how little of the light from our rather luminous Milky Way galaxy reaches us the reason for that is simply because the dust blocks it but visible light is just a small sliver of the energy spectrum and radio waves rush in where visible light beams Fear To Tread on a foggy day you might not be able to see very far at visible wavelengths which your eye can see but you can still listen to your radio or watch your TV the ability of radio waves to penetrate space dust is crucial to the study of of the stars but that use was discovered by accident in 1933 Carl jansy an engineer at Bell labs in New Jersey built an antenna to track down the source of static on transatlantic telephone lines he was surprised to discover the interference was raining down from the center of our galaxy the constellation Sagittarius it took several decades for scientists to realize that jansky was on to something celestial bodies emit electromagnetic radiation and thus radio astronomy was born but radio waves were just the beginning because the human eye can't see all the light that's available we have to resort to technology and one of the best ways of seeing the universe in a very different way is with an infrared camera an infrared camera sees only the wavelengths generated by heat then converts it to something the human eye can see there actually is no visible light at all that passes through this lens this lens only lets heat light through and then you can see what everything looks like in infrared light 2 mine start in 2003 the Spitzer Space Telescope equipped with a battery of infrared cameras was launched into space of our univers its mission is to explore some of the youngest stars and farthest galaxies in the universe the instruments that spits her head on it are actually many times millions of times more sensitive than these cameras but they're basically the same thing this camera doesn't peer into the heavens but is used by firefighters to save lives right here on Earth the camera can see through a smoke filed room to read the body heat from an unconscious or immobilized victim the same technology has enabled astronomer Susan stvy to see 26,000 light years away visualizing the center of the Galaxy as never before this high resolution Mosaic was assembled from roughly 12,000 individual images taken from the Spitzer Space Telescope even though that sounds like a lot of data and it is it only took about 16 hours of telescope time this particular region of the galactic center spans an area of the sky that's equivalent to four full moons in One Direction and three full moons in the other that's the equivalent of 900 light years across by 700 light years High a small fraction of what's out there to see but a phenomenal achievement nonetheless just a few decades ago the galactic center was not a subject of study because you couldn't see it visually nothing gets through only one light wave in a trillion I can penetrate the dust but if you go into the infrared or use radio astronomy or x-ray astronomy you can see what's going on there different wavelengths of the electromagnetic spectrum can reveal different aspects of the Galaxy because they penetrate celestial objects differently radio waves have the lowest energy or longest wavelength but most celestial objects emit them then comes infrared visible light ultraviolet high energy x-rays with wave lengths about the size of an atom are emitted by black holes and supernovas the highest energy gamma rays come from the Collision or decay of subatomic particles like when stars explode at billions of degrees together these waves give astronomers a more complete picture of the activity and shape of our galaxy many if not all of the wavelengths are needed to study the cosmos the various wavelengths of the electromagnetic spectrum are similar to the strings on a violin in music many wavelengths of sound are used to communicate a musical idea this piece has a very large range from a low note to a high [Music] note if we were to restrict ourselves to the visible light spectrum it's almost as if we were only to hear two notes in the middle of that [Music] piece using alternate wavelengths the more we look the more we're discovering just recently we've discovered that there are two small galaxies colliding with the Milky Way right now and the only reason we didn't know they were there is because there was so much dust in the disc of our galaxy we couldn't see them we're living inside this cloud and it's something we're not aware of but with infrared light you can cut through that dust and the minute we turned infrared telescopes to the sky we saw these little galaxies up there coming right at us from our cockey position in the Milky Way it's difficult to gauge what our galaxy really looks like radio and Optical astronomy give us a glimpse of its features but to get the big picture we need to look outward so the way we gain some understanding of our own Galaxy is first of all by looking at other galaxies and seeing what they look like and seeing things in other galaxies that correspond to things that we see in our own Galaxy like clouds of gas that are kind of lined up along what looks like a spiral arm you know we can see parts of spiral arms in our own Galaxy and we figure that they're all connected kind of like the spiral arms of other galaxies that we can see from the outside we know that the Milky Ways four main spiral arms swing out from the downtown Center like wide streets from the inside out they're named Norma scum Crux Sagittarius and Perseus if the arms are the Galaxy's suburbs then our solar system lives on a quiet deadend street between Sagittarius and Perseus on What's called the Orion spur all the stars in the Milky Way add up to a community of about 200 to 400 billion and they're on the Move we are orbiting around the Galaxy we change our position so far we think the sun has always been about the same distance away from the center but we've been in and out of pretty much every spiral arm that there is the spirals are called density waves areas where the stars and gas get pushed together as the density waves spiral around the billions of stars ride over and through them when you think about watching the tour to France and you see all of these bicycles they're all moving forward sometimes they kind of Clump up around one bicyclist and sometimes they're stretched out that's sort of what the spiral arms are like that the stars are going around like the bicyclist sometimes in clumpy areas and sometimes in more spread out areas but they keep going around the center Stars don't usually travel alone while giant globular clusters populate the Galaxy's Halo the galactic disc has open or Galactic clusters these bundles of young stars are barely held together by their Mutual gravity now open cluster implies that the stars are actually free to go it is open so this is a cluster usually of many stars that are formed together all from one of these giant clouds of dust and gas over time they're going to move away from each other distribute themselves around the Galaxy astronomers have counted about 20,000 open clusters in the Galaxy the pleades is the one found nearest to the Earth it Formed 100 million years ago and will be around at least twice that long before the Galaxy spiral arm tear it apart closer to home our own Sun orbiting in solitude may have once been part of an open cluster star that struck out on its own the sun the star clusters our own planet in fact the entire galaxy and the universe beyond are built of dust and gases these particles that now block our view are what got us here in the first place and the star making Machinery is still cranking nothing beats the spectacle of a glorious Sunset but we owe it all to dust and gas the Setting Sun appears yellow orange or even red for two reasons first of all the molecules of air in the atmosphere are scattering the violet blue and green light out of our line of sight leaving the yellows oranges and reds to reach our eyes and second of all particles like dust or smoke or smog in the atmosphere absorb blue light more than they do red light even the Grandeur of a blue sky is really an optical illusion why is the sky blue there's nothing blue about the gases of our atmosphere but as sunlight comes through our atmosph atmosphere the shorter wavelengths the blue light gets scattered more than the longer wavelengths do so if you look at any particular part of the sky you're more likely to see blue light being scattered towards your eye space is dark because there aren't enough gas or dust particles to reflect the light of a billion stars and though space may be a vacuum it's not perfect the galactic disc the largest portion of the Milky Way owes about 15% of its mass to dust and gas gas clouds can span hundreds or even thousands of light years providing the raw material that fires the Galaxy these regions of cosmic dust and gas are called nebula and they produce effects rivaling anything seen on earth a good good example is the Orion Nebula in the constellation Orion this region is active with Stellar formation which makes the gas around the Stars glow it's literally fluorescing in response to the light coming out of the massive stars that are near the nebula and and this nebula literally glows and can be seen you could see it with your naked eye when you see the Orion Nebula in a real way those are baby pictures for us 5 billion years ago we were in a glowing hot nebula and the Sun and the planets were forming together under the influence of gravity Orion which contains hot Stars ionizing its gases with ultraviolet light is called a diffuse or emission nebula astronomers classify two other categories of nebula some nebula are what are called reflection nebula they're simply the dust in these nebula simply reflect reflecting the Starlight from the bright star nearby the witch head nebula is an example of a reflection nebula borrowing light from the Star Riel reflection nebula appear blue for the same reason our sky does blue light is more easily reflected than red and last there are dark nebul like the horse head when low mass stars like our sun die they form another kind of nebula called a planetary nebula these dim short-lived nebuli like the Cat's Eye Nebula spew elements back into the Galaxy these may become raw materials for new Suns and new planets just as dying Stars spew out clouds of dust and gas dust and gas can come together to form [Music] stars at a construction site you have old buildings being torn down and new buildings going up and it's very much the same in the Milky Way galaxy you have old stars explode and they cast out new material raw material gas and dust that can be used to form new stars nebuli are the Galaxy's recycling centers where old becomes New Again recycling is not just a good idea here on Earth it's a natural Cosmic law in fact our own bodies are made out of recycled material from earlier generations of stars that had dispersed material into the interstellar medium before our own solar system formed each generation of stars creates heavier Elements which become the ingredients for everything in the universe most of the Galaxy's hot young stars get built in the Milky Way's spiral arms as gas clouds orbit the center of the Galaxy like the stars do they get squeezed as they go through a spiral arm remember a spiral arm is simply a wave in the pattern of stars and because stars are denser there the gas clouds that orbit through it tend to get compressed that compression allows gravity to get a hold of that gas and cause it to collapse to form Stars more readily there than anywhere else Stars often die in the spiral arms because they are formed here more frequently victims of their own enormous Mass the more massive stars are extremely powerful extremely luminous and to be that luminous they have to use up their their energy source very quickly so massive stars live only short lives and they are thus found in or near their birthplaces the spiral arms because they simply don't have enough time to wander away from the places where they were born although we can anticipate the future of some Stars it's often difficult to learn their history but new techniques are revealing new secrets about a well studied star in the Milky Way called Myra a Myra has actually been a favorite star of astronomers for 400 years it's a very easily visible star in the night sky recently the galac spacecraft the Galaxy Evolution Explorer photographed Myra in invisible ultraviolet light and revealed that it's leaving a trail 13 light years long behind it we think that's actually caused by the fact that as the star plows through the gas the gas heats up in a bow shock very much like waves breaking up against a boat and then that streams out into a wake of hot material you're actually looking at Myra acting very much like a boat plowing through the water when you look at how fast Myra is going right now about 291,000 mph and you do the calculations that long tail is its path for the last 30,000 years we can't predict exactly where the sun will go in its orbit around the Milky Way there's all kinds of things it could interact with but here we have the history of one star we know this is the path it took and that'll help us model how the Galaxy works and how all the stars move around the middle of the Galaxy within the Milky Way Suburban spiral arms young Stars enjoy plenty of space to move around as we move into the galactic bulge conditions get much more crowded and urban closest star to the sun is a little more than four light years away and when we look up in into the night sky even on a perfectly clear night with no lights around you can't see more than about 2 or 3,000 stars but if our planet was down in the middle of the Galaxy there would be a million stars in the night sky as bright as the brightest star that we've ever seen in our sky and it would be so bright that in fact it wouldn't be night time it would be daytime all the time Life as we know it would be completely different so what do we owe our position to scientists believe that gravity has a lot to do with it gravity is the power that drives the Galaxy and at the Galaxy's Center churns the engine it feeds galaxies are like a city in that they are ever changing and you're constantly being rebuilt and re invigorated there's no question that the Milky Way a few billion years ago looked a lot different than it does today it probably was smaller it probably didn't have the beautiful spiral shape that we see today as things collapse under Gravity you tend to naturally form a disc you'll notice there are discs everywhere our solar system is a disc our galaxy is a dis so the stars all start rotating in the same direction just as in a city not all the stars in the galaxy are natives some stars born beyond the Milky Way settle here and begin to make their mark But then if another galaxy comes by the gravity affects the way the stars move and this may initiate the spiral arms so in fact our spiral shape may be some evidence that the Milky Way is composed of more than one small galaxies that came together a long time ago historically the center of the galaxy has been an impenetrable mystery until we developed x-ray vision one of the first ways we really identified where the exact center of the Galaxy was was with an x-ray telescope well the x-rays were able to pass through all of the dust and gas in the disc of our galaxy and so even though we can't really see this Bright Center to the Galaxy in x-rays there's this giant glowing hot source right in the middle the X-ray emitter Sagittarius AAR is associated with the super massive black hole in the Milky Way's Center by definition a black hole doesn't allow light or even x-rays to escape the radiation comes from gas caught in its gravity spun and heated to millions of degrees they're moving at extremely high velocities for example the more extreme cases that we've been able to observe the stars are moving as they pass by the black hole at a speed of 10,000 km/ second that's like going around the world in 4 seconds and we're talking about a whole star moving at that speed when we watch Stars orbiting the very center of our galaxy it's obvious that there's some sort of invisible monster there they're orbiting around a GI giant mass and the orbits of the Stars imply that there's about 3 to 4 million times the mass of the Sun in the very center of our galaxy we're not sure which came first the Galaxy or the black hole but we know that it's there and it's tremendous for all its power and weirdness the super massive black hole is pretty typical for a Galaxy the size of the Milky Way other spiral galaxies and big elliptical galaxies also seem to have super massive black holes in their middle ranging from a million times the mass of our sun up to several billion times the mass of our sun the Stars surrounding the black hole are ancient many are red giants hundreds of times bigger than our sun the galactic center is crowded with them like an urban downtown crowded with people and stars like people can be pushy most stars in the galactic center simply just keep orbiting the central black hole but in the galactic center there's so many stars packed so close together that stars are constantly nudging each other a little bit gravitationally and their orbits are being perturbed changed a little bit a bumped star can get stripped of its atmosphere leaving just its orbiting core or rarely it can tumble into the black hole and vanish but something else is happening around the black hole this turbulent dangerous neighborhood is also a stellar Nursery the stars that we're observing moving fastest around the black hole are the young stars that uh have very recently formed it's something we call the Paradox of Youth because it's hard to imagine how to form these massive young stars in the presence of a black hole and yet there they are recently astronomers discovered that not all stars caught in the black hole's grip are doomed to stay there a few manag to break away and see the universe barreling through the universe at 1 and2 million mph hyper velocity stars are the escapees of the Galaxy and what's interesting about h velocity stars is the only way to explain their extreme velocities is that they're rejected by a super massive black hole for a Star to go ballistic takes a very specific set of circumstances and in fact it requires two stars most of the Stars you see in the sky are not single stars but pairs or binary Stars they orbit around each other linked by gravity's Embrace but a star pair in the galactic center might get jostled by surrounding stars and stray too close to the black hole when that happens the moment that the gravitation pole of the black hole exceeds the gravity that's binding the two stars together the pair of stars is broken apart one of the Stars will be captured by the black hole usually into a very tight orbit around the black hole and the other star will then gain all the energy of that system and it be Ed with this incredible velocity if the Galaxy were a city where most of the Stars would be cars or pedestrians a high velocity star would be more like an airplane or a high-speed train rushing out of the country if you were on the high paloy star the the ride would be quite amazing the sky would be covered with stars as bright as the full moon in every direction but that vieww quickly changed because the hyar moved so quickly out of the Galaxy the stars appear fewer and fewer than night sky the Galaxy is constantly in motion like a giant wheel or a sprawling Metropolis in the heart of town the super massive black holes gravity whip Stars around in an orbit of around 11 minutes where the Earth sits 2/3 of the way out on a spiral arm we Traverse the Milky Way once every 250 million years our solar system has been around the block only 18 times since it formed the Milky Way's incomprehensible size makes it easy to forget it's just one small part of an expanding Universe when people hear about the expanding Universe a common misconception is that everything is expanding and in fact I'm not expanding right now my atoms are the same size my cells are the same size the Earth is not getting farther away from the Sun the expansion of the universe only applies to celestial objects that aren't bound together by gravity since the planets within the Milky Way have stronger gravitational poles than the expanding forces outside our galaxy The expansion of the universe doesn't affect our solar system our own Milky Way a spiral galaxy is on a collision course with another spiral galaxy the largest spiral near us and that is the Andromeda galaxy we think that in maybe 3 or 4 billion years our two galaxies May merge together it'll be very interesting to see what happens what probably won't happen is a collision of stars even though both galaxies contain billions of stars the space between them is enormous they will gravitationally interact changing their direction and motion eventually the merged spirals will settle down to become an elliptical galaxy essentially all of the several dozen galaxies in our local group will be part of one Super Galaxy and then gradually that Super Galaxy will start losing stars because of gravitational interactions among the Stars within that Galaxy some will get flung away into Intergalactic space when it first formed the Milky Way built stars at a rapid Pace using raw materials that were ejected in space from The Big Bang as the Galaxy aged the star production slowed down from a few hundred a year to about four to six new stars each year today over time the Milky Way galaxy has changed dramatically and we don't know exactly what it looked like long ago but probably early on there was a lot more gas and dust and probably fewer stars and you had a lot of very large very massive stars that would have formed early on and then these early Stars exploded fantastically and uh spat out new material heavier metals that could be used to form smaller Second Generation and then third generation Stars some younger galaxies are still enjoying that kind of building boom we can see some galaxies where the rate of star formation is very high compared to our galaxy those are called star our burst galaxies the rate of star formation there can be anywhere from 10 to 100 times what it is now in our galaxy with every generation star production slows down and the Milky Way has been in business for 13 billion years one of the reasons that the rate of star formation in our galaxy has changed over time going from a very high rate to the current modest rate of star formation is because the uh gas is being used up gas is used up to form stars and we're running out of gas literally eventually over trillions of years star formation will stop completely the great Galactic construction project will shut down and one by one the twinkling stars will fade away

Channel: HISTORY

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Keywords: history, history channel, history shows, history channel shows, the history channel, documentary history channel, history documentary, documentary, history channel full episodes, documentaries, history channel documentaries, the universe, history the universe, the universe show, the universe full episodes, the universe clips, full episodes, watch the universe, the universe episodes, planets, the solar system, space documentaries, solar system, alien planets, the great unknown

Id: hTYxFangDHM

Length: 176min 38sec (10598 seconds)

Published: Wed Nov 08 2023