The Supermassive Podcast - 2: It's All Relativity...

Episode Date: February 20, 2020

This month, Izzie Clarke and Dr Becky Smethurst explore relativity, gravitational waves and the photographs that made Albert Einstein a household name. Astronomer Robert Massey joins us to talk through SpaceX's Starlink and what we can see in the night sky. Plus we have a special gift from poet laureate Simon Armitage. With special thanks to Professor Toby Wiseman from Imperial College London and Royal Astronomical Society librarian, Sian Prosser. You can send your questions to the team via [e-mail] or tweet @RoyalAstroSoc. The Supermassive Podcast is a Boffin Media production for the Royal Astronomical Society. 

Technically, right now, we are all travelling through time. E equals mc squared, what does that have to do with anything? Come back! It was like a Wilson moment from Castaway, wasn't it? Not only is it space and time bending, but it's actually also quite mind bending. The man, the myth, the legend, Einstein. Hello, welcome to the Supermassive podcast from the Royal Astronomical Society. With me, science journalist Izzy Clark, and with astrophysicist Dr. Becky Sveathers.

How's it going, Becky? Yeah, good. I just got back from a trip to CERN, so I am both loving life and exhausted. What were you doing at CERN? I was having a fun trip there, seeing all underground and the experiments and everything chatting to some people doing some interviews for some videos it was really good fun so no actual you know in the lab looking at things no unfortunately not no as an astrophysicist that's it's not really built for my science because they look at the tiny things so and so have you noticed anything different about episode two so far um i don't know we're in the council room still surrounded by books still um we're still going to talk about research and

history and what you can see in the night sky but oh maybe there's something different about the name maybe yeah so since the last episode we've learned a thing or two about trademark law and we we don't want to be confused with Space Rocks, a partnership with our friends at the European Space Agency. So we've changed our name. Still, a huge thanks to everyone that sent in suggestions and listened to our first episode on seeing the invisible universe. And if you haven't heard it yet, then get to it after this one. But this month, the man, the man the myth the legend Einstein. Drum roll. Yeah buckle up because we'll be getting to grips with relativity plus we'll be exploring what's in the Royal Astronomical Society's library and we've got a special treat from the society's

200th anniversary but let's get to it. If I asked you to measure an amount of time with a stopwatch or a distance with a meter ruler, you'd probably take that measurement as absolute. It's accurate that it's not going to change. And you'd be correct if we were exploring how Newton looked at the world. But in 1905, a young Albert Einstein came along and shifted fundamental ideas in physics with how we viewed space, time and how gravity works. This is the starting point of exploring relativity. I spoke with Toby Wiseman from Imperial College London who was able to help me get to grips with the subject. We need to start with space and time.

What relativity is, there are two theories, special and general and general follows on from special, they're all about space and time and how we change from the old Newtonian way of thinking about space and time to a more modern perspective on space and time. So what Newton took to be absolute was space and time, and they were just fixed and everything worked within them. And the first thing that Einstein said in 1905 was that actually they're not fixed at all. They depend on who's perceiving them. And the first thing that Einstein said in 1905 was that actually they're not fixed at all. They depend on who's perceiving them. And what is fixed is something quite different. It's the speed of light. That must have shaken things up quite a bit. Yes, absolutely. But then, remarkably, Einstein went and came up with the understanding that in fact not only do different people

experience space and time differently so space and time somehow are not fundamental objects that are absolute but they're actually dynamical objects and in fact space and time as objects and energy move through them get deformed and bent. And it's that, quite amazingly, that gives us, in fact, what we call gravity. So Newton thought that things moved because there was a force acting on it. But Einstein is saying orbits and movements exist because the space around us is bending and shifting. Yes. However, what Newton and Einstein both agreed on is essentially one of Newton's laws. So Newton said, you move in a straight path through space, and indeed time in a sense,

if no force acts on you. And so Newton says, you go in an orbit if you're in a spacecraft around the Earth because there's a force pulling you into a sort of circular orbital path. What Einstein says is that he agrees with Newton. He says, indeed, you travel in a straight line through space and time if there's no force acting on you. travel in a straight line through space and time if there's no force acting on you. But in general relativity, space and time get deformed and bent by matter and energy. So in Einstein's picture, the Earth deforms space and time around it. When you're in your spacecraft orbiting, there is no force of gravity acting on you. There's no such thing as a force of gravity,

according to Einstein. But what you're doing is following a straight line but in a curved space and time. And when you look at what a straight line is in that curved space around the Earth because of its mass, you find it looks like an orbit. So it's a very different interpretation of, or rather a very different physical reality. At the level of the solar system, it gives very similar results to Newton, although not exactly the same. And one of the first big pieces of evidence that Einstein understood already in 1915

was that the orbit, for example, of the planets would be slightly different to what Newton said. And it had actually been observed for Mercury because it's traveling fast, one of the fastest planets, and it's near the sun, of the fastest planets, and it's near the Sun so the gravitational effects are strongest. It's the planet that's most affected by Newton not being quite right. And there were measurements of a deviation from Newton's predictions and they

were resolved by Einstein's theory. And do we only see this on massive scales or are we seeing this all the time? Well, in the early days, you could only see it on big scales if you looked appropriately. But as technology has proceeded, we can now see general relativity on all sorts of scales. So, for example, one of the predictions of general relativity is that because space and time are bent by mass, for example, clocks at different heights above the Earth or indeed any massive body tick at a different rate. I find that fascinating. So technically, could you say that, you know, if you stood, we're in a very tall building here in the centre of London. If I stood at the bottom of this building and you stood at the top, we would experience time slightly differently? Yes. And in fact, I think I can

tell you the numbers roughly for the Shard. If we were at the Shard and we synchronised our watches on the ground floor and you then sat up on a high floor, maybe a couple of hundred metres up and sat there for a year, which seems a little bit unreasonable, but sat there for a year. And I sat in the reception at the bottom for a year. And then you came back down and we compared our watches. And if you had a very good watch, so it kept time. And so did I, they would differ by about a microsecond, a millionth of a second. So it's a very small effect, but it's a very big effect compared to what we're able to measure. And in fact, for GPS satellites, the effect is even bigger. GPS satellites, because the way GPS works, it's all to do with very accurate

timing. So there are atomic clocks in the satellites, there are atomic clocks on Earth, and by comparing all of these various clocks, one can deduce position on the Earth. Now, these satellites are something like 30,000 kilometers up from the surface of the Earth. Now, these satellites are something like 30,000 kilometers up from the surface of the Earth. They're much further away. They're in a weaker gravitational field. They're also moving fast. So they're moving not at the speed of light, but they're moving much quicker than some reasonable fraction. And these effects are large enough that the clocks on the satellites actually tick at a slower rate than on Earth by something quite substantial, like 50 microseconds a day is lost. And also the rates of the clocks relative to each other, because they're in slightly different orbits, moving slightly different

ways at slightly different heights, those relative differences also give rise to quite big effects, all of which would, if we didn't understand them, sort of invalidate GPS. So GPS, one of the things that has to go into the technology, is an understanding that clocks do tick differently. And in future generations of such systems, that will have to be taken even more into account. Not only is it space and time bending but it's actually also quite mind bending. That was Toby Wiseman from Imperial College London.

So clarify Becky, we have general relativity which is looking at space and time bending to describe gravity and then we have special relativity. what is the difference there yeah so general relativity is all about gravity and special relativity has nothing to do with gravity right so relativity special relativity is all about speeds and how you perceive speed and time and distances differently in the universe so everyone will be sort of familiar with the concept of relativity because we associate it our everyday lives we experience it every day so for example if you're playing catch with a friend on a train for example obviously as i do as you do all the time on your daily commute um you would record the speed of that ball at say five meters per second let's say right and this person on the

train who you're playing catch with would record the same speed if i was on a train next to your train going at the same exact speed and i looked over and was like oh look two people playing catch I'd record the speed of the ball at five meters per second but if I was on the train platform and your train terrified me screaming past as it went I'd record the speed of the ball standing still as the speed of the ball plus the speed of the train right okay so it's working out what speed looks like in different points yeah different perspectives yeah and that's what we mean by relativity it's the relative speed of something to you either moving or still where Einstein made the big leap for special relativity

was to say if instead you were playing laser tag on the train right again as you do on your commute then the speed that the light that came out from the laser would be the same for you on the train as it was for me stood still on the platform and that's because it's light it's constant nothing never going to change it's the ultimate speed limit right so and if you think about it that's kind of strange because if you measure the speed the same we know that speed equals distance over time so if the speed can't change then the distance and the time has to change so like the faster you're traveling at like the shorter distances you measure and the slower time passes for you man this stuff is

ridiculous but there is the famous equation from Einstein, E equals MC squared. What does that have to do with anything? Yeah, people often wonder how it all fits into things. And it was just Einstein thinking about, OK, well, if things are moving or if things are not moving, if they're stationary, if they're still, then what energy do they have? If people remember, like at high school, we always used to like kinetic energy. If you're moving like half MV squared, like where M was your mass and v was your speed right but what about if something is completely still does it still have energy well yeah it has the energy that's trapped in the stuff that makes us up right we still have energy when we're when we're stationary and so if you if you run through

the maths which is what einstein did he came out with saying okay something that is completely at rest and not moving would have the energy m c squared right and that's why we see it plastered all over the like chalkboards and films if there's one scientist they're like oh equals mc squared yeah it is the most famous equation ever right i would i would argue that's my hill to die on right it's the most famous equation ever amazing so i could honestly go off on so many tangents here but I'll try and regroup so let's talk about twins because if we're talking about how we experience time if you have twins they are born at the same point essentially if one was traveling through space does that mean it's older like how does that work it's weird isn't it actually so time would pass slower for them so they wouldn't age as much as their twin who was stood on earth or it's technically

stationary and not quite because obviously earth is moving but in relative terms like the twin who is moving through space would be much faster right and so they would be aging much less because time would be passing slower for them so if they could then come back to Earth, like one twin could be like 80 and the other one could still be like 50 or something. Becky Smethurst, are you saying that time travel is real? OK, so technically right now we are all traveling through time. Right. Because time is passing. We are all technically time travelers. It's just we can't control the speed and direction which we travel through time but if you travel fast enough then you can change the rate at which you travel through

time in the fact that you can sort of slow it down for you and then less time sort of passes for you compared to other people so in that sense like if you wanted to go to the future for example then you could technically do that work out the speed and how long you would need to travel at in order to arrive 200 years in the future and it'd be like five years for you or something but the thing is you'd never be able to come back again right what we can't do or with our current theories at least you know never say never what we can't do is travel backwards through time you can never reverse the direction of time. And that's where like I think most people want time travel. Damn it. Sorry to just poo-poo on your dreams. Yeah, well, thanks for clearing that up anyway. Now, back at the turn of the 20th century,

Newton's laws of gravity had been used to describe the orbits of planets in the solar system pretty much perfectly, but they didn't quite predict Mercury's orbit. Now, Einstein supposedly had the answer in general relativity, but scientists needed an eclipse to prove it so that general relativity could become accepted theory. Now, cue Arthur Eddington, who raced to the other side of the world in 1919 to capture a total solar eclipse that catapulted Albert Einstein and his way of explaining our universe to centre stage. And we're joined now by the Royal Astronomical Society's librarian Sian Prosser. Hello. So Sian, explain to us what are we actually looking at here? We've got a range of photographs of the 1919 eclipse. A few of them are on glass plates. We've got some positive prints of the

eclipse expedition photographs that were taken in Prince JP Ireland. That was the expedition led by Arthur Eddington and Edwin Cottingham. We've got a photograph taken in Brazil. That was from the expedition led by Charles Davidson and A.C.D. Cromelin. And we also have a copy of one of the RAS Journal's memoirs of the Royal Astronomical Society. And that contains a negative marked up copy of the plate. And that was published in this summary of the eclipse results that were announced on the 6th of November 1919. I mean, they are stunning to look at, aren't they, Becky? They really are. Like you can see that ring of fire of the light of the sun

sort of scattering around where the moon's blocked it out. You can even see this incredible sort of solar prominence that comes out of the sun here, which I like to call sort of a sun burp, if you will. And you can see this sort of material coming out and falling back down and the markups as well on this one where they say you know there's a star here where they've got sort of crosshairs they're just incredible to see that they've been able to pick those out against the light of the sun they could just be noise it's really kind of great and gives you chills to sort of be staring at them and so

this mission set off just probably as World War I ended, which I would imagine would have been quite difficult in itself to, you know, gather a group, get all the kit together, then, you know, head off to two different locations. Maybe Becky might be able to help with this. So they got there, they set up to try and take these photos. What are they trying to capture? Why are they looking at this eclipse?

Yeah, so what they were trying to see was whether when you block out the light from the sun and then you can hopefully see the stars in the background that we can't usually see during the day because the sun obviously is far too bright and you know it's like looking at an led next to like a stadium floodlight you'd have no chance so you can block out the stadium floodlight you'd have chance to see the tiny stars in the background and what they hope to see is that the light from those stars that came from behind the sun would essentially get bent around the sun so if you sort of follow the idea of where light travels in straight lines and you're watching a bent path come towards you you'd predict that that light

came from a different direction ever so slightly a very slight sort of shift and so what they were going to do is take these pictures during the eclipse when the sunlight would block out and then compare it to an image of the same region of the sky taken at nighttime when there's no interference from where the light is coming from and compare the positions that they recorded and if you can see a tiny shift in the positions then you're like that is the mass of the sun that's literally curved the space that light's traveled across and it's just amazing seeing these images because the stars in the sun that's literally curved the space that light's traveled across and it's just amazing seeing these images because the stars in the background are so incredibly faint as someone who's used to dealing with like very modern astronomical data it's incredible to see

like what they were working with in terms of figuring out what was a star what was noise what might have been a speck of dirt on their you know exposing plate like it's just it really it does really feel like a piece of science history when you stare at it like that, yeah. And Sian, what did this do for Einstein's name, essentially? Well, the results were announced at a joint meeting of the Royal Society and the Royal Astronomical Society on the 6th of November.

And overnight, the results were spread throughout the world. First of all, the next day in the Times, the headline was, Revolution in Science, New Theory of the Universe, Newtonian Ideas Overthrown. And then the news spreads across the ocean. The New York Times has a front page story on November the 10th, Lights All Askew in the heavens. Einstein theory triumphs.

Wow. So it really sort of threw him to headline news. It did. And it made him a household name. And also Eddington continued to play an important role in popularising science. He was not just communicating the ideas of the theory of relativity to his own peers in theising science. He was not just communicating the ideas of the theory of relativity to his own peers in this scientific establishment. He wrote books aimed at the general public, trying to distill and explain this really fundamental theory.

I like the idea of, like, Eddington, if he could, would have started a podcast. Yeah, we'd interview him for sure. Oh, no, no, he'd be the host we're not here massive thank you to sean prosser there the royal astronomical society's librarian for showing us those amazing pieces of science history this is the super massive podcast from the royal astronomical society with me astrophysicist dr becky smethurst and with science journalist izzy Clark. This month it's all relativity we've been exploring

Einstein's work and our universe. If you want to send in any questions for us for a future episode then email podcast at ras.ac.uk or tweet at Royal Astrosoc. What you might not know is that the Royal Astronomical Society celebrated their 200th anniversary in January 2020. I actually keep wanting to say they celebrated their 200th birthday but perhaps that's not as professional. It's a birthday! It was a good one wasn't it? We had a nice birthday celebration. We did. I think my finest moment of the evening surrounded by what 500 or so eminent astronomers was screaming at the prosecco man to come back he was doing refills we were to say hello to becky and we were just there waiting like oh there he is and he turned

around we both went no come back it was like a wilson moment from castaway wasn't it yeah not our finest moment but it was actually such a lovely evening. It was, and the speeches were so good as well. It was so nice to hear from people who are involved in the society and people who've benefited, you know, from grants, so anything from sort of girl guides to postdoctoral researchers. It was great. I hadn't actually realised how much the Royal Astronomical Society

are doing with other little communities like that, and I think that's so great I would have loved to have had that yes when I was growing up that would have been so good and we've also got Robert Massey with us who's the Deputy Executive Director of the Royal Astronomical Society and it has been a busy month for you guys it really has not only did we have the big party which we all enjoyed and like, I was busy looking around for Prosecco Man and the canapes and all those things. Prosecco Man. As well as obviously doing the important work of talking to the people who are members and the rest of it.

But yeah, this month we've also done things like a rebrand, which is, you know, the kind of corporate thing you have to do after a couple of centuries, I guess. We've got a new logo, which reflects our identity, I think, a bit better. It's much more up to date, and it's got these intriguing features like you look at it and it looks either like an eye which is very very appropriate given that our society is about looking up into the sky you can read it as well as being maybe a binary star a black hole with an accretion disc or a planet or all those kind of things so I think it works really well and the planet as well as a nod to the earth because we're talking about geophysics as well as astronomy and if you look carefully you'll notice the whole thing is tilted over at 23 and a half degrees which is the actual tilt of the earth so

you know it's one of those things it tells the story there's a lot of detail in it and actually i i really like the story i think it's very appropriate i love the new logo like this is the hill i will die on a huge i see like hydrogen atoms and like the big bang in the beginning of the universe i don't know how the designer did it but somehow they covered everything from the human eye all the way sort of through exoplanets and planets and black holes all the way to like the big bang in the beginning of the universe i'm like how did you do that we need to hire becky it's been fun But the other thing that's happened this month is the new stamp set. Now, if I'm honest about this, I didn't expect this to be as big as it was.

It's a fantastic thing. We did a stamp set back in 1970. I haven't actually checked whether there was anything like that in 1920 on our 100th anniversary. But the 1970 one is really nice. I've got copies of those at home. But this 2021 was huge. People love stamps. People do mail much more than i expected the royal mail put out this release about it we promoted it uh we worked with them over the last couple of years in designing them and putting in getting images

that inform the artists so things like simulations of black holes pulsars the uh geysers coming out of enceladus sat Saturn's moon, all these amazing discoveries and work where there was some UK involvement and mostly by people who are actually members of the RAS. But I'm really impressed by it. It's gone viral on Twitter. Loads and loads of people were interested saying, where can I buy one? I want to start sending letters again instead of just emails so I can use these stamps. Black hole stamps. That's a fantastic tribute. Now, I'm a bit low to do direct plugs, but you can basically buy the presentation set for under a tenner,

which I think is a bargain. Yeah. I was actually just about to ask where can I start my stock collection? Well, they've actually sold out in some post offices, but you can buy them online. I'm assured that there are enough stocks, so there shouldn't be a problem. Amazing.

And also, going back to the logo as well, if people want to look at that, then it's on our podcast graphic. So, you know, you can just enjoy it forever. And stare at it and see how many things you can see in it. And the anniversary celebrations don't stop there because there was a poem written by the Poet Laureate, Simon Armitage,

and he's kindly given us permission to use that. So we'll hear that at the end of the episode but back to Einstein very quickly and we've explored the history of how his theory of general relativity became accepted and all things considered it was quite a short amount of time from when he you know first proposed this 1905 then it's published in around 1915 but you know a hundred years later and we're still discovering things that he's left behind yeah it's weird the amount of times that we hear ourselves saying Einstein was right again because we're finding new ways and new regimes to test general relativity all the time so had the 1919 eclipse with the sun but what about testing

general relativity around a super massive black hole you know it's those kind of areas that we're now being able to test it in and you almost kind of wish you wasn't right because then you know you might learn new physics and new physics is always what we want we want to learn something new but it's amazing that a hundred years later his theory is still standing up a test of time and we still haven't found a place that it falls down yet back in 2015 we had the discovery of gravitational waves which it was incredible it blew my mind that like that was something that came out of general relativity that einstein was like oh and by the way you could have ripples moving through this space time if you get sort of this big cataclysmic event like oh by the way two black holes merging and everyone was like sorry what um and it took us yeah a hundred years before we actually managed

to discover those because i mean you think of these big ripples and you think they might be massive but in terms of like the size of an atom it literally is sort of that kind of a scale and to detect these we had to build these huge big l-shaped detectors that essentially pinged a laser back and forth along each of the l shapes and measured how far the laser was traveling and if you detected these ripples you'd see that that change ever so slightly of course if a lorry drove across the road nearby or a rabbit ran across the field or something there would also be some tiny change so they'd build two of them and then if they were on opposite sides of the world and they both detected the same ripples coming from space you'd know that's what you detected and they they really are just like a

ripple in time and space just as casual as that as casually but like you know they'll pass through your body and you won't even feel it but we have you know developed these models over the years of what merging black holes would look like and been like, okay, this is the shape of the ripple we'd expect to find based on Einstein's theory of general relativity. And then we finally detected it and it was like, oh yeah, there's that shape. Like it's incredible. And it just opened up this whole new way of looking at the universe. You know, we've been so almost restricted in a way for the past millennia, how long, you know, humans have been around for in the fact that we've only been able to see with electromagnetic radiation so light um and that's one of the whole things about dark matter being not being able to see it with light and we can only see it with its effect on gravity that we

spoke about last month you know if you haven't heard that yet go check it out uh plug for myself but um and so now we're being able to see the universe in a whole different way and as you see in the loosest possible sense there because we've got this whole new wave that we can see with and so do you think that is the future of astronomy like using these gravitational waves to what pinpoint massive events that have gone on within our universe and you can be like okay let's go and explore over there exactly yeah so we call it multi-messenger astronomy essentially like the different signals we're getting in the in gravitational waves and across the full electromagnetic spectrum we are getting all these different signals from these cataclysmic events or even

you know not that cataclysmic but still sort of pretty energetic events that we can then try and really piece together what's happening on the opposite side of the universe. I mean, who knows what the future will hold? Well, exactly. I'm excited. Hopefully Einstein is still right. We'll be parroting that for the next hundreds and hundreds of years. Shall we move on from Einstein? We have to. So Robert Massey is still with us to help with our stargazing from home.

And I gather that some amateur stargazers have hit the headlines quite recently. That's right. Remarkably, you know, amateur astronomers do still make real contributions to the science. It's really unprecedented. Most areas of science, that doesn't really happen, but astronomy is a great exception. And some groups in Finland supported the work of a professor of astronomy there, Minna Palmroth, and she looked at this unusual type of structure in the northern lines, the Aurora Borealis, and two groups of amateur astronomers imaged it. And because they were located at a distance of about 120 kilometers apart, they were able to triangulate, work out how high it was in the sky, understand this weird wave structure that's going on that they think

is a result of some kind of temperature inversion in the upper atmosphere. So perhaps, you know, there being a cool and hotter layer in the wrong places or in an unusual way. And as a result, you know, she was able to work out how high up they are. It turns out they're about 100 kilometers up in the sky over Finland in that case. So it's quirky and it's unusual. It's the kind of thing, I guess, that if you saw a bright display of the Northern Lights over the UK, you could look out for. Now, those are fairly rare if you live in the south of the country, a bit more common if you live up in Scotland, although

I obviously add that that's not the case during bad storms like the ones we had quite recently. But it is the kind of thing that you can look out for. And it shows, I think, that citizen scientists, even the type that go outside and look at the sky and do this kind of thing, can still make a great contribution. What I love is the idea that, you know, a lot of people will think so much is already known, that anything they do see that looks weird like some stranger war in the sky they'll just assume well someone knows about it somewhere or I could just google it because the entirety of human knowledge is at my fingertips but actually there's so much more still to discover and I love the stories like this allow you to to help out and

do that. And it's particularly true with transient things, with things that are short-lived. So for example, you know, although we haven't seen any bright supernovae in our galaxy for a very long time, not yet, we do see stars exploding every so often as novae. We do see events, things like comets coming into the solar system that we haven't seen before. And there are still amateur astronomers that track those down, take the first pictures and then report them to the professionals. And another event that happened earlier this month is the latest launch from SpaceX's Starlink.

So this is what, a series of satellites in one really long row in the very simplest terms. So Robert, can you tell us a bit more about this project? Starlink is an example of a mega constellation. So you have to imagine there are something like 4,000 or 5,000 satellites working and not in Earth orbit at the moment. But the Starlink proposal could add up to 12,000 to that. And they're not just the only operators, not just SpaceX. There's also OneWeb and Amazon have got similar systems in mind too.

That would really change things in low Earth orbit, because most of these are going to be between about 350 and 1,000 kilometres above our heads, which is defined as low Earth orbit, relatively close to the Earth. Now you'd think the aim of these things is to provide a kind of global internet system. So the idea is if you live, say, in sub-Saharan Africa or the outback of Australia, you can use a ground station to pick up high-speed internet wherever you are the difficulty we have is that if you add that many things to the night sky that you might make it a bit harder to do the science of astronomy and the reason is that you have a lot of albeit relatively faint but nonetheless a lot of dots moving around in the sky that can wreck the images

you try to take of things that are more distant because telescopes are pretty sensitive they'll pick these things up and it may mean that you lose say a certain number of the exposures you make and we're in the process of doing a lot of work to try and understand what the impact actually is it's also possibly a bit of an issue for radio astronomers too because these things are if they're sending powerful beams down to ground stations on the earth if you imagine something like the square kilometer array which is going going to be an enormously sensitive radio telescope coming on the stream in a few years' time, if you point a powerful beam down at one of those antennas, it's not going to do it much good. So we want to just understand it. We're working with the operators. We're trying to talk to them about

how to mitigate it. We're obviously not against everybody in the world having internet access. That's clearly a good thing. It's just that we want to understand the effect of this. Yeah, it's like coming to a compromise in a sense, and not just for professional science's sake, but also for, you know, General Joe Public. You don't want to rob them of their night sky because even in the darkest of skies, there's what, like 9,000 stars visible or something?

Compare that to the amount of satellites they're putting up. People are worried. Because they do look quite incredible because, you know, if you have one satellite that goes up this is what is it 60 all in one chain that are connected and there's this stream that goes across sky because i went to i went on holiday in november and i saw it go across the moroccan sky and i was like oh my goodness i i was freaking out in this restaurant um because i could see it was very enthusiastic to the extent that other out in this restaurant because I could see it was very enthusiastic

to the extent that other people in this restaurant was like turning, looking at me, they're looking at the sky like, what is she saying? Thinking doomsday is coming. No, I mean, we've already had emails from people saying, I saw these strange lights in the sky, you know, and for once, normally we say,

no, it's not a UFO, it's a natural phenomenon. In this case, it's not a UFO, but it is an artificial phenomenon. It very much is something that's planned and deliberate. They will get a bit fainter as they get higher in the sky, but nonetheless, if you have thousands of them in the sky, then that might present an issue for astronomy. So we do want to be aware of it and at least try to mitigate it

to the extent that it doesn't have any kind of major damaging effect on our ability to do science. And finally, Robert, so what are some of the other things that we can look out in the night sky over the next month? Well, coming into the spring is a really good time to do naked eye astronomy and to pick up a pair of binoculars and look at these things that you can see in the wonderful sky above our head. Venus is very bright now in the sky.

If you've been going out in the evening and you look, it's very, very obvious after sunset and increasingly, really brilliantly in the sky for a couple of hours after that pick up a beber knock you'll pick up a small telescope and you might just start to see it shows a small disc a small phase as well uh that's going to be around for the next couple of months or so so do keep an eye on that the moon is really good this time of year uh simply because when it gets to what's called first quarter so when it's half lit or appears half lit, it's high in the sky in the spring. And also the craters really stand out well at that phase. So if you haven't looked at the moon and you've seen craters before,

then do that. It's a really good time to do it. But as well as that, there are also, if you have a dark sky when the moon isn't around and you're away from the lights of the city and it's clear, obviously all those things come into play to get a good view of the sky. If you pick up those binoculars again and scout around above Orion and you come to Auriga, the charioteer, you just look around you might see these small smudges or in some cases actually those smudges resolving into groups of stars. There are a lot of star clusters and parts of the Milky Way that you can see this time of year. It's a really good time to do it. One that's particularly noteworthy is over towards the east. So moving in the northern hemisphere from the left of Orion,

you go to Cancer, which is a faint zodiacal constellation. The stars are really not prominent at all. But if you look carefully and you've got a clear sky, a dark sky, you might see this smudge there. That's a very nice, prominent cluster of stars again. Pick up a a pair of oculus and you'll see maybe 40 50 stars there so all of those things come into view at this time of year and uh you know we still have those long nights um obviously it's not getting warmer that quickly but if you have good weather it's a it's a great time to be looking robert thanks very much that's it for the second episode of the supermassive podcast we'll

be back next month to explore the star in our neighbourhood, our sun. If you've enjoyed this episode, then please rate and review the podcast as it helps spread the word. And tweet us if you try some astronomy at home. It's at Royal Astrosoc on Twitter or email your questions to podcast at ras.ac.uk and we'll try and cover them in a future episode but as promised now here's Simon Armitage with his poem Astronomy for Beginners. You were eight and fishing for planets and stars, slopping a bucket of rain into the backyard. You were waiting for cloudless dark, expecting the pinpoint reflections of Rigel, Centaurus or Mars to

crystallise under your nose, or a constellation, whole and intact, to glaze the surface like a web of frost? Or what if the moon grew hard and dense in the water's depths, like some knuckle of dinosaur bone. You'd need a landing net. But only Polaris proved itself in the liquid lens, then dissolved when you lifted it out on your fingertip. A Russian telescope didn't help. Some camera obscura inside the tube flipped the map of the galaxy upside down. In the peephole eyepiece, families dangled from ceilings like bats and sheep hung from green clouds by their hooves.

You were thirty by now. Tired of the stakeout, tired of panning for sunspots and fool's gold, you traded starlight for birdlife, birds with their costumes and songs and shows. Once, in a shoulder of sand on Windermere's west shore, a dunnock curtsied while eating bread from your open hand. curtsied while eating bread from your open hand. Old brightnesses, old loves, and now you're scanning again for omens and signs, apple bobbing for hypergiants and white dwarves, calling down deep space onto a blank page, trawling for angels and black holes with a glass jar, knowing we're dying, knowing we'll never make it that far. Where did that tin of luminous stickers go, and the solar system mobile spinning on near-invisible thread? When she left home, you crashed out on your daughter's bed and woke in a Navajo cave, a remote language of light coming steadily into creation overhead.