Dark Matter Evidence, Oort Cloud Shape, Size of Lagrange Points | Q&A 229

why is the Oort cloud a sphere well Betelgeuse turn into a black hole and how are scientists so sure about dark matter all this and more in this week's question show it's time for the question show your questions my answers as always wherever you are across my channel if a question pops into your brain just write it down I will gather them up and I will answer them here but in addition to you putting your questions into any of the YouTube comment places that you find just tuck them in there you can also join the live show and we record this show every Monday at 5 00 PM Pacific Time right here on YouTube so go ahead uh give yourself some kind of reminder for the next 5 PM that will occur in your dimension and come and join us for the live show it's a lot of fun all right let's get into the questions Paul Davis 1943 why is the ort Cloud a sphere when everything else in the solar system is a disk yeah so when you look at the solar system the Sun and all of the planets are roughly lined up and in fact all of the moons are roughly lined up around all of the planets the whole thing is in this flattened disc and this is a clue to the 4 formation of the solar system that it formed out of this large blob of gas and dust and as it sort of brought itself down in gravitationally it started to rotate and spin and as it spun faster it flattened out like pizza dough like a skater pulling in their arms you know you've heard all of the analogies I'm sure and then you got all of the planets forming in that disc and then they in their little flattened blobs created their moons and so you've got this sort of everything is is aligned in this disc and you're absolutely right that the orc Cloud which is of course this cloud of comments that surrounds the solar system is more in a spherical form and so you know we can't observe the orange Cloud directly we can only observe it indirectly what we see are these comets that are falling down into the inner solar system many of which are doing this for the first time in their entire history 4.5 billion years since the solar system formed and they make this one trip past the Sun and then they fly back out it can take them hundreds of thousands of years to make this journey from the Oort cloud down and your Cloud extends out really far like 50 000 astronomical units far like maybe halfway to Proxima Centauri so like a couple of light years away they are theoretically Oort cloud objects out there and that there is probably a similar Oort cloud around Proxima Centauri and one around the twin stars of Alpha Centauri and then all other star systems out there and a couple of the clues that we get that these other orange clouds exist is that we have seen Interstellar objects passing through the solar system you've got Comet borisov both of these were on Interstellar trajectories they came from another star system and therein lies the clue for why the Oort cloud is spherical compared to a flattened disk so the thought is that when the Oort cloud formed you got this material that was ejected out of the inner solar system through interactions like you've got these large moons around Jupiter Europa Ganymede right these giant moons made of ice they are kind of like comets but with all the gravitational interactions you got these objects being ejected out into the outer stretches of the solar system and a lot of them would have then just come back down inside and crash back into the Sun or one of these other planets but some of them were able to kind of get so far out and interact with other objects gravitationally and interact with the other stars that are nearby that they just kind of are hovering around that everything is kind of balanced out and now they're just this sphere that is slowly spreading out around the Sun like what can happen in four and a half billion years and so the main reason why you get this spherical shape is that you've got these interactions between these stars as they are coming close to each other relatively close to each other in some cases passing through each other's Resort clouds and your Cloud that remains is the just the remnants of all of these interactions over the course of four and a half billion years of all these stars that came really close to each other and it's estimated that there were like 100 times the mass of the earth that was ejected out into space during the Solar System's formation and we see that in the form of interstellar objects that are passing into our solar system the big thought is at the beginning when the sun and the planets formed it formed in a stellar nebula there were hundreds maybe a thousand sibling stars in our region and they were packed together pretty closely together and so you got all of these Stars forming all of their planets all of their icy objects the IC objects were flying out the stars were buzzing around each other gravitational interacting and you got this sphere of icy objects surrounding the solar system that then has remained for four and a half billion years since the solar system formed I'm sure you've noticed the Star Wars planet that appeared above my name what was it like Tatooine I think so there will be another Star Wars planet that will appear above my shoulder through each one of the questions that we do during the show and this is a way for you to vote to tell us which of the questions you thought was the best which answer you thought was the best which combination you know whatever entertained you let us know in the comments down below just put in the name of the planet and then go ahead and put in your question or just the name of the planet and we will tabulate all those votes up and we will celebrate the winner next week and the winner last week was Tom's cubes and games talking about this rise of artificial intelligence uh spam science videos on YouTube and talking about the video that Kyle Hill made about it and that was the last question of the show and yet that was the one that was most voted so it is a big problem um go watch Kyle Hill's video about it and take the actions that he recommends in YouTube I hope you're watching and come up with a solution for this because I think this is existential for you all right let's continue on to questions Stars string stream could field stars be similar to population three stars in that they have no medals so I'll have to decode this a little bit so the old stars are these stars that are not associated with any Galaxy there the stars in between galaxies and there's two sources of field stars that's believed one is that they are ejected in kind of in the same way that that icy objects were ejected from the solar system early on in its formation Stars could be ejected by these galaxies early on in their formation in their interactions between each other stars can be torn away they can be ejected through interactions with the supermassive black hole the heart of the Milky Way or they can be thrown out because of a supernova but they can also just be like part of a tidal tale that's that's strewn out and snapped away off into space and so they were once part of a galaxy and now they have been given the boot now they're flying on their own but the other theory is that they formed in place that yeah the biggest lobs of gas and dust came together to form galaxies but you're always going to have the occasional piece of gas and dust sort of Imagine a bell curve and so most of it is concentrated at the heart of the bell curve but you're still going to have outliers smaller pieces that just never found their way into a Galaxy and so you could end up with a tarantula nebula out there in space that never joined a larger Galaxy and so it's all on its own and there's some really interesting evidence for this but astronomers are still kind of on the fence whether or not some of these Stars could form sort of in-sit you out there in space there's a type of star called an O star it's a very hot star and astronomers have done observations where they've detected these o Stars pretty far away from any nearby Galaxy and the reason is because they're visible like they're one of the hotter brighter stars and so you can see them but the assumption is statistically for every o star that you see because these things die very quickly as a supernova they're going to be a lot more of the G stars like the sun M dwarfs around them and it could be a lot of them out there but the question you're asking is like would they be like the population three stars and the population three stars of course are the first stars in the universe the ones that formed out of the primordial hydrogen and helium left over from The Big Bang and we've never seen those Stars directly but we have inferred that they exist because we know the Big Bang started with hydrogen and helium we see a lot of clouds and gas left over from The Big Bang and then we see that the current generation Stars contain the ashes the bones of previous stars and so the assumption is this had happened and so we don't know I mean this is a good question we don't know if there's a lot of star formation out there and if there is we don't know the ages of the Stars so there could very well be these clouds of primordial hydrogen and helium that formed a bunch of stars some of which were red dwarf stars that have been around for the entire age of the universe and all of the brighter stars died a long time ago and but they're just too far away for us to see and it didn't gets you close to a Galaxy where you can actually see it has now mixed up and and become polluted with other stars and so we just don't know I chose this question as well because I kind of want to talk about population three stars a bit and that's because there's just so many papers that are coming coming out now about population 3 stars thanks to jwst like there's too many to count and I'm really excited it feels like it's one of those observations that we we knew was right at the very limit of what jwst could do and now we're seeing a lot of that results we're seeing the after effects of these population three stars we're seeing the kinds of radiation that those population three stars would give off after they've gone Supernova and so it feels like of all of the Mysteries in astronomy this one is within our grasp now and so stay tuned it's going to be unfolding really quickly I think at this point I think we had three or four stories last week about jwst observations of population three stars and I just and and I'm I'm seeing so many papers in archive and other journals and stuff so it's a it's a pretty great time for this field Martin Charles 1121 will Betelgeuse turn into a black hole we don't know man is it is that what this episode is we don't know um we don't know uh so the problem is the Betelgeuse is right at the line for the mass of stars that will form either a neutron star or a black hole you need a star that is about 10 to 25 times the mass of the Sun to turn into a neutron star so it depends on how much of the mass of Betelgeuse is lost like it's between 12 and 20 but it could be a little more massive than that so it could very well and it sort of depends on how much of the mass of the star is thrown out through its Stellar winds like if Beetlejuice was above 25 times the mass and Sun it would absolutely be turning into a black hole but because it's less now it just matters is how much of its masses it's going to be sloughing off as it's going through this red giant phase and it's already thrown a ton of material out into space around it and this expanding nebula of material and it all depends on how much mass it sheds off into space before it finally runs out of fuel in its core collapses down forms either a neutron star or a black hole and then detonates as a supernova and so I guess better measurement of its current mass and knowing where it is in its life cycle would tell us whether or not it's going to turn into a neutron star or black hole but for now it's too close to call former Rosa studio if a bunch of masks in one place creates a black hole how did the big bang happen would it not be able to escape so this is the classic question um why didn't the Big Bang just collapse back down into a black hole there's a really weird coincidence that if you take all of the mass in the entire observable universe all the stars the galaxy all of the light all of the dark matter and you add up all of that mass you get a black hole with an event horizon that is roughly the size of the universe and so are we living in a black hole um and so we you know I get this question all the time and so back to last week's question show which of course you know I'm sure you watched uh the universe is maybe infinite was maybe infinite before the Big Bang and is still maybe infinite to this day and so in order to get a black hole you need to have a local density that is high enough for it to form a black hole you could have an average density be much higher than what it would take to form a black hole but it's not going to form a black hole because you don't have this over density and under density where the material can collapse so if you've got this side over here and this side over here and they're pulling in opposite directions and this side over here they're pulling in opposite directions it can never find a place to collapse into a black hole if it's perfectly smooth and so if the universe was uniform enough and sort of went on forever then there was no place where the black hole could form now there are some theories that there were minor over densities and other densities in various places and so we might have gotten some primordial black holes black holes that formed shortly after the big bang but there wasn't enough of an over density or under density but you're absolutely right like if if the entire observable universe is all there was then that would have formed into a black hole you would it would have appeared and it would have just gone into a black hole but it's not all there was there was more all around balancing everything out and so there was no one place where everything could turn into a black hole Emil goyal how are scientists so sure about Dark Matter could it be some other mass that acts this way so I want to direct you to one of the best astronomy related channels on YouTube which is a Collier Astro and she is an astronomer and really knows her stuff and is also really good at presenting a lot of these ideas and she did a great video sort of goes into depth about this idea of dark matter that dark matter is not a theory dark matter is an observation it's the most coherent tightest well-said thing on dark matter that I've ever heard and so I'm gonna steal it um but I'm gonna give her attribution every single time that I can so I'll put a link to the show notes and I'll put a link here so you can watch her video and you know where she lays out all of the like the real pillars of observation for dark matter but the gist of this is is that when I say that dark matter is an observation all it is and you know I can give you a thousand observations of examples of what an observation is you notice there's nothing in your fridge that is an observation you're like yo put up your future there's nothing in my fridge you have made an observation you notice that a car drove by is red you notice a red car that is an observation and the discovery of dark matter is an observation so astronomers went to measure the rotation rate of galaxies and they measured the mass of the galaxies and they found the rotation rate was too fast and these galaxies should be tearing themselves apart that is an observation they looked into the cosmic microwave background radiation and it only works if there is dark matter there it's an observation they watched the Motions of various galaxies at the bullet cluster and all the gravitational lensing around it and how the stars and the Dark Matter separated from the gas and dust and that is an observation so that's it like literally that's all now it has a name dark matter um but it's it's just a way to kind of grab all of these observations that are kinda related and put them into a basket together and go what's this right we've made all these observations and there is something here that's more than we understand so like it's really important and so a lot of people say like oh astronomers they're just making up this thing called dark matter because they need more money or they're trying to come up with some form of religion of their own and so they come up with dark matter or what like whatever right but no no dark matter is an observation and if you had the ability and in fact in her video she talks about how amateur astronomers with good backyard gear can make some of the observations that show that dark matter is there you with enough motivation can confirm the observation of dark matter so like what is it we don't know we don't know like just because you get to make an observation right so you know back to my observation of the red car driving by make an observation red car drive driving by and your friend goes what kind of car was and you're like I don't know like I don't understand cars what was the name of the driver I don't know I I didn't see the driver and even if I did I don't know his name right is there a way we could find out what kind of car it was okay maybe like maybe there's some road cameras that saw the car go by there's a way to figure out the drivers well maybe see the road cameras maybe someone saw the license plate maybe we can ask the police they could tell us who the driver was like there are ways you can figure this out but uh but you just made the observation so astronomers of attempting to constrain how dark matter Works they have been making various observations more complicated more sensitive observations trying to sort of focus on very specific variables and we know that whatever this thing is it only interacts with regular matter through gravity but it doesn't interact with itself and it doesn't interact through electromagnetic radiation or if it does it does it very rarely there's a lot of it out there like 10 times as much as there is regular Mass that's it like you know and then various ideas have been proposed like well maybe it's neutrinos oh no it can't be neutrinos because neutrinos move too quickly they're too hot could it be that we don't understand gravity at the largest distances maybe right that's a possibility so right now we're in the um you know calling to find out if we can get the license plate numbers so we can figure out who the person like like it it is a mystery and astronomers are trying to solve it and it seems like an important mystery because you know 10 times as much of the universe is this dark matter than the regular stuff that we see and we're made out of so it makes sense that we should try and solve it but right now where we stand and same thing with dark energy like dark energy is just an observation galaxies are accelerating away from us that's it that's the observation why we don't know what's causing we don't know what's your darling Force we don't know will it cause the universe to tear itself apart we don't know just this is the observation weird huh that's it let's figure it out and so our curiosity leads us forward if you like my answers to your questions as well as the other things that we do at Universe today consider joining our patreon club this allows us to keep a minimum ads for everybody and as a patron you'll get an ad free experience on universeto.com for life even if you're unsubscribed you can add free videos Early Access to interviews as well as other perks that are exclusive to our patreon community thanks to everyone who has already subscribed and welcome to the recent newcomers Brendan Samuel Dahl Nathan Barton Adam Schaefer Anders Lund Brian crote Roger Lee Anders weylander Daniel Llewellyn Ron Gilbert Bernard and Amy Zhang join the club at patreon.com universetoday guy Bisson when Beetlejuice star go supernova will the generic gravitational wave detectable by ligo stations maybe oh God it's like the maybe show isn't it um so okay uh yeah so we talked about Betelgeuse and you know everyone knows the Betelgeuse could very well be at the very end stages of its life it could explode in our lifetime it might not explode for another hundred thousand years but it's going to explode relatively soon astronomically speaking and so the question you're asking is that will that generate gravitational waves so gravitational waves are generated whenever Mass moves and so right now I'm waving my hand and so I am do I'm generating gravitational waves there are ripples of space time they're emanating out from my hand as I wave to you but they're not very big and they are not going to like be detectable as they pass through you which they already have um yeah the gravitational waves that I generated by waving at you have already gone through your body you need really extreme events for them to be detectable by ligo you need colliding black holes colliding neutron stars maybe a colliding white dwarf and a colliding neutron star but it is theoretically possible to detect the gravitational waves from a single Supernova but you need the Supernova to do something weird you need it to be asymmetrical so imagine you've got this Supernova and it collapses Inward and all of its layers come together but it doesn't quite collapse at exactly the same rate so that when the thing when all this material bounces off the core turns into this neutron star black hole the whole thing Jiggles shakes wobbles does something really extreme some kind of kick and so you get this really extreme shifting of mass very quickly like it had a like a balloon popping and you know the balloon is you know flying off into space and it has been theorized in fact there was a paper that just came out a couple of weeks ago I think we reported on University if not like we're about to that ligo should be able to detect the gravitational waves from some nearby Betelgeuse scale Supernova explosions and so it does seem like a star like Beetlejuice or maybe some other star that goes Supernova within a few thousand light years of us could be detectable and it and if it did then it would confirm different kinds of theories like it would give us some theories about the way these Supernova go off what the final stage like it would be incredible to get the gravitational wave signal the chirp coming from a star that just went supernova because it did something so weird so in usual that it proved some theories disproved other theories it would be just an amazing data piece to get but the other thing that beta this is going to do when it explodes it's going to release a burst of neutrinos and in fact there is a network right now of neutrino detectors called the Supernova detection Network which are scanning Sky listening for a burst of neutrinos because when a star like Betelgeuse explodes as a supernova you get all of these layers that are coming down they're collapsing inward they're reaching the core you get this burst of neutrinos comes out and they're moving it close to the speed of light the radiation is kind of trapped inside the outer layers of the star and it has to sort of tear its way through the star to get out into space and that takes it a couple of seconds and so we would see the gravitational waves come first then moments later we would see the neutrinos come at us and then a few seconds after that we would see the light of the Supernova itself and so in theory the gravitational waves could give us this early warning signal all that okay Beetlejuice went off and confirmed by the neutrinos and then we turn our telescopes and watch Betelgeuse actually explode Evo third when the polls change here will all compasses be wrong yeah yeah when the polls flip then the compasses will be wrong but in fact we're in this process of the in wronging of compasses already uh the Earth's north magnetic pole wanders and is wandered fairly significant so where the magnetic pole used to point is off by a couple hundred kilometers from where it is today but in theory you know we've never seen this practically but when the Earth's magnetic pole actually flips you're going to get this sort of you know if you look at the Sun as an analog where what started as a very sharp pole starts to kind of get these magnetic field lines and start to sort of get all more Tangled Up and appear at sort of farther locations down you know lower latitudes and then and then you've got this period where the magnetic field lines are all jumbled across the whole star and then they start to un tangle but now they're flipped vertically and now the South magnetic pole is the top of the planet and the north magnetic poles at the bottom of the planet and so your compass will get worse and worse and worse and then your compass will be useless and then your compass will get better and better and better and then your compass will be backwards hints how is the size of a LaGrange Point determined is it the mass of the planet for instance and is the boundary like a fine line or is it a gradient yes garage point question it's been so long um I feel like we had answered them all but it turns out more have come so a LaGrange point is misnomer it is not a point it is a blob so but LaGrange blob nobody liked that idea so um and this is because nothing in the solar system is perfect Earth has an elliptical orbit around the Sun the moon follows an elliptical path around the Earth Mars Falls elliptical path Jupiter Falls elliptical path these planets interact with each other and they make the locations of the LaGrange points more like blobs so the there are the three points that are lined up between say the Earth and the Sun and so you can never be on the LaGrange point it's not like you could balance your spacecraft perfectly in LaGrange point and then from that point on just like you know like you're stacking rocks right just walk away from it because the position of this LaGrange point is Shifting around depending on the location of the earth and its orbiting the position of the Moon on the distance of Jupiter all these gravitational factors are causing you know it is a moving Target so try stacking a rock on a uh a bumper car right It's Tricky um as is moving around randomly in random directions and then The L4 and the L5 think of them like big wide valleys big Hollows and so when we send a spacecraft Into The L4 or the L5 they're not sitting at a point they are just orbiting around in an area that is gravitationally stable that is fully contained within the LaGrange blob and with The L4 and the L5 they are because they are valleys as long as you roughly get into that area and you don't stray outside of the LaGrange area then you're going to be stable and you're going to be trapped inside the region of the LaGrange point so they are uh they're like a mathematical measurement uh sort of like the the perfect number but it but really they everything is just fuzzy and depends on the Motions of all of the objects in the solar system Joy Thief what science-based Discovery do you most hope will be discovered understood in your lifetime are we alone in the universe like like this is a scientific question right if I fly off to Proxima Centauri and I land on one of the planets around Proxima Centauri will I see life and if not there are they is it at Alpha Centauri or anywhere across the entire Milky Way this is the question that I think is one of the most fundamental most important questions that we can possibly ask and it is a scientific question and I would love to know the answer and and this is like why I think it's so funny that people say like I'm not ready to handle the truth I'm ready tell me like show me the evidence that we are not alone in the universe um I can't wait it'd be so great to find out conclusively that we are not alone and so I just need a lot of evidence to convince me that we that we are alone or Not Alone but yeah that times a thousand like every other thing that I'm interested in is eclipsed by that question must watch must read I recently read a novel where astronauts travel so far they eventually go through the heliosphere termination shock and some scary things happen can we safely pass that threshold sure yeah the so the termination shock or the heliosphere is this region around the Sun where the solar wind is heading out away from the Sun and you can imagine sort of like the wind from the Sun is the dominant particles that are streaming past you and you get to a point you know every Star has this bubble around it of the solar wind that is puffing out at all times and if you sort of zoom out these Bubbles from the different stars are going to be interacting with each other and so you get far and away from the Sun you're going to pass through the heliosphere and you know they call this determination shock that it is this this place where you've got this sort of high density where the solar wind is impacting the collective Interstellar wind from the rest of the stars in the Milky Way um yeah it would be fine like you like if you can handle flying out in deep space away from the Sun and you can handle the solar wind and you can handle the cosmic rays then the interstellar winds are fine because like like just Stellar winds themselves are so much less damaging than cosmic rays like cosmic rays are the worst they're really hard to stop like you can put a little bit of material between you and the solar wind and you'll probably be fine like not during a coronal mass ejection that's a bad day but just in general like you don't want to be in a solar storm but in general it's the cosmic rays that are blasting through what do we talk about 150 times more than the energy of a whisper right in an individual iron particle that is busting through your DNA that is the thing that we need to be worried about and they don't care about Heelys Helio shocks they carry very little about atmospheres but enough that we're safer down here on Earth Ryan Mortensen how large would an accretion disc have to be on Sagittarius A for its light to be visible from Earth so the center of the Milky Way is shrouded in gas and dust and so we with a regular visible light telescope can't see the center of the Milky Way and in fact for the longest time astronomers called this sort of blob the the center of the Milky Way they call this the zone of avoidance but really it was like it should be like the zone of don't bother right just don't bother pointing your telescope in that direction because there's just gas and dust and you're not gonna be able to see anything and you're just gonna be frustrated I know you want to see the center of the Milky Way but it's not going to work and you can't see what's on the other side because it's just obscured so don't bother but then we got infrared telescopes and suddenly these telescopes are able to peer through the gas dust and astronomers were able to see the stars moving around the black hole at the heart of the Milky Way they're able to see through this zone of avoidance the zone of don't bother to the galaxies that are on the other side and be able to figure out what the great attractor is it's a bunch of galaxies so imagine if the supermass of black hole the heart of the Milky Way became a quasar and started to actively feed on Stellar material maybe it would happen during our collision with Andromeda now suddenly this giant supermassive black hole turns on and is like gobbling of material and blasting out we still wouldn't be able to see it with our eyes because it is obscured by the gas and dust by the zone of don't bother so you could Point your telescope at it you wouldn't be able to see it and I could you could stand outside together and look up in the Direction Where We Know is the center of the Milky Way and we wouldn't see anything it's only with very powerful uh infrared telescopes that you could peer through that material and even just like detect the presence of the Quasar itself and it like objectively speaking it wouldn't be that bright so even if you did clear away the gas and dust you probably still wouldn't be able to see it it's just like not that impressive which sucks I know right like you want Quasar like it's you just imagine it's going to be this amazing swirling Cloud that we would see with jets that are coming out of it but we wouldn't see that because we just we have meet cameras in our eyeballs and uh it takes giant telescopes the ability to see another wavelengths ability to make long exposures to be able to see that kind of thing all right so those were all the questions that we had this week thank you everyone for asking them both in the YouTube comments and everybody who showed up live and hammered me with more questions we do the show live every Monday at 5 PM Pacific time so come and join us and don't forget to vote all right we'll see you next week if you want to stay on top of all the important space news join my weekly email newsletter I sent it out every Friday to more than 60 000 people I write every word there are no ads and it's absolutely free subscribe at universeto.com newsletter you can also subscribe to the universe Today podcast there you can find an audio version of all of our news interviews and Q and A's as well as exclusive content subscribe at university.com podcast or search for Universe today on Apple podcast Spotify or wherever you get your podcasts a huge thanks to everyone who supports us on patreon and helps us stay independent and keeps ads at a bare minimum thanks to all the interplanetary researchers the interstellar adventurers and the Galaxy wonders and a special thanks to Antonio 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Channel: Fraser Cain

Views: 43,318

Keywords: universe today, fraser cain, space, astronomy, big bang, cmb

Id: NvQOatYAmIw

Length: 35min 56sec (2156 seconds)

Published: Tue Jun 27 2023