Asteroid Bennu's brine, and DeepSeek shocks Silicon Valley
In this edition of The Naked Scientists: Samples back from space reveal tantalising insights into where the life-linked chemicals that kick-started biology on Earth could have come from. Also, the impact of China’s DeepSeek AI model on society, finance, and the global tech market. And why imported olive trees turn out to be the perfect cover for stowaway snakes and insects…
In this episode
Did life begin with the Bennu asteroid?
Sara Russell, NHM
Five years ago, a NASA spacecraft successfully collected samples from the asteroid Bennu, and they were brought back to Earth in September of 2023. Analysis from these samples is now starting to trickle through, and one startling finding published in Nature has concluded that Bennu contains samples of evaporated brine - which is not dissimilar to the composition of salt flats in the United States and Bolivia. This implies that Bennu’s parent asteroid could have hosted pockets of liquid water as well as plenty of other minerals and molecules that act as the building blocks of life. To talk us through the paper’s findings, we put in a call to the Natural History Museum’s Sara Russell. She spoke to us from NASA’s press conference on Bennu…
Sara - At the Natural History Museum, we have a great collection of meteorites. So we have some expertise in looking at asteroids, which is what most meteorites are fragments of. So we got an allocation of this material and we've been analysing it for the last year or so.
Chris - What does it actually look like when it turned up before you began analysing it? What does asteroid dust look like? Sara - Well, this asteroid is very dark. What we got looked like about a teaspoon full of black sugar, if you can imagine that. So it's that sort of grain size, but completely black.
Chris - Is it black because it's been hit by sunlight or is it naturally like that? Has anyone scratched below the surface so you know roughly what you're analysing?
Sara - Yeah, absolutely. We've basically done everything to it, including cutting it in half, the bits in half. And yes, it's black all the way through mostly, except there are some patches of white, which is part of the interesting part of what we're talking about today.
Chris - So apart from looking at it visually and chopping up the grains, how have you actually analysed it then?
Sara - So we've done a whole suite of analyses on it. So for each individual grain, we CT scanned it. So just as when you go to hospital, you might get a CT scan, which shows what your insides look like. We did the same thing on these grains to see what they look like on the inside. And then we put them in an electron microscope to look at them in much greater detail. And we also looked at their chemistry, what elements they were made of.
Chris - Wow. So come on, put us out of our misery. What is the bottom line?
Sara - The rock is mostly made of a clay mineral, which traps a lot of water. So it's very water rich. And we were kind of expecting that because that's what it looked like from space. But what we weren't expecting was that it also contains little crystals of salt. And that was completely unexpected to us. And we think that these probably formed in little underground pods in the asteroid of this briny, salty fluid that then started to evaporate away and leave the sequence of salts. And we see similar kind of sequences on Earth, on lakes that have dried up, can leave these layers of salty material on them. So we've been comparing them to terrestrial salts. But also we think that this might happen quite a lot over the solar system. So we see similar salts in moons of Saturn like Enceladus, also on Ceres, which is the biggest asteroid in the asteroid belt. And so we wonder if these salts are actually telling us something pretty universal about what happens to rocks in space.
Chris - How would it have been in a salty environment then, this body that's now an asteroid?
Sara - So we think that Bennu's parent body probably formed in the outermost reaches of the solar system. There it's very, very cold and icy. So it would have accreted ice and rock. And then the ice started to melt. And then this water interacted with the rock and produced both the clays. But then there was obviously some leftover that made these pods that became salty because they had had the ions from the rock added into them.
Chris - When you say it melted, would that be when it came closer into the solar system? What would have melted it?
Sara - Yeah, no, it was probably melted very, very early in its history. Because when it first formed, it would have been very slightly radioactive. And so the radioactive heat could have melted the water.
Chris - Ah, right. Okay. So how did it end up in its present position then, if it formed way out yonder in the solar system?
Sara - Chris, that's one of the big questions that we're trying to understand. How things moved across the solar system from the outermost parts to the inner part. So it might have been in the early solar system, Saturn and Jupiter were not in the stable place they are today. They might have been moving inwards and outwards in their distance to the sun. And that might have disrupted these bodies and forced them to hop into the innermost part of the solar system.
Chris - Apart from the saltiness, are there any other interesting chemicals in there that make us kind of go, hmm, that is interesting?
Sara - We also have an organics team. And so they've been looking at all the carbon-based molecules. And they found there's this huge zoo of different, complicated organic molecules. So these aren't things that were formed by life, but they are molecules that may potentially be the ingredients for life. They found things like amino acids and nuclear bases, which are molecules that make up part of the DNA of living things. So what we think is, firstly, these briny fluids might have actually helped make these organic compounds. So they might have been a really great place for these organic stuff to get cooked up and be built.
But then also, if asteroids like Bennu were around in the early solar system, which they certainly were, and they impacted the Earth, they would have seeded the Earth with both the organic molecules, plus also water, plus also essential nutrients from the salts like phosphorus and sulphur that life needs to flourish.
Chris - Do you think then, or would a model then be that in the early solar system, we've got lots of raw materials floating around, some of it accretes into bodies like Bennu, which just also happen to be radioactive, so they've got their own inbuilt cooker. That provides the conditions together with some of that water to cook up, as you put it, some exciting chemistry, which then through gravity is dumped onto nascent planets like the early Earth.
Sara - Yes, you've exactly got it. I don't think this would have been an unusual asteroid. So if an asteroid formed early in the solar system, it would have been slightly radioactive. It's very likely to have had these very common elements of carbon and hydrogen and so on that make up these organic materials and water and salts as well. So I see this as probably being a widespread process across the solar system. It is inevitable that asteroids like this would have raided down on the early Earth and would have made it a lot more conducive to life.
Chris - They would have rained down on a lot of other bodies as well, presumably. So therefore, they were giving everywhere an equal opportunity.
Sara - Yes, absolutely. If this model is right, then absolutely. It should be quite a widespread process. So why not have life everywhere in the solar system that has enough heat to support it? And of course, also in early Mars as well. So Mars is a bit cold now, but it would have been much more habitable in the early solar system. So there's no reason why life couldn't have started there as well.
08:30 - Why China's DeepSeek AI model matters
Why China's DeepSeek AI model matters
Mike Wooldridge, University of Oxford
The emergence of a Chinese-made artificial intelligence model called DeepSeek has shaken the tech industry and the global markets, and bruised the egos of those in Silicon Valley and the White House. Even US president Donald Trump got in on the action, announcing this week that the Chinese DeepSeek AI platform had shaken Silicon Valley and knocked billions off the share prices of some of the world’s leading tech giants. But what exactly is DeepSeek? And why has it unsettled tech innovators and investors? Here’s Mike Wooldridge, professor of computer science at the University of Oxford, where he specialises in artificial intelligence…
Mike - DeepSeek is an example of what's called a large language model. And large language models are the AI programs that have taken the world by storm over the last few years. So the most famous of these is ChatGPT. And they're very, very large scale, very general artificial intelligence systems. And they were surprisingly powerful, which is why ChatGPT got so much attention when it was released. They were unexpectedly powerful. But their capability came at a cost. They're extraordinarily expensive to develop and require really hard to imagine computational resources to build. So we don't have precise figures. But a GPT class model to build would require something like 20,000 to 40,000 AI supercomputers running for months. And the cost of that runs into hundreds of millions of dollars. What that meant is that the number of organisations with those resources at hand to be able to do that is very, very small. It's basically the Silicon Valley giants and a very small number of state level actors. Now, DeepSeek come along, they announce a model which seems to be as capable as the current crop of large language models. It seems to be up there with the best of them. And yet the claim was that it was built for a tiny fraction of the cost of those models, which means that the advantage that Silicon Valley had and what's called the moat, you know, the thing which kept everybody else out of this market, looked like it might be evaporating. And that panicked Silicon Valley.
Chris - Do their claims stack up, not just in terms of performance, but their claim that they can do this so cheaply? Do you think that that was a bit of fanfare to get them traction? Or is it the reality?
Mike - They have, it seems, done it comparatively cheaply, but not so cheaply that we're all going to be building large language models in the shed at the end of our garden. They've told us that they used a network of a couple of thousand of GPUs, so much smaller than the kind of scale of supercomputers that we use to build ChatGPT and the like. But if you dig into the statistics, they required three million hours of processing. So AI supercomputer, a GPU running for three million hours. Now you can only do that if you have thousands of those running in parallel. Now the cost of their cluster, I did some back of the envelope calculations. It looks like something like 50 to $60 million to buy those GPUs and three million GPU hours at $2 an hour. The running cost of those amounts to $6 million. So that's where they get that headline figure on. But still that scale means, for example, my research group has one GPU and my students fight over getting access to it. There's no way we could do that. There's no way we could replicate that. So they haven't exactly given this technology to the masses, but nevertheless, it looks like it's a real advance.
Chris - There were claims made though, that this was being done using lower grade chips than the industry class. And that's always been a sort of political thing, hasn't it? Because China has and some other actors have been prevented from having access to the sorts of technology that would enable them to make these very high end computer chips. So they're using lower grade architectures. Is that the case or have they just sneakily got hold of what the world thought they didn't have? Or have they made a genuine breakthrough in being able to get the kind of computing powers that you're saying they have from lesser materials?
Mike - So there are export regulations in particular from the US about top end silicon processors going to China. So indeed, it looks like they've made some advances in the core architecture, what's called the transformer architecture, which is the neural network architecture that's underneath ChatGPT and Gemini and Claude and all of these large language models. And it looks like they've been able to optimise that architecture. So one of the key ideas, for example, is an idea called a mixture of experts approach. And the idea that instead of having one big, very, very clever neural network, you break it down into a bunch of smaller networks, which is much more efficient. Now, this is not a new idea. It's been around for a while, but it seems like they might have made it work. And that's quite an interesting development.
Chris - What about the quality and integrity of what it generates? Because there was concern expressed in a number of different quarters that when you ask it certain questions about certain things that China has sensitivities about, it doesn't answer the question.
Mike - Yeah. So first thing to say is, we're going to need time to evaluate the model. I think teams all over the world are busy doing that. But at first blush, it does indeed look like this is a model which is in the same territory as the other GPT class models. Around the censorship issue, I think it's pretty well documented now that it appears that the model is censored in terms of some of the answers it gives. My advice to anybody using any large language model, wherever it comes from, is do not tell that model anything that you're not comfortable with your neighbours knowing or the world knowing about. Because you don't really know where that data is going to end up. Don't tell it about your relationship problems or complain about your boss or anything like that. Because really, the text that you give, you just don't know where that's going to end up. Obviously, in this case, there are additional sensitivities, because the model comes from China. And so that advice, I think, is particularly relevant.
Chris - Yeah, if you look at the, I had a look at the terms and conditions and it says, the data are held on secure servers in China. And that is how you interpret that, isn't it? But are they basically creating a giant earpiece for the Chinese government with this?
Because any industry in China has board representation from the government, it has to. And therefore, anything within that company potentially can be accessed by the government, the government can just request it. So are they basically by getting people all over the world onto this, and then feeding it all kinds of things, they might not realise they need to be as careful as you're advocating for. It could be hoovering up all kinds of interesting things and reinforcing its knowledge about all of us.
Mike - Indeed. And I do think that's something that I think people need to be mindful of. That's something I think that governments have very quickly woken up to. So I mean, the advice, I think, is very, very clear. Do not tell any large language model, anything sensitive, private, that you wouldn't want publicly known. Just don't.
Chris - Have you downloaded DeepSeek? Would you use it?
Mike - No and no. We would use it for experiments, I think, with caution. We would evaluate it. I wouldn't use it on my desktop machine.
17:04 - UK to dispose of its radioactive plutonium
UK to dispose of its radioactive plutonium
Claire Corkhill, University of Bristol
The UK government has announced that it will dispose of over 140 tonnes of radioactive plutonium - which is currently being stored at a secure facility at Sellafield in the north of England. The UK has the world's largest stockpile of hazardous material. So, why have we got all of this material, where can it go, and how can we safeguard it for the million plus years it’s going to take to cool down? Here’s Claire Corkhill, professor of mineralogy and radioactive waste management at the University of Bristol…
Claire - Plutonium is generated from the reprocessing of spent nuclear fuel, so that's the fuel that's been in a nuclear reactor that we've finished using. Spent fuel recycling has generated us a large stockpile, 140 tonnes, of civil plutonium.
Chris - And where is it at the moment?
Claire - It's currently being stored at the Sellafield site in northwest England, in Cumbria, in what you can think of as very large, secure, specially designed warehouses that are armed by Guard Police, because this material has security implications. And it also needs to be actively cooled, because it's constantly undergoing radioactive decay, which is generating quite a lot of heat. So we need to make sure that it's maintained in an inert and cool atmosphere.
Chris - Is there nothing we can do with it? Because radioactive material, that's what goes into a nuclear reactor in the first place, in some respects. So is there no nuclear process that could consume this?
Claire - It could be useful for several different things. In France, for example, they use recycled plutonium to make new nuclear fuel. And to do that, they mix it with the recycled uranium that has the right isotopics. We call that a mixed oxide fuel. It's a mix of uranium and plutonium dioxide, MOX fuel. There are futuristic designs of nuclear reactors that could use plutonium as a fuel. And there are also other applications like space batteries, for example. It's a very long-lived radionuclide, which means you can use it to power satellites and rovers on Mars and so on. But that would only use a very small amount of the stockpile that we have.
Chris - Can we not just put it into nuclear reactors where the ferocious conditions in there would degrade the plutonium into other things so that we would turn something that isn't currently useful into something that might be or something that's easier to deal with? Or is it easier to deal with just as plutonium?
Claire - You could use it as fuel. There's a specific type of futuristic reactor conceived of quite a long time ago. And we had an experimental one of these in the UK at Dounreay called a fast breeder reactor. And that would actually use the plutonium as fuel and it would consume some of that plutonium. The problem is with that type of fuel burning is that you end up generating other radionuclides that are quite hazardous. For example, americium is a very strong gamma emitter, and that makes it very hazardous for people to come close to that material. So there's a limit, is what I'm saying, to how many times you can use and recycle it. And ultimately, it will always have to be disposed of one way or another.
Chris - So what's the solution instead then that's being proposed that we do with this? It's quite a prodigious amount, 140 tonnes. We can't just put it in any old place.
Claire - We do have the world's largest inventory of plutonium in the UK. It's not all of ours, some of it belongs to international countries where we reprocessed their fuel, but we've kept the plutonium. What the government policy has always been is to try and put it beyond reach. So the new plan is to do what we call immobilising it, locking it up into a safe, durable form in a deep geological disposal facility, which is something that we're trying to find a site for in the UK.
Chris What would be the nature of the storage though? So you can't just put it underground, because presumably this is what, a powder, if it's an oxide of a metal, so it's presumably some kind of powder. So what can you actually do to make that safe, so it's actually going to stay where you put it?
Claire - Right, it is a powder. And so when we talk about immobilising, what we mean is to take something that's potentially dispersible, like a powder, and turn it into a solid material. So what we plan to do is consolidate it, to densify it into a ceramic material. Most of you will think of ceramics as cups and plates and saucers. It's not quite that kind of ceramic, it's more like a rock. We can kind of think of it as an assemblage of minerals, quite a lot like a rock. And we can do that by adding powders of the plutonium with other chemicals together, we mix them, we bake them at a very high temperature. And that's when they become these very dense, durable, solid materials that then we could pack into canisters, and transport down to the Geological Disposal Facility, which is at a depth of around 500 metres to 1000 metres below the earth. And there it will be isolated from future populations, until it is radioactively decayed to its stable isotopes.
Chris - I had heard from other scientists who work on this kind of thing, that one problem with trying to sequester highly radioactive materials is that every time it undergoes radioactive decay, the nuclei sort of shoot backwards, almost like a gun recoiling, because they're firing out heavy things like alpha particles. And that damages the crystal structure, which makes the material fall apart in thousands of years, rather than the millions of years you need it to stay safe for. Can you get around that?
Claire - You're absolutely right. The plutonium is undergoing radioactive decay to uranium, and then uranium also undergoes radioactive decay, and the alpha particles do damage the crystal structure. But what happens is the crystal structure becomes, it becomes what we call metamict, it's like a glass, it becomes amorphous, all of the atoms inside of the material become all jiggled up, but that doesn't affect its long term durability. And we know that because we've examined natural minerals of the same composition that contain uranium. And these minerals, some of them are billions of years old. There's one in particular I'm studying right now, which is just over a billion years old. And it contains almost all of the original uranium that it had when it was formed a billion years ago. Despite the fact it's undergone a lot of radioactive decay, it's been squeezed in mountains, you know, pushed out of volcanoes, it's been rained on, it's come into contact with high temperature underground water, it's maybe even been subject to glaciation. But during all of that time, the uranium that's inside that crystal structure, despite the fact it's been amorphised through radiation damage, all of that uranium is still inside the crystal structure. So we have a very good natural analogue that tells us that these kinds of materials will do a really good job at immobilising, at locking away the plutonium over the long timescales required, which is on the order of a million years.
24:03 - Olive trees help import invasive species
Olive trees help import invasive species
Silviu Petrovan, University of Cambridge
Airlines estimate that there are over 1.5 million people airbourne around the planet at any moment in time. And where people go, they take their infections and other parasitic freeloaders too, and it’s translating into a problem for disease spread and antibiotic resistance. But it’s not just the movement of people that’s a problem: we’re moving massive quantities of plants, animals and other goods internationally, which are introducing infections and invasive species into new geographies. Historically it used to be just the odd spider or scorpion in a bunch of bananas, but a new study in BioScience suggests that even innocent-looking olive trees, imported to spruce up a patio, are home to stowaway snakes, lizards, spiders and insects. Will Tingle went to meet Silviu Petrovan at the David Attenborough Building at Cambridge University...
Silviu - So olive trees are very interesting for a couple of reasons. One is that, as far as I can tell actually, there's this rather new fashion in relation to having olive trees not just in the garden, but also associated, for instance, with outdoor spaces, of restaurants. But the interesting thing is that actually that a sizeable proportion of these olive trees are not the kind of stick ones, but rather very much actually the quite hefty diameter trees, very often actually trees that are decades old, which in effect means that these are trees that have been recycled from farmland. And the reason why people love these trees is because of their gnarly aspect, right? Almost any town and city in Britain will have some kind of public space that will have one of these kind of old growth gnarly olive trees. One look at it actually would give you an indication that, first of all, to transport it you need a large root bulb, which obviously presents lots of opportunities for things to be moved at the same time within that root bulb. But then you have complicated bark, with sort of small crevices and little holes in between the branches. All of those basically are spaces where species can hitch a ride. And this now has been shown repeatedly as being a really major pathway for species introductions into Europe.
Will - But if we know that, then, if we know that, and we have known for some time that these olive trees and their gnarled pockets and crevices are great places for a lizard or a spider to hide, how is stuff still slipping through the gaps?
Silviu - I think in the same way as with cut flowers, it's basically a numbers game. I think the customs officers are doing an extremely good job. However, if you think about the fact that these are very much actually involving large numbers, which means that ultimately not everything can be intercepted. How do you check a shipment of half a million roses, right? Chances are that actually you cannot verify everything down to the last flower. It's physically impossible, and therefore the chances are that something will slip through.
Will - Are there any main culprits that are coming through because of these olive trees?
Silviu - Absolutely. So the one that we highlight in there is a lizard, which people refer to as the Italian wall lizard or also Italian ruin lizard, Podarcis siculus. And that's a species that very often has been linked directly to the trade in olive trees. And the point that we're making is that that in itself is not great. The fact that we're establishing populations of this species that is highly adaptable. It's actually surviving in a whole range of environments. But ultimately the important point to make here is that the amphibians and reptiles are probably just the tip of the iceberg. And we got a lot of data on the interception of invertebrates. And there are the sort of groups that very often actually represent the kind of main issues in relation, for instance, to one, becoming agricultural pests, two potentially becoming established, and then causing problems for the natural environment.
Will - Are there smaller organisms that are hitching a lift that perhaps we don't even know about that could be causing even bigger problems?
Silviu - Very often, the sort of main issue is the potential actually to introduce new diseases and new pathogens to a host that in effect actually would be completely naive. And the very good example I think in relation to this is to think of the grey squirrel. The grey squirrel does create some competition with the red squirrel, with the native European species. But most importantly is the fact that it's able to transmit a virus that is extremely, extremely damaging for the red squirrels and very quickly actually eliminates them entirely.
Will - Is there anything that can be done to even remotely stem the spread of these invasives?
Silviu - Absolutely. So one of the relatively recent changes was the fact that virtually all plants now should not actually be potted in soil, which means that a huge area of contamination has actually been removed. It has been massively successful, but clearly there's more that could be done. As we have done in relation to potted soil. I think there are increasingly sort of targeted regulations that could achieve better outcomes. One of the things that we also highlight is that while biosecurity in itself is a really important aspect of the environmental risks associated with this ornamental plant trade, it's by no means the only one. And we also highlight the fact that there are important considerations there in relation to water scarcity and for the producing countries. The fact that some of these floriculture in effect actually competes in some cases with land being used for food production. But ultimately it's also a really important economic activity for the producing countries and disproportionately for some groups such as, for instance, women working in rural environments. And therefore we're absolutely not arguing for well-meaning, but knee-jerk reactions such as, 'oh, we should ban this.' This is definitely not the message that we want to put across, but rather that we need to have a careful discussion and see how we could achieve better outcomes for this trade.
30:16 - Can crude oil be refined without producing petrol?
Can crude oil be refined without producing petrol?
James - Thanks Kevin. You’re absolutely correct that petrol (or, gasoline) is a fraction of crude oil, obtained through a process called fractional distillation during refining.
Crude oil is a complex mixture of hydrocarbons, and while refining processes can be optimised to prioritise certain products (like diesel or jet fuel), completely avoiding petrol would be inefficient and require costly modifications.
Your question is a pertinent one, Kevin, because the other fractions of crude oil produced during refining also include the types which fuel planes and ships. We’re going to need these types of fuel for a long time to come, as the kinds of batteries you’d need to power a Boeing 747 or transatlantic cargo ship for an average journey would be prohibitively heavy.
So, what will happen to petrol in a world full of electric road vehicles? Here to help us out is Professor Nilay Shah, Director of the Centre for Process Systems Engineering at Imperial College London.
Nilay - Thanks James. Refineries could adapt in a number of ways:
One option is chemically processing petrol-range hydrocarbons to increase their molecular weight and make them compatible with aviation fuel. However, this would require significant investment in refinery modifications.
Petrol and its lighter fractions could also be used for hydrogen production (another type of green energy) via reforming, with carbon capture and storage to reduce emissions, but this presents its own challenges.
Or, petrol-range hydrocarbons (especially naphtha) could be diverted into the petrochemical industry for making plastics, synthetic fibers, and chemicals. However, this would require investment in naphtha crackers and could lead to an oversupply of petrochemicals, making it less economically viable compared to cracking ethane or propane.
This is perhaps the most promising option, but, as you’ve heard, all of them have their drawbacks.
With lower petrol demand, some refiners may shift towards bio-based or synthetic fuels to remain viable in a decarbonising world. We’ll have to wait and see.
James - So, Kevin, Crude oil refining cannot currently avoid producing petrol, but as demand falls, refiners would need to adapt through a mix of diversification strategies. This could be Long-term, the refining industry may shrink or evolve with different, greener feedstocks.
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