#450: Dark Matter Debate, Flawed Maths & Spinning Black Holes

Hi there, thanks for joining us. This is a Q and a edition of Space Nuts. My name is Andrew Dunty. Coming up, we're going to look at a lot of issues, one involving dark matter. This question, though, comes about as a consequence of someone who wasn't real happy with a discussion we had recently, so we'll we'll certainly reinvestigate that. We'll also look at flawed mathematics. That sounds like my entire school career. We'll also be discussing black holes and gravity and energy in space. That's all coming up on this edition of Space Nuts fifteen seconds. Guidance is in channel ten nine ignition sequence Space Nuts or three. Two more review on. Space Nurse as can I reported Bills good and joining us again to sort all of this out is Professor Fred Watson. Hello Fred, Hello, I do let's get into those questions? Eh, Yes, let's just hit the nail on the head and start. And this first question comes about as a consequence of us answering a previous question. And I think we've kind of put Kevin's nose out of joint just slightly, I might say, though he's used a word that I think is probably not in keeping with the way you deal with things spread, I would never ever accuse you of being glip. However, that said, Kevin does have issue with the dark matter question. Now, so that I don't mash Kevin's question up, I have prepared it with an AI voice so that it comes out clean and. Unadulterated, if you like. So, let's see what the issue is and see if we can pick at the pieces and put it back together again. This is from Kevin. In your four hundred and twenty eighth episode. I was saddened by your response to a listener question asking if space time itself might be dark matter. I found your emphatic and almost glib No. Just doesn't fit with your regular open mindedness. I have asked similar questions before in other forums and received the same dismissive no response without any depth of thinking about the question. For starters, we don't yet know what space time actually is, but if it can be distorted, it has some aspect of a substance to it, and if it is a form of substance, why should it not be considered as a candidate for dark matter. It is everywhere, it is transparent to em it is weakly interacting it can be distorted, which means what that it becomes more dense in some areas than others. So what if areas that are denser have a positive gravitational effect compared to average background space, you might see clumping. So what if areas that are less dense have a repulsive gravitational effect compared to average background. Space, you might see voids. I'm not saying space time is dark matter, but dark matter is not actually a thing that has been discovered yet. Variable density space time maybe all that is needed to explain the gravitation anomalies that we observed, and I think it deserves a more open minded level of exploring than a simple dismissal. What I'd like to know is how would you test it as hypothesis? Has anyone done said testing? Has it been exhaustively ruled out by whom? How did they do that? Otherwise? Brilliant show. Kevin from Melbourne. Okay, Kevin, thank you very much. I hope you don't mind me using AI to put that question out there. I just wanted to make sure it was intact, because you obviously are very serious about this issue, and you have had problems in the past getting a straight answer, and you put a lot of thought into it. I give you credit for that. So, Fred, how can we sort of discuss this question with a more robust approach. By getting somebody who's more of a specialist in dark matter physics and cosmology than me as as a commentator. I mean, what I report on is what I understand from the work of my colleagues who work in this sort of field. And there's certainly nothing I've heard and seen in the literature that would equate dark matter with space time. It is always regarded as something that exists within space time. Now there'll be there'll be very good reasons for that, and almost certainly if some of my friends and colleagues were sitting right here now, they would be able to point us in the right direction as to why that is the case. I haven't checked the details myself, but nobody is making that such. Yes, it is. It's almost universally accepted as being a sub atomic particle of some kind which exists within space time that we haven't yet detected. I'm sorry if I sounded glid, but it wasn't. Certainly wouldn't have been my intention, and dismissive. Isn't something I like to be described as either because you know, we normally, we normally exactly keep an open mind about many of these issues. And part of that open mindedness is because I'm not a specialist in the field. I'm reporting on what, you know, what my colleagues, not just one of them, but many of them are saying, so, yeah, let's keep it, keep it in mind. I will explore it a little bit further, the idea that Jody's going to get involved as well. I'll explore the reasons why we don't consider it to be part of space until later date. Okay, No, that's fair enough. I mean, thanks for your comments. Yeah, and look, I appreciate his frustration because he's obviously tried to get answers on this and may not have liked the way we approached it at that particular time. But it is an area that is under heavy investigation. Everyone is looking at. Even one or two episodes ago, we talked about a particular search for dark matter that came up with nothing, And that doesn't mean it doesn't exist. In fact, we know it exists. They just haven't found it within certain parameters, and so they'll be looking bigger. But that particular equipment hasn't actually been built yet, so the frustration continues. So we hopefully are not a long way off figuring out dark matter. But right now there's lots small questions than there are answers, and it's I supposed to watch this space scenario, but no. We appreciate you passing on your thoughts, Kevin, and hopefully we will be able to come up with some more information moving forward once we've looked into it through the respective experts. Let's move on to our next question. This comes from Simon and he says, hi, is it possible that the breakdown of models at extremes of the universe is due to our mathematics being flawed rather than the models? For example, fluid dynamic models of real world scenarios rely on imaginary numbers. Might our system of mathematics be slightly misaligned with the real world? Thank you, Simon. I think we've kind of talked about the mathematics being off in respect to some things in the past, and even Einstein consider is the model of relativity is probably not right, even though we can't prove it wrong. So it is a good question to ask, and the answer is yeah, probably somewhere along the line, then the numbers don't stack up. Yeah. I think it's an interesting you know Simon's postulate about particularly about imaginary numbers, which is we call them complex numbers. They have a real and an imaginary component. Why is it imaginary because it's the square root of minus one, which doesn't exist. But it's an incredibly useful tool in so many fields of science and engineering too. Your aerodynamics relies on the imaginary numbers, so it's imaginary numbers that keep you plane in the air. Could could that understanding be flawed? Yes? I think it could. And again I think, you know, we are pretty open minded about this idea. What breaks down our physics in the extreme situations that I think Simon's referring to things like, you know, how do you deal with the way the universe behaved immediately after the Big Bang, where you've got temperatures and pressures that we've got no physical experience of in terms of working out how they would behave, and they become what we call highly nonlinear. That means that they behave in a way that is actually really hard to predict. And so that's saying that our physical models are not are not robust enough, not necessarily that the mathematics is not robust enough, but it is an interesting conjecture. I yeah, I think Simon's point is well made. Might our system of mathematics be slightly misaligned with the right real world? Well, in extreme cases it probably is. When you think about, you know, the temperature immediately after the Big Bang. Well, yeah, that's a good point. I mean it's no easy remedy though, is this? No? I mean there are people who are modeling those scenarios where you do have these extremes, and they're probably relying on relatively conventional mathematics, although yes, the other they will involve complex numbers and all the rest of it. But I yeah, I think it gets weirdest. Actually, it gets weirder in the quantum world, where we've got all kinds of interesting notions that do rely heavily on mathematics, superposition, entanglement, all of these things, and they rely on particular types of mathematics Hilbert spaces and things of that sort, which are well understood. I have to say, but to you know, to the uneducated, and I include myself in that, because mathematics was my achilles heel at university nearly cost me my degree. The I think they look these things look like mathematics gone wrong, if I can put it that way, but they haven't. They we'll understood. So the misalignment with the real world, I think it's possible. But in many ways, the mathematics is all we've got to rely on, so we just keep plodding on with what we know. Yeah, you mentioned superposition. I've just finished watching a science fiction series called Dark Matter, right, and they the goal of the main character, the scientist, that was the whole story was built around. His aim was to achieve superposition so they could travel into dimensionally. It was brilliantly done. Brilliantly done. They obviously had to work out how to make it a convincing storyline for those who are so into science fiction and science for that matter, to make it plausible, and they did a great job. It's a brilliant story, brilliant series. Really enjoyed it. Won't spoil it by telling you how it ended, but I doubt there will be a sequel because it did end, and it did end well. I thought, Okay, was it cool to dark Matter? Dark Dark Matter? And I think it was on Netflix. I can't remember now, But yeah, terrific series. Really enjoyed it and just so you know they could have well they did. It got so very confusingly complicated towards the end, but yeah, that's what made it so interesting. Thank you, Simon, And our next question coming up in a moment. Let's take a break from the show to tell you about our sponsor in Cogny, and I'll be giving you a special space nuts Url, so you can get up to sixty percent off in Cogni. But first, what's incognit all about. It's a way of cleaning up your online presence and reducing the risk of your personal information being sold to unscrupulous people via the dark web, or just via a hacker who's trying to fleece you or other people. It's also a great way to reduce spam emails and spam phone calls, reduce the risk of identity theft, which is big business these days. I think most significantly, it greatly reduces your risk of being scammed and that is just such a viral thing that's happening around the world at the moment. So how does all this work? Well, it's simple. All you have to do is sign up to in Cogni. Give them permission to act on your behalf and they'll do the rest. They'll trawl the Internet and remove your personal information from the web. The stuff that can be found on search engines, public websites, even private databases. It's all easily accessible. And let's face it, are you really going to be able to clean up the entire world wide web of your personal information by yourself? Right now? In Cogni is offering a significant discount for space Nuts listeners, up to sixty percent off and that comes with a thirty day money back guarantee. Just go to Incogni dot com slash space nuts that's I Ncogni, incogni dot com slash space nuts to find out more. And they have special prices for students and graduates as well. Make your personal information much harder to find online with in Cogny. Check out all their plans today at incogny dot com slash space nuts. Now back to the show. We're old on space Nuts and that's a moment this right, This one's from Isaac on the Gold. It is from Brisbane, actually in Australia. Isaac is nine years old. He said, I have two questions, how do black holes spin if they take up no space? And why does spin affect space? And his dad's got a question as well. My dad asks how does gravity bend space and thus bend light traveling past it? Isaac in Brisbane, nine years old. Great to hear from your Isaac. Thanks for sending your questions in why do black holes spin? I think someone else asked a similar question percently. We covered this not very long ago. Yeah, and so what you've got to think about is how black black holes are formed. If you have a star which is more than you know, ten times the mass of the Sun, something like that, gets to the end of its life, the nuclear propulsion system of the star stops until gravity takes over and the star collapses or its core collapses to become a black hole. So what you've got is a star that is going to be spinning. It will rotate because everything is rotating or evolving, and as it rotates, the spin will get faster because of the conservation of angular momentum. So spin is conserved. So even when the black hole becomes something that, as Isaac says, takes up no space, it's still spinning. Even though it is a single point. It's still spinning because it's the original style that collapsed to form. It was spinning, so that spin gets imparted to the black hole. So it's just inheriting basically. Yes, that's right. It's a good way of putting it, an inherited spin. I think I've got that as well. So and Isaac's dad wants to know how gravity bend space. We all want to know that actually, because it's what we know is how much in bend space. We do understand the mechanics of what happens when you put mass there. You can you can accurately predict just how and how much space will be bent, but why does it happens. It's the effect of gravity. That's the phenomenon we call gravity, and at that level we really don't understand it very well. Yeah, this is the thing. We know dark matter exists. We can't prove it yet. We know gravity exists, but we don't know about how it exists, in the way it exists, and whether or not it's a subatomic particle called a graviton. Yeah. I mean, we know a lot of things that exist, but we don't know much about why they exist and how they exist. Yeah, I suppose what you could say, is that we know extremely accurately. And this was you know, one of your answers to that last question. Relativity works like a dream. Everything is so precise, following the rules that Einstein laid out in nineteen fifteen. So that describes gravity incredibly well, incredibly accurately. But it is still only a description of gravity. It's not an understanding of how gravity arises. And so yes, we still have big mysteries. Though relatively speaking. Indeed, Yes, thanks Isaac, great to hear from you. Please send us questions again. I always love to hear from our younger listeners. And finally we have a question from our old mate Rusty. I believe Rusty is from Donnie Brook. Gooday, Fred and Andrew and all you space nuts. It's Rusty and Donny Roop, Western Australia. It seems to me that soon, and that may be in astronomical terms, we'll be able to harness the energy of space itself. We know there's a lot of energy in space. It has most of it if you look at the expanding universe and dark energy. But when we do harness the energy energy of space, we should be able to crank up one g drives and that allow us to go anywhere we like with swop over halfway, so the first half of the whege is accelerating at one g and the second half is decelerating at one G. A funny thing happens. The crew. To them seem to be traveling faster than the speed of light, so that they would go to Andromeda under these circumstances. In thirty crew years. So just wondering what Fred and Andrew, what your priorities would be once we do develop this drive both for the Solar System. And in the wider universe. Thank you, Oh Rusty, just put us right there in the middle of it. What would our priorities be over to you, Fred. Well, I've kind of said this before, and it's something that almost you know, rust is almost hinted by referring to a trip to Andromeda. The Andromeda galaxy. The view of our own galaxy from the outside is what I'd really like to see. Love to know how close our models are, just to make sure you got the color right, the color, how many spiral arms it's got? You know what? Don't we know that? No, not really. We think it's a forearm spiral, which is quite unusual. So you know, there's a there's a bar across the middle what we call a bar in the galaxy, not one you lean up against, but one that you you know, a bit like a rod or something like that. That's that's made of stars. And from each end of the bar, it looks as though there are two spiral arms that emerge. And that's based on mapping that we can do from the inside of the galaxy. But just imagine what it would look like if you're on the outside of it. Yeah, yeah, that's a great Yeah. I'd never contemplate a depth. To be honest, I know I have mentioned it before. I'd probably go further. I'd probably like to sort of get right away from our rum I suppose galactic cluster and look at the whole thing. I mean, I don't know how to explain it, but I'd like to be able to have in my view Andromeda and the Milky Way and whatever else is in the vicinity. You know, I'm assuming there are great voids between galaxy clusters, and I'd like to get out into one of them looking back at our galaxy cluster. I suppose that's what I'm saying. I think that would be fascinating just to see it all in one. Yes, yes, I think so. We're the Milky Way and the Andromeda Galaxy are the two biggest members of what we call the local Group, which is about thirty galaxies thereabouts. The next biggest one is the Triangular Galaxy, and then there's lots of small stuff. But we're part of a bigger cluster. I think it's a Virgo cluster that we're part of. I'm shocking it not remembering that that we're a little bit of that. It was certainly one of the bigger galaxy clusters we're part of as well. So you want to get right outside that and see what it looks like and be able to point to our Milky Way and say that's fled. Yeah. Yeah, I mean that's probably very un exciting to most people. I'm sure others have thought, oh, okay, well, if I could get a one G drive, what I would do is this, Maybe they can let us know. But you know, if we get achieved one G drive, it would make travel around the Solar System pretty schmick, wouldn't It is? It's it is. It's a nice concept because you you do two things. You give your spacecraft a long period of constant acceleration. But if you make it one G, then you've you've also provided your spacecraft with artificial gravity. So it means that everybody you know can stand upright on the bottom of the spacecraft as it's accelerating. Yeah, the end away from the the end of away from them, sorry, the way the end away from the point a bit that the bottom of your capsule that the acceleration would would mean that you were you were actually kept there exactly the same weight as you have on Earth. And then if you switched it around to slow down at the other end of your trip, you'd have one G also decelerating it. It's a really neat idea, if ever it can be made to work. Do you think it could work? Yes, well it could, but the main issue is sustaining it for a long period. That's why it's something that we haven't done yet. Maybe ion drive engines. That sort of thing. That's why that's the kind of thing that people think of. Yeah, could be interesting. Thank you, Rusty. As always you you pulled one out of the big black box. It's he's always got a bit of a curve ball for us. Has Rusty nice to hear from you. That is the end of this particular episode. If you would like to ask questions of Fred by all means, go to our website spacenuts podcast dot com. Spacenuts dot io is the other url. I'll both take you to the same place. You just click on the tab at the top and when you go in there, it gives you the option to send us a text or audio question. If you've got a. Device with a microphone, it's as easy as saying, Hi, I'm Fred from Sydney and I want to know and awhere you go. And if you're not named Fred, you can send us questions to just tell us who you are and where you're from, and we'd love to hear from you, especially if you've contemplated sending a question and you've been a bit reluctant. There are no dumb questions in astronomy and space science, so yeah, please please do get onto our website and send us some questions asap. We're done, Fred, thank you very much. You're welcome. It's always a pleasure, Andrew, and we'll talk again to we will possibly in the next few days. Who knows. That's Professor Fred Wartson, astronomer at large here in the studio, is just being here in the studio today. Actually, I think he's been the guy who picks up the kids from school. Hugh in the studio and from me Andrew and Unkley, thanks for your company. We'll catch you again real soon on another episode of Space Nuts. Bye bye. To the Space Nuts podcast. Available at Apple Podcasts, Spotify, iHeartRadio, or your favorite podcast player. You can also stream on demand at bides dot com. This has been another quality podcast production from nights dot com.