Music Discover an impeccably curated collection of hotels. The luxury collection. 130 unique hotels and resorts across 40 countries. This is an ad by Beth D'Elbe. Did I talk too much? I should have handled that better. Why can't I just let it go? Why did I do that? I wish I would stop thinking so much. Take a breath. You're not alone. Counselling helps you sort through the noise with qualified professionals. Get matched with a therapist online based on your unique needs and get help with everyday struggles like anxiety or managing tough emotions. Visit betterhelp.com forward slash random podcast for 10% off your first month of online therapy and let life feel better. Mr Gorbachev, tear down this wall. And yes, we will build the wall. The lad is not for turning. It's going to be a U-turn. It's going to be a U-turn from Labour about the U-turn. Times change, but for over 240 years, the Times and Sunday Times have been on the ground, delivering in-depth, trusted reporting so you can understand what's really going on. Times change. The Times remains. I understand that one method of detecting an exoplanet is to detect the dip in magnitude when it transits a... Oh my goodness. I understand that one method of detecting an exoplanet is to detect the dip in magnitude when it transits its star. When it transits its star. Oh God! Hello and welcome to another bonus episode of the Supermassive podcast from the Royal Astronomical Society. With me, science journalist Izzy Clark, astrophysicist Dr Becky Smethast and the society's deputy director Dr Robert Massey. Before we dive into the Supermassive mailbox, Liam in Amsterdam has sent in a brilliant email about our last bonus episode is, and I just had to read it because it's fantastic. It says, hello astropodcasters. I love the nuclear pasta idea that we talked about on the previous episode. Yes, strong agree. But Liam says, I think you've missed the solution on naming the field. Clearly someone who studies neutron stars is a pastrophysicist. Oh God. I love it. How did we miss that? I honestly love this so much and I'm really, I'm actually disappointed in us that we missed this because it's so brilliant. So well done, Liam. Yeah, well done, Liam. Yeah, he also says, love the show, science education for the wind. Absolutely, yes. I think Liam gets a gold star for a very excellent email. Gold star, Liam. Okay. So let's go into some questions. Robert, Sam has this question. They say, given space time has been expanding, would it the volume of Earth or the Sun, Milky Way, local group, etc. increase over time? If not, what does it say about the nature of space time expansion? Yeah, that's a great question, Sam. Oh, and by the way, in passing, I definitely want pastrophysicist on my office door. In my love of cooking, I've got to do it. Or write a column or something. You absolutely do. It's got to be done. Right, so anyway, Sam, it is a great question. So the answer is that the expansion and the dark energy we think is driving it, this weird stuff that we still don't know what it is again, happens on the largest scale. So we expect to see things like super clusters of galaxies and enormous structures, hundreds of millions of light years long, get to eventually disperses a result. But the smaller things and certainly galaxies, planets and stars, there's much stronger local forces. Gravity on the smaller scale is much stronger than this expansionary force, we think. So they're not expected to be pulled apart in the same way. You know, they hold together. And on the very smaller scales, if you think about people and objects and so on, then they're held together by electromagnetic forces and they're very, very strong indeed, and they're very strong in their gravity as well. So, you know, they're not affected by the expansion. There is this less accepted idea of a big rip, not, you know, pretty contentious, where the expansion does eventually start to pull things to bit. But even if that happens, it's going to be in hundreds of billions of years time. So, you know, not one to add to the list of dangerous things that can happen with virus. We could be relaxed about that. Okay, I'm Becky. Josh in Virginia asks, do you think that the recent finding that galaxies in the early universe are more massive than expected is potentially suggestive of how we get supermassive black holes that are too big to be explained by our current understanding of how they form and grow? Good question, Josh. So I think what you're referring to is like both JDBC's discovery of galaxies that are apparently too massive for our best models to explain, and then the supermassive black holes that have been found in the early universe by JDBC that have masses bigger than we think should be possible for black holes to grow to in the time that they've had, because obviously light takes time to travel to us, so as we see more and more distant things, we're seeing them earlier in the universe's history. So for example, if we see like a million times the mass of some black hole, only like 500 million years into the universe's history, you think how on earth has it grown that big in such a short space of time? Now, it's an intriguing sort of question you've asked, Josh, about like, are they linked to those two things? Because in the local universe, like in galaxies that we see fairly nearby to, it was like relatively nearby, right? There is a correlation between the two things, like a mass of a black hole and the total mass in a galaxy. Like the two are correlated, right? And we sort of interpret that as like the black hole grows together with the galaxy, right? They co-evolve, they co-grow. So it is definitely possible that like one could be fueling the other in the early universe. And that is something that people are looking into, whether those like correlations hold, or whether like the black hole grows first, or the galaxy grows first, and then they move on to those sort of correlation lines that we see sort of in the local universe. Having said that, there's so many explanations floating around to explain either how the black holes got big, or how the galaxies got overmassive. The thing that I think is most likely is that the galaxies that have been found are not actually that massive as we think, right? The masses that we're estimating are estimates, right? They're also degenerate, right? So they can be confused with how distant they are in the models. And so that adds things to it. We also like don't know the spread of stars of different masses that form in the early universe. We assume it's the same of the spread of stars that we see in the Milky Way, and we need to know that to say, okay, we've seen this much light here. So if there's this sort of spread of this different types of stars, giving off the light that we think they give off, okay, that means that this galaxy has this much mass. But if you change that ever so slightly, then you're going to change the mass that you estimate and that you get out. And there's all sorts of different explanations from, you know, it could be that dark matter doesn't dominate in the early universe to, you know, all sorts of different things. Like primordial black holes might form in the early universe and that speeds up galaxies forming or black holes even forming. And so there's so many different things going around that I think it's just more likely that we don't know enough about the early universe yet to make any definitive conclusions. Like, yes, JWST has been what, three years since launch now, two and a half years of science operations. That sounds like a long time, but in terms of getting science done and understanding things, we're still in the like swimming through confusion stage. Baby steps. You know, so it's going to take time for us to peace out, you know, all the puzzle pieces. You know, we got to turn them all over, figure out the edge pieces. We got to then put it in the group of my cut. You know, it's going to take a very, very long time for us to figure this all out. I think we need to have a klaxon that is like, we just don't know. Yeah. Like when the QI alarm goes off. Yeah. Okay, Robert, Phil Banting has emailed us to say, further to the recent discussion about space themed names for babies, on two mornings a week, I helped run my church's toddler group. And one of our clients is a girl called Artemis. And we also had a girl called Luna. I hope that if either of these girls ever applies for astronaut training, she will get ushered straight to the front of the queue. But until then, our toy rocket will have to do. Absolutely. Thanks for showing that. Right. So now onto the question. He says, I understand that one method of detecting an exoplanet is to detect the dip in magnitude when it transits its star. But that is only possible if the earth is aligned with the orbital plane of the planet. This made me wonder whether planetary systems have even roughly similar alignment throughout the galaxy, or are they completely random? If they are random, there must be many exoplanets that are impossible to detect using this current technology. Thank you for your podcast, of which I am a super massive fan. Wonderful. Thank you, Phil. Yeah, and a brilliant question actually. I do hope Artemis and Luna go on to do fantastic spacey things. So, give us updates. Or at least become an archer, one of the two. Yeah, absolutely. But your deduction is actually pretty much spot on. So we only detect transiting exoplanets where the system is quite close to being edge onto the earth. So in other words, that the orbit of the planet around the star is aligned in such a way that it will pass in front of it from our perspective. So if that isn't the case, then we won't see a transit. If it's tilted, then you just imagine it. You know, if you look at it face on, the planet would effectively be going round and round the star, but it won't block the light and they're almost all of them are simply too close to their stars to be seen, you know, directly. So we just won't be able to detect them in the same way. However, and you know, it is also then fair to say we expect them to be entirely randomly distributed. There's no reason to believe that they would be preferentially lined up with the earth. You know, that would be a very weird thing to be happening. So what we can then do is say, well, if we detect, and we detect around 6000 exoplanets confirmed already a huge number. And bearing in mind, we didn't know about any 30 odd years ago. This is this is just a completely novel field still bearing in mind that number. It implies there are a lot more out there that we can't detect directly, but we can just do some statistics and say, OK, then there'll be 10 times as many as the number we can actually detect. And there are other ways you can find them. There's a technique where you can look at the way that the planet, if it's big enough, at least or even if it's fairly small, actually pulls the star back and forth a bit and measure that tiny change in speed and velocity. I call that the wobble method. Again, the wobble method is absolutely fair. Make the planet wobble. And actually, that still is better if it's edge on because, you know, if the planet is going round again, face on to us, then, you know, we don't see quite the same shift. So it's so really it tells us that the universe is absolutely teaming with planets. We can assume that a huge number of stars have planets and that implies there really are a vast number of planets out there. Can I add something to that? Yeah, go for it. It's fun to think about how because transits are easier to detect because all you're doing is measuring the brightness. That's the thing we did first, which is why we know so many planets that are edge on. But the fun thing to think about is how many exoplanets the future or current surveys will detect with these different methods like Gaia. So East is Gaia mission, which is like serving a billion stars in the Milky Way and it's text, its motions. So you'll detect if there's a planet edge on that's making it wobble towards and away from us. But it's also going to do what's called astrometry, which is to, you know, get really precise positions of the stars. So if there's a planet completely face on to us, making the star sort of go around in a little circle, then we should also detect that which we haven't been able to do before in a wide kind of scale. It's only been like individual stars that we happen to have been watching that you spot that. But now we've got this big survey. It's fun to think, you know, will we overtake the amount of planets that have been found because of the wobbles rather than because of the transits? Like, I don't know. We could see like a shift in the field, you know, very cool. And Becky, we're going to end on this singer from Lizzie19 on Instagram who asks, why can't anything go faster than the speed of light? It's a thing that we're really ending on a biggie there. Thanks, Lizzie. You know, I was just winding down. No, no, no. If you'll allow me, I think I did this question the most justice in a chapter of my book, A Brief History of Black Coles. If you want to check that out, Lizzie, we pop it on a Christmas list, way in quick. But I will try and do my best very briefly on the podcast for you. So it's Einstein's theory of special relativity that tells us that like nothing can go faster than the speed of light. And it's all down to this idea of space time. So not just space, but like the four dimensions, space and time, all intrinsically being linked together. And so in special relativity, as an object moves faster, so moves faster through space in a given time, right, it actually gets heavier. So like, you know, when we think about how heavy something is, we're also talking about the curvature of space thanks to Einstein's theory of special relativity, right, in terms of how much gravity it has. And so if it's getting heavier, it's mass increases. And therefore, if you remember, Einstein's other equation he told us about, E equals MC squared, mass and energy equivalent. And it's going to get a higher amount of energy and the amount of energy required to continue accelerating that thing that's getting ever heavier and ever more energetic. You know, if you want to accelerate at higher speeds, what the amount of energy you need is going to increase. And so as you approach the speed of light, the mass, or how heavy an object is, becomes so infinitely large that you need an infinitely large amount of energy to accelerate it to a higher speed until the point that you just reach infinity. Right. And so if you actually plot this out, if you're a fan of a graph, right, if you plot this out, you get who is an autograph, right. If you plot this out, you know, you get this sort of limit approach to the speed of light where you just keep, you know, drawing the line upwards and you never actually cross that sort of speed on the x axis of the speed of light. So that means it is technically physically impossible, according to Einstein's theory of special relativity, general relativity, to accelerate any object with a mass to exceed the speed of light, because it would require an infinite amount of energy that, you know, infinity, you know, draw it's the difficult to reach. It just keeps getting bigger. It keeps going. Amazing. Thanks for that, Becky. And that's all the time we've got for questions. So do you keep sending them in, along with your pictures, your baby name requests, your Christmas list, anything else you need us to help with. We're here. We do love reading them all. So you can email podcast at ras.ac.uk or find us on Instagram. It's at SupermassivePod. And we're going to be having a full on Q&A in January. So just pile them on, send them in because we've got to make a full episode. We usually do that in January, don't we? It's a fun tradition that we've started. So yeah, we're really going to need a lot of questions. Absolutely. Get thinking. Get them sent in. Yes. And also we'll be back in a couple of weeks with our end of year episode on the scientific search for extraterrestrial life, which is very exciting. Think about all the ways that people are doing that. But until then, everybody, happy stargazing. This is what life sounds like in Hertfordshire. This is what a life being saved sounds like in Hertfordshire. At Essex and Hart's Air Ambulance, we rely entirely on your generosity to keep us flying. Every day we react within seconds to bring life-saving care to those in our county who need it most. Please donate what you can today and help save a life. Such Essex and Hart's Air Ambulance. 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