The Supermassive Podcast - 7: Down To Earth

Episode Date: July 23, 2020

Dr Becky Smethurst and Izzie Clarke investigate the cosmic coincidences that formed the Earth and explore whether there are earthquakes and volcanoes on other planets. Plus, astronomer Robert Massey joins them to chat all things #cometNEOWISE and what else to look for in the night sky this month.  With special thanks to Dr Amy Gilligan from the University of Aberdeen, Professor David Rothery from the Open University, and everyone who shared their images of Neowise.  Keep sending your questions and stargazing photos to the team via [e-mail] or tweet @RoyalAstroSoc. The Supermassive Podcast is a Boffin Media Production by Izzie Clarke and Richard Hollingham

We would find it so weird if we saw fire and lava shooting out of a mountain on Mars. It was like, yeah, that's the comet. I can see this huge tail. Is it a series of geological cosmic coincidences that we have the Earth the way that it is? You know, you're saying, oh, it's just molten rock clumping together. And in my head, I'm like, yeah, that's geophysics. I haven't seen anything like this in my life. Life. Yeah, that's geophysics. I haven't seen anything like this in my life. Hello, welcome to the Supermassive podcast from the Royal Astronomical Society with me,

astrophysicist Dr. Becky Svethurst and science journalist Izzy Clark. Izzy, all I want to know this month is how is your new telescope? I love it. I've taken it to the local park a few times because i live in quite a built-up area um but i think i need to apologize to all stargazers because i bought it at the end of june and then for two weeks after it was just solid cloud every single night so i think i probably messed things up a bit there it was your fault yeah it was me so um but no it's been amazing because obviously comet neowise has been around. And, you know, we're going to talk about that a bit more later. But it's been so great. But this month we're coming down to Earth to explore our own planet and how that was formed and the physical processes that have driven it.

Yep. It's all things geophysics. It might sound obvious, but it's all about treating Earth as a planet rather than our home in the same way we would Mars. It's so familiar to us. We would find it so weird if we saw fire and lava shooting out of a mountain on Mars. But that's a process that happens here on Earth. So here with us is Robert Massey, the Deputy Director of the Royal Astronomical Society, not the Royal Astrological Society, as a certain newspaper reported recently.

Sadly, several newspapers just took that report and reiterated it. So that's going to be there forever, I guess. So how did you physicists at the Royal Astronomical Society explore and study our planet? I think the reason that it's connected with us is because the Earth is another planet in that sense. So they were taking the techniques they used to study the Earth and applying them to the rest of the solar system and presumably eventually to planets around other stars. But they do it through all manner of things. These days, I guess some of the things you might be most familiar with are actually, say,

satellite images of the planet to study everything from the atmosphere to the magnetic field to global heating to the water cycle to plate tectonics, to the big plates that float on the surface. They're spreading apart and all of those things. And they do that through in situ field expeditions too. They're climbing down into volcanoes. They're measuring seismic tremors. So there's a whole variety of techniques,

really pretty much everything you can imagine the way that you understand the world around you they're applying it to our planet to its atmosphere to the rocks and to the the interior that we can't see but we can we can try and understand so how does understanding our planet help to explore others in the solar system i think the best answer is that it's one of only a handful where we've actually had any instruments. So, you know, the others being Venus and Mars, and I was trying to think of landers, you know, that's the moon, asteroids. So there aren't that many objects where we've actually sent things to study the very surface of worlds. So if we look at features on the surface of the earth and the processes, and we see similar sorts of shapes and features on other worlds then we

can get an insight into how they mounted form. So if you think of something like the moon where you've got features like craters okay that we see in rather smaller numbers on earth but also a handful of extinct volcanoes and features from where there was lava flowing across the surface then because we see those on earth today, we can understand the frozen fossils of the same processes on the moon. And that's just one example. If we go to Mars or the moons of the planets like Saturn, Jupiter, Uranus, Neptune that are cold, that have similar processes going on with ice, then we can use those techniques that we see right here on Earth and get an inkling of what's happening further afield. Cheers, Robert. Well, I'll catch up with you later in the show

for some more stargazing, or should I say, comic gazing? So we're going to treat Earth just like any other planet, exploring all the weird processes on and beneath its surface, starting with volcanoes and earthquakes. I spoke with geophysicist Dr Amy Gilligan at the University of Aberdeen, who explained the process underlying plate tectonics. On the surface of the Earth, we have the lithosphere, and this is broken up into different tectonic plates.

So there's about 12 ones that are very big. So we think of the biggest is the Pacific plate, which covers most of the Pacific Ocean. And then there's other ones that you might have heard of, like the north american plate south american eurasian and then there's smaller ones um like the caribbean plate the nazca plate and these plates have thousands of kilometers wide the big ones but only maybe a few hundreds of kilometers thick in the case of the thickest parts of the continents and the oceans are maybe about 100 kilometers thick so thousands of kilometers wide and generally relatively thin so like a plate that you might have on your dining table and these plates move and that's what drives most of the landforms that we see on the surface of the earth

today so the mountains the trenches in the oceans volcanoes and things like that they're all driven by the motion of these tectonic plates so how is it that these tectonic plates can move and why is that so important to you know as you say creating mountains and volcanoes and things like that that's quite an interesting question and that there is still some debate about what actually drives the motions of these plates so the plates have different types of boundaries. In some cases, they're moving apart. In some places, they're coming together. So some of the motion is derived because there's been new tectonic plates being made. It's pushing the old plate away. But then when these plates collide in places we call subduction zones, which is where one oceanic

plate plunges beneath another plate. The lithosphere is denser and heavier, and this is what we call slab pull, where it drags the rest of the plate down into the mantle with it. And so these forces combine to move the plates around on the Earth's surface. So how is it then that we get volcanoes, for example, from tectonic plates? Yeah, so there's different types of volcanoes that we observe volcanoes for example from tectonic plates yeah so there's different types of volcanoes that we observe on the earth's surface and if you think of the pacific ring of fire so all the way around the pacific we've got these subduction zones where one oceanic plate is plunging beneath another the rocks that are being pulled down into the earth's mantle have lots of water in them water can lower the melting

temperature of rocks and so as the rocks heat up going down into the mantle they can melt and this melt buoyantly rises up and it reaches the surface this can form volcanoes and these tend to be quite explosive volcanoes so the ones that you think of with the big clouds of ash and pumice being thrown out we can also have volcanoes in the middle of plates and these occur in places like Hawaii for example. Hawaii is right bang in the middle of the Pacific plate not on a boundary and there they tend to be the lava that flows more easily so you don't get these big explosions but you get lava running out and you can sort of see it all on the surface. And then I think another aspect

of tectonic plates that everyone is potentially more familiar with is the idea of earthquakes. So what is going on in tectonic plates to then result in an earthquake happening? So if you imagine you've got two sheets of paper, they can move apart. So that's moving the sheet and the plane, or they can be moving side by side. They can move apart, so that's moving the sheet and the plane, or they can be moving side by side. But as they move, it's not going to be smooth, just sliding past one another. There's friction there. And so as the plates move, the pressure will build up and then eventually it builds up so much that it'll slip. And that's when you get an earthquake. And we observe around the

world that most of the earthquakes that we see happening occur on these boundaries between the tectonic plates. So if you just plot up a map of where all the earthquakes occur in the world, you get a very nice map showing where the boundaries of the tectonic plates are. The size of the earthquakes might depend on the type of tectonic boundary that they're on. So subduction zones, like ones around the Pacific, they're the ones where we've observed the biggest magnitude of earthquakes, so the ones that release the most energy. It depends on how deep these earthquakes are

and where they are in relation to where people live. Well, that's what I was going to ask. What corresponds to the magnitude of an earthquake to what is going on with the tectonic plates is it just like there is a vast movement and you see that ripple out as it reaches whatever area it's in yeah so it depends on um how much the plate moves so the bigger the area that moves the more energy that will be released you might hear things like a magnitude 5 earthquake or a magnitude 6 earthquake it's important to remember these are on a logarithmic scale so what this means is that a magnitude 6 earthquake will release 32

times more energy than a magnitude 5 earthquake oh my goodness so if it's a magnitude 6 it's 32 times stronger than magnitude five. That's actually that's a very significant difference, isn't it? Yeah, it's a huge difference. And in the UK, most of the earthquakes that we get are way, way smaller than that. So one way I like to sort of demonstrate this is if you get some spaghetti. So if you imagine your magnitude 5 earthquake is a one single strand of spaghetti then you get you snap that you can sort of feel how much energy is there then you get your 32 strands of spaghetti and snap that you can really get an appreciation of how

much more energy a magnitude 6 earthquake will release and if you want to count out sort of 900 odd strands of spaghetti for a magnitude seven and try and snap that. That shows just how much more energy is released from these earthquakes. How do we try and understand what's going on within earthquakes? You know, what techniques do you use to analyse this or even to an extent try and predict them? Is that even possible? In terms of earthquake prediction, that's not something we can do earthquakes are such a complex system but what we can do is try and understand the processes that are going on when faults move so we can try and do things in the lab for example simulating what

kind of movements you might expect in different types of of rocks but also look at these earthquake early warning systems. One of the neat things that people do is when volcanoes are about to erupt, the magma moves around underneath the earth. And this might generate little tiny earthquakes, so micro earthquakes, that you can pick up on a seismometer. And if you locate where all of these are, you can watch almost in real time the magma moving through the earth. And this can be really valuable because you can watch almost in real time the magma moving through the earth and this can be really

valuable because you can think about where is it going to erupt and what effects this this might have we can also detect all sorts of other things with seismometers so not just earthquakes but human generated things so when we've had the lockdown recently there's been a real reduction in seismic noise from people moving around and And you can see this on the seismometers across the world. And then now as things are opening up again, you can see this increase in noise. So there's all sorts of things that, as well as earthquakes and volcanoes and natural cause things that we can monitor and observe using similar techniques, which I think is really a really interesting direction to think about the field moving in

absolutely that was Dr Amy Gilligan from the University of Aberdeen with a cameo from her neighbor doing some DIY gotta love some lockdown recording yeah that's a theme for this whole podcast right because we very nearly had people around at my house installing a bathroom lock on my door with the chiseling and drilling away while we were recording here yeah like uh guys do you mind trying to record a podcast so Becky can we talk about this a bit more so I've had a question from Peter Turvey on Twitter who asks will the Yellowstone super volcano erupt again had to ask been watching too many dire disaster movies in lockdown. I think I've been doing the same as well. I was obsessed with those kind of documentary programs as a kid that talked about Yellowstone or the Canary Islands, which are also one of these sort of like mega volcanoes that, you know, if it went off, whole Canary Islands could collapse,

causing a tsunami across the whole Atlantic Ocean that could hit the eastern seaboard. Those kind of like huge, big disaster things are so compelling I think to us there are a lot of geophysicists studying Yellowstone and there's obviously a chance that you know it could but I think that probability is quite low and if that ever changes I think there's many geophysicists recording you know the tremors in the earth around there just to be able to give us enough forewarning if anything did happen yeah absolutely and so back to you know the bigger picture of volcanoes and earthquakes do we see any similar processes like this anywhere else in the solar system yeah so we've actually got um a lander on mars at the minute insight that is measuring mars

quakes so not earthquakes but mars quakes which i think is fantastic you get moon quakes as well and studying those kind of processes obviously the same way that earthquakes on earth led us to an understanding of what the interior of the earth was like we're hoping that the same thing will happen on mars as well as for volcanoes well yeah most planets most rocky planets anyway do have evidence of past volcanic activity so mars obviously has olympus mons uh which is the biggest mountain in the solar system um plus um is it the tharsis region i don't know how to pronounce it but i'm gonna go with it which is thought to be one of the like this huge giant plateau of volcano as well but most of the

volcanoes in the solar system formed billions of years ago. And as Robert said before, we've not actually seen very recent activity in the solar system, except in four places, right? So you've got the Earth, obviously. You have Io, which is a moon of Jupiter, Triton, which is a moon of Neptune, and Enceladus, which is a moon of Saturn. They all show current volcanic activity. And the majority of that is sort of like gas plumes and vapor plumes that will escape rather than necessarily lava except on io right io is one of my favorite bodies in the whole system solar system right it's one of jupiter's four galilean moons you know the closest into jupiter and it is incredibly active so much more active than the earth and it's caused

by the huge gravity of jupiter as io orbits it essentially pulls on the very rock of io itself deforming it and causing huge amounts of friction in the interior which causes this volcanic activity and so again a lot of this is sort of like silicate bits of rock that sort of like eruption so people have dubbed the eruptions on io sort of like volcanic snow in a way but you also do get lava on Io as well when you have a very explosive reaction. So it's actually one of the only other places in the solar system except from Earth that we know to have had at least recent lava eruptions.

Now, obviously, we still can't access the Royal Astronomical Society's library, but we've got some science history for you of sorts. Anyway, the history of planet Earth, starting from the very beginning. David Rothery is a professor of planetary geoscience from the Open University and joins us now. Hi, David. Hi, Zeke. So, how did our planet form?

Well, Patrick, more style, I could say we just don't know. But there are theories. I mean, cloud of gas and dust around the young sun, contracting under gravity. If a cloud exceeds its genes mass, which RAS people might know about, it's contracting. And because it's rotating, it flattens into a disk. And within that disk of gas and dust around the sun,

as temperature drops sufficiently material condenses and collects together in bodies which eventually grow into planets and it happens differently in the inner and the outer parts of the solar system but how you go from grains to planet-sized lumps of rock is the issue we don't know quite how quickly it went and we don't know how quickly it passed through each phase. But we have got some time constraints on, for example, the Earth must have been here with a core within 50 to 100 million years of the supernova explosion that seeded the whole cloud in the first place. Gosh, so quite a long time we're talking about here. No, that's quick.

I mean, the solar system is four and a half billion years old and then you grow the planets to their present size in little more than a hundredth of that time i forget how long processes actually take sometimes yeah compared to my stuff which is galaxies that's like billions of years this is nothing in comparison but i'm really curious david though what would earth have looked like as a young planet like how would it compare with other planets in the solar system when they first formed well if we just restrict ourselves to the terrestrial planets for rocky bodies they would all look much of a muchness in the very early stages while collisions, collisions are still going on. They haven't formed their present personalities.

And slightly before we get an Earth-sized body, we'd have had maybe a dozen bodies of about, you know, a tenth or twelfth the Earth mass in the Earth's orbital space, planetary embryos, which will be growing by random collisions with one another. And you couldn't point to any one and say that's going to be the earth because the two smallest ones might collide together and merge and then become the biggest of the family and well is that the proto-earth well it is until two other ones collide and become bigger so you can't talk of the proto-earth is

often misplaced until the final collisions have gone on and you've merged all the embryos that are going to collide with each other you haven't got your proto-earth or your proto-mars or your proto-venus and each of these collisions has probably got sufficient kinetic energy in it that you're melting the outer part of a new body so you've got bodies covered in magma oceans metallic iron may settle towards the middle to form cores of these bodies so you have an iron core surrounded by magma which is molten rock and just a skin on the top that would be losing its heat to space very rapidly and that would be like the top of a lava lake so you'd have bodies covered in magma with a thin dark non-glowing crust continually ripped apart

by smaller impacts hitting it and by bubbles of gases escaping or the crust cooling and sinking and ripping itself apart but each planet would look much the same at that stage and it's been quite an active area as well so how have asteroid impacts changed earth and is that how we've got our moon? Okay, well, these are not asteroids yet. These are just lumps of cosmic debris, it's a hackneyed phrase. But the big, the ones that are 100th planetary mass or bigger are called planetary embryos, these things which are colliding with each other. Now, the last such impact to affect the Earth appears to be what gave us the moon. to affect the Earth appears to be what gave us the Moon.

Usually when two planetary embryos collide, they merge together. But if it's more of a glancing blow, you can spin some of the material off into orbit around a larger target body, and that's probably what happened to form the Earth's Moon. The incoming impactor probably had a core already and joined the collision. That core sank down to join the target body's core, the Earth's core if you like, but most of its rocky outer part, the mantle, got scattered into space and then recondensed to form the Earth's moon. And the

argument is that, well look at the Earth's moon today. It has a very small or perhaps no segregated iron core. That's because the debris from which the moon formed had lost its iron because the iron had already formed the core of the incoming body, which ended up joined onto the Earth's core. So there's none of that in the debris cloud to form the moon. So how do we know all of this, though? Well, we don't know any of it for a fact. It is always contested but we got pretty good chemical isotopic fingerprinting of the Moon when we started bringing samples back from the Moon in the Apollo era. Isotopically it is very very similar

to the Earth so it formed in near-Earth space, but it's not exactly the same as the Earth. And we know from the size, mass and density of the Moon, that it can't have a large, dense core in the middle. So you're piecing a theory together. And this giant impact origin of the Moon has been around since sometime in the 1970s. So it's coming up for 50 years old now,

and it's stood the test of time. And I think it's fairly robust. And during that period, models of planetary growth by embryo-embryo collision have come to the fore and they've gained robustness. So there's lots of refinements going on to the theories. I study the planet Mercury today. You go back to four and a half billion years ago, Mercury would have looked like a smaller version of the Earth, a core, a magma ocean and a thin skin on top that was continually being ripped apart. It's not till things have settled down and there are no more giant impacts and all you do have happening is asteroid-sized debris hitting the surface, giving recognisable impact basins and craters that we see today.

But the planetary growth by embryo-embrow collision is much more violent and much more devastating to the surface. It completely reshapes the surface because it melts the whole damn surface. I love this idea that, you know, we often say that the giant impact of proto-Earth with whatever ended up forming the moon, you know, we do say that it collided with proto-Earth, but you're saying that until that happened, it wasn't proto-Earth because it was still missing a piece.

And that's such a nice way of looking at it in the context of horrendously violent embryo collisions that happened in the early solar system. But it's like, yeah, we weren't complete until then. You know, it's kind of poetic it's not just that we're not complete it's that you can't point to a body if you've got a dozen bodies competing to grow to the earth size like i said the two smaller ones could collide and then become the biggest of the family and is the biggest one of the family the proto-earth because

if that's the case the leadership keeps changing by these random collisions so is it a series of geological cosmic coincidences that we have the earth the way that it is oh it's cosmic coincidences it's not geological there's no geology yet you haven't got a stable planetary surface uh where you can start forming rocks and deforming them and eroding them and transporting them and layering them. That's geology. This is just growing a planet by shoving lumps of largely molten material together very hard. This is what I love, right? The crossover of astronomy and geo stuff. There isn't that fine line almost because, you know,

you're saying, oh, it's just molten rock clumping together. And in my head, I'm like, yeah, that's geophysics. But you're like, what? No, this is astrophysics. We're talking about the solar system. So you can do geochemistry, you can start to look at an isotope separating and so on. And the geophysics is the density and the layering developing. But geology is a cognate field. It not the same i have i have friends working on exoplanets and i think because they can tell it's got a silicate atmosphere they're doing geology because it's an atmosphere made of rock that's not geology geology is stones and wind and water blowing stuff around and and forces folding folding it and breaking it apart in faults.

Thanks, David. That's David Rothery from The Open University. This is the Supermassive podcast from the Royal Astronomical Society with me, astrophysicist Dr Becky Smethurst and with science journalist Izzy Clark. This month, we're exploring our own planets. Yeah thanks for all your messages this month as well if you want to send in any questions to us for a future episode then email podcast at ras.ac.uk or tweet at the royal astro sock. Or send your pictures so many have sent in their images of comet neowise and I have honestly loved it I mean I have definitely been distracted

from other work that I should be doing, but these photos are so amazing. So thank you to Hannah Bellanel on Twitter, who said, we hiked Pennyfan a peak in Wales and saw the comet's noctilucent clouds and cloud inversion in the valley below. It was so beautifully surreal,

a unicorn could have strolled by and not felt out of place. We hiked up to celebrate our belated wedding anniversary as borders were shut in June. It was definitely the greatest fireworks in the universe. This photo is amazing.

You've got noctilucent clouds and you can see the corner of the mountain and then just Comet Neowise just at the top of it. It's amazing. So we'll put all of these on social media for everyone else to see. Yeah, you guys need to see that. That was really an amazing photo.

Congratulations to the both of you as well. Also, pilot Carl Chappers snapped an image of the comet at 45,000 feet as well, which I feel like it just trumps everybody else. It's just like, oh, wait. But I love the fact that he can have a break while just piloting a plane to take a picture of a comet. That's some skills. And also Skydive Phil has sent his image of NEOWISE

over the Tower of London as well. And I can't stop staring at this photo. It's just, it's gorgeous. The tower is all lit up. You can still see the comet. You've got this sort of purple glow on the horizon left over from the sunset as well oh I almost want to make it my phone background it's gorgeous I know it's like absolute photo goals this is what I'm aiming for um and we've also

heard from the Northolt branch observatory in West London who have amazingly captured the comet's beautiful tail in such wonderful detail so I was quite worried that you wouldn't be able to see the comet in London which is where I'm based as well because of the pollution and all of that but we we went to a park in East London at like 2am in the morning and I was amazed like we got out of the car and you could just see it with the naked eye and I I haven't seen anything like this in my life like and I think it's going to be one of those moments that I will remember for so long yeah me too like it's so remarkable it really is yeah I mean I don't

remember Hale Bop in 97 like I think I was just too young to even register it perhaps but like it I can't I can't believe that you can see something like that with your naked eye like i saw it so i'm out in the suburbs of southeast england and i saw it despite the fact that there was a giant street lamp just about a palm's width below the comet so even with that you know we're not that much light pollution out here but with the fact that i'm staring at a street lamp i can still see it you know it's this sort of fuzzy smudge with like a fuzzy smudge tail above it but you really can just see it with the naked eye and I mean I'd love to see one of these what they call great comets at some point in my life where you know you can see them even at like

sunset or during the day or something like that you know where not even sort of Joe Public on the street could walk underneath and not start it is it a bird is it a plane exactly I was still amazed and especially that so I was sort of like okay it's a fuzzy smudge I'm pretty sure that's the comet I ran upstairs cracked open the spare bedroom window as wide as it would go and basically just like rested my phone on the windowsill and sort of held it while it did sort of a night mode three second shot that it does and it was so clear it was like yeah that's the comet i can see this huge tail and it's only when you break out a camera that you really realize how big that tail is like i heard someone say that it's it's three full moon widths wow and it takes up which is

crazy yeah robert can i bring you in on this because what do we actually know about comet neo wise yeah the comet neo was as an example i think a third time lucky where we talked about I bring you in on this? Because what do we actually know about Comet NEOWISE? Yeah, the Comet NEOWISE is an example, I think, of third time lucky, where we talked about Swan and Atlas that broke up. And then lo and behold, NEOWISE actually does make it around the sun. And it's turned out to be brilliant. I mean, a fantastic views we've had. But it was discovered by an orbiting infrared observatory, NEOWISE, on the 27th of March. And what you find now is that whereas in the past, a lot of comets were named after people, they quite often have acronym names

because they're named after the instrument that detects them, and that's why it's got this unusual one. But it's a fairly typical one in many ways. It's a few kilometres across the nucleus in the centre, and it was probably in the inner solar system maybe 4,500 years ago, so around the time Stonehenge was being built because it's gone round the sun. I know, amazing, isn't it?

Gone round the sun. Okay, fine. Gone near a planet, it's had its orbit deflected and now it'll be nearly 7,000 years before it comes back. But it's classically a comet in terms of appearance. The great thing is you can see that tail, which is in many photos really stretching right across the sky. Probably a bit harder to see that with your eye.

But they can be tens of millions of kilometers long. So this tiny object, really, which is the size of a mountain, the ices, when it gets close to the sun, they vaporize, they stream back out into space. They're pushed back by literally the pressure of sunlight as well as the material that comes off the sun. and we get the sun and we get this beautiful sight so you should be able to see it i think with the naked eye probably till the end of july just about and then with binoculars for quite a bit longer than that so it's a really special object it's i did say sadly i am old

enough but definitely old enough to remember hay or bot very well and that was that was much brighter but uh I'm pretty confident that in our lifetime, we'll see at least another couple like that. At least this one is so easy to spot though as well, because it is pretty much at the minute anyway, just directly below the plough. And I think enough people can recognize the plough in the sky. That's like the one thing they say that they can do, right? So if you could find the plough, you've no excuse. You've got to go find Comet NEOWISE. It's unusual. It's placed well in the in the northern hemisphere quite a lot of times we hear

about things that we that people are seeing in australia and zealand so i've actually for rarely had somebody from australia complaining they can't see it you know it's and i think well you know you guys get the better skies a lot of the time i've had so many messages either from southern hemispherians complaining that they can't see it or from people like up in finland and norway being like oh it's too bright still daylight yeah we're in the sweet spot which you can't usually say about the uk exactly and in other news solar orbiter has captured the closest images ever of our sun so we've talked about this in a previous episode so go back and listen to that if you haven't heard it already. But these images are quite incredible.

They've captured a new phenomena, which look like little campfires is what everyone is calling it. So what do we actually know about these, Becky? Not much at the minute, let's put it that way. So just from these first images, sort of like a first look and a first sort of, you know, think about what they could be. They've sort of been linked to sort of solar flares, you know, these huge, big loops of material that come off the sun and they, you know, stream particles into space that eventually, you know, cause our aurora. These things are, you know, orders of magnitude smaller than that, right on the surface. You know, this is why Solar Orbiter has been the first to actually spot these, because they had to zoom in so far to be able to even spot them. And they do look like sort of tiny little campfires burning on the surface of the sun. One thing that people are really excited about, though, is sort of an unsolved

mystery about the sun is why the corona, which is sort of the very diffuse outer sort of atmosphere of the sun is so much hotter than what you consider sort of the surface of the sun so you know when there's there's a total eclipse yeah and you see all those incredible images where the moon's blocked out the sun but you still see this sort of glow and haze around the sun that's the corona and the corona is thought to be like one to three million degrees kelvin whereas the surface of the sun is that sort of you know often perished like 5 500 or so kelvin and for ages no one has been able to explain how the corona is that much hotter than the actual surface of the sun because it doesn't really almost make sense but people have said well perhaps it's these little campfires that actually could be the sort of source of that energy for heating the corona which would be really exciting if it was so i'm really looking forward to sort

of seeing you know all the other sort of data and analysis and results that come out of solar orbiter's mission yeah so watch this space all right well let's bring robert back in here because you know the sun is a star after all and robert is our uh person on hand to talk about stargazing so if people want to look at the sun obviously they should never look directly at the sun with their own eyes robert but if they wanted to observe it from earth how would they go about doing that yeah and i think that can only you can't over emphasize it's something you've got to do safely there are quite a few ways you can do it the easiest way is probably if you own a pair of binoculars or a telescope to project it now that means you point your telescope or binoculars towards the sun but on no account look through them because it would be focusing all that light and heat into your eye which would clearly be

really dangerous well if you do that if you minimize the shadow as you're turning it towards the sun you know you move around and you can see the shadow getting smaller you will see a bright spot of light if you've got a bit of card say about half a meter away from the eyepiece binoculars or the telescope you can focus that and you'll get quite a nice big image and if there are any sunspots they're really really obvious that's that's a really reliable way of doing it uh you can also if you know what you're doing and you buy it from a reputable supplier you can buy special solar filters and these go over the front end of a telescope or binoculars. They should never, ever go at the eyepiece end because that's where the heat is concentrated and that can block out the light safely as well. But I should stress that only buy them from a

reputable supplier. So if you find an astronomy shop or an astronomy shop online that has the safety marks on the filter paper, I should stress, they're selling. And that's the kind of thing you can use. So methods like that are fine. Certainly, though, you're right, never look directly at the sun. It's just really bad for your eyes. And we all want to enjoy the sky at night and during the day as well. So don't look at the sun is the advice.

And what are some of the other things that we could look at, say, at night and stargazing for this month? Well, unless you're doing something simultaneously, looking up at the sky at night is completely safe. I think I can say that with a very high degree of confidence. It's summer. We're moving into the darker bit of summer, which is nice because it's still warm. And yet as you move into the end of July, into August, you get longer nights in the uk in the middle of the summer we suffer a bit because twilight never quite goes away and it's never probably dark particularly if you're further north but this time of year is great for the summer triangle and the milky way if you're

say camping somewhere if you're away from the cities for your break in the uk most likely this year you should see the summer triangle which is the three stars of Altair and Aquila the Eagle at the bottom and then Vega at the top right and Deneb at the top left and that that straddles the Milky Way in this beautiful way and if you're if you've got no moon in the sky you'll see this lovely band of light stretching across the sky and that's an inside view of the galaxy and if you pick up a pair of binoculars or and you look up and down at that you'll see it's absolutely festooned with stars it's really packed with those and clusters and nebulae and so on these really really lovely objects and you can even

see this dusty dark lane in it as well so you're getting a wonderful view of the inside of our galaxy so that's one of my definite tip for this time of year aside from the comet you don't actually get to say that very often you know just, just casting the comet to one side. The other thing to look out for in August is the annual Perseid meteor shower, which is one of the most reliable ones. And meteors are just the result of dust coming into the atmosphere at high speed or small particles. And they come in about 60 kilometers a second, many times faster than the bullet. They burn up, they heat the atmosphere around them, and you get a short streak of light and there's a shower of those in in august called the perseids they appear to come from the northeastern part of the sky and the result of a comet that was last near the earth

about 30 years ago and every year pretty much you will see a few tens of meteors an hour at the peak and this year that's roughly the nights of 11th to 12th of August. So if you're out and you're particularly in the late evening, just before midnight, you should stand a good chance to see shooting stars, meteors. The general advice on seeing them is you don't need any equipment. It's best just to sit on a deck chair and lie back and look up at the sky. Yeah, it's always my favourite thing to spot when I'm on holiday. And I've got like a sun lounger just happily there. It's a star lounge. But it's have them this year is it so well you could set one up in your garden i might still i might still so what's actually the best way to see this meteor shower

the best advice is to look uh in the late evening but actually just really up until midnight because later on in the evening the moon will be rising and it'll be quite bright it's still about half full so it's a really significant thing to light up the sky and that washes out the fainter meteors so really it's probably a good idea to look from say when it's properly dark through to about midnight or so which is actually at least a nice comfortable time of night if you're in your own back garden it's not one of those things where astronomers are telling you to get up at four o'clock in the morning yeah i think that's always one of the cases of meteor showers isn't it it's like to avoid the moon go at like 3am and you're in your own back garden. It's not one of those things where astronomers are telling you to get up at four o'clock in the morning. Yeah, I think that's always one of the cases of meteor showers, isn't it? It's like to avoid the moon,

go at like 3 a.m. And you're like, no one's going to do that. It's hard to encourage the public with these things, isn't it? It's like, oh, you can have this great view if you get up in the middle of the night. The other thing is, if it's obviously not clear

on sort of the 12th or 13th around, then it actually might be a little better to wait until sort of the 15th and 16th because then the moon won't be around for as long. It won't be rising until sort of one two o'clock but obviously then you sort of play off the fact that the peak might have dropped a little bit and there might not be as many meteors an hour but you know just play it by ear if you're seeing meteors around sort of mid-august time they're very likely to be from the percy it's meteor shower exactly and actually we should really encourage people to send in pictures as well because it's a lovely thing to see.

If you're lucky enough to get a meteor streaking across the sky in your image, it's a beautiful thing. Well, thanks so much for that, Robert. And that's it for this month. Next time, we'll be venturing to the Earth's core and exploring geomagnetism. And tweet us if you try some astronomy at home.

It's at RoyalAstrosoc on Twitter or email your questions to podcast at ras.ac.uk and we'll try and cover them in a future episode. All of the images we've talked about today on this podcast will also be posted on the same social media. So check those out as well. Until next time, happy stargazing.