The Supermassive Podcast - 25: A Supermassive Q&A!

Episode Date: January 28, 2022

The Supermassive team is finally doing something about all the questions that have been sent in. It’s Q&A time! From "fluffy" planets, to cake on the moon, join Izzie Clarke as she puts your questions to Dr Becky Smethurst, Dr Robert Massey and science and space journalist Richard Hollingham. 

If you could find a body of water big enough, Saturn would float. The story doesn't have a happy ending for the worms, I'm afraid, either. Do you think we'll ever be able to plan missions or even travel outside of our solar system? Hello and welcome to the Supermassive podcast from the Royal Astronomical Society with me me science journalist Izzy Clark and astrophysicist Dr Becky Smethurst. Yep this month we're finally doing something about all those messages that have been sent in. We have a little Marie Kondo aren't we Izzy of like every single message and email that's been sent because it is Q&A time finally. Finally I mean we say all those messages I don't

think we could ever possibly get through all of those messages but we'll try our best. Robert and Becky are ready and waiting to take on your astronomy questions plus we're joined by someone who has been at pretty much every recording we've ever done lurking in the background but finally jumping on the mic it's richard hollingham our editor who happens to know a lot about missions and space flight so we'll be sending those questions his way you make that sound a bit sinister yeah i thought it was lurking you're the one who said that richard was like do we need to tell them that i'm actually on every show i was like probably yes silent participant so a basic question to start everyone off uh sent in by me obviously um what

is your favorite space related fact oh i'm gonna go for a classic one that i read as like an eight year old and i and it's buried itself in my brain and i have not forgotten since right it's that if you could find an ocean or you know just body of water big enough that saturn would float it has a density less than water and as an eight year old that blew my tiny little mind that's brilliant that's a strong start robert can you match it how do i complete i don't know i i just think about the sheer scale of the cosmos so one of the things i that sticks in my mind is if you do something like you observe sunspots on the sun you realize they're as big as the earth and then a quick bit of basic maths tells you that 1.3 million earths fit inside the sun so you know the

ridiculous variation in scale in the size of the universe always blows my mind and then of course we get to things like galaxies and super clusters of galaxies it's utterly crazy but that that that local one about just how big even the sun is compared with the earth is impressive for me yeah okay that's a good one there's nothing to make you feel so small and tiny by comparing earth to the sun and be like yeah my life doesn't count okay great moving on this is just reminding me by the way when you're talking about scales i heard something cool the other day that because you know how if you if you talk about million versus a billion in time yeah a million seconds is 12 days yeah and a billion seconds is 31 years and you know what today is it is my billionth second birth second i turned a billion second old today at 10 49 this

morning do we need an alarm during it went off during our journal club this morning i was like i'm a billion seconds old. Oh, it's funny that you said that, Becky, because I've got you a cake to celebrate. Okay, Richard, what's your one? Can I just say, before we started recording, Richard's like, my space fact is going to be the best. He threw the gauntlet down.

I fear it might sound a little trivial in comparison but relevant to what becky's just been saying each apollo mission to the moon carried six portions of pineapple fruit cake oh my god that is my favorite why why six why pineapple why well i could give you some backup answers to that there were also three packs of brownies chocolate cake and jellied fruit candy cheese crackers a barbecue beef bites 15 packets of chewing gum with four sticks in each one this sounds like you list you'd right to go to the one i spent a disproportionate amount of 2019 researching these sorts of facts ahead of the Apollo 50th anniversary of the moon landing. So any opportunity to share them suggests my time wasn't wasted.

But I love the idea that if another life form and the only trace of humans would be like pineapple cake left on the moon, what advanced civil civilization is making you imagine they'd be like what was the significance of it being upside down told you it was the best space fact it was really it's very good it's very good right okay so that's my silly question over we'll get on to the proper ones we've got some big questions lined up for you guys robert perhaps you can start with this one from Wayne Borley. And he says,

In your episode about the James Webb Space Telescope, Robert mentioned that we could see a galaxy that was 32 billion light years away. Given the universe is approximately 13.8 billion years old, how come we can see light that's been travelling for over twice the age of the universe can you shed some light on the matter please double pun intended love that i love it great pun there wayne much appreciated yeah and this is actually also then when you when you throw these things casually into the podcast you realize you're gonna have to justify them so i will do that um well it comes down to the fact that there's a difference between how far light has traveled to reach us and thereby how long and that's at most the age of the

universe okay we can't see before the beginning of the universe by definition and then how far the objects that light was emitted for a mile away from us now and the difference comes down to the expansion of the universe so light light left those very distant galaxies, including one with the very, very exciting name GNZ11, which more or less holds the distance record at the moment, a bit over 13 billion years ago. But in the meantime, the universe expanded a lot. So now the same objects, if you had some instantaneous measurement of their distance, would be, we think, about 32 billion light years away, which is described as their proper distance. Now, they then get into all kinds of questions about, they certainly wouldn't look the same way now and all of those things, but the distance has increased greatly in the meantime,

just down to the expansion of the universe. Amazing. Well, I hope that answers your question, Wayne. And actually, we've had quite a few questions about the expansion of the universe I think our end of the universe episode probably set some minds buzzing and I feel like there's only so much you can fit into about 40 minutes about you know the entire end of days but also just the life of a cosmologist really yeah Mark Lowry has sent in this one Becky and he says as I understand it wherever we look galaxies are moving away from us except maybe Andromeda which is moving towards us the further back we look both in distance and in time the faster objects are moving apart does this mean the universe was expanding faster in the past and is expanding more slowly now no weirdly it actually means the opposite so expansion has

actually only started accelerating recently i say recently as the astronomers recently um it's all about scales here which is why we see the first ones expanding sort of moving away from us faster i should say so for every volume of space so for every um what we call a mega parsec is what this is usually measured in right you know like the the guess of running in three parsecs or whatever it's an astronomy measure of distance it's like 10 to the power of 16 meters or something right so for every mega parsecs of space the universe is expanding a few kilometers a second faster and so if you think of it as the distance the light has traveled again like what robert was just talking about the further away the light is having to travel for longer and so that light is more affected by the expansion of space and so you

see a bigger effect right um and because it's it's it's encountered more of these little chunks these mega parsecs of space along the way and so the more the universe's expansion affects it um it's sort of like you can think of it as like the longer the light has been kept from us by the expansion of space the further away something is um because again it's nothing to do with the galaxies themselves it's the space in between the galaxies that's crucial here it's kind of like not being able to see the wood for the trees kind of thing when you're very close in but when you look further out you see this bigger picture yeah absolutely and john has a part two to that and he says i'm having a hard time wrapping my head around how we know so how do we know that this is what's happening yeah how the universe is actually accelerating so um you know all of the pop culture references oh here we go so you know the scene in lord of the

rings when the beacons are lit in Return of the King? Yes, yeah. Right, and there's just all these mountains with these big piles of flame on top, right, that are all being lit. Okay, I'm going to steal that premise here to explain this, right? So imagine you had like 10 friends who all went and stood on mountain tops that, let's say, for our purposes, were evenly spaced a kilometre apart. We do that every weekend, to be honest. Yeah, exactly. It's how we spend our days.

And you told them, you know, light your beacon or perhaps maybe like flash a torch or something, right, at exactly the same time, say at like midnight or something. Yeah. Because light takes time to travel to, you would see a succession of flashes, right? You'd see 10 flashes. And because obviously speed equals distance over time the light's traveling the same speed the difference between each successive flash would be the same if everything was stationary right if you could draw a nice little plot you know a graph of like

you know the distance away the flashes and then and then um the the time difference between the previous flash it would just be a straight flat horizontal line right because they'd all come like constantly yeah get it yeah nice rhythm right now let's imagine that like this that space is expanding which means that like the mountains are getting further apart yeah by a constant amount each of them right so now uh it takes so if a mountain is twice the distance away it takes twice as long for the light flash to get to you so if you're going to draw the same graph and you're going to draw like distance away of mountain and the time difference between the previous flash you would get a diagonal

line going up right it would take longer and like i said like if it's twice as far away the light takes twice the time to get to you yeah okay now imagine that the space between the mountains is expanding at a constant rate but also at a constant acceleration right okay so not just not just constant speed anymore but constantly accelerating as well okay like a car is accelerating right then the time between each flash gets bigger every time by more than by more than double or more than and the further away the mountain is the further that light has to travel the more it's like accelerated away from us and so instead of a nice diagonal line you essentially get well i'm sure now after

covid we all know what an exponential curve looks like but like we get something that is curved right and it just gets even bigger and bigger and bigger as you get further away from you. Essentially, that's what we do when we look at galaxies further away from us. We actually see, instead of a straight line, we see this curve. And again, like the previous question, it's nothing to do with the galaxies themselves

moving faster or anything like that. Like I said, like our mountaintops, they're moving with the constant speed and then the constant acceleration or whatever, the space is expanding. It's just to do with the space itself and how far the light has traveled and so we can look and see that exact thing when we when we plot that like a distance away to galaxies and and how how long the light has taken to get to us essentially we can see that curve and so we know the universe must be accelerating there we go john that's how we know because becky stands on

mountaintops with torches. And you'll never watch that scene in Lord of the Rings the same again. And just to prove some of us are paying attention, I've actually drawn a graph of that. Oh, nice. Oh, it's beautiful. So I was working it out in my head

and the graph was really helpful. Thank you, Becky. Gold star. Yes. So Richard, you know, when it comes to spacecrafts and missions, I think Cammie's question is probably as big as it gets. And she asks, it's well known that distances in space are huge and that it would take us a lot of years to get even to our nearest star.

Do you think we'll ever be able to plan missions or even travel outside of our solar system? Yes, I think we've established that space is really big. I mean, yes, you look at the Voyager spacecraft. So that was launched in 1977, which is 44 years ago. Voyager 1 left the solar system in 2012, but it won't leave the Oort cloud. So the area around the solar system with the sort of diffuse icy cloud of dusty objects surrounding the solar system for another 56,000 years, it won't come close to stars till 570,000 years.

I mean, to be fair, it's partly the trajectory of Voyager 1. It's not sort of heading. It wasn't designed to head for stars, but gives you a sense of the sort of distance. Now, our nearest star is just over four light years away. So if you could travel at the speed of light, you could get there in four years. And we know we can't travel at the speed of light. So you could perhaps build a drive, some sort of spacecraft system that could get close to the speed of light. And engineers have certainly looked at that,

some sort of nuclear propulsion system. One of the really neat ones is a laser-powered spacecraft where you fire a laser at a solar sail and use literally the light hitting that solar sail to push it along. But when you look at the maths on that, I've seen some of the maths on this, I think you carry an ant it's a gram isn't it it's a spacecraft weighing about a gram yeah so yeah the spacecraft has to be really small i mean the other big big big issue with this is acceleration because you can't go from zero to almost the speed of light

instantaneous we would break apart so that that's one of the enormous problems. Star Trek gets around this with the inertial dampener, which I always thought was really, they obviously thought about this and think, I know, we'll have the inertial dampener. That'll sort it out. And in the Expanse, like they accelerate for half the journey

and decelerate for the other half of the journey. And then that also generates gravity as well or something. They like flip the ship around halfway through and I'm like, well, no need for the damp half of the journey. And then that also generates gravity as well or something. They like flip the ship round halfway through. And I'm like, well, no need for the dampeners anymore. I think the dampener always reminded me of Jules Verne's. I think he had giant cushions for being fired from a cannon. There are two options. So the answer is yes, you could do this.

It could take a very long time. So you could put your space explorers to sleep, which is one option. But that assumes you can develop technology so we could hibernate but not age so that's i mean it's not impossible i can see that would be possible to do that i think the more likely scenario is what we're already doing which is sending our avatars out there so sending space probes sending rovers out there and sending artificially intelligent rovers i mean the new exo mars rover so the mars rover that will land on mars in june 2023 now the rosalind franklin rover is has a lot of artificial intelligence on board it's far more intelligent than the previous nasa rovers be able to do quite a lot of artificial intelligence on board it's far more intelligent than the previous

nasa rovers we're gonna do quite a lot of its own thing so i think that's probably the future is sending artificial intelligences out or even you know if we could develop the technology uploading our consciousness is consciousnesses consciousness our conscience to some sort of robot yeah and sending that out that into space but people i'm not so sure the thing is though that gets me is that even if so say we did send like an a robot that has some very high ai ability to like say proxima centauri b like the planet that's orbiting around one of the nearest stars four light years away you'd know it had arrived but you'd have to wait four like four years to get any data from it or any like thing had arrived.

You'd be so angry. And I think that would just kill me is the wait. I mean, the wait for JWST nearly killed me and that was all the time. This is, yeah, this is like the whole thing of designing. I was reading I think last week about the idea of designing an interstellar probe whereby the mission designers wouldn't live to see the results as well. So even without, you know, if you don't have something like an elaborate stellar sail system so just imagine you know you

work on this project knowing you simply won't see it come to fruition it takes absolute vision doesn't it there's a huge movement of people who are working on these sorts of interstellar spacecraft interstellar uh colonies this idea of sending people out um and you know starships that go for multi-generational starships that just carry on but can you what sort of life would that be and then there's all the moral issues of raising children in this you know interstellar starship you make a decision for them as well don't you yeah you've made that decision for them and then there's the irony that as technology advances, you send off your interstellar starship.

Technology advances and 100 years later overtakes it and gets there first. And you arrive and you find it's already settled. Oh my God, you'd be so angry. Okay, Robert, we have this question from Richard. Not our Richard, a different Richard. He says, hello, when taking photos of far away galaxies, how do you manage not to get anything in the way of the photo? Well, Richard, the answer is it really often does happen.

And, you know, there are many natural alignments where you see one object in front of another one and only uh very recently in december there was a hubble photo of another you know memorably named galaxy ugc 11537 230 million light years away beautiful galaxy and uh there were two bright stars in our own galaxy that dominate the picture which are probably about 10 000 times closer to us so the simple answer is it does happen a great deal. There are sometimes, I mean, sometimes you seek these things out. So you might, for example, like, you know, if you get a planet in front of a star cluster or something of that kind or near a comet,

these are photos that add a lot of interest. And so people, you know, will look for the time when that's happening and deliberately take a picture then. They'll also look for examples like there are star clusters that are associated with or in the same line of sight as nebulae but aren't associated and there's a good example in the winter sky called Messier 46 which is fairly far south from the UK. You can see it but it's not very high and that is a star cluster that has a planetary nebula, the remnant of a star like the sun, probably in front of it.

You know, it's perfectly lined up with the cluster, but it doesn't seem to be part of it. So this sort of stuff does happen a lot. And frankly, when it's a natural alignment, there's obviously nothing you can do about it. Now, the more regrettable one is when you've got things like abundant satellite trails that, you know, maybe you want to take a picture of those trails, or maybe they're spoiling the view. And obviously's that's happening more and more as we launch more things into space but but yes i mean the simple answer is a lot of the time we just can't avoid it and we we just enjoy the view and as long as you know it it's fine and there are i suppose there yeah there are also examples where we're not quite sure and we have to measure the speed at which the different objects are moving to

understand if they're genuinely associated yeah it's actually sort of something that massively affects my research especially when you so there's a lot of people who try and work out if galaxies are merging if they're just close by to each other you know if they look like they're sort of coming together but are they actually at the same distance and if you if you can't get what robert was just saying about getting the speed that they're moving away how do you actually know and stuff like that but there's also the really famous image of hoag's object which is this really famous ring galaxy. So just like a blob central

and then this beautiful bright blue ring. And it's so rare to see it. But if you look in the gap between the ring and the blob in the middle, there is another ring galaxy in the background. No way. Yeah, so it's so crazy that you see those two aligned like that.

But most of the time, yeah, it's just a great whopping big star and it takes ages to mask it out in your data and it's really annoying and yeah well that's what i was going to say because how do you counteract that because it's not like you can just say oh excuse me um do you mind just being less bright uh you're kind of ruining my image here how do you go about interpreting that data and trying to undo yeah that brightness as well yeah it's what becky is saying you know you've got to find a way of masking out put it aligning your spectral slit so that it doesn't go over the star and so on but you

yeah you have to accept and understand probably some level of interference it's it's just how you when you look at your data knowing what's coming from what that's important. And yeah, that certainly can be difficult. Yeah. Okay, Becky, so this is a question from Sophie Pouser and she's got a question about quenching. So this is when a galaxy has stopped forming stars. So Sophie says, having listened to your podcast for the first time, I know I'm late to the party,

though I suppose astronomically speaking, I'm not that late at all. It's very true. I like that. But she says she had a few questions. So if galaxies can die via quenching, can all galaxies in the universe eventually be quenched?

Will they be able to return? Or are the conditions to make the galaxies not there anymore? So let's just start with that first one. Will this happen to every galaxy in the universe? In theory, yes. Yeah, all galaxies. If you starve them all of their fuel of hydrogen gas,

you know, whether that's an inflow of hydrogen gas from the surrounding regions, or if you take away the hydrogen gas in the center, in theory, yes, you could take away their fuel to make more stars, and they would all become quenched right now that's not to say though that those galaxies can't then be what we call rejuvenated so we talk about a rejuvenation in star formation instead if you then add a little bit of extra hydrogen back in again either if you have two galaxies merging or something like that so what we do it when we when we sort of think about how this is happening we sort of think about it as a closed box system right so you have the amount of hydrogen you have um but if you rejuvenate you actually you it's no longer a closed box system right you're actually adding

something in that wasn't in there anymore you're sort of adding ingredients so the question is really when we model it are galaxies really closed boxes or are they not you know and so are there other things that can not just cause quenching but also rejuvenate too right you know do you have supernova blowing out gas and then that circles back down and eventually falls back into the galaxy and then that's how you've got this sort of like cycling going on recycling you know hydrogen gas as well um the main thing is mergers bringing in extra hydrogen but if the universe is expanding and everything's eventually getting further away then it might there might be a scenario in the future of the universe where everything is too

far away that you don't have a rejuvenation of star formation and then you're just gonna have to wait for the hydrogen you do have in your galaxy to cool back down after being heated up by all these supernovae to form more stars but that takes a very very very long time nice thanks becky okay so i want to take a break from the questions for a moment because we all had a pretty excellent christmas present didn't we if you hadn't heard especially from mine and Becky's streaks across London to Lancashire uh the James Webb Space Telescope launched on the 25th of December 2021 and since then we've had confirmation that it's fully unfolded it's deployed it's made it um so before we get ahead of ourselves there was anyone watching on Christmas Day? Absolutely, yes.

How could you not? You know, it was extraordinary. And I was a little sorry for the launch team having to give up Christmas, babe. I guess they didn't mind too much. I mean, it was one more delayed weather day, wasn't it? They had high altitude winds prevented the launch on Christmas Eve. And then it went to Christmas Day. And I thought, oh, please launch, please launch, launch please launch and it was just great to see it happening I know that the

it wasn't quite as photogenic as we'd like it's beautiful to see the launch and it was in clouds so we couldn't see anything anything at all and I was so stressed I was like this is not a Christmas present I'm already stressed cooking this bloody turkey now it was stressful that and also i just thought you know what i missed looking at it was a chase plane so you saw it working through the cloud deck yeah that was that there was nothing you know we didn't see any but that was the last few of the telescope except from all these amateur astronomers well until they had that camera that was on the second stage when it actually released the telescope from the rocket but you know that was a really late like last minute addition to the whole thing?

They weren't going to do it. And someone went, yeah, that is the last view of it we're going to have is like when it's put into the actual rocket. We should really, you know, see if it disconnects okay. And that was how they knew that the little solar panel popped out early as well. Because they actually saw it happening right after it had been jettisoned by the second stage of the rocket which was amazing yeah i think i've been anxious for weeks about this i was anxious for the launch i was anxious for you know reaching the correct trajectory i've been anxious about it all unfolding properly you know having covered this for well it

seems an eternity i guess it's only 10 years. Having seen some of the components of this, I've been lucky enough to see the mirrors, which were in a clean room, within a clean room, within a clean room when they were, you know, getting these working. And we still obviously got to align the primary mirror with this. But it's such a shame, as you said, we haven't seen more. I was sort of wondering, because I've read about why they couldn't have cameras they can't have cameras on it yeah and there are lots of reasons why you can't have cameras on it it's too cold mainly yeah um but it would have been great if they'd almost sent a little spacecraft alongside it

yeah like a little drone you could take pictures you could see it i'd love to see it in space there's nothing to stop us sending a little CubeSat. We launch stuff to L2 all the time. Yeah, that's true. So that would be amazing because we can see Hubble. I mean, when Hubble was serviced in orbit by the space shuttle, seeing that in space, I just think it's one thing seeing something on the ground, but actually seeing these things in space is just awesome.

What if we can take pictures of Pluto? Surely we can take a picture of something at L2. But Pluto reflects the sun's light. This thing's got a giant sunshield on it to not do that. Blocking the view. It's reflecting starlight, isn't it? But apparently just about enough that you could see with your eye. What I loved about it, though, I mean, Richard, you'll know,

the first rule of any space mission, right, is like no moving parts because everything can go wrong right and it's like the james webb went and so they had obviously all this unfolding obviously palaver with it all which i had learned had 344 single points of failure yes i know all if any one of those things had gone wrong the whole mission would have been scrapped. But also, one of the instruments on board, the NIRSPEC, no, yeah, the NIRSPEC's like multi-object spectrograph, has 250,000 apertures that can be mechanically opened and closed.

A quarter of a million moving parts on one detector. And I'm just like, it just puts it into perspective, like just the sheer scale of all of the different new things that they've gone on to try and he said richard that you were bothered about you know aligning all the mirrors i'm like we we do that all the time on the ground that is the bit that i am least worried for right because the actuators on the back that are going to move and tip and tilt and curve and everything they're using adaptive optics on telescopes on the ground all the time so i'm like i'm sure it'll be fine i think we've got that bit but all the moving parts i was like oh god i think the other issue with this

and the other extra peril this is all the problems that we know the james webb space telescope has had over the years particularly quality control you know when they tested them in the reason one of the reasons it's so delayed is because when they did testing a few years ago, all the fast things fell out, you know, when they started shaking it for launch. So, you know, there's just all these issues and they think there was so much resting on this, so many careers resting on this as well.

And obviously we've had some questions in about James Webb. So Frederick Cossette has emailed about its destination, which is Lagrange Point 2. And he asks, we all know and heard about Webb heading for L2 and that it will not really be on L2, but going around in a circle around that point. How does it orbit around the empty space at that point? Becky, do you want to take that one? Yeah, I mean, I have had people ask similar questions. I mean, most people have actually asked why does it orbit around l2 not just how it orbits around two so why for first of all is because so l2 is this point which is 1.5 million kilometers further away from the sun than earth

is in a direct line with the sun and the earth so it's actually shadowed by earth and yes james webb has fuel on board but it also needs power to run all of its electronics which it gets through solar power power, which is on the other side of its big sunshield. And so if it's shadowed by Earth, it actually gets about 60% less solar power than it needs. So that's why it's orbiting L2, is so that it's actually orbiting at a further distance than the moon orbits from Earth, so it's not in the moon's shadow either. So that's why, so it gets gets power the how is a funny thing just to do with the fact that like how all of the gravitational forces essentially interact between the earth and the sun so when we picture gravity we picture it in einstein's picture of like mass curve space time and you picture the sun and earth sort of depressing space and the lagrange points that the sort of like the

hills the saddles where everything is nothing's going to roll down either earth's earth's valley or the sun's valley if you put them there and i think that's what frederick is getting at here is that how can it orbit around something that there's not actually any mass there it's this hill but what i just described is sort of in what you'd call like the xy plane that flat plane but obviously there's also the z axis going up out of that as well yeah and so if you actually work out what it looks like in that plane say the zy or the zx it actually looks more like a ball and so essentially what what james webb is doing at l2 is sort of being set flying around the edge of a ball essentially um so yes it's a stable point in

one plane but in another plane it's a bone so it can do that and actually orbit around it even though there doesn't isn't anything actually there obviously the fuel on board keeps it in orbit it wouldn't actually stay in orbit if you left it there it would eventually drift and that's why the fuel is so important as well as aboard james webb and it was great to hear that it didn't actually have to use that much to correct after the launch either. So should have a lifetime of a lot longer than we originally thought. Yeah, that's great.

Twice as long. And so Robert, what is that next stage for the James Webb Space Telescope? So the telescope is now, at the time we're recording this, almost in its deployment orbit. I checked the NASA website yesterday. It's 96% of the way there.

So perhaps by the time this goes out, it'll be all the way there. It's Monday the 24th, I think, is the arrival. I've got it in my calendar. I think by the time this goes out, it'll be there. But then you've got about another six months before we start to see the first images back from it. That's the estimate.

They're being a bit cagey about exactly when we'll see those first images because you still have to do things like make sure the optics are working properly, switch on all the instruments, try them out, and so on. And after that, then you start to see the first images, we hope, and you know, they'll presumably get refined over time. So we should, but that will be really exciting. In the middle of this year, we should see those things. Now, it won't look at the cosmic microwave background in the same way that some other probes has, because it's using a different wavelength it's not using radio microwave wavelengths it's using mid-infrared but what it will do is look almost back to that or further back to that by looking at the first stars and galaxies the very first stars and galaxies so even further away even further back in time than gnz11 we hope to see

the very first stars switching that when they when were born. And the thing is they're moving away from us so quickly that the light is really redshift. It's really reddened. So you need an infrared telescope like James Webb to see them. So that's really what we're looking for. I think one of the biggest tasks of James Webb is to do that. Yeah. And it's so exciting to think about. I mean, you said like six months until the first images.

That's going to be the first science images as they do all the commissioning there's probably going to be like pr images released well i'm so excited to like see those but also i'm like a load of my colleagues we've all got bets going on what's going to be the first like pr image they release that they take with james webb so it's like a lot of people saying you know the pillars of creation i was gonna say the eagle nebula because the other day right the hubble space telescope twitter account tweeted like it's yeah optical image and infrared image that hubble took of pillars of creation be like oh look at the difference look what you can learn with infrared and then james webb retweeted it oh we. We're like, right. I reckon it's going to be Pillars of Creation, right?

Because it's so iconic. It's one of those iconic Hubble images. Or I think it'll be the Hubble Ultra Deep Field. The one where it's like 4,000 galaxies in this tiny square patch of sky. Because James Webb will be able to see even further back fainter things that the light for Hubble can no longer see.

And it'll be like whoa look look how many more things yeah james webb sees i think that'll be a great pr image too yeah i just yeah i can't i think there's just bets going about what it's going to be um it's first light i'm so excited oh my gosh can you tell yes i think i think listeners should probably tweet tweet us and say what they think what's their money on don't part with any money whatsoever but obviously don't give me your money yeah um okay so let's move on to more questions becky we have this question from gaurav sharma and they've asked i've always wondered why are hydrogen and helium so rare on terrestrial planets in our solar system why why are some elements more abundant than others?

Yeah, it's all to do with, you know, how much each element weighs. So hydrogen and helium are some of the lightest elements. So you have to have a really big object with a very large gravitational field to hold on to something that's so light. Otherwise, radiation from the sun can come along, hit into those gases and essentially take it off and take it with it so we think in the formation of the solar system like heavier elements almost sank towards the center whereas the lighter ones were sort of pushed out to the outskirts by the newly formed sun essentially with this what we call this solar wind this radiation from the sun um and so we know that there has to have been hydrogen around to form the sun, obviously. Um, but then that was sort of dispersed after that and cleared out. So there's no planetary atmospheres with hydrogen closer in anymore, but it's likely that when they were forming, they probably did like Earth and like Mars and Venus when they first formed probably did have quite large hydrogen atmospheres, very fluffy, not very very dense and the sun just sort of came along

and whooshed them all back out yeah they're out to reach the solar system yeah um and so from then let's move on to gas giants with this question from gerwin and they've asked how or maybe why is a better question do all of the gas giants have rocky moons when they themselves were formed in an area of space that led them to being gas giants yeah they're the leftovers essentially so it was the region of the solar system where you could have hydrogen there it wasn't affected by the solar wind but you still had all these clumps of rock as well so if we remember how sort of we think planets are formed from like what essentially look like asteroids right we call them planetesimals sort of baby

planets lumps of rock all these collisions of these smaller bodies come together and eventually it's sort of rounded over time so where jupiter for example if we take jupiter as an example where it formed it will have been a big sort of like messy clump of lots of bits of rock embedded in a big clump of hydrogen the hydrogen was all attracted to the biggest object in the center which ended up being jupiter and then as that happened sort of the rocky bodies probably were dragged into jupiter as well by that condensing gas that's all falling down into jupiter once more once that's all sort of settled you know then everything that was left over the rocky lumps would then form the moons because all that all the gas has sort of ended up on jupiter instead and also collide but also jupiter saturn uranus neptune they're so

bloody big if there's an asteroid gets so like too close it's gonna get captured by its gravity you know jupiter even has these two little we call the trojan asteroids that trail and lead jupiter in its orbit as well these big sort of messy clumps there as well. So half of it's sort of how it formed in the first place and half of it's sort of the four odd billion years that you've had since of it just capturing lots of lumps of rock that strayed too close. I love that, the scientific definition. They're just bloody big.

Okay, Richard, we've had this question from Elena Jolkva. And she's asked, I liked your episode with astronaut Samantha Cristoforetti very much. I mean, so did we, best friends, obviously. And while she was telling you about all of the experiments the astronauts perform in space, I was wondering how they handle experimental controls so that samples aren't exposed to microgravity, especially for living things like worms. And Elena actually went on to say she was worried about the worms well being. I mean, I would absolutely be fuming if I was a little worm going about my business and suddenly I found myself blasting off into space. I'd have something

to say about that. So yeah, the story doesn't have a happy ending for the worms i'm afraid either so these are microscopic worms about one millimeter long so not like earthworms um they live in bags with the food um the reason they study them is because they have a similar body wall muscles to our own skeletal muscles right so scientists can study them to understand about muscle wasting particularly in space but that can be applied back on on earth as well and so all this is based on genetic analysis so they're looking at what changes they see genetically in microgravity with the the worms and what effect that has on the muscle genes of the worms, and they compare that to what they already know about the genetics of these worms on Earth.

So there's your control, if you like. They already know this stuff. Some will be treated as well with drugs to see if they can counter the effects of muscle wasting. So using similar drugs that we'd use against muscle wasting on Earth. So that's the experiment, essentially. We know a lot about these worms,

send them up into space, see what happens, compare the genetics. So to stop them getting the effects of gravity when they come back to Earth, they freeze them on the space station and then bring them back. So that's how they bring them back and then they can analyse them and study them, find out what's going on genetically,

and you've got the comparison. Okay. Well, Elena, I hope that... Sorry, it's not a happy ending. Sorry, it's not a happy ending. RIP worms. And Robert, Tom D on Twitter asks, what percentage of the stars we can see with the naked eye

are actually stars, and what percentage are actually everything else, like galaxies, novae, planets, etc? Etc. Yeah, well, it's a good question, Tom. And the answer is that with our eyes and absolutely specifically with our eyes, most of the objects you see in the sky are stars. So there are, you know, maybe on a very good clear dark night, you might see a couple of thousand stars. And you can see at most six planets, just about including Uranus, one asteroid, Vesta, a few star clusters, and they generally look like

fuzzy blobs with the eye. You might see there's a few exceptions like the Hyades and the Pleiades in the winter sky. And then a few external galaxies like Andromeda and the small and large Magellanic clouds in the Southern Hemisphere that orbit around our own galaxy, the Milky Way. And then beyond that, you know, you're looking at things like patterns in constellations, the arch of the inside of the Milky Way, the occasional bright comet, and obviously things like meteor showers too. But the answer to the question is, with your eyes, most of what you see is stars. It's completely different.

As soon as you get a big telescope, then most of the background objects are galaxies. But with your eyes, it's stars. And on that final note, Robert, what are some of the things that we can see in the night sky this month? Yeah, well, it's still very much the winter sky. You know, in February, we've got Orion and the stars absolutely stunning and obvious throughout the night. You know, get a bit easier in the evening as February goes on. Most of the planets are pretty hard to see at the moment. So it's not really worth putting much to effect into that. But if you're lucky and you're up early enough, not

terribly early in the winter, you can see Venus rising in the morning sky if you just look towards the southeast. And if you have a pair of binoculars or a small telescope, you might see it as a crescent. And also this month, I was thinking about other things, other kind of challenges, and it's a good time in the winter months to look at them into the spring to look at the moon, the kind of challenges and it's a good time in the winter months to look at them into the spring to look at the moon as it'll be pretty high up from a few days in early February through right through to full moon and a good a particularly good time to look is around the 8th of February when it'll be in Taurus above Orion that night high in the sky get a pair of binoculars or telescope and you'll easily see all the usual things like craters and mountains and these big lava plains and rills and wrinkle ridges and all the evidence of ancient volcanic activity.

But if you want a fun challenge that night, then you should look out for something called the lunar X, which is an optical illusion, a so-called clar obscure effect, a contrast effect. And that's when the sun rises over the rims of craters of Blanchinus, Lakai and Puerbach. And as the sun rises, the tops of the rims of the craters create an X shape. And just a bit higher up the terminate, the night and daylight, you find a V shape as well. And an excellent time for the UK, because it's very time sensitive, is late afternoon. So still when it's daylight and early evening on the 8th of February. So that is my kind of top tip for an unusual thing. You might not have seen this in the coming month.

And apart from that, when the moon isn't in the sky, it's glorious at this time of year because they've just got a very bright, bright stellar vista. Look out for some of the star clusters like Messier 44, Persepe the Beehive, which is in Cancer, just a little over to the left of Orion, around towards the east of Orion. And it has at least,000 stars in it. You can easily see a few dozen. And then another one is Messier 50 and Monoceros the Unicorn, which is a really faint constellation, but helpfully it's above and to the right of Sirius, which is the brightest star in the whole sky. Gosh, tons to do. Beautiful.

Also, my thing, because I love seeing the big planets, Jupiter is leaving us soon. So catch Jupiter while you can you can right because it's going to go behind the sun we're not going to see it again till like april but i it gets that part of the year obviously orion is so obvious that this part of the year when i can see mars the evening ritual is to say hello to mars and now we're at the stage of the year where it's say hello to Orion. So that's what I end up doing. That's it for this month. We'll be back next month with an episode about our good pal, the moon.

How has it actually taken us two years to do an episode on the moon? I have no idea. We've just, we've been like scanning the night sky going, no, not you, not you. Not yet, no, hang on. Not yet. No, hang on. Not yet. In a moment.

Stop being so bright. Anyway, thank you to everybody who sent in questions. We're sorry we couldn't get to all of them. We have a growing pile, so we'll keep adding to it. If you have a burning question for the team, email it to podcast at ras.ac.uk and we'll try and cover them in a future episode. Until then, happy stargazing