The Supermassive Podcast - 60: Q&A - Space Potatoes and Christmas Stars

Episode Date: December 21, 2024

Our final episode of 2024 is a SUPERMASSIVE Q&A.  Izzie Clarke, Dr Becky Smethurst and Dr Robert Massey make their way through your questions.  What’s the farthest star we can see with the naked eye? Why do black holes expand and shrink? And what would happen if we accelerated an uncompressed medium sized potato to 99% the speed of light?  And remember, do not confuse the ISS with Santa's Sleigh in the run up to Christmas. To avoid any confusion, find out when the ISS is flying over your home using https://spotthestation.nasa.gov/home.cfm If you have any questions for a future episode, email [e-mail] or find us on instagram @SupermassivePod. And thank you to anyone who has listened or reviewed the podcast this year, we really appreciate it.  The Supermassive Podcast is a Boffin Media production. The producers are Izzie Clarke and Richard Hollingham. 

What's the furthest star that we can see with the naked eye? To answer this question, you have to make some assumptions about your potato. And there could also have been a supernova. Why can't we predict the sun's magnetic field? I'm going to say good question, probably for the last time this year. Hello and welcome to the Supermassive podcast from the Royal Astronomical Society with me, science journalist Izzy Clark and astrophysicist Dr. Becky Smethurst.

Now the eagle-eyed or eagle-eared among you will notice that our last podcast of 2024 is not an episode about the scientific search for extraterrestrial life as we promised. A slight change of plan. We weren't quite ready for that one. No, it turns out getting, you know, someone who studies like the search for alien life in the universe, trying to pin them down in December is just as hard as trying to find the aliens themselves. So we thought we'd just swap things around. So we're going to tackle some of your brilliant questions for this episode. And obviously, we can't have an episode without Dr. Robert

Massey, the deputy director of the Royal Astronomical Society. So I'm going to kick things off with an easy question for the both of you. Do you have a favourite festive astronomy fact? Well, I don't have a huge number, but I think there is a sort of Christmasy night sky object, which is the genuinely truly named Christmas tree cluster, part of NGC 2264, which has got a nebula as well, just happens to be visible right now as in the constellation Monoceros, the unicorn, to the east of Orion. So if you're in the north Amazon, that's looking to the left of it. And it just so happens that infrared images and telescopes

of this Christmas tree cluster often happen to be coded to show it in green. I really can't imagine why they would do that in their PR. But yeah, it's a really lovely object. It does look a little bit like the lights of a Christmas tree. Yeah. Why on earth would they make that false colour in the shade? It's impossible to guess. My favourite fact for this week, I feel like I'm on the No Such Thing As A Fish podcast, this is great. My fact for this week was in 2017, undergraduate students at the University of Leicester calculated the number of Christmas

lights you would need to add to the outside of your house to make it visible from space. Heather Miedkowski Amazing. Samar It's like I want to find these students and I want to shake their hands because this is fantastic. So it turns out if you're interested, you would need 10,060 lumens, so that's the you know, magnitude of lights you would need, or the equivalent of 2,638 LED Christmas lights. Oh my gosh. I know it's wonderful. They were inspired by the Christmas film from 2006, so deck the halls for those who've seen it, because I think that's the whole premise of the film. And they were like, well, let's visit. Also, speaking of Christmas films, Izzy, did you, have you seen the new Netflix Christmas

film with Lindsay Lohan? It's called like Our Little Secret. No, but it's on my list and I saw her one from last year, which I would really recommend. But there is an astronomy link here, I promise people. But I was watching the opening credits and the premise of the film is like something happened in 2014 and they have to zoom through to 2024. and the opening credits of the scene is them basically going through like you know a load of like world events to show time passing and three astronomy news stories made it in there and they were the only science things that were shown in that

global sort of news recap from 2014 to 2014 in an X-ray film. Yeah it was Pluto's so the New Horizons flyby of Pluto with that first image of Pluto we got was Perseverance landing on Mars. And then the first ever image of a black hole in Messier 87. There was also William Shatner going to space, which I guess you could also count that I didn't. And then for me, the best one was obviously the Eras tour from Taylor Swift at the end of it. But I figured that one of the projection team on the on the film must have been a big astronomy fan. Maybe they're listening now. Who knows? Amazing. I mean, that's just made me even more excited to watch this, Lizzie. Actually,

I'm going to throw something in here as well because I was looking at Christmas on the ISS, and then I got into a bit of a rabbit hole. So my fact that I want to bring to the table is in 1973, on board the Skylab orbital station, astronauts Gerald Carr, William Pogue and Edward Gibson made their own Christmas tree. They use discarded food cans and sort of push them all together to create a stem and then like various branches of the tree and then use little stickers as decorations and put a cardboard cut out of a comet on top. So sweet.

Do you know what, I bet they're the kind of people that once they were back to earth they were like, yeah, your Christmas tree is nice, but it's not as good as the one we made in space. Exactly, exactly. Nothing ever compares to it ever. Yeah, totally. Okay, so let's get on to the listener questions. And Robert, Matp24601 wants to know which star or planet do you think was most likely to have been the star of Bethlehem?

Well, Matp24601, definitely a perennial question there, I think. One that funnily enough comes up every year at this time of year. I think the answer is something we'll never know for sure. As an atheist, I'm probably going to get into at least warm water over this. I'm treading carefully. But on the other hand, I'd be genuinely interested in astronomical phenomena that coincide with the suggested date or dates actually of the birth of Jesus. Now, there's actually a nice piece on the Vatican Observatory website, which is a respected

astronomical institution actually, and invites us to use our sense of wonder over what it might have been. I think that's absolutely fine. It's a totally reasonable way of looking at it. Happy Christmas to the astronomers in the Holy See. But turning to the suggested ideas, so it ranges from it didn't exist at all to all manner of things. It could have been invented as this so-called pious fiction or midrash where the star was added in to emphasize Jesus' divine nature. In astronomy though, there are quite a few obviously significant things in the sky that could be candidates. For example, there was a really incredibly close conjunction of Jupiter and Saturn in 7 BCE or an even ridiculously close conjunction in Jupiter and Venus in 2 BCE where the two worlds would actually have a pitch of merge. That's very, very rare indeed. So I imagine if you were looking at that in

the sky, thinking of the astrological significance rather than the astronomical significance, if you're thinking about the mythology associated with that, you would have thought, wow, something very unusual is happening here. That came after Jupiter and Venus were close together a year earlier and they were also near the star Regulus, the bright star Regulus in Leo as well. Another idea is a comet, although they don't seem to be records and the Chinese are really, really good at keeping those records at the time of anything that bright in that period of time. There's possibly one in five BCE, you know, just, just again, really quite uncertain what it might've been like. And there could

also have been a supernova, although, you know, again, he sort of imagined somehow that would have had more of an impact in historical texts. But anyway, there could have been a supernova, although again, you imagine somehow that would have had more of an impact in historical texts. But anyway, there could have been one in the year 4 BC that happened to create the system with the unromantic name PSR 1913 plus 16, which happens to be the first binary pulsar discovered. But of all these things, my personal hunch is either the star never existed at all or it's probably the dupe to Venus conjunction seems to me like a good explanation because the idea, which I don't think anything like that happened in the 20th century, it certainly

hasn't happened yet in the 21st century, the idea that two planets are so close together that they're actually touching is extraordinarily rare. So maybe that was so significant that people drew on that. Yeah, there was a Jupiter-Venus conjunction, was it like a few Christmases ago now? Like two, three Christmases ago? And I remember that was really nice to see that they were coming so close together and they were so bright. But I mean, they came still like a like a few, a thumb with the part or something. I can't even imagine what it would look like if they overlapped completely from our perspective here on earth. Absolutely. And even the Jupiter Saturn one that we all got

very excited about. Again, that was what, 2021 or something, wasn't it? No, that's what I'm thinking of. I mean, you could still see they were separate. You know, they were very close. They were well under a fairly small fraction of a degree, but they were still not touching. And it must be so extraordinary rare that that happens. I want to look now when the next time that's going to happen, like, is it going to happen in our lifetime? We'll get back to you in that. I have a feeling from memory, no, but we

can check. Yeah. So not my lifetime at least. Well, at least now we'll have an answer when someone asks like, if you could go in the future, if you could go anywhere to see something, I'll go to the next conjunction. Okay. Well, we'll stick on the theme of spotting things in the night sky because Robert, there's a question here from Perring-Pulsar. What a brilliant name, can we just say? And their question is, what's the furthest star that we can see with the naked eye? Yeah, I mean, Perring-Pulsar, great name, great question. Well, I started, funnily enough, with a Google search because it's not the sort of thing

astronomers collate in papers and part of the reason is, you know, it depends how good your eyes are and circumstances to what the faintest thing you can see with the naked eye. Mine is not very good. Yeah, yeah, see, but you can probably see the Andromeda galaxy right two and a half million light years away. So on, you know, for non-stars, for big things, it's a really long way. But, so when I looked around, there were several articles saying, oh, this is variable star V762 Cassiopeia, which means it's in the constellation Cassiopeia, 16,000 light years away. But then you dig around quickly and the Wikipedia article says, oh, actually it's two and a half thousand light years. So I went into the SIMBAG database, which has things

like parallax. So looking at how it shifts back and forth as the earth goes around the sun measured by the Gaia satellite. And indeed that comes up with two and a half thousand light years. So a lot closer. You can get these numbers for yourself if you good, good luck remembering this. But if you put HD 7389 into that SIMBAT database, you get, get those numbers and then there are calculators to help you work it out. So then I was looking around a bit more and there isn't, I don't think there's any definitive answer to this yet, at least somebody needs, probably it needs to be some sort of, you know, post up with time on their hands. I think he doesn't really have time on their hands, but you know, yeah, exactly.

Yeah. But and that's because the stars get fainter. We see a lot more of them. So unless something is very luminous or very notable, you know, we can just about see if they're naked. I might not have a record of it. Two examples are stars in Cepheus, which happens to be visible at this time of year quite well, and one of them is Mu Cephei, famous as an incredibly

red garnet star and it might be about 3,000 light years away, but it's actually quite hard to tell the measurements are not that good. As it happens, that one is also so large that even without uncertainty it would fill the solar system as far out as Jupiter, absolutely enormous colossal star. The other one called Nu Cephei is a white-blue supergiant that might be as far away as 4,700 light years, with a lot of uncertainty. But both of those are actually comfortably a lot brighter than the naked eye limit of about magnitude 6.5. Even the fainter one is about 7. half times brighter. So somebody really needs to go out there and trawl through the catalogs, write some crawler

software or something to try and work this out. And the one thing I'd add is if you get a supernova, then they're obviously visible over much greater distances and exploding star is really very bright indeed. The one in 1987, which I remember but didn't see, down in the Large Magellanic Cloud, seen for months in the Southern Hemisphere and that was 170,000 light years away. So supernovae, single star, really are so bright. You see them a long, long way off, but nothing like that around at the moment. I really hope I get to see one in my lifetime. That is just like, fingers crossed. 2025, amazing. But lifetime. Four centuries since we have one in our galaxy. Four centuries so we are over you. Yeah.

Oh and Becky in true Q&A style we have a question for you about black holes and I think we've got quite a few on the way to go. I'd be disappointed if they didn't come through. Actually no one wants to hear about black holes this episode. Girls are pretty stupid. No. So Joe has a question about planet X which which is also known as the solar systems Planet 9.

We did an episode about this back in May 2021. So do go and have a listen back to that. I thought that was more recent than that, but time is doing its thing. Anyway, Joe says, I have a question about the possibility that Planet X could be a primordial black hole. I know it's unlikely, but if it were true, could it be close enough for NASA or ESA to send a probe to it? If they could, what instruments would they put on the probe?

Would there be a point in having a camera? Could we push something into it to see if spaghettification is real? What observations slash experiments would be possible?" Yeah, Jo, this is the dream, right? So if the solar system did have this baby black hole just hanging around, you know, and if you work out the maths from sort of like, okay, the reason we think this black hole might be the edge of the solar system is because, you know, there's all these dwarf planets at the edge of the solar system, sort of like asteroid style things, and their orbits are being affected by something and we don't know

why, we can't explain it, and people people have been like maybe it's a black hole. And so if you take their orbits and you think okay if there was a black hole out there it's probably around 400 to 800 AU distance. So an AU is the distance from Earth to the Sun. So 400 to 800 times more distant than the Earth is from the sun. That's like 10 to 20 times the distance of Pluto from the sun to give you an idea. The Voyager probes, which launched at the end of the 70s, are not that far out yet. There is something around 150, 70ish, something like that at AU. So we would definitely need to send something quicker. We've sent the voyage of probes. Big problem there though is slowing something down once it's that far out so that you could actually

maybe orbit this little baby back hole from a safe enough distance for the probe, for example. Otherwise, essentially you're just going to yeet something straight past it, which is not what you want. This is why we haven't put a probe in orbit around Neptune or Uranus or even Pluto, right? The New Horizons probe, it did a flyby of Pluto. The Voyager probes did flybys of Uranus and Neptune because it's very hard to slow down and people have sort of talked about this idea of atmospheric breaking, almost kind of like skimming a stone off the surface of the pond, right? It's kind of like what you do to your probe. You just skim into the top of Uranus

or Neptune's atmosphere to slow it down. No luck there though with a black hole. So assuming we can solve that problem, then yes, we would totally send a probe to orbit around this black hole if it was there on the edge of the solar system. Of course, we send a camera. I think it would be stupid if we didn't. It's not like they're overly expensive right, it's not the most expensive part of sending a probe is the camera these days. And I think if you're thinking would we really even see anything, like yes I think we would, we would definitely see the black hole's impact on the light from stuff behind it for example, so as it passed in front of you know stars in the Milky Way for example we would basically have this sort of perfect gravitational lens telescope right. The

light from stars behind it got sort of bent by the gravity of the black hole. In terms of other things you'd send though like one thing we want to test for is gamma rays because if this, so it's a black hole that's thought to be a primordial black hole, someone that was formed in the very early days of the universe like you know 13 and a half billion years ago, 13.8 billion years ago, let's say. And so because it's been around for that long, it sort of would have collected like a little halo of matter over the years.

Like it's just sort of wandering through the solar system and empty space, like, you know, is the vacuum of space, but it's not quite empty, it's like one particle every, you know, huge volume, right? It would have slowly sort of gathered those things like close to it and around it. So it would have gathered matter, but it also would have gathered like anti-matter, right?

And anti-matter and matter when they collide and meet, they annihilate and produce gamma rays. So you might expect if there's quite a bit of a halo of stuff around that black hole from over the years, it might annihilate and we might see those annihilations going on, which would be really cool to see as well. And finally, the spaghettification question. I think we'd be stupid if we didn't send something towards the black hole.

Like if we've got a probe orbiting it from a safe distance and then we just send, you know, like a little cube set or something to almost do the like the test where it's like, okay, you've got an Alice who's observing Bob fall into a black hole and they'd be called Alice and Bob and it would be the most physics nerd out ever right as you sent this little cube set that would probably have a camera on board as well sure but also probably send out some sort of beep of a signal that we would probably be able to see sort of have that time dilation to it where we would detect that beep that was going off every minute gets slower and slower because of the gravitational effects as it got closer

to the black hole and things like that. We could almost directly test it and yeah, all right, you think well at some point it's going to get spaghettified around a black hole like that but you know, it's like sending probes into Venus's atmosphere, right? And then you just get crushed and destroy balsamic acid, right? We still did it. You know, I think it's that to the extreme. Yeah. I was just like, we're sending something to break it. In a good way. In a great way for science.

What do engineers always say? You learn something more when it breaks and then you got to fix it. Absolutely. Well, there we go, Jo. I hope that answered your question. We have this question from Matt in Australia. Hi Hi Becky, Izzy, Robert and producer Richard. We know that Richard always appreciates that dimension. So there we go. Merry Christmas, Richard. In the last bonus episode, Lizzy19 had a question about accelerating particles with mass to the speed of light. So I thought I'd throw a wrinkle at Dr. Becky.

If you accelerated an uncompressed medium sized potato to 99% the speed of light, would that potato become a black hole due to Einstein's mass energy equivalence? This question so, so much, Matt. It was like, it was like an undergraduate maths question combined with a puzzle in the morning newspaper like all in one and I was in heaven honestly right so let's go through this so for those not aware first of all let's do a little Einstein's general relativity 101 as you accelerate objects close to the speed of light the more energy you put in it doesn't go into increasing an object's speed, but instead increases the object's mass, at least when you get close to the speed of light. So that's what we were talking about in last month's bonus episode.

So as for our potato, sadly no, the potato would not become a black hole at 99% of the speed of light So essentially the equation for this is quite simple You have the mass of the potato originally and it gets timed by this thing called the gamma factor to give you the relativistic mass right, so The gamma factor is 1 over the square root of 1 minus the speed over the speed of light all squared Okay minus the speed over the speed of light all squared, okay? So if our speed is 0.99 times the speed of light, 99% of the speed of light, then our gamma factor is about seven-ish.

So our potato only increases by mass about seven times and that's not heavy enough to become a black hole. Like potatoes aren't that heavy in the first place. I don't know if you've noticed. I've seen lumps of metal that are seven times heavier than a potato. So, you might ask Izzy and Matt and Robert, since everyone's here, how fast does a potato need to be traveling to become so heavy? Well, yeah.

If it becomes a black hole, I'll go into that. It's on my mind for Christmas. You know, I just, I can't fall asleep thinking of all the presents I've got to wrap and how Well, yeah, it becomes a black hole I think of all the presents. I've got a wrap and how big a potato a potato and need to be Okay, serious time to answer this question You have to make some assumptions about your potato. Okay, so Matt said a medium-sized potato So, you know not a new potato not a new potato, not a baked potato, a medium sized potato. I've got loads of those in my cupboard, ready for roasting on Christmas day. Is it floury or waxy? It's a Marist Piper, I don't know.

Floury, floury. Anyway, so I grabbed a few, I had a little measure. I basically decided on some round numbers in the end because I was like, well, let's say roughly it's about a 10 centimeter wide potato. Let's assume it's a sphere, because I'm a physicist and that's what we do. And let's assume it's around about 100 grams. For those saying at home, I should have done it properly and taken a specific potato and I should have got the numbers right, you will very quickly see the numbers don't matter. So we are going to go with a 10 centimeter potato that's about 100 grams. So because we know that black holes collapse

when you squish an object into a volume that's less than what's called its Swatch Shield radius, right, so that's essentially like the radius of which you'd have to be traveling faster than the speed of light to escape it, right? So we need to work out the mass of a 10 centimeter diameter black hole that matches our 10 centimeter potato.

So that's a Swart Shield radius of five centimeters, which if you do the math is 30 trillion trillion kilograms. It's about 5.6 times the mass of earth. Or instead of, you remember our gamma factor before being seven-ish, it would be 300 trillion trillion potatoes. So a gamma factor before being seven-ish, it would be 300 trillion trillion potatoes. So a gamma factor of 300 trillion trillion, which unfortunately actually makes the maths very, very difficult because if you try to get back from your gamma factor to what the velocity would be, remember I said gamma was like one over the square root

of one minus the velocity over the speed of light all squared. To get back to it, you need to do like one over gamma squared, which if you've got a gamma factor of 300 trillion, a trillion, if you square that number and then do one over that massive, massive number, most calculators are going to be like, you've got zero, if you're going to do one minus zero, you've got one. So I managed to hack this with Python code, thankfully that lets you're going to do one minus zero, you've got one. So I managed to hack this with Python code, thankfully, that lets you go out to a ridiculous number of decimals to get you an accurate answer for this potato. And it is 99.99... 52 nines percent of the speed of light is the speed a medium-sized potato would have to be traveling at

to collapse into a black hole. And there you go. That's your Christmas sword. I mean, who knew that that's where it would lead us? Matt in Australia, thank you so much. Honestly, Matt, I had an absolute joy answering that question. And that's all I'm going to be able to think about on Christmas day, making my roasties. We know what you're going to be talking about on the dinner table. Did you know? Okay, Robert, Jay Payne on Instagram asks, do we need a moment to read? We probably do.

I'm just thinking whether it applies to sprouts or what size of turkey would be cut. Oh, God. If we had a medium sized sprout. Exactly. Big or small turkey, geese, you know, nut roasts. Oh, brilliant. Okay, Robert, Jay Payne on Instagram has a question and they ask, is there a certain criteria for a planet or moon to become tidally locked?

Yeah, well, I'm going to say good question, probably for the last time this year. Yeah, the, I'm going to say good question probably for the last time this year. Yeah, the answer is yes. And it's, but first of all, I should say what it is. So tidal locking is captured rotation is where the rotation period of a body or how long it takes to spin on its axis matches its revolution period or how long it takes to complete an orbit around its parent body. So the example being the moon and the earth is the classic one because the moon more or less keeps the same face to us and we see a bit more than half of it because if you're

further north or south or depending on where you're looking at moonrise or moonset or the fact the moon's orbit is an ellipse you get to see a bit around the back but there are still two-fifths of the moon we never see from earth for this reason because its face is locked towards us. Now it happens because you get energy dissipated through tidal heating the object and stretching and so on and that eventually over a long time scale typically billions of years it depends on the system means that the rotation that object slows down until it locks into place. And that happens to both of them actually so you know it will happen to the earth as well and about 50 billion years time which unfortunately is much much

longer than the lifetime of the sun, the Earth-Moon system would do the same thing and the Earth and the Moon would both be tidally locked with each other. But to give you a kind of number for when it happens is quite hard because it depends on what the object's made of, it depends on how rigid it is. What you can say is that the more massive it is, you know, compared with its parent body, the quicker it will happen and the closer in it is, the quicker it will happen as well. And it's very strongly dependent on that. It goes to the power of six in the equation. So if it's close in, it really is going to rapidly lock. And I think with the Earth-Moon system, that might have happened very quickly as well because we think the Moon was much, much, much closer

to the Earth when it formed in this big collision between the proto-Earth and a Mars-sized body and the debris forming the Moon. And we, you know, it may have been that the Moon locked into place quite quickly as a result. It's really hard to say exactly how long though. But if you sat around, if you had an infinite amount of time, then in theory, all systems will eventually end up like this. It's just that it takes a very, very, very long time if they're further apart and if

the body is less rigid and all of those things. So there's no easy answer, but the criteria is just really that they're in orbit around each other and that this process is going to happen if you sit around long enough. But that could be, I guess, hundreds or billions or even trillions of years in particular cases. We do, by the way, also see it with lots of satellite planet systems in the solar system. And famously, Pluto and its biggest moon, Charon, are already mutually tidally locked. They keep the same face to each other all the time as they orbit round. We see it with other moons in the solar

system. I think there's about 20 of them doing that, particularly the big moons, Sajuta and Saturn. Also, with planets going around other stars as well, because if you get, say, a planet very near to its star, then it's locked in place in the same way. So I'm not giving you a very precise answer, but the criteria are essentially pretty much everything we'll do if you've got enough time to wait. You know what you should have done, Robert? You should have worked out how long it would have took a medium-sized potato. It probably is more than the lifetime it is, but yeah, right. Now that is another Christmas dinner question. Or a sprout.

Well, we should do it with a sprout this time. Yes, we do a sprout. It's more round, so yeah, it would make more sense. I want to take a moment to break from the questions and reflect on the year in space. So for the two of you, what have been some of your favourite astronomy moments of 2024? Well, mine's from the very start of the year. I'm still not over it. And that is that Neptune is not as blue as we all collectively thought it was. Do you remember this story? It's wild, yes.

So wild. Yeah. So this was, there was one in Oxford, actually, it was by Irwin and collaborators. And the thing that makes me laugh about this is that they started wanting to study Uranus, and then they were like, oh, let's find out this thing about Neptune. And we're like, oh no. But yeah, they were trying essentially to work out sort of with the seasons on Uranus as it orbits the sun, how does the colour of Uranus change? And so to do that, you need obviously like observations of Uranus over the past like, you know, as many decades as you can get your hands on from the ground.

But then essentially you need to calibrate all of that data from the ground with the Voyager probes flyby of Uranus that actually took like true color images of what Uranus would look like. And so that calibration, you need to grab the true color images from Voyager. And they were like, oh, okay, well, we should probably reprocess them ourselves again.

And they were like, wow, we're here, we're doing Uranus, should we do Neptune as well? Should we grab the Voyager images? And they did it and they realized, oh, the true color of Neptune isn't like the blue image that we, you know, is like the image that you always show for Neptune. And they realized that NASA like very clearly communicated like in the press conference from the Voyager probes back at the end of the 80s, like, oh, hey, we fiddled with the sort of levels here and the saturation just to show you the features in Neptune's atmosphere that like Uranus is super smooth and Neptune has all these features. And you can only see them if we like play with the levels. And they released that image to like, hey, look, you can see the features. And people were like, great, that's Neptune. Yeah.

And like amazing blue color. And instead, like if you actually make like a true color image of Neptune, yeah, you don't see the features as much because the color difference, you know, isn't quite as apparent, but actually the color looks more like what we're used to seeing for Uranus. That sort of hazy pale blue rather than that sort of dark royal blue.

And I still am like, but that's Neptune's identity. I have to reprogram my brain to accept that. No, it's you know, it's still a bit it's like I've been 11 months and I'm still thinking about it. And Robert, how about you? Well, hopefully not not quite such a, you know, traumatic answer. No, I think, look, I mean, this year, while we had two displays, the Northern Lights, honestly, when does that happen? If you live in the south of England, this is absolutely unprecedented.

And we had a bright comet as well. So, you know, really brilliant, actually, absolutely phenomenal. At the start of the year, I thought, it's only that exciting in terms of night sky events, you know, not much in the way of eclipses and stuff. And there you go, it just shows what I knew and my powers of prediction were completely useless. Again, but- Wasn't there an eclipse in the US though this year? I guess that's a must. I wanted to do like- So I wanted to do a case-centred-

Yes, because that was going to be one of my highlights. Oh, okay. That was going to be one of my highlights. So just like honourable mention to you. Yeah, it's fair. I know. I'm just resenting my colleagues across the Atlantic who had that too, you know, and the Aurora and the comet. But I loved, I also, not a discovery, but I did love the JWs team, which is all of them

obviously, but particularly the horse-sad nebula, which is always a special horse-like object in the sky. And it's, you know, taking a really, really powerful telescope and putting it, pointing it as something familiar is always, it was great. It's always just fun as well. Did you see that recently released a sombrero image as well? So I did the Sombrero galaxy. Sorry.

I can imagine hanging it in front of the telescope. But that one was wonderful for me to see because I studied galaxies and they're about course and stuff so it was really cool to see the differences between the Hubble image that you get which is just looking at the starlight and then the JDST image that they released was looking at the dust light so like light that was giving off by dust that was glowing and it's a completely different shape like it's completely lost that like hat like shape that the Hubble image so famously has so it's really nice to see that though you know the dust is doing very different things to

the stars, which was quite cool. Yeah, very cool. Okay. Back onto the questions. And we've had a great question here from Yelf on Instagram, which is, are there jobs you can do with an astrophysics degree outside of academia? So I think this needs to go to both of you. Um, and I'll ship in if I have anything else

to add. Yeah, exactly. I'm going to answer this first. The answer is definitely emphatically yes. Probably not going to be working in astronomy, but hey, there's loads of things you can do with it. The big secret is that most PhD astrophysics students, let alone astronomy undergraduates and then graduates, go on to work in completely different areas. That shouldn't really surprise us. There's only a limited number of hired

astronomers or there's a vast number of amateurs and vast number of people with an interest in it. We at the RAS actually collect examples every so often because we want to know what people are doing. The last time we did it, we found people using their skills in this amazing number of areas and they were doing things like data science in the city. No surprise there, kind of processing all these big data sets, doing that in the home office to detecting cancer cells, you know, like using machine learning techniques to try and identify cancer cells because they've done that with galaxies as well. It's just a science of imaging, right?

School teaching definitely because astronomy is really inspiring for teachers, really good subject for them. And even conserving paintings in the National Gallery. And I think we also, you know, it's a family, the techniques being used in archaeology and a whole range of things they could really do with them. So it is a good course to do for that reason. You know, you don't have to use those skills in those areas, but you're going to get essentially a physics degree.

You're going to be mathematically literate. You're going to be able to do a lot of them things. And if you're good enough to do astrophysics, you're pretty much good enough to try your hand at a lot of other things too. I'm going to have to say in my case, I'm not recommending, say, I take up music, for example, because the world really doesn't need that. But there are lots of astronomers who do that very, very well. Terri Smith is not going to encourage me to sing. I can tell you. Becky, Becky, your time will come. I promise that duet is waiting.

Sure. I mean, yeah, I think for this question though, I always say Astro is basically applied many things, right? Applied data science, applied problem solving, applied software development these days as well. Applied teaching, applied maths. Like there's so many skills that you learn from doing astrophysics. Like Robert was saying, like you can't, you can't be a lecturer in so many different things. And I mean, even I'm an example, right? Fresh out of my undergraduate degree in physics and astronomy at Durham, I got hired on an engineering graduate scheme.

Right. So that was like in the world of work in engineering and they sort of, their, their thought process was like, yeah, we hire both physicists and engineers because almost the physicists haven't learned the bad habits at university. We could like train you up fresh, you know, how we want you to be trained. Obviously, I realized that wasn't for me and I did come back to academia. But I've got mates that did, you know, physics and astronomy at uni with me that are in data science, teaching, finance, you know, that could be

anything from like insurance and all the stats that come with that to, you know, investment or anything like that. Medical physics, I said, right? It's just whether that's working with the big machines or doing a lot of the sort of research side of things from all the sort of skills you've learned with maths physics. There's people in publishing as well, whether that's like,

you know, publishing public science books, so like non-fiction books, or it's publishing like as an academic publishing. Yeah. People working in the civil service. There's even a friend that works at the Met Office, right? Because, yeah, whether again, it's satellites, you're just pointing the satellites in a different direction, right? Looking down at Earth and not up into space. And I think one thing I want to get across right now is that there is a weird sort of like idea that pervades academia that like if you do like a science degree or like a science PhD and then you don't go on to be a scientist, it's weirdly classed as a failure. But I don't see it like that at all.

Like I'm like, yeah, if you want to spend three years doing a PhD in, you know, some area of research or four years doing an undergraduate degree because you love the subject and you think it's really cool and you want to contribute to the tiny, in your tiny way, to the sort of collective human knowledge that we have. That's a great way to spend three years of your life. Do you know what I mean? And then if you go on and do something else, that's another great way of spending however many years of your life, then that's great. It's my de-changed direction. I totally agree totally agree because I think I did physics at Nottingham. I did a master's. I didn't do a PhD because I knew that I didn't want to do a PhD, but I still loved physics.

I didn't let that, you know, I just thought of a different way that made it more suitable to my skills and what I could do. But I've got friends that have gone on to be science patent attorneys and medical physicists. Some are doing coding for like massive supermarkets as well. But it's just like, oh, okay, this is just really, there are so many skills that you pick up. The path from astrophysicist to Google, by the way, is worrying. So yeah, exactly. So I think, I mean, I totally agree with you both that if you can get your head around astrophysics, I think you can get your head around quite a lot of things. And it's totally fine if that is not something in academia. You can make podcasts.

Hey, I'm not doing it. But not this one. Okay, but he's really contributing to the whole, what do you want to be when you grow up kid? You can be a podcaster. You can be anything you want to be. Now they say, I want to do an astrophysics degree and then do a podcast. They'll blame you Izzy. Yeah. Hey, that's fine. It's fun.

Okay. So Becky, can you help with this follow up question from Sam after listening to our Fast Radio Burst episode and they've written to say, after listening to your podcast on Fast Radio Burst, I would like to know more about how experts decide where to look for Fast Radio Bursts. Your guest Stuart mentioned being able to get time on JWST and a sample sky shot, but since FRBs are so short and so unpredictable, how do experts decide where to aim?"

Yeah, so I mean, it's a great question, Sam. So the big radio telescopes that detect these fast radio bursts, like, they don't aim, right? They stare at the biggest patch of sky that they can at one time in the hope of detecting one and the hope of, you know, pointing in the right direction at the right time. But they could easily be missing so many fast radio bursts in a night just because wrong place, wrong time, right? In terms of JWST follow-up, the field of view of JWST compared to a radio telescope

is very, very small, right? This isn't something you can, you can't search for FRBs in the hope of detecting one with JWST because you just can't mobilize the telescope quick enough to follow up on one that's just gone off. They last milliseconds, right? Unless it's a repeating source, there's nothing you can really do with JWST in terms of discovery. With JWST, what it's more about is finding the host galaxy that the fast radio burst has gone off in. So whatever object is producing this fast radio burst,

which galaxy does it live in basically? And oftentimes that doesn't seem to be a galaxy in the direction that the fast radio bursts seems to have come from, at least in sort of like the archive imaging we have from like ground-based telescopes, right? That obviously, you know, can't see things as faint as JWS-T can

or in any sort of resolution. So what we do with JWST is this sort of, as you said, like a sky shot where we point JWST in the direction we think that the fast radio bursts has come from and just sort of like collects as much light as possible and be like, is there a galaxy there that we can now detect with JWST? Or sometimes we do find that there's a smudge of a galaxy there in

the direction we think the fast radio bursts has come from, but we don't know the distance very well because again, we can't really resolve it. We've not been able to get what's known as a spectrum where you take the light and you split it into its like trace of how much light each wavelength you're receiving. And from that, you can pinpoint things to say how much has the light been redshifted by the expansion of the universe to work out how far away it is. And so with JD-Burst-T, we can actually look at that galaxy in more detail, get that spectrum that we need to pinpoint where the fast radio burst is coming from and how far away it is.

And that gives us a lot of information because if we know how far away the fast radio burst is, then from how bright it appeared to us, we know how bright it was when it went off. And so we can put some limits on like how much energy was involved in the production of this fast radio burst and things like that. That gives us a better idea of like what's producing them. You know, is it magnetars like everybody suspects. And also perhaps if that's changing

with how distant we go out as well and with how distant we find fast radio bursts, is there different things that produce them and does that change with time in the universe? Like lots of questions like that. Amazing, thanks Becky. And Robert Lucy on Instagram asks, why can't we predict or understand the sun's magnetic field? Yeah, thank you Lucy. When I read this I thought, oh is that Lucy Green, so the physicist who I know quite well trying to catch me out, but probably not.

She's secretly marking you. Exactly. I definitely feel judged. But it is a very fair question. The answer is we can predict the 11-year solar cycle of activity reasonably well. We know the number of sunspots, risings and falls over that time. Then when there are a lot of sunspots, the sun is generally more active. There are more solar flares. There are more coronal mass ejections when big eruptions of material

are ejected into space, and those rise and fall over that time. Then a new cycle begins with the poles of the magnetic field reversed, so you get north to south and south to north. Right now we are at solar maximum, that's why we've had two amazing displays of aurora this year. Interesting, we've also already seen signs of the next cycle starting up and there was a researcher presenting that at our National Astronomy meeting in Hull back in July. But the details are much, much harder. And I remember a decade ago when some solar physicists were absolutely adamant that solar activity was headed to record lows. And that was going to happen in the next few years. And it was

going to be like the kind of very low numbers we saw back in the 17th century, not long after people first started observing the sun properly with telescopes. And it didn't work out like that. You know, it was low and now it's high again. And we also definitely can't predict exactly when a large sunspots group is going to produce a flare. You know, we see them, we don't know exactly when they're going to erupt if at all, when a coronal mass ejection will happen, the direction it'll take. And we can only guess that it will probably be happening if we see a big sunspot group in the first place, we just don't know exactly when. And that's because the Sun is not this sort of super smooth, easy to model object, it's a ball

of plasma, it's electrically charged particles with magnetic fields, with currents of material, you know, eruptions, flows in and out of the atmosphere, even tornadoes on and under its surface and trying to work out how that hangs together is really hard. Not in the sense that we don't understand a lot of the processes that make it happen on a micro scale, but understanding or predicting how it will change over time is quite hard. So we do understand how the magnetic fields work. We do understand that the magnetic fields work.

We do understand that the interaction with charged particles, the fact they're tied together with electromagnetic forces, that's okay. But trying to estimate those long-term trends is really very, very difficult indeed beyond that basic 11-year cycle or 22-year cycle if you prefer from going from when the poles go back to the position they were in before. So really, frankly, Lucy, I don't know what you're doing, but if you take up a solar physics PhD and you solve this problem, then you'll probably be on your way to Stockholm for a Nobel Prize because astronomers are really

struggling with it. Okay, and Becky, we have another black hole question for you. Yeah, obviously. Abigail Smith says, Hi, love the podcast. My question is, why do black holes expand and shrink? Oh, good question. So I mean, expand and shrink, I think you mean they're like the size of them. So like the size of the event horizon, which was like inside that we class as the black hole, right? So the size of the event horizon is actually correlated with the mass of the black hole, so how heavy it is. So black holes expand if they grow in mass. So if they take in more material over time, so we see that in what we call X-ray binaries where you've got two stars that are orbiting around each other. One goes supernova, becomes a black hole, and the other star is close

enough to start almost like feeding the black hole and like the black hole pulls material off that one. And so in that respect, the black hole will expand its radius, its vent horizon will grow and therefore the black hole is expanding if you will as it's growing in mass. Shrinking however is an interesting question because you think, okay, well, if black holes expand because they get heavier, then they should shrink when they get lighter and they lose mass. But the whole point of a black hole

is that all the material and the light and everything is trapped there, right? That's the point of a black hole. However, enter Stephen Hawking's stage left because Stephen Hawking was very concerned about like the fact that black holes seem to break one of the fundamental laws of physics, fundamental laws of thermodynamics, right? And that's the entropy. It's like almost like the chaos in the universe should increase over time. Whereas black holes, they're sort of like

the Marie Kondo's of the universe. They really organized little boxes, right? And the entropy seems to go down. And so when he was looking at the maths of trying to figure this out, he sort of came up with this hypothesis that essentially there's sort of like an interaction of the black hole with sort of what's going on in terms of quantum physics,

sort of in this sort of like vacuum energy of space. I won't go into the details here because it gives me a headache every time I try and it takes me a good chapter of a book every time I try to explain this. But essentially what happens is you then get radiation given off at the event horizon of a black hole. You get like a pair of particles created, one of which escapes and one of which ends up going back into the black hole. And as Einstein told us, E equals MC squared.

So if you've got light, energy, escaping, you've also got mass escaping. So Stephen Hawking's theory is that you have what's known as Hawking radiation that allows the black hole to evaporate over time or to shrink, as Abigail put it, right? That, however, is still just complete hypothesis. Like those papers were published in the early 70s. We have no observational evidence that

this does happen, that we've ever detected like this kind of radiation that you could get from a black hole. It could just be that it's so rare that this ever happens that of course we haven't ever detected it yet or there's not a black hole close enough for us to detect the tiny amount of radiation that you would expect. Maybe if there's a Planet Nine in the Sol system. Oh, I was just about to say, well, who knows if we're sending a probe to a Primordial Black Hole actually. Exactly.

If there's a Planet Nine, there's a Primordial Black Hole in the source system, that would be an ideal place to test for this as well. So I guess this brings us back to the question that was Aelia. So we know why black holes expand. Whether they can shrink or not is another thing entirely. Okay, thank you. And a final one for both of you from Sam Downs on Instagram. Do you think there are aliens out there? Robert?

Oh, you know, I kind of do, but with the caveat that they might be really simple aliens, you know, really much harder question is whether there's any advanced life even remotely like us, which might be extraordinarily rare. I mean, I have to say, of course, as well, at this point in time, we haven't found any evidence for any life us. No hard evidence anyway. We found hints of things. We found worlds that could support it, chemical processes that allude to it, but no more than that. So we're a long way from confirming this. But they're not here. The Fermi paradox is applying. You know, the aliens haven't definitely haven't visited the earth, whatever you might hear on some YouTube channels. And that's not really surprising given how big the distances are. It's a really difficult

thing to travel between the stars. Beccy? Sorry, one sec. There was a strange noise and now I'm convinced that the cat's in here with me. The cat is in there because I saw it walk past. Disturbing noise in the background. She pushed the door open. I didn't even realise. Yeah, I saw her walking in the background. Yeah, your cat is in your room. My cat used to, my cat, my cat used to play the piano at random by walking, that used to terrify me, actually.

She was scratching like on the far back of the sofa. Anyway, that was really creepy. Because I almost interrupted your previous answer, being like, oh hello! Anyway, Pip's in the room. Aliens aren't in the room with us, but the cat is. I agree with Robert, right? I think there has to be life that has started on another planet somewhere in the universe. Whether that's in our own galaxy, the Milky Way,

I don't know, or more likely a far flung galaxy. I think just because everything we see, when it comes to life, like, dude, she's scratching again, the cat, like tardigrades surviving in the vacuum of space on the outside of the International Space Station. We recently saw that a chunk of asteroid that we brought back from the

asteroid Ryugu, right, on the Hayabusa 2 mission, Jax's mission, like went to the asteroid and brought it back to Earth. Like Earth life colonized the surface of that asteroid very quickly and very happily. Like that's, you know, alien rock that has never been exposed to, you know, Earth systems. I've been in a clean room and anything and it's got slight contamination that all of a sudden just proliferated. So I think as Ian Malcolm in Jurassic Park

so wonderfully puts it, life finds a way. And I think it would be very rare indeed if we'd be the only one where those conditions are right. I think if you think about the numbers of how many stars there are and how many galaxies in the universe and how many many planets they must have, blah blah blah blah. Yes, I think life must exist somewhere, but I do not think that they have visited us at all. Okay, well we'll be getting into that topic more in January 2025. I'm so excited.

in January 2025. I'm so excited. So thank you to everyone for your questions. Do keep sending them in. And Robert, as always, what can we see in the night sky over the holidays? Over the holidays? Well, the bleak midwinter, you know, cue some carols or something, I'm not going to sing. But it is just after the December solstice. So for the northern hemisphere, it's the longest nights of the year, pretty much. The other way around, if you So for the northern hemisphere, it's the longest nights of the year pretty much. The other way around if you're in the southern hemisphere, wherever you are in the world, Orion is now really dominant in the late evening sky, the brightest constellation in the whole sky, two first magnitude stars, Betelgeuse and Rigel, the Belt, you know, a wonderful thing to see. Particularly, it's a signpost of the stars around it so you can follow up and down and all that kind of thing.

Do look at the Nebula under the belt and definitely have a look around if you were given a pair of binoculars that we recommended for Christmas as a potential gift or maybe you got some for yourself or borrow some, but it really opens up your enjoyment of it. While you're there, if you're in the Northern Hemisphere, look down from the belt stars down to Sirius, which is the brightest star in the whole night sky. Now apart from that Jupiter is sitting above Orion in Taurus it's completely unmissable very very obviously bright and if you've got a small telescope then you could look at it look at the belt the weather systems and you might also if it's half decent be able to see things like the moons passing in front of it and their shadows and I I was looking up, there's a predictor on the sky and telescope website, which

we should probably link to actually, but on Boxing Day, the closest in moon, IO does this for people in the UK starts at 8.16 in the evening and it moves away by 10.48, so it's really well placed. So if you have a clear sky that night, have a look, you know, it's really quite a nice thing to see the shadow moving on and off. Venus is high in the sky after sunset. Looks slightly fatter than half moon through a look, you know, it's really quite a nice thing to see the shadow moving on and off. Venus is high in the sky after sunset, looks slightly fatter than half, moving through a telescope, obviously dazzlingly bright and it's good for the next couple of months. And if you're up before dawn and you've got a good southeastern horizon, it's also one of the best times to see

tiny mercury. It's visible in the dawn sky, so don't wait till sunrise, obviously it won't be there, but as it as it's getting light, you know, maybe when you're getting up for work, it'll actually be easy, although it'll actually be easiest to spot over Christmas itself so you might not be working at all over those days. And finally, do look out for the Quadrantids meteor shower that's peaking on the night the 2nd to the 3rd of January more or less, it depends on where you are in the world. It's very, very sharp in its peak and that's actually best for the Pacific this year but even if you're in the UK you might see say 25 meteors an hour and helpfully the moon is a thin crescent, a waning thin crescent,

so it won't interfere too much. Now, I have to say, I've always really struggled to see it because weather in January in the UK is not always what it could be. I'm going to try again. I'm going to try. I'm determined to try again and I encourage you to try. I'm determined to try again. And I encourage you to do the same. Do go and have a look. You know, wouldn't it be great if we actually got that? It's really quite a strong shower. It's just, I've never managed to see it in 50 years. Well, maybe not 50 years, 40 years of trying. I have something to add to this as well. For the Christmas stargazing period. I want to give a warning to all the parents of children out there that the International Space Station can look very convincingly like Father Christmas' sleigh.

And I wouldn't want anybody to confuse the two because it was very fast, it's very bright. So there is actually an International Space Station Passover of the UK at 6 a.mam on Christmas morning. So if you have been gotten up that early, because you have children, maybe a little look out of the window to see it passing directly overhead just past six o'clock. And you know, just be very careful that your children don't confuse it for Santa Claus, because I obviously wouldn't want that confusion to happen. It's a good public health warning, public safety warning. Yeah. And if you'd like to know for your own region, so that no confusion happens, spot the station

from NASA is the website that you should Google and you can put in your area and see where to look and when to look as well. Yeah, it's brilliant. I'm well, I think that's it for this episode. And for this year, we'll be back in a month's time, starting with the search for intelligent life. We will come back with that. It's gonna happen. We've said it so much. Now I have to go and find people to talk to. Thank you.

We know the people to talk to. The people to talk to are like, sorry, we're busy. We're searching for the alien life. I don't know what you want us to say. So we will get that to you. But thank you to everybody who sent in questions for this episode. I really enjoyed this episode. Thank really enjoyed this episode. Thank you so much. We do have a growing pile of questions and we will keep adding to it as well. So please do because we have these bonus episodes, right? Where we always do the Q&A as well.

So if you have a burning question for the team, email it to podcast.ras.ac.uk or you can find us on Instagram at Supermassapod and we'll of course try and cover your questions in a future episode. And if I can be really cheeky and ask for a Christmas present for us, if anyone wouldn't mind rating and reviewing the podcast, then it really helps. And we love seeing all of your reviews. So thank you for anyone that's already done that. Yes. Yes. And we will be back with more episodes for you in 2025 as well, but until then everybody, happy holidays and most importantly, happy stargazing.