Are There Galaxies Around Little Red Dots? | Q&A 440

[00:00:00]Is Sagittarius A star even massive enough for a super massive black hole?

[00:00:04]Are there galaxies around the little red dots? How important is plate tectonics?

[00:00:09]In Q&A plus, what's the biggest showstopper for an interstellar crew?

[00:00:12]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 in your brains, write it down. I'll get them up and I will answer them here. All right, let's get to the questions. Nomad 77. Considering our black hole is only 4 million solar masses, is it really super massive? Well, compared to a stellar mass black hole, it is definitely super massive. When a star with more than 20 times the mass of the sun goes supernova, it will leave behind a black hole. And you know, those black holes will start out in this sort of three to four solar mass range and then grow from there. And so on the one hand you have the ones that are 4 10 20 100 at the most times the mass of the sun and then you've got yeah the Milky Way is one merely 4.3 million solar masses. You've got Andromedas which is about a 100 million solar masses. But then we see examples of super massive black holes out there with hundreds of millions even billions of times the mass of the sun.

[00:01:18]So they can get very massive. But I still think that 4 million is a lot and qualifies as super massive. The the interesting sort of search is the ones that are in the middle, the intermediate mass black holes, the stuff that's in the thousands of times the mass of the sun. You would expect that those would be out there. And when you sort of consider the mass distribution that is very common when you look at stars, there are a few stars that are very massive. Most stars are small. You would expect to see more of the black holes that are in that kind of middle range, but we don't. We see the the ones that are a couple of times to hundred times the mass of the sun and then we see the super massive ones. But where are all the ones that are inter intermediate mass? Billions and billions of stars.

[00:02:00]Are the little red dots super massive black holes inside galaxies? That does appear to be what little red dots are.

[00:02:06]Um you know there's been this ongoing scientific question about the little red dots since James Webb first discovered them. Uh, in fact, it was one of the most dramatic new things about the universe that James Webb had turned out.

[00:02:18]Like right now, if you said, "What is the the biggest thing that that James Webb has found? It's the little red dots." And these are these weird almost point source objects that are giving off an enormous amount of radiation, but it's all in the red. And they're seen within the first billion years or so after the Big Bang. And then we don't really see them after that. And whenever you see something that is giving off that amount of energy in a very constrained, very tight location, then you assume that it is probably, you know, has something to do with a super massive black hole. The size definitely matches. These things are in the order of tens of light years across. So they're very, very small and yet they are pumping out enormous amounts of radiation. But there's one big missing problem and that is normally when you see super massive black holes, especially actively feeding super massive black holes, they're giving off a lot of X-ray radiation. The accretion disc around the black hole is so compacted together that it's almost like the interior of a star. So fusion is happening around a black hole just in the accretion disc and that gives off X-ray radiation and X-ray telescopes can are the are the way we find many of these super massive black holes. But these little red dots aren't giving off the X-ray radiation in the way that that you would expect. And so there's been lots of other ideas. You know, my personal favorite is that these are baby globular star clusters in formation.

[00:03:43]That would be really cool. But there's been a bunch of ideas. But recently, probably in the last couple of weeks, astronomers have have found an example of a little red dot that is giving off some X-ray radiation. And what they think is happening is that these sort of new super massive black holes are feeding on so much material. They're producing so much dust around them that the dust is obscuring our view into the X-ray radiation. We're seeing the red and the infrared light coming out of it, but we're not seeing the X-ray radiation that you normally associate with a super massive black hole. So that's kind of the leading theory right now. And what's you know even more interesting is how the evidence is building for this idea of direct collapse black holes. So you know one of the long-standing questions about the universe was like what came first the galaxies or the super massive black holes at the centers of them that you know in one case you could have this giant super massive black hole and that could serve as a kind of anchor for other material to start to go into orbit around it or you could have like a whole bunch of stars the stars go supernova turn into black holes. The black holes find each other, they merge, the black holes feed, and you get this accumulation of of black hole at the center of this galaxy at the same time that the galaxy is is forming and you know there was like kind of like the bottom up versus the top down and there was two camps. But the real kind of general consensus is that no, they it's kind of they go hand in hand that isn't it weird that the super massive black hole and the galaxy around it are kind of roughly similar to each other in in scale. There's got to be some kind of relationship. But it is really starting to look like it's the black holes came first and that there could be ways that you could get a black hole that is millions of times the mass of the sun, not by merging black holes, but just directly that there's a giant cloud of gas and dust. Some way of, you know, material gets funneled into this central area and it just turns into a black hole. And that would be groundbreaking.

[00:05:45]like that would be Nobel prizes if we can get to this place where they they know this kind of thing for sure but it's sort of where things seem to be indicating so it's it's a really exciting time carro about the invisible black hole in the Uklid image will Uklid plus James web data force a revision of dark matter models or could something unexpected emerge right so the the whole purpose of the Uklid mission was not to take this amazing image of the center of the Milky Way to use this pair of instruments to map out the history of the universe, its evolution. So, it has this visible light telescope. So, very similar to, you know, the kind of observatories you're probably familiar with and that allows it to measure the shapes of galaxies. And then it has this infrared instrument on board as well, which allows it to measure the the chemical composition of these galaxies.

[00:06:38]And so it can put these two things together and it can measure the the the shapes of the galaxies and the composition of the galaxies. And what astronomers are looking for is they're looking for gravitational lensing. So we know that when you have large amounts of of mass in between you and something that you're looking at, then that mass acts like a natural lens that subtly distorts the pathway that the light is taking to get to you from those more distant objects. And so Uklid is doing this just giant survey of a huge swath of the sky, but it's taking long images.

[00:07:14]Like it's really staring at each spot in the sky for long periods of time, long enough that astronomers can start to detect all of that warping caused by the by the matter that's out there. And that is the dark matter, right? The dark matter is invisible and yet astronomers can detect how it warps stuff that is behind it. You know, the the example that I always use is that you're down at the bottom of a pool. You're laying on the bottom of a pool and you're looking up and you're looking at trees or people or whatever and they're all, you know, all refracting around uh distorted because you've got the water in between you and those and those people. And the the dark matter acts like this thing that is warping the light that is coming to our eyes. And Uklid will allow astronomers to look back into time because of course the farther away we look the earlier we're seeing back in time and really measure the concentration of dark matter at different points in the universe.

[00:08:10]Measure the influence of dark energy on the expansion of the universe at different times in the universe. James Web is is not a survey telescope and so it can't do these wide field views of the sky. it can be directed at specific targets. Nancy Grace Roman is a lot more like Uklid. It's going to be doing these wide surveys of the sky. Uh Ver Rubin is is doing these wide surveys of the sky, watching how things change. So there's a bunch of instruments that are doing this this same job and they're going to try and all approach this problem from different perspectives. But web is is when you found something unusual and you want to get really good images of it, you call on web in the same way that you call on Hubble, right? Hubble is like looking through a straw. Uh it doesn't have a very big field of view. And so when you've got a specific target, you want to look at a newly forming planetary system, you want to look at a very specific star, you call in web or Hubble. But if you want just a wide view of the entire sky, that's what you're doing with Uklid. And these surveys are going to help us understand what is the influence, what is the percentage of dark matter in the universe, how has dark energy changed over time, if at all. It's time to shout out the new patrons at the $5 level and above.

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[00:09:38]Casey villain, have we found evidence of plate tectonics on any bodies beyond Earth? Do we have any idea about how rare this geological phenomenon is? Do you have ideas about the role of tectonics in habitability? No. No. Yes.

[00:09:52]Moving on. No, I'll give you an answer.

[00:09:54]Um, so plate tectonics is unique on Earth. You know, this is this idea that the earth is broken up into these separate plates where they are floating on top. So the sort of like the the the lightweight um continents are floating above the heavier ocean plates and so you get the subduction and you get this, you know, material going underneath other parts.

[00:10:24]You get earthquakes and all that and lav and all that kind of stuff, but you get this refreshing of the material on the surface of the planet. And it appears vital for the habitability of of planet Earth. And that if you don't have plate tectonics, you have a place like Venus.

[00:10:38]Venus is called a stagnant lid, which means that it is this sort of entirely probably solid shell around the mantle on Venus. You don't get the plate tectonics that we have on Earth. And then instead it's possible that you just get the entire surface of Venus just inverting itself from time to time like like so much pressure, so much heat builds up and the whole thing just sort of flips over, liquefies. It's a mess.

[00:11:08]And we don't see plate tectonics on Mars and we don't see it on Mercury. And so those are the those are the only places that we can compare here in the solar system. We see something kind of like plate tectonics when you look at some of the icy worlds out there. You look at Europa, you see these cracks on the surface. You look at Titan, Enceladus, um, Ganymede. So, it might be you have a very similar process on these ice worlds, but it's ice floating on water.

[00:11:33]But we don't have any evidence. We don't know what's out there around the universe. You know, it could be that plate tectonics is very normal that that there's a certain size of planet, a certain distance from the star, certain composition of the atmosphere, and that that gets you plate tectonics. And it's, you know, there's one in every solar system. But it might be that it's incredibly rare that there is some very specific recipe for the for the conditions on planet Earth that allowed us to have these plate tectonics. Is it important for for for life? It it appears to be vital. Uh you know, again, just look at Venus, right? Venus sucks.

[00:12:10]And part of it is that Venus has no way to sequester the carbon in its atmosphere. On Earth, we have life. life forms biology. The biology sequesters carbon onto the surface of the planet.

[00:12:22]You get geology that is subducting that is essentially pulling that material under other uh plates on planet Earth and sequestering that carbon away from the surface. And so you have this regulation of the amount of carbon that's available in the atmosphere and the amount of global warming temperature rise that you get on Venus. That process maybe never happened or stopped at some point in the ancient past. And so the carbon dioxide just built up and built up in the atmosphere from the outgassing from volcanoes, right? Volcanoes are outgassing and then nothing is soaking it back up again. And it just keeps building and building and building. We actually talked about this earlier in this episode, how great those volcanic gases would be if they would build up on Mars. And yet on Venus, it's too much, right? You want to be able to dial that back. So you want the perfect amount.

[00:13:10]And it could be that just this process of tectonics constantly sequestering, you get this cycle that's going on in the atmosphere of of the planet and the surface. And that is what's necessary for habitability. Now, we don't know.

[00:13:23]And and the universe has a way of showing us that things can be weirder than we had ever expected and still work. And so, it might very well be that in fact we don't need plate tectonics.

[00:13:35]that there is a version of Earth that's at the right distance and there's other mechanisms that sequester the the carbon and allow for the cycle to happen that don't require plate tectonics. But it really does look like like the plates are key. Could be that we have a large moon that somehow the influence of the large moon nearby has helped create plate tectonics. could have been that it was the impact when Theia crashed into Earth and created the moon that that shattered the planet surface in a way that created the plates and that kept on going forever. So, you know, without another world to compare to, we just don't know the answer to this question yet. And figuring out if another world has plate tectonics is going to be a tricky move, right? We can barely detect the presence of these planets at all.

[00:14:23]the the most advanced technology that we have for studying exoplanets is to be able to measure um the composition of their atmosphere. Um but maybe from you know composition of the atmosphere that will start to tell you whether or not there are these you know methane cycles, carbon cycles on water cycles on these planets and that could give you a hint at the habitability or maybe even whether there's some kind of tectonic activity on them. Did you know that you can watch the same video with no ads and get a bonus question over on Patreon completely for free? We call it Q&A Plus. This week's bonus question, what is the biggest showstopper for an interstellar crew? And I'll put a link in the show notes. All right, those are all the questions we had this episode.

[00:15:04]Thank you everyone who put your questions into the YouTube comments, everybody who joined me for the live show that we did that this episode questions were recorded in. Um, I'm gonna give you something to just chill out and relax to in a second. But first, I'd like to thank our patrons. Thanks to Abe Kingston, Andrea Pretty, Brian Bod, Caravan, Chuck Hawkins, Commander Block, Darkfinger, David Guild, David Mats, Enthall Reading, and Math for Toddlers, Evan. Pro, James Clark, Jerry Madden, Jim Burke, Marcel Smiths, Michael Parcel, NASA Ocean Guy, Nordspace, Onesteperan Animals.org. Please follow my nephew at Vreick6994, Ring Kaidu, Richard Williams, Sean Sergeant, Steven Fam, Money, Team49, Tills Canada, Vlad Shiplin, and Wolf Gang Clots who support us at the Master of the Universe level and all our patrons. All your support means universe to us. So, normally I give you some kind of of rant or I tell you about media that I am consuming, but now I just want you to look at a hummingbird. So, these are some videos of some hummingbirds that my wife took in our garden. Enjoy. Just chill, relax, just just watch them quietly contemplate nature. And we'll see you next time.