Instant Genius - What meteorites tell us about life on Earth and the Universe

Episode Date: February 17, 2025

Meteorites are one of the best indicators that we can get of what is out there in Space. Helen Gordon, author of the new book The Meteorites: Encounters with Outer Space and Deep Time, talks us through these mysterious rocks landing on Earth. She touches on their cultural importance, what they tell us about our early Universe and their potential for risk. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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This podcast is sponsored by name, audio and focal. Streaming has made music more accessible than ever, but true listening is about more than ease. It's about quality. British audio experts name Audio, alongside French acoustic specialist focal, combine handcrafted tradition with cutting-edge innovation and high-end materials, delivering digital precision with analogue warmth. So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com to learn more. Hello, I'm Alex Hughes and this is the Instant Genius podcast, a bite-sized masterclass from the BBC Science Focus magazine, where we interview some of the biggest names in science. science and tech. Meteorites can tell us a lot about space and in many ways are our best

link to what is out there. They might have brought life to our planet and still to this day they are teaching us new things every year. Helen Gordon, author of the new book The Meteorites, encounters with outer space and deep time, takes us through everything you need to know about these hugely important rocks that have landed on Earth. So when we talk about space objects, There's three that I think often get mixed up in the process as asteroids, comets and meteors. Could you just clear up the difference and what exactly is it about a meteorite that makes them so important? Yeah, so asteroids are these small, rocky objects in space. They're things that didn't become planets during the formation of the solar system 4.6 billion years ago.

Meteorids is the term we give to meteorites when they are. in space, and they usually derive from asteroids. Size-wise, there's no official point at which one becomes the other, but the curators at the Natural History Museum suggest that a meteoroid is typically less than hundreds of kilograms in mass and about one meter in diameter. Meteors shooting stars, so things like the Perseids display in July and August, their meteoroid burning up as they enter into Earth's atmosphere. And they're related to comets. Comets are also things left over from the formation of the solar system.

But they are, rather than being the sort of small rocky objects, they're composed mostly of ice and dust. And they're very fragile, so we don't expect to find meteorites from comets, from a meteor shower that comes from a comet. And specifically about meteors and meteorites, what is it about those that are so exciting? So I think meteorites are so exciting because they provide our only tangible link between Earth and the vastness of space between down here and up there. Most of it, I guess they are the only extraterrestrial visitors that we have. Most of us will never travel beyond the Earth's atmosphere, but we can pick up a space rock.

So meteorites have been found all over the world. Are there any particular locations that are especially rich in meteorites or have particular significant meteorite areas? I guess Antarctica and the Sahara would be the two big ones. The Sahara is very interesting. So around the turn of the century, sort of 1999, 2000, the numbers of meat, coming out of Morocco, coming out of the Sahara in Morocco, just exploded. And today Morocco is one of the world's greatest exporters of meteorites. So the officially recognized number of Moroccan meteorites exceeds 1,000.

And the actual number is probably far, far higher, because not all the meteorites are officially registered. And just to give a comparison, the UK, So Morocco has over 1,000. The UK has 23. And I think the reason for that, the reason why Morocco has become this great meteorite hotspot is that, so it has a dry climate, preserving climate. So there are meteorites lying around in the Sahara. There's thousands of years worth of meteorites. They haven't all disintegrated. Then you've got the sand. So you've got this very good surface against which a meteorite which typically has a black fusion crust, not always but often,

will stand out really well. And you haven't got all sort of undergrowth and trees and things that make meteorite hunting so difficult somewhere like the UK. Many Moroccans have become highly skilled at searching in the desert, especially members of nomadic groups. It's a politically stable part of the Sahara, and it has very favourable export legislation. So, for example, somewhere like Australia also has areas that are good for collecting meteorites, but you can't export them. In Morocco, people have got so good at finding meteorites that the price of lunar meteorites, so meteorites that come, not from asteroids, but from the moon, has actually gone down because so much of it was being found compared to before. I mean, the really exciting

stuff I think that's been coming out of Morocco are the Martian meteorites. So these are super, super rare. Fewer than 0.3% of meteorites in collections are Martian. Particularly in 2011, there was a meteorite, a fall that's been called Tissant. And that was actually, it was seen to fall and then collected. So it was picked up when it was very fresh, is the term meteorite collectors use. So it was very fresh, it was dry, it was picked up almost immediately. And when the scientists examined it, they could even see signs of weathering that had taken place on the planet Mars. So it was almost as though it had just been picked up off the surface of the planet.

So what can meteorites tell us about the formation of our solar system and the early history of Earth? So stony meteorites that have not been melted or changed since their formation preserve information about conditions in the primitive solar system when the sun and the planets and the moons and then the asteroids were forming. And we just don't have that information on Earth because Earth rocks are so much younger. In most cases, they're much, much, much younger because Earth has plate tectonics. So there's this constant destruction and recycling of the crust. And we also have the weathering on the surface. So any information about the very early Earth has been destroyed. But scientists studying meteorites can learn things about these early planetary building blocks.

They can start to say things about age, about the composition of the rocks, about temperature, about past impacts and collisions in space. They might gain insights into how smaller bodies coalesced to form planets and how our own planet developed after it had been formed. I think, you know, without them, we can't begin to really answer the questions. Where did we come from? How did we begin? And you've mentioned that, you know, meteorites have touched the lives of a lot of people from scientists to collectors. Could you share a particularly compelling story of someone from your book?

So what I find compelling about meteorites is the element of sort of chance, coincidence, luck. So for example, there was a meteorite that fell in 2021 in Winchcombe in the Cotswolds. And it fell, of all the places in the world it could have gone, it ended in the middle of a driveway in a suburban house at the edge of Wichcombe. And it's, kind of incredible to think that if it had gone just a little bit to the right, it would have ended up in a hedge probably would never have been found. If it had gone a little bit closer to the road, Catherine Wilcoq, so Catherine and Rob Wilcox are the people whose driveway it landed on. And she said, you know, had it ended up closer to the road, she would have probably

just thought it was some rubbish and swept it up, something that a car had churned up. It was also incredibly lucky that it fell when it wasn't raining because it was a particularly fragile type of meteorite. And it was also lucky that it fell in the driveway of people who had happened to read about the meteorite possibly falling in their area. So when they saw it, they immediately suspected it might be something very exciting. And so Robb and Catherine, Rob's a retired civil servant. Catherine's a retired teacher. And since the meteorite landed, they've become sort of meteorite ambassadors and celebrities. They've given over 100 interviews.

They've been on TV, on radio, magazines, books. They do a lot of work with schools now. And I think it's that collision between this really kind of, I don't know, prosaic everyday English suburbia and this great otherness of outer space. I'm also interested in the private meteorite hunters and the idea that, you know, if they find a particularly rare meteorite, they can make their fortune just overnight, just like that. I spoke at a meteorite fair that I visited.

I spoke to a French meteorite hunter slash graphic designer called Theroy Monty. And he said he'd always been dreaming of becoming, stopping the graphic design and just becoming a meteorite person. and he was on holiday and he heard that a meteorite had fallen back in France. And he thought, oh my goodness, bad luck this time. Like, what are the chances? He'd been waiting and waiting for a meteorite. And the time it comes, he's on holiday with his girlfriend who won't let him rush back to Normandy

to collect a meteorite. So he got back as soon as he could. He was seven days late. So he wasn't really expecting much. he went to the place in Normandy where it had fallen and went to a tennis court. So tennis courts are good places to look for meteorites because they've got a very uniform, flat, uniform surface. And he saw something that looked a bit like gravel, but it was sparkly. And it turned out to be a meteorite.

And incredibly, he'd actually managed to find something. And he was selling that at the meteorite. and he was also selling the bit of the tennis court where it had landed. So there was a very small kind of tiny, tiny impact crater. And if he could sell it for enough money, he was hoping he could realize his dream of setting up as a professional meteorite dealer. Amazing, I love that. Meteorites, I guess, often described as this sort of message from space.

If a meteorite could speak, what do you think it would tell us about that journey and, you know, the vastest of the universe that's out there? So, I mean, meteorites are ancient. The oldest are over 4.5 billion years old, older than the earth. So I think, you know, if we live in human time, which is measured in the minutes, hours, days, years, they live in deep time, which is measured by the millions of years, by the billions. So, you know, a human life, sort of seven, 80 years versus 4.5 billion years. I think from the meteorite's perspective, we'd just be these little flickers, less than flickers scurrying around on the surface of a rock. Another way to think about it is, if you imagine a meteorite's life beginning kind of in the middle of your chin, and then you stretch out your hand to the side, and that forms the meteorite timeline. So on that timeline, dinosaurs appear around the middle of your palm. And if you were to take a nail file

and make a pass over your middle fingernail, you'd wipe out the whole of human civilization. But I think also if a meteorite sees our lives as so much briefer than we do, I think they'd also see them as much more cosmically connected. We mostly don't go around thinking of ourselves as creatures living on a planet. We think of ourselves. I think of myself as living in London, maybe in the UK, in Europe. But from the meteorite's perspective, we're part of a vast cosmic environment. You know, we live in space among stars. You're great at protecting your data, but lots of places could still expose you to identity theft. I thought it was safe. If that happens, LifeLock gives you a US-based restoration agent who will

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This podcast is sponsored by name, audio and focal. With over 100 years of combined expertise, name and focal have been bringing music to listeners just as the artist intended. Since day one, this mantra has shaped every innovation in hi-fi design, technology and acoustic engineering, balancing craftsmanship and tradition with pioneering thinking. Name Audio pushes cutting-edge technology to ensure digital precision whilst sustaining Pratt, pace, rhythm and timing, the elusive quality that makes music feel alive and gives it emotional texture. Today, in partnership with French acoustic specialist focal,

name audio creates systems that deliver exceptional sound and unforgettable listening experiences at home. Try it for yourself at a focal powered by name boutique. Visit focal powered by name.com for more information. So in your book, you explore the, I guess, the cultural significance of meteorites throughout history. How have different cultures viewed and interpreted these objects from the sky? So there are many myths, superstitions and cults associated with stones that are said to have fallen from heaven.

So possible meteorites. Some cultures have celebrated them, others have seen them as signs of misfortune. They've been worshipped as deities, as the children of gods, and treated as gifts from the heavens to the people. In Sun Temple of the God Ra at Heliopolis in ancient Egypt, there was a stone, the long-lost Ben Ben Stone that was venerated, and that may have been a meteorite, we think. Near Camp Verdi in Arizona, archaeologists found a stone coffin

containing an iron meteorite swaddled in a blanket of turkey feathers. So buried in the same way that a respected human might have been. Tutankhamun was buried with a dagger that was made of meteoritic iron. And we don't know, but was that because iron from meteorites was seen as a high-status material. Was it because it was seen as a gift from the gods to the kings? In Japan, the Nagata meteorite, that's still kept today in a Shinto temple and once every five years it's taken out and shown to the public and drawn through the streets on a decorated cart. I mean, conversely, others have seen them as much more troubling,

So First Nations groups in Australia have tended to view them negatively in a lot of their history. During the late medieval period in Europe, again, meteorites were generally viewed as ill-omenes, though not always. There's another famous meteorite story about Enzisheim. So this was a meteorite that fell in Alsace in 1492. And it's the earliest witnessed meteorite fall in the west from which, which pieces are preserved today. And when it fell down, King Maximilian, who was the son of the Holy Roman Emperor, Friedrich III, was at war with the French. And his supporters immediately claimed

that the stone was a portent of victory and a sign of divine favour. And it became this brilliant piece of propaganda for them. And then he did actually go on to win his battle. And the stone became even more famous as a result, and it's still kept in Enzheim today. So on a very different note, would it be possible for a meteorite to bring a virus or particular bacterial strain that isn't compatible back to Earth when it lands? So I was talking about this with some scientists at the University of St. Andrews, Paul Savage, Eva Stukin and Claire Cousins. And they were saying that, you know, theoretically that's possible, as long as,

the stone, the meteorite is big enough and the insides aren't massively heated up on their way through the atmosphere, then those layers of rock could protect any organisms from solar and cosmic radiation as it travels through space. And assuming also that the bacteria could survive the stresses of impact shock, either when it was originally blasted off the asteroid, say, or when it landed on Earth, so possible, but current understanding suggests highly unlikely. There's also the fact that terrestrial pathogens have co-evolved with the rest of life. So it could be that extraterrestrial pathogens just couldn't interact with terrestrial life. The conditions on Earth wouldn't allow it to thrive.

There's quite a positive view of meteorites, as we've discussed, in the sense of being a window in space, comes back in time, or. just a symbol for people. But there is also that sense of it being a risk factor. Should we be worried about the potential for collisions with, from asteroids or meteors? Yes and no. We know that rocks from space, very, very big rocks from space, have hit our planet before. Most famously, of course, the Chixilab event and the extinction of the dinosaurs, which we think

a meteorite or asteroid played a role in. And it's calculated that an object that could completely wipe out a major metropolitan area might hit Earth once every 20,000 years. A very large object that could end most of life on Earth, maybe every 100 million years. And I mean, if you look up at the moon and you see all the craters are the famously the craters on the surface of the moon, and that's what Earth should look like. we should be covered in craters, but we have erosion which kind of wipes them all away. And of course we have vegetation and trees, etc.

And I guess it makes us think that it can't happen here. But of course it can and statistically speaking one day it will. On the other hand, our sky scanning has improved so rapidly in recent years. Over the past 10 years, we've discovered about, 20,000 near-Earth asteroids. And of course, once we've discovered them, we can track them, we can assess them. We've got new survey telescopes. We've got better techniques for surveying.

NASA have the Neo-surveyor, which will come online in 27. And that's the first dedicated telescope in space to be searching for, or dedicated to hunting asteroids. and the United Nations has a number of protocols and initiatives to address the threat of asteroids, including the International Asteroid Warning Network. I was talking yesterday to a scientist at the University of Kent, Lord Dover, about the asteroid that's been in the news recently. So right now we have an asteroid with around a 2.4% chance of hitting Earth in 2032.

and he was saying the thing about this asteroid is that usually you find an asteroid, it's got a 2.4% chance of hitting Earth at a certain point, you do more calculations, you look more closely at the orbit, and usually that risk decreases. So far it's not decreasing. So that's interesting. And the other thing about this asteroid is that because of its orbit, we only have a couple more months to observe it,

and after that it will disappear from view, and we won't be able to see it again until 2028. And 2028 is kind of close to 2032. So, I mean, I wonder whether there's going to be a decision to try and do something about this, because if you wanted to do something about it, you can't make that decision in 2028. So in 2028, you can do some more calculations

and you can find out maybe it's all fine or maybe it isn't fine, but if it isn't fine, it's kind of too late by them. So I wonder whether something will be set up. And that's something would be... So in 2022, we had the Dart mission, NASA's Dart mission, which is when a spacecraft was sent up to hit an asteroid. And by hitting an asteroid, this particular asteroid,

it wasn't an asteroid that was headed for Earth. This was just a test. So by hitting it, you change. the speed of it just a tiny amount by about a millimeter of a second, but that was enough to change its orbit. So the idea being, if it was headed towards Earth, you'd change its orbit and then it misses Earth. I mean, the DART mission was kind of incredible. It was a huge success, and it meant that humans took the first step to becoming, you know, the first creatures on Earth to be able to protect themselves from a meteorite strike. So yeah, we might see another dart. I mean, I've been speaking to

some scientists and they reminded me a little bit of some earthquake scientists I spoke to once in America who was saying like, I kind of want it to happen because I kind of want to see. And so some people are like, I kind of, not that they want the asteroid to hit, but they kind of want it to be considered bad enough for a mission to take place. So to finalise the kind of whole conversation, what are some of the biggest unanswered questions about meteorites that you hope will be answered in our lifetime? So I think one of the big questions in planetary science is where did Earth's water come from? So the early inner solar system was a very, very hot place,

and there shouldn't have been any liquid water on the early Earth. So how do we end up living on a blue planet? And I think that idea of the blue planet is just, it's so fundamental, isn't it, too? as how we think of ourselves and those iconic pictures of the blue marble in space. And one theory is that it was brought here by meteorites and I'd love to know definitively

whether that is the case. So, you know, is Earth's water actually all extraterrestrial? There's a particular type of meteorite, a carbonaceous chondrite, which is rich in water. And these meteorites thought have originated from asteroids in the outer solar system, which is a cooler region where water

may have existed at a time when Earth was dry. And these meteorites could have delivered that water to us. And so, you know, without meteorites, so the theory goes, there would be no rivers, no oceans, no lakes, no streams, no blue planet, no us. Thank you for listening to this episode of Instant Genius. That was Helen Gordon talking about meteorites. The Instant Genius podcast is brought to you by the team behind BBC Science Focus magazine, which you can find on sale now in supermarkets and newsagents, as well as on your preferred app store. Alternatively, you can come and find us online at sciencefocus.com. This podcast is sponsored by name, audio and focal. The texture and emotional depth of music can be lost through digital sources or poor signal.

Name Audio believes you can have digital precision with analog warmth. Alongside French acoustic specialist vocal, Name creates high-end audio systems combining innovation with craftsmanship, so you can listen to music, just as the artist intended. Discover more at nameaudio.com. In a place like Los Angeles, people don't stop being who they are. Writers, thinkers, creators, people with stories still unfolding. That spirit lives on at Kingsley Manor, a community shaped by individuality, creativity, and lives well-lived.

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