Quasars: Monsters From The Early Universe - Answers With Joe

this video is supported by Skillshare quasars are incredible now before we get into quasars though I want to take just a second and talk about that word incredible what does that mean the root of that word credible means worth believing so if you're somebody that doesn't lie if you're somebody that can be trusted if you're an expert in a field per se then you are a credible person and the prefix in means not so if something is not edible it's inedible if somebody is not sane they're insane if something is not flammable its inflammable hello inflammable means flammable what who is this hello well that's weird anyway incredible does mean not credible because generally when you put the N in front of the word it means that's the opposite of what the root of the word is so when you put in in front of credible excuse me just for a second height inflammable means flammable it's incredible the point is if you want to use the word incredible nothing fits the definition of that word better than quasars quasars are incredible because they're too big too bright and just too massive to exist as the most famous eyebrows in astrophysics once said they are the unicorns of space he's not wrong from earth quasars look just like stars but they're super not they're insanely far away they're incredibly bright and they emit these Jets of subatomic particles that are just beyond the scope of our imaginations according to the best theories we've got at the heart of every quasar is a supermassive black hole and around that supermassive black hole is an accretion disk of hot gaseous plasma about the size of a galaxy it is literally like a galaxy sized star and as this galaxy worth of gas gets close to the black hole it releases unimaginable amounts of energy some quasars that we studied out there have over a thousand times more energy coming out of it than all the stars in our galaxy combined but again they're so far away from us that to us they just look like a star and that kind of immensity in the universe is something we've only been able to even contemplate for like the last 50 years around the year 1514 ad Copernicus challenged the notion that the earth was the center of the universe in 1771 Charles Messier published a catalog of astronomical objects that included what we now know of our galaxies but to them galaxies were a type of nebula just a blob in the sky a part of the Milky Way by the 1920s this was starting to become the question there was a famous debate in 1926 between two leading astronomers Harlow Shapley and Heber Curtis about the size of the universe Shapley argued that the whole light show fit inside of our own Milky Way and Curtis disagreed he thought the universe was much bigger and that there may be other galaxies out there but he didn't have conclusive proof at the time and most of science at the time was split along these lines but it wasn't until 1929 when Edwin Hubble was able to prove that galaxies existed outside of our Milky Way is vast independent groupings of stars he was able to prove that the astronomical object Messier 31 was way further away than it should have been possible 2.5 million light-years away now the Milky Way galaxy we know is only 200,000 light years across so there's no possible way that this was a part of our galaxy this was a galaxy of its own in 31 also went by a different name at the time the Andromeda nebula today it's known as the Andromeda galaxy by the way Hubble was able to prove this with the help of a computer how he had a computer back in 1926 you may be asking well that's because his computer was named Henrietta Swan Leavitt leave it worked at the Harvard College Observatory and her job was literally to compute things she was a human computer this was a job back then if you ever wondered how people did things without computers that's how we had people to compute that for us we had to figure it out ourselves so many astronomical departments researchers engineers had their own computer department which was just a room full of people with slide rules and those people were often women but Henrietta Swan Leavitt worked with Edwin Hubble and in doing so she got to do some groundbreaking science she actually came up with the method of the standard candles that's used to this day to measure distances across the universe she figured out the mathematical relationship between the pulses of certain stars and their brightness so if you could measure the pulse of a star then you could tell how bright it was and if you knew how bright it was you could tell how far away it was so stars with a known brightness are called standard candles and on top of being a woman in a male-dominated world she was also deaf and was able to achieve all this stuff and her work was nominated for a Nobel Prize so now we knew that there were galaxies outside of ours and over the coming years we found many many more of them we were also finding something else these sort of radio blobs they only existed in the radio range and they kind of shine like a star and kind of didn't so they became known as quasi-stellar radio sources these remained a mystery until 1963 when a Dutch astronomer named Martin Schmidt took a look at readings from a quasi-stellar radio source 3c273 and saw something familiar 3c273 was catalog in 1959 it was named that because it was a 273rd object recorded in the third Cambridge catalog of radio sources it's light spectra was collected in 1962 by a British astronomer named John Bolton he took advantage of the moon passing in front of it known as an occultation to get a clean spectrograph of the light if you're not familiar with astronomical spectroscopy I will just put a link right here to a crash course video that explains it really well but it basically allows us to kind of break apart the light and when you that you find these sort of emission lines which are unique to each element it's sort of like the fingerprint of each element so you can take the spectroscopy of a star or even a planet and by seeing those emission lines you can tell what it's made of the point is they took a spectrograph with 3c273 and yeah they couldn't tell what it was made of it didn't match any known element and you know at this point they were freaking out could it be bad data could it be an element that we'd never heard of before could it be unobtainium these were the readings that Martin Schmidt got his hands on and he noticed that if you in his words squinted just right it kind of looked like hydrogen shifted over 15.8% and it was shifted over into the red or red shifted because something had caused this light to stretch that something was space itself so we got to bounce back to Edwin Hubble and and here we just want to leave it for just a second because they had already blown our minds by showing that there were other galaxies out there in the universe but they were not even close to being done using their standard candle method that they had devised they were actually able to determine that these galaxies that we were now finding all over the universe all seem to be moving away from us except Andromeda actually but that's a whole other thing the universe was expanding and at a constant rate and this meant so many things not only was the universe not static which was an argument that was being had for centuries at that point but it had a beginning because if you wound the clock backwards for billions of years all that matter in the universe comes together we had a big bang it's really hard to overstate exactly how much Hubble's research changed the way that we see the universe it changed it completely it's no wonder that they named a telescope after him and if you're wondering there is a telescope named after Henrietta Swan leave it it's at the McDonald Observatory here in Texas and this is why that 15.8% redshift was such a big deal Martin Schmidt was able to do the math and plug in the expansion rate and figure out that that light was coming from something 2.5 billion light-years away to cross that much space and still be that visible Schmidt determined that this must have been the brightest object they had ever seen this was a whole new thing a superheated cloud of hydrogen shining brighter than a billion suns from billions of years ago and quasi-stellar radio source was shortened to quasars and since then millions of them have been found in fact 3c273 is nowhere near the oldest or brightest that we see now just in case you're having trouble conceptualizing exactly how bright quasars are consider the star Vega it's the fifth brightest star in our sky and it's about 25 light years away cosmically speaking not too far away but if the quasar 3c273 was where Vega is right now it would shine as brightly as our Sun no sleep for you but that superheated plasma around the black hole that's shines so brightly that's not even the brightest part of a quasar because a lot of this superheated plasma gets kind of twisted up into the poles and radiated out in insanely bright Jets and there are various theories as to why this happens a lot of physicists believe there is sort of like a twisting motion in the gravitational field of the quasar that kind of forces it up to the poles and flings it out now whether it's the matter itself being dragged up to the poles and flung out or whether it's the actual space around it being twisted by intense gravitational fields that is definitely up for debate but you might be wondering are there any quasars out there that have that jet pointed right at us yes there are and we have a name for it blaze ours but seriously blaze ours are the brightest objects in the universe in fact their beams are so bright they seem to break the laws of physics they seem to go superluminal faster than the speed of light this is an effect called relativistic beaming where the plasma that is generating the light is traveling so fast that it almost catches up to the light that it's emitting and this creates a transverse velocity effect that from the perspective of the viewer seems to be going faster than the speed of light now conversely this means that the jet going in the opposite direction is traveling so fast that it's invisible to us as you can see in this picture of Messier 87 equate our photograph by the Hubble Space Telescope ejects a visible jet in our direction but there's also a jet moving the other way we can't see it because the light emitting particles don't reach us and without the relativistic beaming effect the Jets just too dim to make out in the visible spectrum how's your brain doing is it melted is it like mine is it melted I'm done of course considering how far away these objects are and how long their lights been traveling it's mostly assumed that quasars are ghosts that expended their fuel and died out a long time ago ghosts from a bygone era that cosmologists call the age of quasars there was actually a period in the early universe the first billion years or so where quasars were everywhere the universe was much more compact back then galaxies were a lot closer so they were a lot more likely to collide and combine their supermassive black holes into these monsters of course not every supermassive black hole becomes a quasar a supermassive black hole has to have fuel in its sphere of influence to create what they call an active galactic nucleus or an Ag N and an Ag n has to be sufficiently bright enough to then be considered a quasar so clearly we're still learning things about quasars but quasars are actually helping us to learn things about the universe for example we know about the expansion of the universe I just talked about that a minute ago but recently NASA used the light of some distant quasars to do a measure of the expansion of the universe in a new way that they never tried before they looked at the light of a quasar as it passed through a distant galaxy through isn't the right word around ya around you've probably heard of gravitational lensing before well that's what this galaxy did it Lyn's the light from the distant quasar and split it into multiple beams and since the beams took slightly different routes to get there their light arrived at different times measurements were taken of the distance to the galaxy and the distance to the quasar through those various split beams as we know things that are further away or traveling away faster than us this was a way of measuring how much faster the answer from the quasar measurements with 73 kilometers per second per megaparsec put another way for every 3.3 million light years that had traveled these objects added 73 kilometers per second to their speed and this is interesting but mostly because it differs from the rate of expansion that's been measured using other methods the Planck satellite which measured the cosmic background radiation measured it at 67 kilometers per second per megaparsec so it's it's a slight difference but it is definitely a difference some scientists think we're gonna need a whole new kind of physics to explain this discrepancy so once again quasars have trashed confidence and left us wondering just what the hell is going on out there thanks quasars and actually that's fine contradictions and science sir are a good thing they lead to new insights and you know just generally keep things interesting here's an interesting thought in something like 4.5 billion years the Andromeda galaxy is expected to collide with the Milky Way galaxy creating milk dromeda which sounds like some kind of lactose intolerance now most of the stars are expected to miss each other but the supermassive black holes at the cores are expected to eventually merge and when they do they could form a quasar and maybe even feed off of our Sun and what's left of the earth meaning someday our long since fossilized bones could be ground up atom by atom into a superheated plasma surrounding a supermassive black hole and maybe we'll be part of that matter that gets spun up into a relativistic jet will be speeding across the cosmos so fast that will be writing right alongside the photons that we're emitting writing a beam of energy across the infinite universe now that's what I call going out like a bounce by the way this photo that I showed earlier of Messier 87 it's a pretty cool picture right but that like most space pictures took a lot of work not only is this a collage of many different pictures but it's also false-color you know that jet that you're seeing there that's radio waves that's not visible light but that's the power of photo editing to bring ideas and images to life and you can learn this power and apply it to your own photographs through the fundamentals of photo editing course on Skillshare this class is taught by photographer justin bridges and he shows how he uses lightroom to turn his photos and an inspiring works of art using basic techniques and concepts that anybody can learn I mean 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Channel: Joe Scott

Views: 475,330

Keywords: answers with joe, quasars, astronomy, hubble space telescope, edwin hubble, henrietta swan leavitt, black holes, supermassive black holes, active galactic nucleus, milky way, andromeda galaxy, astronomical spectroscopy

Id: s9W5x3SMBH4

Length: 16min 12sec (972 seconds)

Published: Mon Mar 02 2020