Stellar Questions, Black Hole Mysteries & the Dance of Dark Matter

Welcome to Space Nuts. I'm your host today, Heidi Compo, and I'm here with Professor Fred Watson, Astronomer at Large, and we are going to be answering some of your questions today. For fifteen seconds. Guidance is internal ten nine ignition. Sequence dot space nuts nine four. Three two more Space Nurse as the nat reboard. It feels good. So we have a question from Keith Wilson. Keith did not list where he was from. Are you from Earth, Keith, or are you hailing us from another planet? That would be my question for Keith. Keith's question for Fred is I have a question, because the Sun burns, it's feels so fast. How much smaller is it now compared to its size two billion years ago? And there's an answer to that which we can calculate. We weren't around two million years ago, so it's not easy to measure it then, but we can work out what it was by the rate at which the Sun is burning its fuel now. So the sun goes through these numbers always stagger me. Roughly four million tons of fuel hydrogen fuel per second, and that means you think, my god, that's so awful. A lot of hydrogen every second. That's what it's turning into helium. And it's that process, the nuclear fusion, that is releasing the energy that we see with you know, with all the light and the subatomic particles and everything that comes from the Sun. Is the underlying process is that nuclear fusion. There is also I've not seen this statistic before, but I did look it up about one and a half million tons per second. That is the solar wind, that's the particles coming off the Sun. So there's this loss of about you know, roughly five million tons per second. So you can do the calculation and it turns out that what saves the day is the Sun is very big. It's you know, it's got the huge amount of material in it. When you think of it, it's one hundred times the diameter of the Earth. It's a very very massive object. So there's a lot of it. So that release of energy and solar particles over its lifetime four point six billion years amounts to a loss of mass of wait for it, zero point zero five percent. It's virtually negligible. The Sun's mass has changed, but by a very tiny amount. There's a number of places on the web where you can find that calculation, but that's what we believe. It's lost mass, but it's only lost a tiny amount compared with it's the mass of the Sun itself. That's interesting. I have never thought about that, but it's good that this is something that doesn't need to also keep me up at night along with the other things I worry about. Our next question is from Michael, who is in New York. Hello, this is Mike from New York and I have a question about primordial black holes and dark energy. I believe you guys have addressed questions before about primorial black holes and how a concentration of them could result in dark matter and the gravitation that we observe behind them, and that's I believe generally been disproven. My question is, how could primordial black holes potentially relate to dark energy if we assume that they are spread evenly across the universe, if there's a sufficient amount of them as they evaporate, and that loss of gravitation goes with them as they evaporate, could that explain the increased acceleration of the expanding of the universe being driven by dark energy. I'm just curious to know if you've heard of that being tossed about before as an idea, and as I imagine, the math doesn't bear out as any studies been conducted to definitively say that is not the case. Thanks guys, and keep up. The good work. Yeah, thank you, Mike, A good question. You're right, the mask doesn't bear it out. But the bottom line here there were two things. I guess what was it. The basically got rid of the idea that dark matter was made up of primordial black holes. It was experiments done in the nineties nineteen nineties to look for the gravitational lensing effect. If we had a universe that was filled with black holes that we couldn't see because they weren't gobbling anything up, so they didn't blow in X rays as you do when you gobbling stuff up. If you're a black hole, those black holes should have distorted the images of stars behind them, magnified them, and we should have seen these If we measured the brightness of large fields of stars regularly, we should have seen stars brightening and dimming all over the place due to all these black holes, and that was not seen. It was an experiment called Macho a Macho actually was basically the acronym for those objects massive compact halo objects matt shows. So it was at that point that we decided it wasn't match chose it was WIMPs. WIMPs being weakly interacting massive particles, and that's what we've been looking for ever since with dark matter not finding it. If to say, but then going on to your comment about black holes relating to dark energy, black holes do evaporate. We know that from the effect of well, the theoretical work that was done by by Stephen Hawking back in the seventies. Actually that demonstrated that there is a radiation that comes from black holes is by quantum processes rather than relativistic processes, and that is called Hawking radiation. And what it leads to is the evaporation of black holes. But the timescale for that doesn't tally with the dark energy problem. Black calls evaporate, but on timescales of tens to hundreds of billions of years. It's a slow, slow process, and it's hard to imagine how that could contribute in any way to the dark energy that we see that is making the universe expand ever more rapidly. So a nice idea which I think doesn't as exactly as you said, doesn't hold up because of the mathematics. Thanks a lot, Thanks again, Michael. Yeah, that's very very interesting, a lot of deep thinking questions here. Now let's take a break from the show to tell you about our sponsor in Cogny, and get ready to write down the URL and the keyword to get a special deal as a space and that's listener. Do you ever wonder just how much of your personal information is floating around the Internet? Your name, your phone number, even your home address, all being bought, sold, and shared by data brokers you've never heard of. And guess what. That's why your phone won't stop ringing with spam calls, your inbox is overflowing with junk mail, and you're more vulnerable to identity theft than you probably think. That's where Incogniti comes in. In Cogni is a powerful automated personal data removal service that fights back for you. Once you sign up. 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Visit in Cogni dot com slash space nuts and the special word space nuts to get that great deal today and take back control of your data. Now back to the show. Three Space Nuts and speaking of deep questions, we have Duncan Sargent from Weymouth. It's a follow up question and it is a thesis that he's having me read here. So buckal up listeners, we have the question of the episode coming at you. Hello to both of you. This is a follow up question from one I asked ages ago, well over a year, if I recall, it was the one about how can two black holes merge into one? If no mask can come out of a black hole, neither can take the matter from one, neither can take the matter from one to the other to become one. Of all the questions I have sent the answer to, this is the one that was the least satisfying. I felt. Normally I feel you give good answers, but on this one I was. But this is the one that I was suggested that I read up on the process. Well, I have spent months doing this. He has done his homework, he has read it, and I still do not have a definitive answer. But I will lay out what I have discovered. Basically, as black holes near merger, something happens within them that creates massive amounts of gravitational waves. This accounts for roughly ten percent mass loss in the eventual combined black hole. I initially thought this mass loss was from the event horizon only, but apparently not, and the actual black holes themselves lose mass. Now, neither mass or energy can escape the black holes. But apparently this is what the math says, and words can't really describe it other than just to say that the mass says so as it does. It is something to do with the mass energy that is not really defined in the way that we think it is, and it becomes a bit fuzzy. The gravitational waves are in space time itself, and the whole merger process is somehow carried out with the actual confines of the space time they occupy, rather than the actual black holes themselves. As we know, neither of them can actually take mass from the other. Apparently, at the very last point before they merge, each black hole sends out a very thin tentacle of something, which when they touch together the merger happens. However, whilst this mathematically defined, it is not able to be easily defined by words. So could Professor Fred please attempt to put into words for me, as with all the reading I have done, my head hurts and I cannot think of a way to put it myself. How much does matter from one black hole or two of them get extracted from one from sorry, get extracted from the other and combined, what happens to the actual singularity? Do we end up with nested singularities? And how can that exist? Please help me understand then easily in easily defined English. I get impressed from I get impressed from what I have read that a lot of this comes down to the math that says we see it happening. So it does, but we actually don't know, We actually don't know. How Is that pretty much it? Okay? Thank you for looking into my answer my follow up. I look forward to your podcast each week, listening carefully for new snippets of information. Please keep up the good work. Well done, Heidi. Thank you Duncan put me through the challenge my first Q and A. Yeah, it's like a script for a whole show. But thank you Duncan. Yeah, Duncan, fellow Brits living in Weymouth there in the south of England, always nice to hear from him. But this, yeah, look Duncan, this is it's a challenging thing and it challenges the whole, you know, the whole of astrophysics because we don't really know what happens to black holes within that last well three point twenty six light years is the number. It's called the final parsec problem. A parsec is a distance. It's what astronomers measure rather than light years. You can't measure light years because we don't have to stop watch is good enough. But a parsec is three point twenty six light years, and it's what we in the trade of astronomy, what we actually talk about. So the final parsec problem is that there's not the way the energy from the merging black holes is released into gravitational ways, which is exactly what you've said. That is the issue. How does it happen? I'm going to read a paragraph from actually space dot com, one of the websites that we are big fans of at space nuts, they had an article a few years ago called what happens when black holes merge? And I'll read a paragraph from that because it sort of illuminates what you said and actually sort of quotes almost quotes to the letter what you had in your what you had in your question. The final partic problem, reading now, is currently an unsolved riddle in astrophysics. But whatever mechanism takes place, eventually black holes get close enough that the gravitational waves can really pull a lot of energy from the system that this point, the black holes only have a few seconds before they merge. At those close distances, the black holes start to deform each other. They don't really have surfaces. The event horizons are just invisible boundaries that mark the region of no escape. But the shape of the event horizon depends not just on the black hole itself, but also the geometry of space time around it. So as the black holes begin they're deadly dance. The event horizons elongate and stretch towards each We understand what happens next only through complex computer simulations that monitor and track the evolution of the event horizons. In the milliseconds before impact, each black hole sends out a thin tendril, a tiny tunnel of its event horizon, towards its companion. These tendrils meet and merge, forming a bridge between the two black holes, as if they were connected by an umbilical cord. Very quickly, the bridge widens and the event horizons glue together like two colliding soap bubbles. Within an instant, the black holes merge into one. But here's the crunch. What happens inside is anybody's guess. The center of a black hole is known as a singularity a point of infinite density. This is where our current understanding of physics breaks down. Simulations show that the singularities quickly find each other, briefly orbit, and then merge, but what actually happens is unclear. So Duncan, your question is at the forefront of astrophysics, and I applaud you for asking it. I don't think you'll find this answer satisfactory, as you've commented before, because you're asking questions that really we don't have answers to. But thank you for getting your head around the problem in the way that you have and thanks again for your question, Fred. Are there any theories yes? On are the leading theories? Well, it's basically what we've said. We you know that somehow the black holes actually come together, that there is a there's a sort of all This happens very much in the last absolutely the last few milliseconds of a merger, and that's the bit that we see with the gravitational wave records that we get from instruments like LIGO, the Large Interferometric Gravitational Wave Observatory and other gravitational wave detectors. So somehow they come together, there is a phenomenon which is talked about in black hole merger parlance as being the ring down. And this is when the merger is complete, the gravitational waves from the collision have been emitted, they've basically stopped, they've switched off, and the thing rings down and it's got I suppose implications of something vibrating. So it may well be that there is a bit more to the story than what we've just been talking about. But that's after the event, that's after the collision has happened. And Duncan's problem is trying to understand how something that you know, that won't let go of any mass, how it can come together with something else. And the answer is it does you know? I think of this and probably this might be the strangest metaphor you've ever thought of for black holes, but I'm thinking of this like cooking an egg. If we have two cracked eggs in a frying pan, they're they're you know, the the yolk would represent the singularity and the white would represent the event horizon. If these two eggs were to let's just say, because eggs don't do this, but let's just say they they were being pulled towards each other and merged. That point where they're merging is when the yolks both break, So there is kind of a point where it's two broken eggs. But then if they merged together to form one super egg, there would be something going on there. I don't know. This is how my brain is trying to wrap around these really complex problems. Is something as simple as. Food, Food's a good right to do it? And if in doubt turned to food, and so I think it's a good metaphor. Okay, technical space nuts. All right, So our lit question for today is from Lawrence Lawrence Ingham, and this is an audio question. Hi, Fred Andrew, It's Lawrence from Ingland Here. I have a question about your favorite subject matter, that being dark matter, and I got straight to the chase. Could dark matter not simply be energy manifest And what I mean by that is it seems that during really intense periods in the universe, we don't really have the current scientific models to explain how those processes occur. And my main example will be the epoch of inflation, where such a rapid expansion of the universe in such a small period of time. To me, it seems as though there must be processes going on there which we just do not understand and we cannot recreate, we cannot test it. But there must have been in such an intense period certain processes in which events happened which created things like potentially dark matter. And when you look at the expansion of the universe and reasons why there's all this unaccounted mass, all these things we attribute to dark matter, could that not potentially be simply energy manifest during that epoch of inflation, Energy itself could potentially have been transformed into a different type of matter, which we do not understand yet and cannot understand. But that would explain why universe is expanding. It would explain why we can't visualize and test dark matter, because once that energy has been used, you can't then test it because it's expanding universe. And I guess it also somewhat aligns with Einstein's equations with energy and mass being almost interchangeable. I don't know. It seems that as there are certain periods in which we cannot explain what's going on, and our current scientific models aren't fit for purpose because those events so unique and so extreme. Is this something that's been explored is it something that's currently being explored. I'd love to hear your answers. Many thanks, so so yes, in fact, you know the answer is Lawrence the the you basically said exactly what the situation is as we understand it. Sorry pausing for words there, trying to find new words. So the idea of dark matter being energy manifest in other words, energy turned into matter because they're related by equals mc squared, is how we think it got there. That's how we what we think the origin of dark matter is within the Big Bang itself, which was an energetic phenomenon that very quickly created the matter that we see in the universe. So it's that some of the processes are actually quite well understood. It's not that we're not understanding that, it's just when it happened. That it happened right at the beginning. The dark matter was created at the same type whatever it is, was created at the same time as the normal matter what we call the baryonic matter, and basically formed this as the universe expanded, formed this web of material that we call the cosmic web, and that led to the distribution of galaxies that we see today. So the answer to your question is yes, but it doesn't change the issue. We yes, energy was turned into particles, but we don't know what those particles are. The dark matter particles are as yet undiscovered. It's some form of super you know, sub atomic particle, which is very important in the universe. We think it's why galaxies formed. Without it, maybe they didn't, They wouldn't have formed. So the quest is still on to find out what dark matter is. But you're right, it came from energy. Excellent, Fred Well, I feel enlightened myself. These are fantastic questions, and it's interesting, you know, there's always so many questions that everyone always wants to ask about dark holes and dark matter, and the big, heavy hitting questions is the questions that all humanity has. And I think that that's just the exciting thing is to remember that's the thing in space is there's more questions than there are answers, and we do our best on this show to provide answers, but ultimately it's up to the scientists and the people who are discovering these things. And you can even get involved as a citizen scientist. I'll give a little plug for NASA and some of the opportunities they have for free online. You can help contribute to some of this research if you look up citizens Science with NASA. That's something you can get involved with yourself. Always as a fan of citizens science. Absolutely some great things have come from citizens anti Yeah. Absolutely. Do you have anything else you'd like to say about citizens Science. No, we might do it. We might have a chat about that down the track in one of our upcoming episodes, because it is it's such a now a fundamental part of what we do. It's very very important, not just in astronomy and astrophysics, but of course in the you know, the whole world of research, whether it's botany or arctic arctic evil sorry, ecology, all of those things can benefit from cities and science. Yeah. Well, and there's the really really fun one. If you guys have telescopes and you're into astronomy, as I assume these listeners are, you can even look up some of the exoplanet opportunities that you can have now sort of try and help discover and identify exoplanets. But with that being said, I think we've answered some questions, we've gave some questions, and we have more questions yet to answer. So Fred, thank you so much. That concludes another Q and a session of Space Nuts. Great pleasure, Hide always good to talk, and we'll speak again. To You'll be listening to the Space Nuts podcast, available at Apple Podcasts, Spotify, iHeartRadio, or your favorite podcast player. You can also stream on demand at bites dot com. This has been another quality podcast production from nights dot com.