The Supermassive Podcast - 52: BONUS - Why does the Aurora Borealis look better on my phone?

Episode Date: May 23, 2024

The UK witnessed the most amazing Northern Lights in years.... And Izzie missed it. In this bonus episode, Dr Becky Smethurst, Dr Robert Massey and Izzie Clarke talk about those Northern Lights and answer your questions. What is Jupiter's giant blue dot? If the sun is losing mass (by giving out energy) will that affect the gravity and orbit of the solar system? And how do you date a rock? 

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 we dive into the Supermassive mailbox and answer all of your brilliant, brilliant questions that make us scratch our head and be like, do we even know anything? I'm just like, okay. But before we do that, we've had some really nice messages

and emails that I would like to run through. Booker Shavir on Instagram loved that we did an episode on Voyager and she said, my dad sold a sensor to NASA that's on board. I don't have any questions but i got to do the coolest show and tell in school that's amazing isn't it so i went back and said to her i was like oh my god what did this sensor do i need more details please more detail please so

she said it it was about temperature using a heated wire their other main products back then measured fluid flow and particulates dad trained us setting up experiments at home using his company's equipment how to design an experiment controls parameters etc from a very young age then we'd get to go with him on business trips boeing could hardly say that the equipment was too complex if a six-year-old girl in the 1960s could demonstrate it and recommend on the fly and experiment after seeing their top secret military jet wing for the first time great sales pitch and we really enjoyed it i got to meet the professor who invented the tornado f scale and demonstrate a sensor on a mini tornado he spun up in his lab oh i know how cool

is this dad was great way ahead of his time in treating girls equally and then taking them to work ages before that was a thing i mean what a guy that's so yeah so so cool and nice to know that like that little piece of him sort of lives on in voyager as well just leaving the solar system that's really i know it's amazing and we just happen to be recording this bonus episode at a very important time because at the point of recording last week um there was a big old bright flashy sky so did anyone see the aurora borealis yes over Oxford I was just like absolutely gobsmacked I just never believed in my life that I'd see what I did. Like when we were even talking,

oh, there's been a solar storm, everyone go outside and look north. I expected like just a little fuzzy green glow on the horizon, you know, and sort of pointing it out to people who'd be like, really, is it there? But it was like insane, wasn't it? It was like right above like my head.

There was just these big streaks of green and purple and pink that like at one point I could even see the pastel colors with my eyes. I know obviously like phones brought it out better ahead there was just these big streaks of green and purple and pink that like at one point i could even see the pastel colors with with my eyes i know obviously like phones brought out better the color but like oh just incredible i was up with my local astronomical society in lewis and we'd gathered at this site the old race course above the town as it happens for this sort of stargazing evening with telescopes looking at the moon that kind of thing um obviously we just got lucky we knew it was coming on the alerts and we thought will it happen then i was sitting there thinking

this always happens you get this alert don't see anything but yeah extraordinary started this northern glow then expanded over the whole sky and it was really remarkable for me to actually see colors with the eye as well see greens and reds and blues and yellows so easily the best display i've ever seen only the second time in my life i've seen it at all and really unprecedented so really astonishing you know i might not get to see more than one or two more of these in my life in the uk at least uh so yeah thoroughly recommend if you get alerts if you know something's coming just on the off chance go and take a look guys i have a confession i didn't see it. Izzy, no!

And then did you try and see it Saturday night? And then it wasn't there? Yes, and I cannot tell you how heartbroken I am. I'm actually not okay about it. Is this one of these times when it's okay to phone you at half past twelve? Yes, oh my God, yes. It's not even, believe me, my phone was going mad. So I was basically, I love my friend,, my phone was going mad. I was,

so I was basically, I love my friend. She's probably listened to this. I was at her hen do. And I was occasionally just leaving it to go and stand in the street to be like, now, now. And I just,

I don't know, just couldn't see it. And yeah. Maybe you were a bit too well refreshed on your hen do. No. Do you know what? Perhaps, but I, it wasn't that bad. I wasn't that bad. And I don't know.

I'm just really gutted to be honest. I feel really bad now for like. No, no, no. I'm celebrating everyone's and I'm just like leaning into the, we're going into a solar maximum. There will be other opportunities. Yeah, you know, there'll always be another solar storm, you know?

Yes, exactly. Do you know I missed the bright aurora in 1989 and 2003? I think in the first case, because I was just in the pub and, you know, so 2003, I just didn't hear about it till afterwards. What was cool though was like, because I just saw the aurora last year in iceland like the first time what was cool was comparing like what i'd seen there to what i'd seen here because when we were in iceland like it was it was directly overhead like a ribbon but you could see it you could see that it was bright green like with your eye and also you could see it move like in real time as well you could fully see it rippling like just staring at it and looking at it um and so it was cool like comparing it to how you couldn't see the colors but you could see the

faint sort of fuzz here but it was still right overhead and if you looked for long enough you you could tell that it changed from like when you were looking at it like a minute earlier but you couldn't necessarily see it like ripple dead quickly and move so it's cool to compare i did see the colors yeah that was impressive i thought the colors you know they were really obvious which i wasn't there was only five minutes or so where i could see the colors with my eye and it was very pastel rather than like neon green you know so yeah so i'm gonna sorry to keep talking about it i'm just don't worry i'm gonna start like my own solidarity club with any other listeners that might have missed it and we're just gonna go and do our own thing and then it's fine it's fine I tell myself it's a support group hi Izzy

basically basically okay right let's go on to some actual questions so robert can you help with this question from alex in bristol absolutely love the pod i was lucky enough to catch a glimpse of the northern lights the other evening despite being all the way down in sunny bristol an absolute beautiful sight and if it wasn't for my neck ache i would have stayed out all night. My two questions to you are firstly, what causes the aurora borealis? And secondly, why did my phone camera pick up so much more of its colour than the naked eye could? Thanks so much, Alex. Actually, a brilliant question there, Alex. And well done for you seeing it in Bristol. My old friends in Bristol Astronomical Society had a great view as well and do approach them if you want to share pictures or find out other ways to look at the sky. But to answer your questions, it's often said, not least

by many media outlets, that the lights are a result of particles in the sun directly crashing into the atmosphere. And that's a misconception I had for a long time as well. And it's not quite true. There's a really good article in The Conversation, if you look online, from Alex McKinnon from the University of Glasgow, who wrote an explanation of this a couple of years ago. So it is true that the originating source is a coronal mass ejection, a big eruption of material from the sun, or a CME as we call them, and these eject a lot of charged particles from the sun into space. Moving charged particles have magnet-generating magnetic fields and if they reach the earth they then buffet our own magnetic field, the magnetosphere of the earth that can cause a breakdown twist

around the lines sort of cause a bit of chaos in the field and when it all connects together again it releases a lot of energy and you get electrical currents and those accelerate electrons they're pushed into the upper atmosphere and those particles then collide with oxygen and nitrogen atoms and that's when we see the beautiful display. They excite and de-excite the atoms. And as they de-excite, the photons that come out of them give us these wonderful colours. Now, the second bit of your question, I should say, by the way, a small proportion of those particles does come from the sun, but most of it is excited locally.

But the second question about the colour and why your smartphone does so much better is that at night our eyes are using the so-called rod cells and they're very good for night vision if you're out and it's really, really dark. So they're good for detecting low light but they're only in black and white. So to see colour we need more light and we need it to be bright enough to trigger these cone cells in the centre of the eye. So most faint aurorae will look like a whitish glow. But last week we were really lucky enough to see colours cone cells in the centre of the eye, so most faint aurorae will look like a whitish glow. But last week, we were really lucky enough to see colours with our eye, pretty dramatically. I mean, I've never seen anything like it, and I've seen one aurora

displayed before. This was astonishing. And they're even brighter on a smartphone, because smartphones are just much more sensitive. They're geared up to detect colour in low light level with the chips they've got. And in a single exposure, they're also gathering that light for a lot longer, typically any way than your eyes do. So that's why your smartphone will see colours that much more easily. Becky, Kizran says, Hi, this is me, Kizran, a young listener of your amazing podcast, to which I owe my longtime fascination with space, further fuelled by the incredible enthusiasm that becky shows for astrophysics on her youtube channel oh thanks kizran having a growing interest in the peculiar giant of our

solar system i'm writing to you to ask about jupiter's great blue spot what exactly is it how did it form how is it detected and does it have any connection to its more well-known red counterpart? All right, well, let's start there, Kazaran, because the Great Red Spot is like a real actual spot, right? That we can see with our eyes. It's a real storm on Jupiter, right? So you can really call it a spot, right? This one, the Great Blue Spot, is definitely not blue. And I don't know if you could call it a spot either, really. So this is actually a feature in Jupiter's magnetic field. So we look at the magnetic

field strength across Jupiter and we plot that out and we like draw it on a diagram in terms of like the face of Jupiter. You end up seeing like a really strong concentration near the equator. And because of how we plot things so that like the human eye can interpret data, like scientific data, we use color to do that, right? And so the color scheme that the authors of this paper picked where this was first published, like picked it so that it was bluer, right? In this blue spot on the equator. And that was what was like showing this strong magnetic field. And so they dubbed it the great blue spot to sort of, you know, have a play on like the big red spot of Jupiter. So it's not really blue and it's not really a spot it's just this really strong blob of magnetic field as for how it formed um if anybody knows yeah we're still working on it

really it's really not clear like what drives it at all because i think we've talked about this on the podcast before right that like these magnetic fields of planets are generated by sort of you know charged particles in the core of the planets you know very like liquid metal moving around it's very chaotic um and so we're not really sure why there's this like big blob that's so much stronger like we don't know why that like it's kind of an anomaly really like why it's even there in the first place so there's been a lot of interest in it now and how we're studying it and how it's been detected in the first place as well is through juno the probe that's currently in orbit around jupiter it's been doing lots of like targeted flybys so that they're like closer and closer to the surface of Jupiter and it's got an

instrument on board that can detect the strength of the magnetic field and it's thought to be that there's perhaps just sort of like wave-like behavior really deep inside the core of Jupiter that could be leading to these sort of like anomalies and also the fact that it's kind of moving as well all the time so again just something else we can't explain about this great blue spot but you know maybe if we if there's a new paper that comes out about it is we should definitely cover it again uh on a on a future podcast episode yeah definitely and as kids around as a young listener hey maybe they might go on to actually discover oh yeah a little bit more about it so no pressure but that's yeah she said

grow they did say they had a growing interest oh yeah there we go you never know where that might grow to that interest so okay and robert sarah torres it might be sarah torres um has sent us an email she says hi all super massive podcasters i love the podcast and i've binged listened to all of the episodes nice and i have a question probably silly if the sun loses its mass by giving out energy will that affect the gravity and orbit of the sun itself and the planets in the distant future for example when it runs out of fuel and starts swelling as the larger planets exert more gravitational influence on the sun and the sun exerts less gravitational pull on the planet or will it be negligible thanks all and keep up the good work well hi sarah uh keep listening and um when you say silly question for us we tend to say great question which means we're thinking very very hard about the answer

um so it definitely isn't a silly question at all. And you're right that actually, as the sun's fusion reactions convert hydrogen to helium, there's a mass loss of about 4.3 million tons every second. Mass and energy is sort of equivalent, if you think about Einstein's theories. And that mass is transferred to electromagnetic radiation, so light and heat, et cetera, that ultimately warms and lights the earth. And you're right that that mass loss does indeed reduce the pool of gravity between the sun and the planets including the earth and it means that the earth is moving away from the sun by about a centimeter and a half a year so not very much really very hard to detect a change that small now it does have a then have a very marginal effect on the sun too and it's marginal because

the sun's got about a million times as much mass as our planet and even Jupiter is only a thousandth the mass of the sun so the effect is pretty small there as well but on very long time scales billions of years it starts to add up to something and it might help say Mars escape being consumed by the sun when the sun becomes a red giant but that said there are other effects too over billions of years like the long term stability of all the planetary orbits not absolutely certain they will be over a whole time scale of the solar system gravitational radiation being emitted from planets that orbit the sun so they lose a bit of energy and spiral in a tiny amount as well and even in not in the sense that we understand it on earth but even a sort of friction as planets hit

particles and other things and that's minuscule but it was very important in the sense that we understand it on Earth, but even a sort of friction as planets hit pascals and other things. And that's minuscule. But it was very important in the early solar system because of more collisions and more material around. And it could be really important for the Earth if the Earth does end up on the edge of a red giant sun. I mean, forget it, the Earth will be definitely a baked rock by that point, nowhere to live. But it could then mean that the Earth is more likely to be consumed by that red giant sun in billions of years in the future however we have at least hundreds of millions of years of hopefully anyway clement life on earth before any of this happens so you know don't have nightmares about this one i think oh good okay i'm becky william morgan says

hello from the us i've been having a great time listening to your podcast and learning a ton from each episode but i've been hearing something come up pretty often that i'm not quite sure i fully understand many times i'll hear something about how some kind of sample rock comet planet or other object in the universe is X number of years old. But how exactly is that age determined? If everything was created at the same time from the Big Bang, is it difficult for scientists to determine specific ages apart from, you know, the beginning of the universe? Yeah, that is another great question, William. So like, yes, in the very early days of the universe, like when the universe was

very, very young, and everything was just this like hot plasma of particles, right? And you still have like, electrons and protons completely separate from each other. The first atoms and elements to form were solely like hydrogen, helium, and like the tiniest amount of lithium. So when we age things, it's not like we're aging things all the way back to those original sort of like atoms that formed like 13.8 billion years ago like what we're aging is almost like when stuff came together to to be what it actually is so it took like many generations of stars to then create all the other elements that we find in nature today, like in the big nuclear forges that stars are, that then produce things like carbon, oxygen, nitrogen,

that make up like all the things that you listed, right? Rocks and comets and planets and stuff like that. So the way we then date rocks and the material that makes rocks up, whether that's, you know, rocks we find on Earth, so terrestrial rocks or rocks outside of Earth, extraterrestrial rocks, right? You know, like so meteorites or, you know, lumps of rock from the moon or Mars or anything else. If they've gone through very complex chemistry or have been affected by radiation, like it's really difficult to get a date on their age.

But the approach that we tend to use for sort of the oldest rocks that you can do this with is radioactive dating. So you might have heard of that before, right? Essentially, what you're doing here is measuring the amount of like an original radioactive substance, what we call an isotope, which is like a specific flavor of a particular atom. It means that the nucleus has a certain number of neutrons, essentially. And so, for example, you can use like uranium-238, and that decays into lead-206. So it's two different types of isotopes of an element. And it does that with what's known as a half-life of 4.5 billion years. So that means that essentially in four and a half billion years,

you'll have half the amount of uranium that you did in the beginning. And so, for example, you can also use an even longer decay, right? Rubidium 87 goes to strontium 87 with a half-life of 49 billion years, right? That one typically used by meteorologists, right? So I guess that makes it sound very simple, right?

Is all you have to do is just measure the ratio of how much of this thing do you have and how much of this thing do you have but it can get quite complicated right because to do that you need what's known as a mass spectrometer essentially like this device that where you can put a sample in and then it will split all that sample apart into its separate atomic nuclei right it does it using like magnetic fields and stuff and then you can get a really accurate measurement of how much of each element that actually is plus also you have to understand like the history of the sample too like how much like radiation from the sun was it exposed to all of that kind of stuff and it means that we essentially know that you know a

lot of meteorites were formed not long after the solar system itself and so we can sort of age date the solar system in that way and the oldest things in it and know that the sun and all of the solar system formed around about four and a half billion years ago and that's how we get those kind of numbers yes we specifically get those numbers the three of us yes yes yeah when we do the calculations using the royal we there when we specifically run the numbers that's the answer that we's amazing well thank you everyone for sending in your questions do keep them coming you can email podcast at ras.ac.uk and we're also on instagram at supermassivepod we'll be back next time with a full-length episode all about the

lunar standstill which is very mysterious sounding i love. You'll have to tune in to find out what that's all about. But until next time, everybody, happy stargazing.