Extreme And Interesting Weather On Other Planets In Our Solar System

From the chaos on the outer planets to the broiling heat of Earth's closest neighbor radical weather is the norm in the solar system we do have our own extremes here on earth but they pale in comparison to the fastest dustiest wettest and most brutal alien storms on earth the sun drives our weather and sometimes drives it wild when hot and cold collide in the atmosphere watch out this is true locally and globally but storms on other planets are bigger badder and stranger than their counterparts on earth why is that because of the sun if not what else fuels their fury the basic laws of nature the rules of the game are pretty much the same wherever you go in the solar system but every planet has its own way of playing the game right now on Mars the entire planet is being covered in dust this global dust storm blocks 99% of the sun's rays from reaching the planet's surface it's actually a system of smaller but still massive storms churning dust high into the atmosphere once it starts it takes months for Martian skies to clear Mars is just the most dramatic weather in the solar system in some senses very rare in the solar system you get a weather event that can take out the whole planet so if the basic rules of hot and cold are the same on Mars why is the weather so different from earth for one thing Mars is half the size of earth it's also 50% further from the sun so it's much colder the average temperature on Mars is minus 80 degrees that's almost 130 degrees colder than earth and the atmosphere is extremely thin and composed mostly of carbon dioxide but perhaps the most important difference is this Mars is a global desert what would earth be like without water well it'd probably have a lot of dust there's no liquid water at the surface of Mars and there's very little water in the atmosphere and so there's nothing to sort of keep the dust down on earth dust storms are localized and short lived the reason for that difference in scale is that the storms are generating their own weather on Mars whereas on the earth they're slave to the weather that's going on around them in other words on earth the global weather system creates dust storms on Mars the storms create a global weather system astronomers have always been able to see big Martian dust storms easily with earth based telescopes but what they couldn't see was what caused them that would require a trip to Mars itself in 2003 NASA landed two rovers called spirit and opportunity on the Martian surface their mission to learn more about the geology of the Red Planet NASA engineers always assumed that as these two vehicles roamed the Martian surface dust would build up on their solar panels if you have a lot of dust that's falling down out of the atmosphere and coating the panels pretty soon you're not getting much sun to the silicon and in fact we thought that that was what was going to kill the rover spirit and opportunity only it never happened the rovers didn't die as expected as dust built up on the panels somehow something would clean them off but how could this be NASA engineers were baffled until the rovers themselves saw the culprit Martian dust devils it turns out that dust devils were sort of our white knight they came along and cleaned off the solar panels just at the time we were expecting to start having some problems there are beautiful photos that actually show dust devils moving across the Martian atmosphere and ghostly soldiers moving out there in the distance a dust devil is really an extreme form of rising hot air or convection and that hot air wants to go up and it comes up just like you know water going down a drain well this is air that just spirals up into the colder parts of the atmosphere whenever warmer air which is less dense rises up through cooler air which is more dense it rotates as it swirls upwards convection can be very powerful strong enough to lift things up on earth it lifts moisture and that's how thunderstorms form but on Mars there is no moisture so it lifts dry dark dust and creates giant dust storms instead once airborne Martian dust clouds absorb sunlight and heat the atmosphere this supercharges the convection lifting still more dust that produces more winds which bring up more dust and these things can spread up to thousands of miles across or even in some cases they can envelop the entire planet and because the Martian atmosphere is so thin it doesn't take much to get this cycle going you get a lot more difference between the surface temperature and the air temperature and so the convection on Mars is very much more vigorous as a rule earth doesn't get the temperature extremes that Mars does but sometimes here and there in the deserts of earth convection can be very Martian like and we get dust devils too but at Arizona State University Lynn Necrace makes dust devils to order in a lab to study them up close he uses a vortex generator and substitutes lighter dry ice for dust what he creates is not an exact replica of how real dust devils form but good enough to see how they pick up dust and debris natural dust devils usually form from the bottom up as opposed to tornadoes which form from top down so what happens when we turn this on we have the air flow starting and as the air flow starts to rotate from the fans down to the floor we actually end up having the vortex form in other words the vortex generator basically a huge vacuum cleaner imitates the swirling action of convection you can see here there's a wider base where larger particles of the dry ice are being swept up and gets wrapped up and tightens as it expands upward the center of the core is where the majority of the lifting would occur Martian dust devils have been helpful keeping the rovers clean but could they actually be making a mess of the rest of the planet some scientists think there are so many at any one time and they lift so much dust into the atmosphere that together they trigger these much larger dust storms it starts wind patterns and the air's warmer over here and it's colder over here and the air starts moving around pretty soon you're spreading dust over the whole the whole planet and and we found measurements that indicate there's up to maybe 200 dust devils per square mile per day during some parts of the summer and they can range from a couple of hundred feet tall to devils that stretch six or seven miles high you can get just towering monsters of dust devils that we would never see on the earth the kind of maximum sized dust devils you see on Mars are more like tornadoes on the earth where they're going up almost 10 km so these things are just real monster systems back at Arizona State University scientists blow crushed walnut shells as silicate particles in the Planetary Geology Wind Tunnel to replicate dust and wind conditions on Mars if we can understand and sort of replicate what's going on then we can in a sense understand how the Martian surface has been changing and continues to change as time goes on oddly enough their studies reveal that it's easier for winds to loft larger sand particles into the air than smaller dust particles this is because there's cohesional forces and static forces between the small the very small fine dust grains we imaged the rover deck and actually found that sand seemed to have bounced onto these solar panels and we can see the skip marks across the surface and this is interesting because we don't usually see sand typically reach that high dust devils on earth never have the punch to produce that kind of chaos here lucky for us but what would happen to earth if a giant Martian style dust storm did overtake us if you had dust storms or Martian size on the earth you would find your city being enveloped in an orange tan haze air quality plunges as the storm churns dust blots out the sun shutting down photosynthesis no plants no food temperatures would plummet 65 million years ago an asteroid may have struck the earth creating these same conditions wiping out the dinosaurs it's not going to happen on the earth though because there's going to be rainfall and moisture condensing on the dust grains and so forth and dropping them out of the atmosphere so it's very hard for something like that to spread in the climate conditions that we have on earth forecasting Martian weather may someday be just as important as forecasting the weather on earth if we ever want to send a man mission there the word environment no longer really applies just to the meadow next door and the little stream down down at the end of town it's the whole inner solar system I mean that's really our environment now the sun's energy bathes all the planets on earth it creates hurricanes on Mars planet wide dust storms but with almost no solar energy distant Neptune produces violent and powerful winds where do they come from and just how bad are they if Neptune's winds were to travel to earth these alien storms would literally blow us away the orbit of Neptune lies 3 billion miles from the sun at the outer edge of the solar system there's a lot we don't know about this big blue planet Neptune's jet stream winds blast as fast as 15 miles an hour in its upper atmosphere but how the sun controls the weather on earth and Mars but it barely reaches out here no sunlight means freezing temperatures an average of minus 392 degrees Fahrenheit so if there's no sun and no heat where do these incredible winds come from one of the interesting puzzles is that as you go further out in the solar system you get further from the sun the winds don't go down you still get very strong winds the energy for Neptune's winds must come from somewhere and scientists are working to figure it out Neptune's energy is certainly not going to be powered by solar radiation in fact the energy we detect coming out from the planet and the infrared as heat is two and a half times the energy coming in from the sun so the planet is creating its own heat not from its core which is made of rock and ice but wrapped around this icy center is a mantle of ammonia methane and water all being squeezed by enormous pressure and generating tons of heat so while Neptune is frigid on the outside on the inside it's giving off a lot of heat this heat may help generate Neptune's winds but they're still too strong to come from the mantle alone something else is pushing them faster and faster earth has a hot core too and it's a lot closer to the sun so why don't we have winds like Neptune for one thing our oceans store and release energy and that helps generate our weather it adds energy in places takes it out another is a very complicated system this complicated system produces a lot of wind and just where our Earth's fastest winds found surprisingly not over the ocean they blow instead over the top of a fairly modestly sized mountain New Hampshire's Mount Washington the highest winds ever observed by human beings were right here on Mount Washington at 231 miles an hour on April 12th in 1934 Mount Washington Observatory a private non profit scientific institution is responsible for tracking the weather and climate atop the 6,288 foot tall mountain this remote weather station accessible only by snow tractor in the winter has kept daily records for the last 76 years it's definitely one of the most extreme locations on the planet we regularly see in the wintertime winds exceeding 100 miles per hour every few days nowhere near as ferocious as Neptune yet still pretty strong but why does this mountain one fifth the size of Everest produce such fierce gusts we're at a place where we have winds converging from various directions coming from the Ohio River Valley coming down from the ST Lawrence River Valley coming up the eastern Seaboard all converging here in this area on top of Mount Washington the elevation change from the valley floor to the summit of Mount Washington is very significant for any mountain range it's over 4,000 feet so air is forced to go over the mountaintop and forced to squeeze in there and is accelerated as it squeezed over the mountaintop and they measure it every hour on the hour 24 hours a day seven days a week it's blowing over 100 out here right now ice is forming on the instruments more quickly time to go up and de ice the instruments even though it's blowing over 100 we got to do it every hour now ironically Earth's uneven surface which channels winds into powerful gusts on Mount Washington ultimately knocks them down over time and this is the big difference between weather on earth and weather on Neptune Earth has mountains that slow winds down Neptune is as smooth as a cue ball it's not so much a question of you're driving them stronger because you're not it's just that there's nothing to slow them down simply put once Neptune's winds get blowing there's nothing to get in their way so what would an average Neptune wind speed of 850 miles an hour due to us here on earth we have parking level winds in the air sometimes about 100 miles an hour you can say that pretty dangerous so if we sat with 900 mile an hour winds from Neptune on the earth we would probably start wiping out everything on the surface and scraping everything off giant Neptune takes wind and transforms it into something extreme and almost unrecognizable but orbiting just beyond the rings of Saturn is a small moon that does the same thing to rain this is Titan where an everyday rain shower will turn earth into an explosive fireball it's a cloudy day and a gentle rainstorm starts here on earth you'd grab your umbrella and consider it a minor inconvenience but this isn't earth and it's no ordinary rain you're on Titan a small moon of Saturn and in this chemical downpour you'd need more than an umbrella to protect you the rules of earth weather definitely don't apply here but earth and Titan are alike in a lot of ways on earth we have a solid surface a protective atmosphere and plenty of water all these things make life on our planet possible there's really nowhere else quite like earth anywhere in the solar system but Titan comes close like earth it has a solid surface and that's not all Titan has an atmosphere that's in general very similar to earth in some ways it's mainly nitrogen like Earth's atmosphere it's rich with organic material also like Earth's atmosphere but similar isn't the same here on earth our atmosphere has a huge supply of water in it all the time constantly evaporating and raining back down Mike here on the Hawaiian island of Kauai today we're on the slopes of Mount Wyoli which is the cloud trouted mountain behind us it rains over 40 feet a year here Earth's water cycle starts when warm moist ocean air rises forming clouds that eventually condense into rain the rain falls back onto the land where it eventually drains back into the ocean starting the cycle again when water evaporates it absorbs solar radiation when water condenses it releases all that energy into the atmosphere and this transfer of heat helps to moderate conditions on Earth Earth's water restores as much as 80% of the sun's heat helping keep our temperatures steady from the equator to the poles scientists theorize that Titan might have water or some other liquid that might produce a similar effect and in 2004 when NASA's Cassini probe visited Saturn it found some pretty good evidence to support that idea if you went to Titan and you were looking at the landscape you would see something that in some ways would look almost familiar to you you might see big mountains and valleys that were carved out by running liquids in fact as Cassini flew past hazy Titan its radar read the surface below scientists saw channels cutting across the surface much like rivers on earth do some as long as 900 miles the first strong evidence of liquid on Titan there are large bodies of liquid on the surface of Titan nowhere else in the solar system except for the earth are there any large bodies of liquid could water the liquid that carves Earth's mountains and valleys also be carving these features on Titan's surface or could it be something else the problem is that Titan is too far away from the sun if it was water it would be frozen solid it's about minus 300 Fahrenheit on Titan so things behave very differently on Titan than on earth because it's so cold methane which is a gas on earth is a liquid on Titan one mystery solved but just because methane is a liquid on Titan's surface doesn't mean it's part of a weather cycle like water on earth so how do we know that this methane also falls from Titan's sky that answer is shrouded in mystery literally Titan is completely covered in a thick haze of smog particles like a very very bad day in Los Angeles despite the haze the Cassini probe once again revealed the answer we can see the upper clouds and we can see evidence for rainfall because the clouds drop precipitously we hypothesize that we're seeing the the effects of rainfall methane rainfall we think that Titan has metane monsoons so we think that sometimes Titan has a lot of rain that is able to carve rivers and leave a large fluvial deposits on the surface Cassini's radar imaging also revealed large methane seas on Titan's surface if you have liquid methane on the surface and a lake for example that methane can evaporate off and become methane gas on the atmosphere so you have kind of a cycling of methane liquid phase and gaseous phase and between the surface and the atmosphere that's very similar to the water cycle that occurs on the earth but methane is a flammable gas so why isn't Titan on fire for any combustion you need two things you need both a fuel which methane is but you also need oxygen and on Titan you lack the oxygen so the whole thing is basically a big fuel canister but there's no oxygen with which to burn it and so it's all very stable if it were cold enough here on earth to produce methane rain the oxygen in our atmosphere would create a worldwide firestorm luckily for us that can't happen Titans methane cycle makes it both alien and familiar to us to me Titan is very exciting because all the materials are so different and yet this process is produce very similar landscapes to what we see on Earth Titan proves that where alien weather is concerned looks can be deceiving on Jupiter it's all about size drop the Great Red Spot onto our world and it makes even our worst hurricanes look like a breeze this is the biggest and oldest storm in the solar system and Jupiter's most famous feature it even has its own name the Great Red Spot it's about two or three times the size of the earth which makes it the mother of all storms we've known about the Great Red Spot in Jupiter's southern hemisphere for more than 300 years when Galileo invented the telescope within a few tens of years people had seen the Great Red Spot and it's still there familiar yet mysterious nobody knows how the Great Red Spot formed but scientists are finally probing below Jupiter's cloud tops to uncover more about this enormous alien storm the storm is powerful with wind speeds of 300 miles per hour it rises miles above the surrounding clouds on earth we have storms that seem similar those smaller and milder hurricanes also known as cyclones or typhoons depending on where they form they're our most destructive weather systems but is there more than just a passing resemblance between Earth's cyclones and Jupiter's red spot when you look at the earth from space at a Hurricane it's this big swirling pattern it's round it rotates Jupiter's big swarms look big and round and cloudy and they rotate but they're the similarity ends in a Hurricane there is an internal core which is called the eye of the tropical cyclone and that's a region of very calm winds and no clouds and usually has a size of about a 10 20 kilometers in diameter and then away from the eye there is the eye wall those are really cloudy regions with a lot of rain and as you move outward there is a whole region of about a couple of hundred kilometers with very very strong winds and very strong rain Hurricanes draw power from heat in our oceans but Jupiter has no oceans and the sun isn't close enough to power a storm as big as the Great Red Spot so where does it get its strength part of the answer is Jupiter's size it's the largest planet in the solar system almost as big as all the other planets combined this mass generates a very strong gravitational pull which in turn creates interior heat that rises to the surface another piece of the puzzle may be Jupiter's hypersonic rotation despite being much larger than Earth Jupiter's day lasts only 10 hours in other words it spins incredibly fast could energy from this dizzying spin feed the Great Red Spot the weather is really dominated by this fast spin their shearing between different latitudes and that shearing plus a lot of heat that comes up from the interior of this very massive object 290 times the mass of the earth leads to very violent storms both Jupiter's and Earth's storms spin around in a familiar spiral shape on earth it's because of an effect called the Coriolis force I'm sitting at the North Pole and I want to throw a ball down to a friend who's in Los Angeles and so if I threw the ball in that direction the earth rotates and the ball will end up in the middle of the Pacific rather than in Los Angeles so it's like if the trajectory was deflected to its right and that's what we call the Coriolis force this force spins storms clockwise in our southern hemisphere but there is a stark difference between earth and Jupiter The Great Red Spot is in Jupiter's southern hemisphere and yet it spins counterclockwise this is because of some other powerful winds it's bounded by jets which are moving in opposite directions and so like a cog between two conveyor belts there is feeding energy and momentum into the system Jupiter's complex jet streams spin the storm into organized chaos but the greatest difference between Jupiter's red spot and our storms may be Earth's solid surface once a Hurricane hits land it comes apart pretty fast where they come over land or over mountains their behavior is very different from where they form over the oceans and over warm oceans in particular where we get hurricanes and on Jupiter there's obviously no solid surface with no land mass to stop it the Great Red Spot just keeps on spinning and spinning and spinning scientists hope to learn more about our weather by continuing to study the storm on earth there's a limit to how far ahead you can predict the weather on Jupiter we can forecast where the red spot is going to be months in advance it's practical value to understand what makes weather on earth so unpredictable aspects of the weather on Jupiter are much more predictable unpredictable or not Earth's weather never gets as violent as on Jupiter that's lucky for us because if we shrank the Great Red Spot down to fit on earth we'd be in for disaster on the earth we go to category 5 hurricanes they look category 10 Hurricane here not much would be left alien storms are vastly different everywhere you go in our solar system even our next door neighbor Venus they say we're sister planets lucky the resemblance doesn't include weather otherwise we'd get seriously burned Venus may be our nearest neighbor but somehow its weather is radically different from ours the second planet from the sun is a cross between a toxic waste dump and Death Valley but even worse so it's really it's almost a planetary definition of hell the temperature is 900 degrees Fahrenheit the pressure on the surface is the same as half a mile below the Earth's ocean and if that's not enough the upper atmosphere of Venus is choked with sulfuric acid clouds and winds clocked at 250 miles an hour to get a comparison for Venus the best thing to do is climb inside of your oven and crank it up and then in terms of pressure you're talking about deep sea diving it's like nothing there's nothing comfortable on the earth it's just a very very extreme object on Venus there's just no escaping the heat if you built up a hot spot on Venus the massive atmosphere would just carry that heat away and spread it around but Venus shines so brightly in the night sky because its thick clouds reflect almost all the sunlight it receives in fact some early scientists assumed Venus would have moderate earth like temperatures when we went by Venus in 1962 with a spacecraft we thought we would find a surface at 90 degrees Fahrenheit sort of like Miami Florida we were dead wrong something else must be at work on Venus but what so why doesn't Venus cool off the same way earth does on the earth for example we have sunlight coming in hitting the surface of the earth earth warms up a little bit but the oxygen and the nitrogen in the atmosphere don't impede the light so when it gets released out in the infrared it goes right through the atmosphere and leaves and goes into space but on Venus the atmosphere is 97% carbon dioxide giving a whole new meaning to the greenhouse effect it becomes very very hard for the surface to get its energy out so Venus really taught us a lesson that if you have a blanketing gas a greenhouse gas you can warm up the atmosphere tremendously but why does Venus have so much more CO2 in its atmosphere than earth the two have much in common they're even called sister planets they're almost the same size at roughly the same amount of carbon and billions of years ago both had lots of water but eons ago their paths mysteriously diverged on earth water fostered life the earth is most of its carbon in life forms and the trees and the animals but if you took all that carbon that's in the near surface rocks and burned it up or released it you would then create an atmosphere very much like Venus Venus's close proximity to the sun made it too hot to sustain liquid water instead its water evaporated into the atmosphere trapping the heat deposited by the sun and creating a runaway greenhouse effect once in the atmosphere the water molecules were exposed to solar ultraviolet rays that broke the molecules apart it really wasn't recognized by the scientific community how important the greenhouse effect was prior to going by Venus and seeing this amazing place where it was 900 degrees Fahrenheit not ninety it took several doomed missions to Venus to figure it out starting in the 1960s both the United States and the Soviet Union sent unmanned probes past the planet and down to its surface it didn't take long before Venus crushed and burned them then in 1981 the Soviet lander Venera 13 set a record for survival on the surface of Venus 2 hours and seven minutes it was able to take pictures and samples of the surface before being overcome by the heat you're sitting there with us 900 degrees Fahrenheit heat all around you it's going to get in there and bake you after a while scientists one day hope to send a probe to Venus that can survive its hellish environment to help us confirm our theory of how this planet went astray because if circumstances were just a little different our sister planet might just be our twin remove our atmospheric shield and you're on the road to hell as soon as you're heated up to something like 400 degrees or so you probably start getting some smoldering smoke and way before if the 900 degrees the earth would burst into flames because all the oxygen around once the oceans boiled away the carbon locked in rocks on the ocean floor would cook and over millions of years re enter the atmosphere probably if you came back to the earth system after this happened you'd find a plant looking much like Venus we're a long ways away from such a drastic change but it's sobering to look at Earth's sister planet when the sister planet went on a very different track than we did so cosmic forces turned Venus into a planetary barbecue but on this violent stormy world time and the elements have produced some of the strongest thunderstorms ever measured welcome to Saturn lightning cuts the sky this violent weather system grows bigger than the entire United States as it pummels the atmosphere with the most powerful lightning ever seen except this lightning can't be seen because these bolts are electrifying the skies over Saturn despite the raw power of Saturn's lightning scientists have been unable to see it partly because Saturn's rings are too bright the rings are so bright if you were on the ninth side of Saturn it would be considerably brighter than the earth under a full moon but Saturn also hides its lightning within thick choking clouds of ammonia it's probably 100 km down that the lightning is happening and that complicates seeing the lightning flashes but the lightning is there and scientists know it because they've heard it radio wave detectors on the Cassini orbiter have recorded the sound of Saturn's lightning we can hear the static of lightning just as you could with an am radio going down the highway on earth and this static reveals the power of the lightning that we can't see you can measure the energy in those radio waves and compare it with the energy that your radio picks up when there's a thunderstorm around on earth and the Saturn ones are big they are more powerful maybe 100 times and Earth's lightning can help scientists understand how storms work on Saturn within Earth's storm clouds just like in Saturn's updrafts drive moisture higher causing ice to form these ice crystals rub against each other take on a positive charge and become attracted to negatively charged water droplets lower in the cloud this sets the stage for a potentially powerful discharge of energy once you get that charge separation that builds up so intensely that some theorize that it can be as strong as 100 million volts that the cloud then must release that energy on Saturn the same thing happens on a much larger scale in fact the lightning is 100 times stronger than Earth's that's a staggering 10 billion volts of electricity thunderstorms in Saturn's southern hemisphere span thousands of miles and can last as long as a month but scientists aren't sure what makes Saturn's storms bigger and longer lasting it could be Saturn's super saturated atmosphere probably the fact that there's more water in the atmosphere pound for pound on Saturn is makes the storms bigger more water droplets means more friction which means bigger lightning bolts but energy emerging from the planet may also contribute to the power in Saturn's thunderstorms it turns out that where Lightning Alley is on Saturn is a place where the winds are flowing the slowest if you go deep down in the atmosphere you'll see the same winds as you do up high it's a place where the energy being released deep down below and make it on up to the upper atmosphere without being sheared apart and allows storm systems to be organized Earth's atmosphere isn't built that way so as violent as our storms get they're nothing compared to the systems on Saturn even a run of the mill mega thunderstorm on Saturn would devastate us here a Saturn sized thunderstorm on the earth would mean a thunderstorm that grows to cover all of North America and presumably has very strong winds and rain this is something that's unprecedented on the earth Saturn's hyper violent thunderstorms are proof that our planetary neighbors have weather far more ferocious than ours but the laws of physics that create Saturn storms are the same laws that create our own weather massive dust storms unrelenting winds killer lightning powerful hurricanes and searing heat from the drama of our planet's origins and the birth of our solar system comes one of the most startling revelations of modern science the solar system we see today quiet stable was once a battlefield Newborn planets blasted through space competing for stable circularized orbits inside a grunge style mosh pit of gas and dust for those that find the right balance the prize is survival for the rest world shattering destruction a new look at the chaos of creation and a frightening possibility in our distant future Mars the curiosity rover is searching for clues about the origins of the Red Planet it confirms the presence of oxygen and nitrogen isotopes hidden in the rocks and soil we use isotopes to try to figure out the history of planets partly because they are immune to many of the changes the chemical changes that occur when you have things like collisions and so forth isotopes the relative abundances of these isotopes are like fingerprints curiosity confirms a unique mix of isotope fingerprints the isotopes indicate that Mars formed elsewhere in the solar system and moved into our neighborhood our solar system is full of oddities pointing to an imperfect birth and a malformed evolution all of our planets go around the sun in the same direction that the sun is spinning this is the same direction that the clouds within our original nebula began to rotate six planets spin around their poles in the same direction for them the sun rises in the east and sets in the west yet two planets spin the opposite direction for Venus and Uranus the sun rises in the west and sets in the east Uranus not only has a retrograde spin it rolls on its side like a bowling ball at Neptune the icy moon Triton orbits backwards opposite from the direction of Neptune's spin do these planets spin backwards because they were rocked by Titanic collisions in the past so we see evidence in the architecture of the solar system for not only collisions like Earth's moon and the fact that Venus is rotating in the wrong direction and Uranus is on its side and so for all these things are attributed to collisions we also see in the asteroid belt and in the Kuiper Belt the outer asteroid belt if you like we see that the orbits of these things look like they've been disturbed closer to home our own earth has an inexplicable twenty three and a/2 degree tilt its spin axis is radically misaligned from its magnetic pole and our moon is comparatively large for a planet our size now a new theory may be able to explain many of these oddities it is called the grand Tak hypothesis four and a half to 5 billion years ago a gas giant planet arose inside a primordial disc of gas and dust Jupiter didn't just form where it is but formed then moved inward towards the sun as it spirals toward the sun Jupiter herds asteroids and rubble Jupiter's natural tendency is to drift in slowly through this debris field that it's traveling around the inner solar system is also thick with gas and dust the birth of our planetary system is well underway numerous worlds are born in this region including the earth primordial skies are ruled by chaos Jupiter's approach destabilizes these planets their orbits decay into wildly swinging ellipses some are tossed out others fall into the sun their numbers are unknowable these are ghost worlds from a bygone age Jupiter just causes all heck to break out in the solar system and all that debris in the outer solar system gets flung inward towards the inner solar system and it was a busy time in the very early solar system and since we were colliding with each other all the time and then it stopped Jupiter's invasion of the inner solar system is mysteriously halted the planet makes a turn or in sailors parlance a grand tack lurking behind Jupiter is a second gas giant Saturn so as Jupiter was migrating inward Saturn was following it and growing and as Saturn was growing it came to have a size that it had a gravitational impact on Jupiter which became more important than the gravitational interaction between the gaseous disk and Jupiter they reverse direction and in a sense you can think of Saturn and Jupiter feeding off one another and moving back out gravity tugs each passing planet this transfers orbital energy from one world to another all you have to do is exert a very subtle little periodic force at the right time and you can have amazing changes in the motion of the object you're pushing on once enough energy has been transferred the planets synchronize their orbits they are said to be in a resonance for planets resonances are achieved and maintained through the mutual push and pull of gravity through the fabric of space they're a key factor in the continuing evolution of our solar system this effect can be duplicated in the lab we have 10 metronomes here set up on a swinging platform they have little weights on pendulums here but they've all been set at the same frequency and I'm going to try to start them as best I can completely out of phase randomly so their oscillation is going to transfer energy by the swinging of this plastic sheet to the other metronomes that are out of phase to get into phase with the majority it's inevitable that there is going to be some majority group which starts out swinging more or less together and they are eventually going to win out just doing this as randomly as I can aha maybe in this corner I see four that are pretty closely synced yes now it's more like 5 6 now you have one that's almost completely out of phase every time the majority hits a beat it's going to give a little impulse a little push to the platform and that push is transferred to the metronome that's not in sync because the platform you can actually see this platform vibrating back and forth in sync with the majority of these metronomes working on this one we're pretty close to resonance right now as the metronomes achieve resonance it's important to notice how the platform shakes now it doesn't have to just be the force that's being transmitted by the plastic platform it could be a force at a great distance for example the force of gravity just these small little seemingly insignificant pushes building up over multiple cycles can have dramatic energy transfer that is how planets do it like the metronomes the two gas giants form a resonance we don't know exactly how long that took but we have some fiducial marks for timing in the solar system formation and that means that the grand tack had to have occurred relatively quickly talking hundreds of thousands of years perhaps 2 million years the two planets retreat until they reach their current positions the sequence of planets as we find them today is based on Jupiter and Saturn's orbits the planets eventually achieve a sequencing that many students learn through a mnemonic such as my very educated mother just served us nine pizzas was there a time when the mnemonic was scrambled seems very likely the answers yes not to mention a lot of additional letters were probably in there as well Jupiter's menace of the inner solar system is finally over if Saturn had not formed at the right time in the sufficient size Jupiter would have continued migrating in throwing out objects unfortunate objects in the inner solar system and ending up very close to the sun where it would stay yes the earth would be gone the earth would have had a terrifying encounter with Jupiter and would have been at its orbit changed dramatically to gosh knows what there is mounting evidence that earth had a terrifying visitor not Jupiter but another world Thea Thea was essentially another proto earth where there were a number of these objects flying around and Thea took time to grow just like the earth did they probably had rather similar histories and for one reason or another the orbit of Thea was perturbed such that it collided with the earth Saiya was this planetary body that was roughly the size of Mars and through this collision a lot of particles were ejected probably completely destroyed we don't really know how much of Saiya was preserved earth is rocked off its axis its surface liquefied chunks of Earth's mantle are shoved into space as a planetary body Thea ceases to exist its remains are absorbed by the earth and intermingled with the debris field a new planetary body is formed the moon further evidence is found in rock samples from the Apollo moon landings this is a sample from the moon if you can see it this was collected by the Apollo XV mission moon rocks contain isotopes identical to those found on earth when the moon arose it is first covered with a magma ocean people imagine the Luna magma ocean to be like this magnetic chamber I am describing but at the surface and covering the whole planet I see it as this ocean like the Pacific but this has to be like completely magnetic orange and like probably like fluxing around and probably moving conditions in the lunar magma are as hellish as we can imagine but a microscopic treasure forms in the magma crystal zircons these are the same gemstones used in jewelry but the zircons and the Apollo moon rocks yield a different treasure so the zircon are very important because we know they crystallize in this Rena magma ocean we know roughly when they crystallize in the Rena magma ocean so they are one of these old peas of the moon that we are looking for one of these old peas that we can use to date the origin of the moon zircons not only give the age of the moon they set a specific date for the collision the edge of the moon is 4 point 51 billion years old 4.51 billion years ago Thea becomes part of earth and forms the moon but the story is not over space probes measure the moon slipping 3.8 cm further away each year one day the moon will break free when that day comes there will be no more tides no more romantic moonlit nights could planetary orbits be inherently unstable could the chaos of planetary migration return oat Provence Observatory France it's here that a discovery from a far away star gives one of the biggest revelations about our own solar system the story begins when Swiss astronomers Dda Quello and Michelle Mayor notice something unusual about a star 50 light years away in the constellation of Pegasus everything about this star is ordinary a main sequence midlife yellow dwarf just like our sun but with one strange difference the star at Pegasus 51 is rocking back and forth it's a weird anomaly astronomers have never seen before they check their instruments everything is working including their new spectrograph a device that splits the starlight from Pegasus into rainbow colors hidden inside the colors are patterns of lines by tracking the day to day movement of these lines astronomers make a startling discovery Pegasus 51 has a planet but no one has ever seen a world like this it's half the mass of Jupiter yet it's extremely close to its star nine times closer than Mercury is to the sun the planet at 51 Pegasus must be inside the Corona broiling in temperatures over a million degrees Fahrenheit soon another planet is found around another star and then another and another astronomers have now confirmed over 3,700 exoplanets beyond our solar system nearly all of them are Jupiter class planets grazing their host star they're a new previously unknown type called hot Jupiters they're so numerous hot Jupiters challenge theories about the origins of planetary systems it's very difficult to make a planet close to the star because there isn't enough mass to build a giant planet very close to the star and there's gravitational frustrations for trying to build a planet very close to the star astronomy is shaken with a new revelation planets do not stay put where they're born when they're big enough they migrate it's a process called planetary migration and yet our own solar system has no hot Jupiter astronomers realize the Jupiter in our solar system was once on the move as well but its migration was halted by a resonance with Saturn Pegasus 51 shows where a planet lands when its migration is not blocked the strongest evidence for the grand Tak hypothesis comes not from our solar system but from exo worlds charted around other stars planetary migration is a universal concept we see it evidence of it out there in extra solar planets other solar systems there's no reason why planet migration shouldn't have operated in our own solar system music the New Horizons probe finds evidence for roving planets within our solar system while charting ancient craters on Pluto and on the surfaces of its moons the science team discovered many craters are the same age this suggests that they were formed by a single event even way out here tiny Pluto was smashed by a wandering planet the Pluto catastrophe may be related to other planetary migrations in the outer solar system it was noticed that the exact orbits of the giant planets particularly the outer giant planets the icy planets Uranus and Neptune can be explained by their migration outward there's a point in time about 3.8 billion years ago where Uranus and Neptune trade and it's because of what some of these mean motion resonance interactions that we were talking about earlier so this mean motion resonance involving Jupiter and Saturn and so forth just causes all heck to break out in the solar system Uranus and Neptune all of a sudden at 3.8 billion years they literally swap places and all that debris in the outer solar system gets flung inward towards the inner solar system the disruption in the outer solar system causes a new wave of violence astronomers call this epic the Late Heavy Bombardment much of the cratering we see on our moon today is from this period it may be possible that swapping orbits with Uranus is how Neptune got its moon today the epic of planetary migration appears to be over the solar system seems stable but what does the future hold computer simulations reveal what may be the greatest threat to the solar system in over 4 billion years it comes from a very special relationship between Jupiter and Mercury Mercury's orbit is slowly perturbed thanks to a subtle but constant gravitational nudge from Jupiter a new resonance like the one between Saturn and Jupiter that saved the inner solar system is forming between Jupiter and Mercury in 2001 computer models for the solar system were run 2,500 times they plug in the positions and the orbits of all the planets in the solar system in a computer and they just let it run through time through millions of years hundreds of millions of years billions of years to find out whether or not these orbits are stable change the location of one planet say Mercury by 1 millimeter and you find that that change will give completely different predictions about where everything is going to be millions of years in the future to see how quickly and easily things can change we have only to go back to our metronomes all I have to do is stop this platform from moving so that it cannot swing freely now there's no way for the metronomes to influence each other they're good metronomes but they're not perfect they can't be going at exactly the same frequency in the same phase and they're just going to fall apart because they have no way forcing the others to go to resonance the same applies to planets any small change can disrupt their harmony or restore it now that the platform is free to swing again it can again transfer energy and sync them up just like we saw the first time scientists want to understand the consequences of a destabilized planet Mercury in one case Mercury leaves the solar system the loss of its gravitational pull disrupts the balance of both Venus and the Earth Earth and Venus swap orbits the superheated atmosphere of Venus cools massive rains pour onto the face of the desert planet oceans arise the land cools and the air thins even the remains of an ancient visitor begin to cool off Venus becomes like earth but the reverse happens to the earth as earth settles into Venus's orbit temperatures rise the air becomes unbreathable glaciers melt oceans boil the sun looms larger in the sky only to be obscured by a thickening cloud cover suffering will be great but brief the entire 4 billion year pageant of life is cooked in a matter of days complete and utter destruction and elimination of all life on earth I'm not just talking about higher life I'm not just talking about civilization but everything a sterilization of the planet is something that I would want to think about a bit sterilized uninhabitable and quiet there is another possibility equally dark and apocalyptic a runaway Mercury is deflected by the gravity of Venus and barrels toward the earth it may be a frightening encore to the opening act of our solar system the equilibrium of the ages is over if this scenario is correct Mercury crashes into the earth just as they did 4 billion years ago the question is could it happen today or is it a fate far away in the future at a time when mankind itself is but a distant memory the problem is that even with a perfect computer that understands all of the laws of motion perfectly not just gravity but all the other subtle forces that go into it you cannot give it accurate enough initial information about the locations the masses the sizes the speeds of all of the objects in the solar system odds are we may never see such a calamity and yet among the billions of stars in our galaxy how many worlds are on the move how many will share this faith 2017 was a busy year for scientists of all sorts the professional and the enthusiast alike from a predictable astronomical rarity to surprise discoveries deep underground it was a year that saw long held beliefs challenged by newly found wonders and a glimpse 130 million years into the past in August 2017 alarm sounded at the most sensitive scientific devices ever constructed in Washington state the Laser Interferometer Gravitational Wave Observatory LIGO detected faint disturbances from deep space the signal also hit LIGO's sister facility in Louisiana gravitational waves had reached earth gravitational waves are ripples in space time space time is incredibly dense so to cause ripples you have to have some sort of object that has enormous gravity like a black hole or a neutron star and when these objects are rapidly accelerating they bend space time and create these ripples that then travel through the universe like the one last August the Lego team quickly reached out to Virgo and then as if by destiny to pave the way to a groundbreaking discovery just two seconds later with the Fermi Gamma ray Space Telescope that we call a gamma ray burst this alerted the entire astronomical community to the fact that something very exciting was happening using data collected from LIGO 70 ground and space based telescopes scoured the edge of galaxy NGC 4 9 9 3 some 130 million light years away from earth searching for a small flash of light amidst a sea of stars it would take less than 12 hours after the alarms rang at LIGO for earth to have visual confirmation of a never before seen astronomical event what we saw was the result of the merging of two neutron stars when they merged those ripples went out across the universe as gravitational waves and were detected on earth the matter involved gave off gamma rays and other forms of light neutron stars are the collapsed cores of massive stars left behind after a supernova explosion no larger than a mid sized city these dense stars have 10 to 60% more mass than our sun 200 miles apart were locked in each other's orbit for over 11 billion years but as they started accelerating and moving inwards their orbit quickened from 30 times a second to an astonishing and unsustainable 2,000 orbits a second then 130 million years ago they collided in a resounding explosion peering into the past telescopes were able to see the remnants of one of the universe's most impressive firework shows growing redder and duller as the days passed until eventually fading to black the conditions around these merging neutron stars have densities and temperatures the violent explosion was observed to have produced 200 Earth masses worth of gold and 500 Earth masses of platinum revealing for the first time the origins of heavy metals in our galaxy we think that all the gold in the universe was formed in explosions of this kind after the explosion happens the gold is spread out into the gas and dust of the interstellar medium later on that gas and dust collapses into brand new stars and brand new planetary systems and these weren't the first gravitational waves two separate events have been measured before including a pair of monstrous black holes that collided to form a single spinning hole 53 times more massive than the sun we received a perfect signal from this last merger it traveled 3 billion light years to get here in any given galaxy one of these events might only happen once every million years but we're now able to monitor about 10 million galaxies at a time it's a new type of astronomy but while we wait for gravitational waves that can open a window on the origins of our universe volcanic activity off the coast of Japan is presenting scientists with a picture of Earth's early history when land first rose from the seas violent eruptions spew a steady stream of lava and rocks expanding the newly emerged island of Nishinoshima but could resume at any time situated atop the junction of four tectonic plates the Japanese islands offer stunning insights about the formation of a variety of landscapes analysis of Nietzionoshima's magma shows it to be anaesthetic similar to the composition of continental crust monitoring the growth of nation ocean geologists hoped to learn more about the forces that LED to the birth of the world's eight continents yes not 7 8 in February 2017 the Geological Society of America published a startling paper Zelandia Earth's Hidden Continent Geologist Nick Mortimer was the lead author to discover Zelandia is to change the map of the world quite literally beforehand most people would say yes we got seven continents but now the world maps change and we got an eighth one on there in the beginning there was no search for Zealandia Mortimer and his team discovered the shallow submerged continent while performing geological work aboard a research vessel off of New Zealand's coast and so what the various geological investigations have LED us to is that we do have the components of a continent here when you pull a plug on the world's oceans you literally reveal the continent of Zelandia Mortimer and his team confirmed four geological markers a varied geology or diversity of rock types a thick crust and ultimately size is it big enough corroborating data include rock samples ocean drill cores and satellite microgravity measurements or elevation maps of the sea floor situated between the Pacific Plate and the Australian plate tectonic forces squeezed Zeelandia raising out of the water what we know today as New Zealand with 94% of Zealandia underwater the islands of New Zealand and New Caledonia are just the tip of this continental iceberg in measuring in at 4.9 million square kilometers Zealandia is six times bigger than the so called microcontinent of Madagascar and more than twice as large as Greenland to understand Zealandia's origins we must travel back in time to the time of the supercontinent Gondwana Antarctica and Australia when Gandwana split apart 80 million years ago it was a bit like the stretching of bread dough in a kitchen and if you pull slowly some of those pieces will stretch and get thinner just like sealandia which broke off and slowly sank it's not as thick as the main continents but it is thicker than the ocean crust and geophysics know that when you have thin crust it floats lower in the mental and that explains in very simple terms why is the land here is so submerged we do hope to consolidate it and to promote Zelandia in New Zealand schools first of all and we hope to get in atlases on globes we hope that Zelandia will become as common and well known can only help its name recognition could be hidden for so long I think captured people's imagination of course not everything that's undetected is so obviously obscured and one remarkable discovery this year offers clues about how some prehistoric creatures could hide in plain sight in northern Alberta Canada is providing the world with an unprecedented look at a new species a fossil so pristine and complete that it shows the texture patterns and color of a prehistoric giant the Dinosaur is the best specimen we have and it's the closest you'll come until we find a better one in terms of coming face to face with a Dinosaur the Notosaurus next to surreal a petrified beast caught by Medusa's gaze we knew it was good I think it's the best preserved armored Dinosaur in the world I'm calling this the Rosetta Stone for armored dinosaurs the anatomy of the new species has already given scientist clues to how these animals evolved how they radiated and diversified through time and it doesn't stop there the skin is preserved it's not just the impression of the skin we actually have some of the original biomolecules preserved one of the cool things that they tell us for this specimen is that the animal had at least a component of reddish brown pigment to its skin the coloration aspect is very exciting so it's cool to know what color it was when that has implications for how the animal lived researchers believe the notosaur was darker on the back a method of camouflage called counter shading now keep in mind this was a five and a half meter long 10 and a half animal covered in armor but it still has camouflage and to us that just illustrates how intense the predation was back in the Cretaceous you had these very large meat eating dinosaurs and they would have also been very visual predators so it actually kind of just shows you how extreme that ecosystem likely was back in the Cretaceous the plant eating slow moving beast only stood a chance because of its impenetrable coat of armor we see three rows of osteoderms those are what are called cervical rings and it's armor that would have protected the neck of the animal and as we move to the side we see this giant periscapular spine coming off the shoulder and it's about half a meter long and the spectacular specimen still has many secrets to unveil the next focus of study are the contents of the Notosaurus stomach in addition to having skin preserved all over most of the surface of the animal we also have abundant gut content so the last meal of the animal preserved inside and this is what that stuff looks like geochemical work histological work and CT scanning trying to figure out what these spheroid structures are and there's been many ideas that part of the diversification of dinosaurs and it would be great to see exactly which types of plants this guy was eating and if that hypothesis makes sense we know what dinosaurs ate how they fought and now what they looked like but there are still many questions to be answered and Alberta might just be the place to find them it's estimated that there are thousands of fossils hidden underneath the earth but when a Six Mile wide asteroid struck the Yucatan Peninsula 65 million years ago dinosaurs had nowhere to hide and the resulting global cataclysm of earthquakes firestorms and tsunamis ultimately LED to their extinction some animals however manage to survive but have since its discovery in 1978 investigations of the asteroids impact crater include data from seismic images and recently collected core samples from deep within the site at Chicshaw the data paints a devastating picture of destruction and LED scientists to create a broad new survival theory focusing on habitat and diet adaptability when dinosaurs perished and a vast new eco space emerged the surviving species expanded rapidly to fill it this is called adaptive radiation a recent study shows that one out of 10 frog species descend from the original three frog species that survived the cretaceous tertiary extinction event frogs were able to escape extinction for a number of reasons they live in an aquatic habitat that offered Protection eventually when vegetation returned they were able to diversify worldwide and adapt to new lives in trees birds too exhibited the same adaptive radiation around the same time which survived the event warm blooded birds feathers insulated them from temperature extremes their small size and ability to fly allowed for easier and their diet of seeds worms and insects gave them the edge after much of the earth's surface plant life had died in the end the ability to adapt to changing conditions including our smallest mammal ancestors as we confront the challenges of climate change the city of Miami Beach already knows what it means at certain times of the year known as king tides these events are clear evidence of incremental increases right now we are definitely witnessing sea level rise impacts these high tide flooding events that are growing in severity more often deeper more widespread that's sort of a pattern that we expect will continue that means huge financial costs another predicts two and a half million Miamians could become sea level refugees and leave the area it's not only Miami all around the world sea levels are expected to rise the question is by how much in adopting a multi pronged approach Miami Beach has committed 400 to 500 million dollars to combat sea level ice building water pumps and raising their defenses and sea level rise we're seeing an increase of water level every year we had to make changes we put a boardwalk initially to give some height but we found that that wasn't protecting the city what we've done here is we've increased the levels of our new sea wall the new wall you see in the background here is our new standards this was good for approximately another 50 years and we're going to see water levels challenging even that new sea wall raising its elevation Miami Beach seeks to stay dry and take control of its future the city's philosophy our culture is rising above we believe that we can meet the challenge and the challenge is not only in rising above meaning elevation it's rising to and withstanding the challenges that come with sea level rise due to climate change I have complete faith that we can we can mitigate we can survive of course the Earth's oceans have risen and fall in many times during the planet's history and new archaeological evidence suggests these shifting shorelines may conceal clues about the earliest Americans until just recently that the earliest people to populate North America were the Clovis people dating back to some 12 to 13,000 years ago but a group of scientists in San Diego California have a different theory we have the bones the fossils the distribution we have evidence for humans in North America 130,000 years ago we realize that that is a startling claim is struggling with the idea that humans arrived in North America 130,000 years ago the study of early humans in the New World has been very political and very controversial for over 125 years it's an old mystery yet to be solved welcome and thank you for joining us this morning at the San Diego Natural History Museum well back in 1992 which involved adding a couple new travel lanes and Richard Seruti whose field paleontologist here at the museum was monitoring excavations and saw this little puff of let's say tusk material being scraped up by an excavator and said stop let's let me go look at this that's one tooth and it's characteristic of American acid 130,000 years ago the answer may lie in the position of the bones and tools found at the site there are anomalous fragments of rock anomalous flight fragments of tooth enamel scattered throughout the site that just don't make sense have been in early form of primitive tools we felt that it was important to produce a map where we carefully plotted or precisely plotted the position of all the bones and the stones or whatever else is in there so that we can understand what the general pattern is found with the mastodon bones were used for butchering the animal so this is one of the cobbles that we hypothesized was used as a hammer stone 130,000 years ago where there was a carcass of a Macedon these people were trying to recover raw materials from it they had a problem how do we break these bones they look over into the active river channel find some cobbles of the appropriate size and weight bring them back to the site and if you look closely there's some striations coming off of that that are indications of where this flake has come off the cuts in this rock LED the San Diego team to conclude that these were actually tools used by humans an idea that Demir says might not be so far fetched Dr Stephen Holand is co director of the center for American Paleolithic Research in South Dakota he was part of the team that evaluated the findings looks like vertebra that does I said I can't get my mind around this this site has to be really really old but here's evidence of humans I said it goes against everything I thought I knew and the stone tools recovered from the excavation site we would take the drawers out of the cabinets in here paleontologists and archaeologists together Richard Cerutti came in so there were four of us my wife Kathleen Tom and I and we would look through and we would look for these very diagnostic pieces and one of the things that we got all excited about and based on the experiment that we'd done in Africa breaking an elephant femur with a big hammer we saw the same kinds of fracture patterns that we did experimentally Poland specializes in evaluating broken bones looking for human causes as this video shows from a test he conducted in Africa two years prior to working on the San Diego project oh my god this one explanation that explains all the data was that humans did this the detective work by the San Diego Natural History Museum team was capped by the age dating that Richard Ceruti had done to prove the age of the mastodon bones he discovered this is one of the specimens that he and after analyzing over 100 microsamples from this specimen and two other specimens of bone from the site yielded an age of 130,000 plus or minus 9,000 so after the article came out critic come out to say that the dating is incorrect in fact other specialists in uranium series dating have come out and said the dates look perfectly good while humans arrival in the Americas may have occurred earlier than previously thought new dating of another paleontological find found in a South African cave could soon upend long held theories about the evolutionary tree of primates and early humans when we actually got into the chamber and could start removing it we realized that not only was there one individual line there on the surface but the floor was literally comprised of homeland already there are thousands and thousands and thousands of remains down in those chambers and there they are so the first time into the open area where the chamber is and sort of started looking around you know you're only wearing a headlamp so you just see flashes but every flash of my headlamp showed bone I realized that we had a lot more than the original photographs actually had portrayed so that was pretty exciting ominolae isn't really similar to any known hominid species in its entirety of its package you've got little bits and pieces of almost everything we've ever found parts of the skull if you just look at it quickly look a little bit like Homo erectus got a very small brain other parts of the skull look very modern like Homo sapiens it gets stranger and stranger as you move down the body you get the ape like shoulders you get these more and more human like arms which end with a hand I was actually at the London Natural History Museum and Oman Alade was on the wall and then there was an estimated age between 1.2 and 1.8 million years of those teeth this is when scenes got very interesting because then we got an age of 200 to 300,000 years old when we got a date much younger than that a quarter of a million years give or take we realized that we were dealing with a primitive creature almost like a time traveler that had come down from deep times to a point where it is very possible that tomonally was in direct contact with the emergence of modern humans we never thought that was possible in Africa until this moment we thought that there was effectively during that entire time period of the Middle Pleistocene late Middle Pleistocene one form a big brain form of Homo sapiens now there are two and that adds incredible complexity to our record the world of Homo noletti and other early humans was different than it is today teeming with life pure and free from pollution few places like this still exist but look just a few feet underwater scientists recently Learned that seagrass meadows help scrub the surrounding water clean of bacteria from raw sewage and other pathogens a recent study of polluted waters in Indonesia showed levels of harmful bacteria to be 50% less in spots with robust sea grass beds leading to healthier fish and coral in the surrounding area trap sediment that might otherwise float freely and host tiny microbes that kill many harmful bacteria eliminating toxins improves the health of any system and the workings of a human body is no different in athletics a nod to the physical effort required to increase endurance and enjoy the health benefits of exercise but new pharmaceutical research also aims to make those benefits more easily accessible in the way in which you normally get tuned up by exercise could have really dramatic effects playfully known as the exercise pill the experimental drug shifts metabolism by triggering genetic instructions for the body to burn fat instead of sugar during exercise something that doesn't normally happen until after extensive training and conditioning recent tests increased the endurance of otherwise sedentary mice which also proved to be resistant to weight gain while on the drug we have two groups of mice and one group on the drug without the treatment of the drug so we were quite surprised to see the astonishing results the mice treated with the drug they can run almost 100 minutes longer than the one that are not treated the increase was around 70% researchers ultimately hope their product can improve the health of the disabled elderly and obese there are many reasons why people can't either walk or run or exercise and the idea is you could really help a lot of people from energizing our bodies to powering societies so we are just waiting for the next experiment it's going to happen in 10 seconds there you go you see the flickering of the plasma we are creating fusion here this is our little sun it's extremely hot each day every 20 minutes generating temperatures these nuclear fusion trials the joint European torus a donut shaped plasma containment vessel at this point we're the most important experiment in the world thanks to jet right there's heavy hydrogen and the super heavy hydrogen they bang into each other with immense speed what we call the strong force which binds the nucleus of atoms together grips them pulls them together and they make helium and they spit out a neutral fusion really is the perfect way to make energy and yet despite fusion's transformative potential to provide safe and sustainable energy to the world the program faces an uncertain future while the British government committed to pay for its share of the experiments up to the year 2020 Brexit its planned departure from the European Union may also lead to the UK's withdrawal from scientific agencies like the European Atomic Energy Community some say this could jeopardize jet logistics and operations next generation fusion experiment currently being built in southern France harnessing the physical power of the sun a moment of darkness reflected its emotional power an all induced euphoria experienced by millions as the first total solar eclipse over North America in three decades made its way across the United States it's the most unnatural natural phenomenon I ever saw this is a solar eclipse and just what people witnessed on August 21st along a 70 mile wide path first along the Oregon coast at 10:00am Pacific Daylight Time and last in South Carolina 94 minutes later the uncommon coupling was the most viewed and photographed eclipse ever recorded some earthly domains remained as always far removed from its rays like the cave chambers 300 meters below Mexico's Nika mine enormous razor sharp crystals dwarf human explorers while today the king was totally submerged previous expeditions collected bizarre life forms they call this place hell on earth with over 80% humidity even with life saving bodysuits no visit can safely last longer than a half hour yet deep within this extreme environment are life forms which exist nowhere else NASA astrobiologist Penny Boston and her team some dormant but alive estimated to be between 10 and 50,000 years old including genetically unique any extremophile system that we're studying and we add it to this atlas of possibilities and where to find it Boston's findings could impact the search for life beyond our planet on places like the proto planet Ceres and one of the scientific targets of NASA's Dawn space probe and in February of 2017 startling and unexpected news began coming in my colleague found a spectral signature in her data that is consistent with or the same signature of allophatic hydrocarbons so here we're finding maybe the building blocks of biological material seen here in red the organic materials are thought to have originated in the dwarf planet itself also revealed evidence of water and volcanic activity no longer considered a barren rock however Dawn isn't the only NASA spacecraft uncovering new surprises about our solar system seven months after the Juno explorer became fully operational in February of 2017 astonishing researchers with the steady stream of images and scientific data it's sending back to earth Jupiter is by far the largest planet in our solar system and although it is the second brightest planet its formation and composition have left us in the dark previous NASA missions have given us some understandings of its moons small dust rings and atmosphere but we've not been able to see past the Van Gogh like swirls of dense red brown yellow and white clouds that paint the planet at least not until now each individual image is all inspiring especially those captured when Juno came within 5,000 miles of Jupiter's Great Red Spot the planet's most famous storm pouring over data from Juno's microwave radiometer scientists hope to learn more about what powers the tempest and how it differs from other Jovian storms this critical instrument measures six distinct ranges of Thermal radiation as it peers more than 300 miles beneath Jupiter's clouds to create a three dimensional model of Jupiter's atmospheric environment so the first time we're looking inside of Jupiter into the interior is that it doesn't work at all like we had predicted almost every model that has the interior motion how the magnetic field the gravity field how the deep atmosphere works below it there lies a 13,000 mile layer of swirling hydrogen and helium that changes states from gas to liquid as it nears the center if we can probe it and work out the abundance of elements in it hydrogen helium the higher elements as well and work out roughly what that mix is it'll tell us something about not only how Jupiter was formed but how the solar system might form if there is a bunch of rocky material in the center of Jupiter it means that in the early solar system before Jupiter form that rocky substances were probably coming together and Jupiter got built around those it could be that Jupiter was built without any of those and that it just collapsed sort of like the sun and there is no rocky material or core of heavy elements in the center gravity data collected so far points to a new possibility a somewhat larger than previously thought and perhaps partially dissolved core leaving Jupiter experts with more questions than answers we're putting the pieces of the puzzle together and it's exciting but we don't have the whole picture yet is scheduled to continue until February 2018 but this past year NASA saw another of its extraordinary explorers come to the end and we are in the atmosphere as the Cassini space probe plummeted into Saturn's atmosphere roughly 1 minute to loss of signal the culmination of the craft's revolutionary scientific quest Colossal Signal at 1 1 5 5 4 6 the signal from the spacecraft just gone congratulations to you all and you're all an incredible team she has rewritten the textbooks about Saturn the rings the moons Titan so many things have changed because of Cassini the Cassini Huygens mission has unveiled some amazing discoveries Saturn is ablaze with storms of unimaginable force the place crackled with giant lightning strikes the rings are even more dazzling than imagined they're made of particles of pure water ice so there's this beautiful cosmic dance going on inside the rings Cassini also carried a little lander called Hoygens which became the first probe to land on a moon other than our own because of its atmosphere we just saw more and more haze and fog until finally the probe broke through that haze for the first time next Cassini had Cassini then captured giant jets of water from the tiger stripes shooting out at 12 miles per hour vaporizing and then freezing back on Earth quickly reprogrammed the probe to fly right through the jets collecting particles and what they found was even more organic molecules the basic building blocks of life Enceladus is really special it's giving us free samples because the geysers are erupting wherever there's liquid water whether it's deep in the ocean and very hot or in rocky places or in ice there's microbial life so it certainly suggests microbial life could have evolved on encelaus because it has all the properties that the earth had when life began here NASA controllers plotted the probe's deadly descent productive until the end Cassini relayed detailed information and then she burned like a meteor and vaporized scientists will build on Cassini's contributions within our solar system and beyond perhaps around the star system 39 light years away the first place found NASA announced to have multiple planets three here circling a single star where liquid water can exist well with this discovery we've made a giant accelerated leap forward in the search for habitable worlds the Trapus 1 system has really captured our imagination because with this amazing system we know that there must be many more potentially life bearing worlds out there earth like in size and temperature these three far away worlds suggest endless possibilities the discovery gives us a hint that finding a second earth is not just a matter of if but when these questions about are we alone are being answered as we speak in this decade and the next decades so I'm really excited about this it's been an astonishing year for sure and as our universe reveals more of its secrets far out in space and closer to home 4.6 billion years ago our sons started to form about two thirds of the way out on one of the spiral arms of the Milky Way our sun is a third generation star starting from gaseous clouds and dense nebulae containing many heavy elements it condensed under the inexorable pressure of gravity until it was hot and dense enough to experience nuclear fusion at its core as stars go our sun is an average yellow star but it is so massive that it contains 99.8% of all the mass in the solar system its radiant energy supports almost all life on earth and it drives Earth's climate and weather it is almost 900,000 miles in diameter it has a core temperature of about 15 million degrees and a surface temperature of about 6,000 degrees the sun will be fairly stable over the next 5 billion years at which time it will enter its red giant face it will expand enormously so that its outer layers will reach the current orbit of earth giving it a diameter of almost 200 million miles after that it will live a few billion more years as a white dwarf Mercury is the smallest planet in our solar system it is only about 3,000 miles in diameter and has a surface that is pop mart with craters like our own moon this is the innermost planet and has an elliptical orbit that takes it within 28 million miles of the sun at its closest approach and out to 43 million miles at its most distant it takes Mercury 88 days to orbit the sun and figure this out sports fans although it rotates once every 59 days the day on Mercury is 176 Earth days long oh it doesn't really have a tail we added the one in the video to make it easier to see and to show its orbit and although the scale is correct for the size of the sun relative to Mercury's orbit we are showing the planet 100 times larger than it would be if it were to scale as well except for the sun and the moon Venus is the brightest object in the sky and since it is closer to the sun than we are it shows phases like the moon shrouded in permanent clouds Venus rotates on its axis every 243 days and it rotates backwards from the other planets it is only slightly smaller than the earth and it orbits the sun every 225 days at a mean distance of 67 million miles but its surface is terribly inhospitable the atmospheric pressure at the surface is 92 times that of the earth similar to the pressure at half a mile down underwater its temperature is a bombing 900 degrees Fahrenheit all in all not a good vacation spot our earth is 8,000 miles in diameter and rotates on its axis causing sunrise every day it is the largest of all the planets that have a solid surface and it possesses an unusually large moon or planet of its size since the moon circles the earth we think of the moon's motion as circular but since the Earth moon's system revolves around the sun at about 65,000 miles per hour the moon's motion in the solar system isn't much different from our own at 93 million miles from the sun the earth is the third innermost planet and is the only place in the solar system that we know of that has liquid water Mars is the planet most similar to earth in terms of habitat although smaller than earth and Venus it has a thin atmosphere and probably had liquid water on its surface in the past this attracts our interest and has prompted us to send a plethora of probes it has two orbiting irregular shaped rocks graciously called moons which are probably captured asteroids a day on Mars last about 24 hours very comparable to our own the volcano called Olympus Mons or Mount Olympus is the highest known mountain in the solar system it is an extinct volcano and is over three times the height of Mount Everest Mars is a fourth planet from the sun and completes its orbit every two earth years Jupiter is huge if it had only been a little larger it could have become a brown dwarf star circling our sun it is a gas giant and has no solid surface its atmosphere forms bands of poisonous clouds that circle the planet in opposite direction the giant red spot is a huge storm that has been raging for hundreds of years four of its mini moons are so large that Galileo spotted them with his primitive telescope in 1610 in addition to moons all of the gas giants have rings but Jupiter's rings are so faint they are not visible the fifth planet out Jupiter orbits the sun at a distance of 480 million miles and takes almost 12 years for one complete circuit notice the large separation between the orbits of Jupiter and Mars this is the realm of the asteroid belt it is the debris of a planet that failed to form because of Jupiter's gravitational influence Saturn is the second largest of the planets only Jupiter is larger like all the gas giants it has a system of rings and the rings of Saturn are glorious like Jupiter Saturn also has dozens of moons and one of them is particularly notable Titan is the second largest moon in the solar system and it possesses an atmosphere remarkably like Earth's it is primarily composed of water ice and rocky material it is even possible that under the clouds and surface ice Titan has liquid water and maybe even microbial life it is 50% larger in diameter than our own moon and 80% more massive Saturn takes 29 years to orbit the sun and does so at a distance of 890 million miles Uranus rolls on its side it is an icy giant of a planet the third largest in the system like the other giants Uranus has a ring system and numerous moons it is the seventh planet out and it orbits the sun at a distance of 1.9 billion miles a year on Uranus last 84 Earth years because of its extreme axial tilt seasons on Uranus are worth a look at the time near the solstice one pole continually faces the sun while the other faces away only a narrow strip near the equator experiences Uranus is 17 hour day at the other side of Uranus's orbit the orientation of the poles is reversed so each pole gets 42 years of continuous day followed by a 42 year night okay let's head to a point high over the ecliptic so we can see the relative sizes of the orbits of the sunward planets Neptune is a blue world it is the smallest of the giant planets in our system but still 30,000 miles in diameter since the demotion of Pluto it is the furthest planet from the Sun Neptune's rings are very faint and of its 13 moons only Trident is massive enough to be round it rotates every 16 hours and orbits the sun every 165 years at a distance of 2.8 billion miles Pluto is now deemed a dwarf planet and a member of the Kuiper Belt the Kuiper Belt is a region of the solar system that extends just beyond the orbit of Neptune at about 2.8 billion miles out to about 5 billion miles like the asteroid belt it is crammed with many small bodies orbiting the sun most of which are frozen methane ammonia and water here's a size earth Ganymede Titan our moon and several bodies from the Kuiper Belt currently the largest known Kuiper Belt bodies are Eris Pluto Sedna and many more without formal names like FY9 and EL61 a day on earth is a deceivingly simple concept today we'll examine that day on earth in detail perhaps uncovering a few surprises a day is a length of time takes the earth to spend 360 degrees on its axis or is it 361 here is a simple model showing the earth the sun and some background stars the earth travels around the sun in an ellipse with the sun at one focus the model of course is not to scale let's begin our examination at noon one day the sun is directly above the red line that will be our reference point watching from a high Vantage point we see the earth complete 360 degrees of rotation but during that time the earth has also moved a bit in its orbit so even after a 360 degree turn the sun is not directly above the same point on earth that it was at the beginning of the spin it is not noon of the next day the red reference line needs to spin a little more than 360 degrees to get us to noon the 360 degree rotation is called a sidereal day while the noon to noon rotation is called a solar day earth orbits the sun once for about every 366 point 26 Siberia days and once for every 365 point 26 solar days not only that the length of the solar day varies throughout the year and for two different reasons first because of its orbit is an ellipse and not a circle the earth moves faster when it is near the sun and slower when it is further from the sun so the little extra amount of rotation that the earth needs to do to get from noon to noon changes throughout the year second because the earth is tilted on its axis the little extra rotation to get from noon to noon is largest at the solstices and smallest at the equinoxes so solar days grow progressively longer as we move from equinox March and September to solstice June and December and did we mention the Earth's spin is slowing down and the length of the solar day is increasing due to gravitational tides between the earth and the moon the length of the mean solar day is increasing at a rate of approximately 1.4 milliseconds every century two billion years ago there were about 750 days in a year now let's talk about daytime that period out of 24 hours when it is light outside day versus night due to refraction and scattering of light by the atmosphere there can be daylight even when the sun is slightly below the horizon but day length is usually about the sun's disc being on or above the horizon so the day begins the moment the sun's disc appears during sunrise and ends the momentha sun's disc disappears during sunset at the equator daytime and nighttime are equal to within a few minutes but it distances north and south of the equator the length of the day varies with the season with the longest and shortest days being on the solsticist at the poles once the sun has risen it stays up for six months before it sets again and during the course of each day it travels in a complete circle around the edge of the sky because the earth travels at different speeds in its orbit the sun is north of the equator for almost four days more than half a year and the length of the average day in the Northern Hemisphere exceeds the length of the average day in the Southern Hemisphere by a few minutes in the Northern Hemisphere the Arctic Circle is the southernmost latitude where 24 hour daylight can occur at least one day in a year in the Southern Hemisphere the Antarctic Circle is the northernmost latitude where 24 hour daylight can occur at least one day in a year and daylight savings time is like the old man who cut off one end of the blanket and sewed it on the other end to make it longer a year on earth is measured by one complete trip around the sun seems simple enough but there is a problem the earth doesn't travel on a path around the sun that returns to its starting point so how do we know when a year starts or ends well one way called a sidereal year measures our orbit against the distant stars as viewed from the earth our orbit causes the sun to appear to move through the constellations of the zodiac on a path called the ecliptic and when the sun returns to its starting point a sidereal year has passed this motion is difficult to observe directly because the stars cannot be seen when the sun is in the sky however if you look at the sky before each dawn the annual motion is very noticeable the last stars seen to rise are not always the same and within a week or two an upward shift can be noted as an example in July in the Northern Hemisphere Orion cannot be seen in the dawn sky but in August it becomes easily visible measuring a year this way gives a period that is 365 days 6 hours 9 minutes and 10 seconds long another possibility is to measure the year against the passing of the seasons because of the tilt of the earth on its axis the position of the sun in the sky changes from day to day throughout the year if we were to take a picture of the sun at noon regularly throughout the year we would see the sun moving on this path called an analymal on the days in its orbit when the earth is at a maximum tilt towards or away from the sun the length of the dayline is at a maximum or a minimum these days are called solstices and the sun will be at the top left or bottom right of the analyima on the days when the Earth's tilt is perfectly sideways to the sun the day and night are equal in length these are the equinoxes and the sun will be at a latitude dependent position in the analemma when the sun goes from one vernal equinox to the next a tropical year has passed measuring this way gives a year that is 365 days 5 hours 48 minutes and 46 seconds long the length of a year on earth is affected by several gradual and cyclical changes in its orbit and its tilt first there is the procession of the Earth's axis over a period of about 26,000 years the Earth's axis traces out a circle in the sky one result of this is that the North Star changes over time right now the earth axis points towards Polaris 5,000 years ago the axis pointed to a star in the constellation Draco and 12,000 years ago the brilliant star Vega was the pole star and because of the 26,000 year cycle Vega will be the pole star again in 14,000 years the procession of the equinoxes is caused primarily by gravitational forces of the sun and the moon acting on the earth while the axial tilt is the primary cause of seasons on the earth the distance from the sun which changes throughout the year because of the elliptical shape of the Earth's orbit contributes a small bit of temperature variations throughout the year as well when the axis is aligned so it points towards the sun during perihelion one hemisphere will have a greater difference between the seasons while the other hemisphere will have milder seasons the hemisphere which is in summer at Paleon will receive much of the corresponding increase in solar radiation but that same hemisphere will be a winner at aphelion and have a colder winter the other hemisphere will have a relatively warmer winter and cooler sunlight when Earth's axis is aligned such that aphelion and perihelion occur near the equinoxes the northern and southern hemisphere will have similar contrast in the seasons at present perihelion occurs during the Southern Hemisphere summer an ap helium is reached during the summer and winter so the Southern Hemisphere seasons are somewhat more extreme than the Northern Hemisphere seasons when other factors are equal in addition the gravitational effects of other planets cause the ellips of our orbit to slowly spin around the sun it takes about 112,000 years for the ellipse to revolve once relative to fix stars when considered together the two forms of procession add and it takes about 21,000 years for the solstice to go from aphelion to aphelion the dates of the perihelion and the apilion advance each year on this cycle an average of one day per 58 years the eccentricity of the Earth's orbit is a measure of how round or how oval the orbit shape is over thousands of years the eccentricity of the Earth's orbit varies as a result of gravitational attractions among the planets primarily Jupiter and Saturn the orbital eccentricity cycles with a period of roughly 100,000 years as the eccentricity of the orbit evolves the semi major axis of the orbital ellipse remains unchanged so the length of the sidereal year remains unchanged as the earth travels in its orbit the duration of seasons depends on the eccentricity of the orbit when the orbital eccentricity is extreme the seasons that occur on the far side of the orbit are substantially longer in duration in addition to axial procession there's the axial tilt the angle the Earth's rotational axis makes with its orbital plane it is currently about 23.4 degrees and is declining this tilt varies from 22.1 degrees to 24.5 degrees it makes one complete tilt and back every 41,000 years this change in tilt is directly related to ice ages on earth the last maximum tilt occurred in eighty seven hundred BC and the next minimum tilt will happen in 11,800 ad the inclination of Earth's orbit drifts up and down relative to the present orbit with a cycle having a period of about 70,000 years and the orbit also moves relative to the orbits of other planets as well by calculating the plane of unchanged total angular momentum of the solar system we can define the orbital plane called the invariable plane it is approximately the orbital plane of Jupiter the inclination of the Earth's orbit has a 100,000 year cycle relative to the invariable plane this 100,000 year cycle closely matches the 100,000 year pattern of ice ages a year on earth is directly determined by all the various orbital motions of the earth so if someone tells you how many years old they are you might ask them is that sidereal tropical or anomalous shears want to see something really big well watch this our starting point is our own moon we've seen men walk on the moon and it's pretty big but even the smallest planets are bigger here are Mercury Mars Venus and earth and the gas giants in our solar system are huge in comparison your Neptune Uranus Saturn and Jupiter and of course our sun makes even Jupiter seem small but let's look at some really big stars here's Sirius and Pollux and art tourists and all the Baron and Rijal and and and Terry and Beetlejuice and the largest star we currently know about is VY Canis Majoris on this scale our sun would be one tenth the size of the tiny little dot you see to the left we know mass distorts space we know light is affected by gravity and we know Einstein's theory of general relativity makes possible one of the strangest objects ever imagined by physicist if you could create a large enough distortion in space time by placing enough mass in a small enough space you could create a region space time so strongly curved that nothing not even light could escape it and since nothing can travel faster than the speed of light anything that entered this region of space time would be trapped there until quantum mechanical effects allowed it to escape black holes can come in any size and have any mass all that is required is that enough mass can be concentrated to the point where it collapses under its own gravity stellar mass black holes are formed when stars 20 or more times the size of our own sun finally run out of fuel in their cores they rapidly cool and collapse and the shockwave from the collapse blows the outer layers of the stars to bits in a colossal explosion called supernova but the small dense core of the star can remain bound together by the force of gravity as it continues to collapse inward under its own weight the atomic particles of the core are smashed together until all that is left is a black hole in its center lies the singularity the mass of an entire star crushed into a single point in space surrounding that is an invisible shell called the event horizon this is the cosmic point of no return once inside the event horizon nothing not even light can escape except through quantum mechanical processes supermassive black holes may contain billions of times the mass of our sun these monsters lie at the center of every large galaxy micro black holes have tiny masses at which the effects of quantum mechanics are very important black holes of this type have been proposed to have formed during the Big Bang and would quickly evaporate due to said quantum mechanical effects at the end of their life it is believed that they would emit a sudden burst of energetic particles but no such burst have been detected as of 2008 we can never see into or directly know about what happens inside the event horizon of a black hole in effect any object that crosses this imaginary line has left our universe for good but if nothing not even light can escape a black hole then how do astronomers manage to detect them it is possible to imagine spotting a solitary black hole by observing the bent starlight from behind it but a better chance of detecting one would arise if they were not alone in space but accompanied by another star this black hole is drawing matter from a companion star which orbits it at a distance safely outside the event horizon as the gas spirals into the black hole it heats up and emits huge quantities of high energy radiation intense radiation emerging from a small area or stars orbiting small invisible companions these are tail tail calling cards of a black hole twelve and a half billion years ago the universe was littered with the remains of first generation stars and billions of second generation stars were born from these clouds small groups of these new stars were drawn to each other gravitationally and merged to form ever larger and larger groups our own galaxy The Milky Way is an example of a spiral galaxy born in this early era today it contains about 200 billion stars and is still growing as it absorbs small neighboring clusters of stars the center of our galaxy is in the direction of the constellation Sagittarius and like most large galaxies there is a monstrous black hole at the center the disc of our galaxy is about 100,000 light years across and on average is only about 12,000 light years thick our own sun is a third generation star and is located about two thirds of the way out on the spiral arm named Orion we are about 26,000 light years from the center The Milky Way is a member of a group of 20 or 30 galaxies and star clusters called our Local Group the largest galaxy in this group is our sister spiral galaxy Andromeda is it possible for distant galaxies to be moving away from us faster than the speed of light and if it is would it be possible for us to see them surprisingly the answer to both questions is a resounding yes how is that possible how can something travel faster than the speed of light today we will try and paint an accurate picture of the universe based on the Lambda cold dark matter model which is the best cosmological model today once we have painted that picture the answers to our questions will be straightforward let's assert that some kind of space time quantum foam sort of something existed before our own universe began before our Big Bang then we simply let Heisenberg's uncertainty principle go to work for us if we look at the tiniest spec allowed by quantum mechanics a small volume with a plank length as its linear scale the spec would have a volume of 10 to the minus 99 cubic centimeters and the largest amount of mass or energy that we could put in this volume without it becoming its own black hole is about 1/100,000 of a gram interestingly the uncertainty principle allows this much stuff to be created out of nothing for as long as 10 to the minus 43 seconds not a very long time but it will prove to be enough because if that much energy is created in the form of a certain type of scalar field then we have just successfully created a universe the best model of how our early universe grew after that initial quantum fluctuation created it includes inflation a period when the scalar field divides space into a brief period of extreme exponential expansion during an inflation space erupted from its tiny beginnings into an unknowably huge volume this enormous expansion generated an enormous amount of gravitational binding energy at least 10 to the 85th grams and this was counterbalanced by a corresponding group of positive energy in the scalar field what began as a mere fraction of a gram of energy has now become 10 to the 85th grams this is a huge number large enough to account for all the matter and energy that exists today but notice that the total energy in the universe is within a quantum fluctuation of equaling zero as a byproduct of the enormous growth of space during the inflationary period tiny quantum fluctuations grew into macroscopic fluctuations in the density of the scalar field making it ever so slightly lumpy this lumpiness provided the seeds for the formation of stars and galaxies and all the structure we see in the universe at the end of inflation the temperature throughout all of space was still enormously hot but as space continued to expand it cooled and the energy of the scalar field which now filled all the new and enormously huge volume of space decay into dark matter and dark energy and normal matter the photons and quarks and electrons which in turn settle down into the protons neutrons and atoms that populate the universe today after about 380,000 years of expansion and cooling charge particles got together to form neutral atoms and suddenly the photons that were bumping into charge particles every second or two we're free to zip unhindered across space this is the origin of the cosmic microwave background that we see today let's let this volume of blue dots represent all of space at that era then let's focus our attention on this tiny portion that has a radius of about 42 million light years this is the region that will be all of our observable universe in 13.7 billion years our earth will form somewhere in the center of this region in about 9 billion years but we have a lot of expansion to experience first imagine that you are standing on a 100 meter track and someone 99 meters away is going to walk towards you there's the starters pistol and the walk begins but there's a problem the track is stretching growing longer as it walks he takes a one meter step every second but the track grows one meter for every 100 meters every second after 10 seconds the walker has taken 10 steps but the remaining 89 meters has grown so that he still has 98 meters from you another 10 seconds and he's still almost 97 meters away it will take him 460 seconds but he will eventually reach you and during that time the track is stretched so that it is now 10,000 meters long the other end of the track is now moving away from you much faster than the walker can walk if he had to start there now he would never get here and the question of how far he walked is ambiguous we could say he walked 99 meters because that was the distance at the beginning or we could say that he walked 9,900 meters because that was the distance at the end or we could say 460 meters because that is his normal speed times the time it took the expanding universe exhibits the same characteristics light from the edges of the 42 million light year sphere began their journey to the spot where the earth will develop about 13.7 billion years ago but during the trip the intervening space multiplied itself 1,090 times and now the spherical shell from which the light began is about 46 billion light years away this is the farthest into space we can see right now and it is called our particle horizon 100 million years after inflation the first stars formed they were massive giants that formed in every region of space including our little sphere of observable universe those that formed on a shell a little inside our expanding particle horizon are just visible today the light from these primitive giants has been traveling over 13 billion years and the shell of space where they formed is now over 36 billion light years away so light from the microwave background was emitted from a distance of just 41 million light years away and that distance is now 46 billion light years and light from the earliest stars was emitted from a distance of 1.5 billion light years and that has grown to 36 billion light years due to the faster than light expansion of space in those early years the light was actually moving away from us for billions of years before the slowing expansion allowed it to start moving towards us light we see today from some distant galaxies that was emitted from 5 to 6 billion light years away comes from objects that were the most distant at the time the light was emitted massive objects like the earth in the sun that are gravitationally bound to one another can overcome the expansion of space between them space is expanding in our system but the distance from the earth to the sun does not change because of this expansion why because as space expands the Earth's orbit continually adjusts to keep the earth at the correct distance that is demanded by the law of gravity this is also true for stars inside a galaxy that are gravitationally bound and is true even for local clusters of galaxies as space expands the distance between the bodies constantly adjust to comply with the laws of gravity the wavelength of light from distant objects is shifted toward the red end of the spectrum if they were moving away from us and the expansion of space is measurable by measuring the red shift and unlike the Doppler red shift the cosmological red shift says nothing about the recessional velocity of the emitting object either at the time the light was admitted or at the time the light was received Hubble's Law says the further away an object is the faster it is receding without limit so there are always objects far enough away to be receding faster than the speed of light objects we see with a red shift of about 1 point 46 are moving away from us at the speed of light and all objects with larger red shifts are receding faster than the speed of light most objects in the extended universe are traveling away from us with velocities fast enough that we will never see them in effect we have an event horizon and events beyond our event horizon are effectively unknowable to us objects that have a current red shift of about 1.8 are currently about 18 billion light years away and are now crossing our event horizon never to be heard from again finally this is a time sequence of the evolution of our universe Big Bang followed by inflation reheating or the birth of matter birth and death of the first stars and the ongoing formation and growth of galaxies when we look out into the universe we're looking backwards in time looking at the universe as it was when it was a lot smaller and a lot younger oh oh oh music

Channel: Endless Universe

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Id: d9_8xioTylM

Length: 175min 41sec (10541 seconds)

Published: Tue Jun 13 2023