The Supermassive Podcast - 47: BONUS - Could Space Junk Block JWST's View?

Episode Date: December 21, 2023

From barbie dolls, to birds baths, what will happen to all the stuff we have made between now and the end of time? Could a large black hole spaghettify a small black hole? Could more satellites block JWST's view? And what came first, the Big Bang or Inflation? It's time for another deep dive into The Supermassive Mailbox with Izzie Clarke, Dr Becky Smethurst and Dr Robert Massey.  The Supermassive Podcast is a Boffin Media Production for the Royal Astronomical Society. The producers are Izzie Clarke and Richard Hollingham. 

Hello and welcome to another bonus episode of the Supermassive podcast from the Royal Astronomical Society with me science journalist Izzy Clark, astrophysicist Dr Becky Smethurst and the society's deputy director Dr Robert Massey. This is the place where Robert and I take on even more of your questions from the Supermassive mailbox which has been inundated by so many of them that we just had to add these extra bonus episodes in between the main ones okay so robert let's start with this fun question from peter theophilus bevis they say what will happen to all the stuff we are made of between now and the end of time is it possible likely improbable or

impossible that all the stuff the earth is made of will eventually be smashed into bits and then used in the formation of different planets will the people on those planets still be finding our old nappies barbie dolls enameled bathtubs cut diamonds and concrete bird baths well that's a sort of fun and slightly depressing question isn't it the idea i mean this would be the ultimate signature of alien life when we've had space dolls on earth space nappies what a thought yeah so yes no no i mean look okay so it works at different levels this so you have to think back to well or forward to rather the fate of the solar system first of all

and probably maybe maybe not the earth will get swallowed by the expanding sun and as it swells up to become a red giant in five billion years and more in the future and even before then we'll have lost our atmosphere as it heats up so the odds of most of our junk surviving is pretty low and as you get closer to that point even if the earth isn't swallowed then the surface is likely to be covered with lava so all of that stuff is basically going to be destroyed um if you had some of that stuff in space it would survive differently but even plastics don't survive particularly well because they expose to radiation they get broken down into bits so they're not going to do well concrete might but again i'm not sure running the clock forward billions of years

whether we have anything really that would be recognizable after so long so in a sense i suppose you could argue that the atoms from which this stuff is made they would be the legacy so if you if you have the outer atmosphere the sun being dispersed in space having swallowed the earth then bits of us will be indeed spread out among the stars and some of that might just end up in new stars and planets so philosophically maybe just about. And if you consider it on the very long time scale, then there are ideas about whether matter itself breaks down, whether protons decay or not.

Probably not from what I've read, but if it happens, it happens in 10 to the 36 years, which has the wonderful name of an undecillion of years in the future, which I had to look up this morning to check how far away in the future it actually was. That is amazing. And Becky, Chris Ryan has this question on black hole mergers hello everyone from Australia I love the show and I've been reading Dr Becky's book and have convinced the book club in my office to read it as our next monthly challenge my question is can the event horizon of a small black hole spaghettify as it approaches the event horizon

of a larger black hole lots of love from down under chris um so can you start with spaghettification please dr smothers yes well spaghettification is the idea it's also first of all my favorite word in the english language spaghettification let's just have another moment for it um essentially what this is is when if you approach a black hole, the strength of gravity, like the gradient of the strength of gravity, is so steep that it's so much stronger, say if you were falling feet first towards a black hole, be so much stronger at your feet than at your head that you would get stretched out like spaghetti into this long, thin chain of atoms essentially and we see

this happening to like stars if they get too close and they swoop around a black hole they get stretched out by sort of like tidal forces essentially so chris in response to your question about can this happen to event horizons yes but also no not what you're thinking and not what you're picturing. So like an event horizon is not a real object, right? It's not a solid entity of any form, right? It is this boundary around whatever is, you know, the central mass of the black hole, whatever that happens to be, singularity, exotic matter, whatever it is, is this boundary around it where you're no longer getting any light from. Now that depends on the curvature of space itself, right? How Einstein tells us that mass curves space, right? And so at some point the curvature gets so strong that like, you know, light can't escape from it anymore. So as two black holes get closer together,

the curvature of space changes around them. Like you can picture it, you know, as having like two basketballs or two footballs on a trampoline, right? And then you're like, if you're moving them around, you can see how the trampoline is sort of constantly curving and uncurving as you move them. And so what happens as they get closer

is that like the curvature of space changes. So almost like the event horizons reach out to each other and they sort of make like a dumbbell shape in a way uh like a dickie bow kind of thing you know so in a way they do get stretched but it's not because of spaghettification it's just because of the curvature of space around the two black holes changing that makes sense so yes and no because it kind of looks like spaghettification but it's actually two different effects okay there we go hope that clears things up you're probably not Robert here's a question from Klaus about the stuff we send into space and

they say I just read about India sending a solar observatory to the L1 Lagrange point so I started thinking about how many things we can actually send to these points. A quick search told me that we have already parked quite a few objects out at L1 and L2 but can we keep doing that? I'm aware that while the Lagrange points might mathematically be points they are probably more likely to be areas in reality but how big are they also do the different space agencies coordinate where they'll place objects in space or could we someday risk something being sent to L2 and it end up blocking the view of the James Webb Space Telescope hope you can answer this bit of very practical thinking about

space exploration yeah Klaus well help helpfully, as you know, although you're talking about a point actually in practice, what the missions do when they go there is they travel in an orbit around that point. And in the case of JWST, which is the one that we think of as the most recent famous example, I guess, that travels around the L2 point in an orbit that's actually hundreds of thousands of kilometres wide. I hadn't appreciated how big it is and needs to fire thrusters to stay in place. So there is a lot of space to play with them and hundreds of thousands of kilometers is similar in size to the moon's orbit around the Earth. So very, very big volume of space to play around with. But despite that, there's actually some good sort of

space station keeping and space management because some of the missions have actually been moved away at the end of their life to prevent the very very unlikely collisions so WMAP, Herschel, Planck and the Chinese mission Chang'e 2 were all moved into orbits around the sun to make that even less likely so I think you don't have to worry about it in the same way that we do about collisions in low earth orbit which is very congested because you've got tens or hundreds of kilometers with perhaps by the end of the decade many hundreds of thousands of satellites there and that's a real challenge for astronomy as we've talked about before as well as space junk and all the associated issues but i think those missions out at l1 and l2

they're pretty safe yeah and also like blocking the view of jwst like jwst's view is very very tiny i mean the odds of that happening must be so vanishingly small. And it would only be such a transient thing as well. Yeah, it would be like a blink and you'd miss it, pass in front of the view of JWST if something orbited near it even. But it's really cool when you see those videos of... There's a video that ESA have done with the launch of the Euclid Space Telescope back in July, because Euclid's gone to L2 as well.

Gaia is also there orbiting L2 and jdbst so you've now got these three telescopes all in orbit around it and it's really fun like watching sort of like they leave the trace of the orbits on as well in the video so it's almost like that game spirograph yeah yeah it's kid right and you just watch these orbits like build up around l2 and with all three of them just sort of like avoiding each other in this amazing dance, it's really cool. I just don't think I'd appreciated how much space there is at L2. That's incredible. You can't keep something at L2 because you would also have to fire boosters.

Like, yes, we call it stable, but at the same time, it would still sort of roll away from there. So it's much more efficient to keep it in orbit. And they do that every few weeks, don't they, with JWST at Red. It's quite often they have to adjust it to keep it there. Yeah, exactly. So, yeah, because obviously it's moving as well as Earth moves. So that's the thing is that it's actually more efficient to put stuff in orbit rather than trying to keep them at what should be a stationary point if Earth and Sun were stationary, but they're not.

Okay. And Becky, can you answer this question from Sebastian? He says, hi, greetings from Oslo. And first and first of all hope you're getting some good aurora oh yeah exactly um first of all thank you for producing the best astronomy podcast in the known universe which i've eagerly been following since the first episode that already was rocking space but never mind the change of name so that's when you know yes even i don't remember this oh becky it was a big moment in my life when we we first launched as never mind the space rocks and uh oh yeah no i do remember this anyway we move on um here is my cosmological question

what came first the big bang or inflation i grew up when the big bang was synonymous with whatever flashy moment that came first and had no yesterday but have heard more recently that astronomers started putting inflation first on their diagrams representing the history of the universe or rather remove the words big bang near that flash shown as inflation. So what is the big bang, if not the first instant in time and if happening after inflation? Thanks again, Sebastian. Thanks, Sebastian. Yeah.

You have two minutes, Becky, go. Okay, so I think the thing to get across is the big bang theory is not some moment or point in time of creation. Although that pair of words has sort of entered the public psyche and begun to be used by people and also astronomers through the years as well as some moment of creation, which is technically not. So the Big Bang Theory describes everything.

So from the universe in its very hot and dense state to expanding to what we see today in the universe around us. That is the entire Big Bang theory. Inflation is just one part of the Big Bang theory where the universe expanded at an exponential rate for an incredibly, incredibly short space of time. And it went from just expanding in size into to numbers that if even if i said them they would you just wouldn't even comprehend how small and how big it went from and to right and it's just this very initial part of sort of that expansion of the universe and so the reason you've probably seen this sort of like big bang being taken off these diagrams is because using the phrase big bang to mean sort of a moment of creation actually adds so much misunderstanding of how the universe sort of evolved and expanded

that people have sort of corrected their sort of linguistic mistake where it's been picked up to mean this moment of creation and stopped sort of labeling like time equals zero as that because that is not what the big bang is the big bang theory is this evolution of the entire universe and so when we think about sort of like what happened when the universe was much you know younger and it was in this hotter denser state our physics starts to break down you know 10 to the minus 36 seconds well you know into the universe's history so you know even then i wanted to say 10 to the minus 36 seconds after the big bang because it's become so like used in in sort of language but that it's not what it means so yeah 10 to the minus 36 seconds into the universe's history is what i now you know

try to say to be consistent with the idea of the big bang theory being everything yeah because i would actually say it's one of the questions we get sent the most of everything starting from a single point yeah and i often respond like we've done a whole episode on this here you go but it's uh it's interesting what impact that has throughout you know the more and more we look into and talk about astronomy yeah and so i guess if there's any like sort of language nerds out there they'll be absolutely geeking out over this about how it entered like the phrase entered like common language and then just got used in the wrong way and then has like you know sort of skewed people's understanding of it to

the point where it's entered like i'll read papers that have been published by astronomers that colloquially use like big bang as meaning like time equals zero and it's just not right to use it in that way very interesting well thanks everyone and keep the questions coming you can email podcast at ras.ac.uk tweet us at royal astro sock and we're also on instagram at supermassive pod we'll be back next time with an episode about the multiverse i mean like marvel look out we're coming for you but until next time everybody happy stargazing