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  • NATURE PODCAST

Podcast: The earliest Americans, 2D magnets, and 25 years since the first cosmic microwave background image

This week, the earliest Americans, 2D magnets, and the legacy of the Universe's first 'baby picture'.

In this episode:

00:40 First Americans

A fossil find hints that humans may have arrived in America 100,000 years earlier than previously thought. Research paper: Holen et al.; News & Views: Unexpectedly early signs of Americans; Nature Video: The first Americans: Clues to an ancient migration

08:16 The universe’s ‘baby picture’

The lessons from the cosmic microwave background, 25 years since the first image that captured it. NASA COBE homepage; ESA Planck homepage

15:24 Research Highlights

Conditions for life on one of Saturn’s moons; and salt is making life tricky in some of Earth’s lakes. Research Highlight: Hydrogen geysers on Saturn’s moon suggest the possibility of life; Research Highlight: Lakes face a dangerously salty future

16:59 Podcast survey

Help us improve the Nature Podcast by letting us know who you are. Podcast survey

17:26 2D magnet

Creating a magnet in a single slice of atoms. Research paper: Gong et al.

24:00 News Chat

The March for Science; and a threat to Chinese fossil site. News: What happened at March for Science events around the world; News: Mining threatens Chinese fossil site that revealed planet’s earliest animals

Never miss an episode: Subscribe to the Nature Podcast on Apple Podcasts, Google Podcasts, Spotify or your favourite podcast app. Head here for the Nature Podcast RSS feed.

doi: https://doi.org/10.1038/d41586-019-03093-3

Transcript

This week, the earliest Americans, 2D magnets, and the legacy of the Universe's first 'baby picture'.

[Jingle]

Interviewer: Kerri Smith

This week: the space mission that changed how we see the Universe.

Interviewee: John Mather

So I said to my new boss, well you know my thesis project didn’t work but we should try it in outer space.

Interviewer: Adam Levy

And physicists cast doubt on a 50 year old theorem about magnetism.

Interviewee: Jing Xia

This is a very familiar theorem that we would regard as a law that you cannot break.

Interviewer: Kerri Smith

Plus, hints of the first humans in America. This is the Nature Podcastfor April the 27th2017. I’m Kerri Smith.

Interviewer: Adam Levy

And I’m Adam Levy

[Jingle]

Interviewer: Adam Levy

Immigration is a hot topic in America right now, and no, not just because of Donald Trump. The archaeological community is interested in when the very first humans migrated into America. Various bits of evidence point to Homo sapiens moving east from Siberia, into Alaska, and down into the rest of America around 14 or 15,000 years ago. There are claims of archaeological or genetic evidence for even older movements of people, 20, 30 or even 40,000 years ago, but this is still controversial. Now, a new claim is blowing even these dates out of the water. Shamini Bundell finds out more.

Interviewer: Shamini Bundell

Despite California’s sunny, modern climate it was once an icy wilderness, home to ancient ice age creatures like mammoths and mastodon: hairy relatives of elephants with shaggy hair and long tusks. We know this because, now and again, construction workers stumble across their bones. One such site was accidentally uncovered back in the early 90s and Tom Deméréof the San Diego Natural History Museum was called in to investigate.

Interviewee: Tom Deméré

I first visited the site the day it was discovered. I was at the museum and a field palaeontologist, Richard Cerutti, was out at a freeway construction site and had discovered a partial skeleton of an American mastodon.

Interviewer: Shamini Bundell

Tom headed over to the site to meet Richard whom the site was later named after, and to have a look at the mastodon bones. It didn’t take long for the team to realise that they had found something quite unusual.

Interviewee: Tom Deméré

The skeleton was buried in a fine-grain sediment and it’s not unusual to find fossils in fine grain silt layers. What is unusual is to find them in association with large rocks.

Interviewer: Shamini Bundell

There were a number of large cobbles at the site. Fine silt is usually left by slow moving water but the cobbles were too heavy to have been washed there by a gently flowing stream. There was nowhere nearby that the rocks could have come from. So how did they get there? And that wasn’t the only mystery. A few choice mastodon bones seemed to have been smashed whilst still fresh. These included thick, strong bones such as the thigh bones, while other bones including the more delicate ribs were intact. It seemed unlikely that wind, water or animals trampling over them would have left such specific breakages. Looking at the pattern of how the rocks and bones at the site were distributed, started to reveal a possible answer.

Interviewee: Tom Deméré

As the excavation proceeded over a 5 month period, we found interesting concentrations of bone and rock, concentrated in two distinct clusters.

Interviewer: Shamini Bundell

The two clusters each had a heavy cobblestone at their centre with pieces of broken bone and rock scattered around each one. It looked like someone had used the heavier rocks as hammers and anvils to smash the bones open.

Interviewee: Tom Deméré

The only plausible hypothesis we kept coming back to was that humans were processing mastodon bones at the site. They were breaking the bones and that material that they would break would be raw material for making bone tools.

Interviewer: Shamini Bundell

Tom’s team were excited to have found evidence of humans interacting with a mastodon, something unusual for this part of California. But it was also not that surprising. There are other sites in America where humans were interacting with the ice age mammals that still roamed the continent, back when humans turned up around 14 or 15,000 years ago. Now, this excavation was back in 1992, so why are people getting excited about it now? Natureeditor Henry Gee, who handled the paper, joined me in the studio to explain.

Interviewee: Tom Deméré

In 25 years they haven’t been able to get a good radio-carbon date for this site, which you’d expect if it was only a few thousand years old. But using uranium-thorium, using radio-metric dates, they finally found a good date of around 130,000 years ago which is ten times the age of anything we’d have found of any human activity in the Americas.

Interviewer: Shamini Bundell

So, 130,000 years old compared to 15,000-ish. That’s a huge leap, so it’s pretty exciting to think there could have been people in North America that long ago. But, in the context of where humans were in the rest of the world at that time, it’s a slightly wacky idea isn’t it?

Interviewee: Tom Deméré

It is slightly wacky because we don’t really know of any humans, any modern humans, outside Africa until about 130,000 years old and just to say that there were modern humans outside Africa 130,000 years ago would be quite startling. So, whatever these humans were, they might have been early modern humans that got there before we ever realised modern humans got out of Africa, or they could have been some earlier form of human – some sort of homo-erectus. There were loads and loads of earlier hominins all over the place in the old world, certainly, for a very, very long time. So it’s not inconceivable that there was some hominin activity in the Americas a very long time ago, it’s just nobody’s really looked for it because people have assumed that it wouldn’t be there.

Interviewer: Shamini Bundell

And what was your reaction when you first saw this paper?

Interviewee: HenryGee

As a Natureeditor, I’m working at the very cutting edge of science, so occasionally one does get papers that are pretty startling and then you have to get them assessed on the evidence.

Interviewer: Shamini Bundell

So you sent it off to be assessed by the referees of the paper and what were their reactions?

Interviewee: HenryGee

The referees’ reactions were surprisingly welcoming. Some of them said privately that they didn’t really believe it but then of course they also know that just because you don’t believe it, doesn’t mean it can’t be right. But all the actual evidence checks out. It’s just rather startling, so who knows what’ll happen.

Interviewer: Shamini Bundell

Would you care to take a guess?

Interviewee: HenryGee

Now, goodness me, this is sticking my neck out here. I think people will reassess archaeological sites that have been found earlier and try and see if some of the evidence fits earlier human activity in the Americas. Now, of course, when I see evidence of human activity, I actually want to see human bones and that would settle it but of course we have to work with what we have and certainly in the archaeological record, evidence of actual humans is very rare, but evidence of human activity is slightly more, well slightly less rare.

Interviewer: Shamini Bundell

Thanks Henry. If this does turn out to be true, it’s a huge change to what we thought we knew about where humans were evolving and moving around the planet. Let’s have a final word from Tom Deméré.

Interviewee: Tom Deméré

Like most scientific endeavours, a discovery like this poses sometimes as many questions as it answers. We don’t know what species they were. We don’t know how they arrived here. We don’t know how long they stayed here. We don’t know how they’re related to modern humans, if at all, and those are really interesting questions, but although our study can’t really answer them at this point, it does serve as an interesting piece in this puzzle, exploring the evolution of people on this planet.

Interviewer: Adam Levy

That was Tom Deméréof the San Diego Natural History Museum, as well as Henry Gee, talking to Shamini Bundell. Tom’s paper and a News & Views are on nature.com/nature this week and there’s also a mini documentary film about the find. That’s on youtube.com/naturevideochannel.

Interviewer: Kerri Smith

Still to come in the Research Highlights: conditions may be ripe for life on one of Saturn’s moons, and salt may be making life tricky in some North American lakes. But first, reporter Davide Castelvecchi looks back at a picture that changed the way we see our Universe.

[Music]

Interviewer: Davide Castelvecchi

This week marks the 25th anniversary of a landmark discovery in Cosmology. On the 23rd of April 1992 NASA unveiled a picture painted in microwave light. This was the first image of the cosmic microwave background: the afterglow of the Big Bang. It revealed what the Universe looked like shortly after its birth: the Universe’s ‘baby picture’. John Mather was one of the key astrophysicists behind this image. His interest in the microwave background went back to his student years when he was hunting for a thesis topic.

Interviewee: John Mather

And I looked around and I found a project which was to build an apparatus to go up on a high altitude balloon, so that was my main thesis project. And we built it and it did not work and then I got a job at NASA so I said to my new boss, well you know my thesis project didn’t work but we should try it in outer space so that became the cosmic background explorer satellite.

Interviewer: Davide Castelvecchi

The microwave background had first been spotted back in 1964. But no one had been able to precisely measure it, let alone map how it varied across the sky. This new satellite, COBE – the cosmic microwave background explorer – would shed new light on its properties. But developing COBE took fifteen years, and huge efforts.

Interviewee: John Mather

The COBE Satellite took about 1500 people to build. When we started the COBE mission people still were designing NASA satellites with pencils and pieces of paper.

Interviewer: Davide Castelvecchi

But all this work paid off. The first major discovery from COBE arrived just weeks after launch, in early 1990. It was not yet a map, but an analysis of the bands of light – the spectrum – that make up the radiation. John distinctly remembers the reaction he got when he first showed this graph.

Interviewee: John Mather

When I put up my viewgraph, that showed the spectrum of this cosmic background radiation, I didn’t say anything and within moments the entire audience stood up and was applauding, so I got a standing ovation for a chart.

Interviewer: Davide Castelvecchi

Until then, cosmology had earned itself a bit of a bad reputation. There were plenty of theories, but not much data to back them up. This chart was different. The data returned by the satellite was indistinguishable from the theoretical predictions, but COBE’s most astonishing finding was yet to come.

Interviewee: John Mather

My second great discovery was that the Universe has hot and cold spots. In Greek we call them Anisotropy.

Interviewer: Davide Castelvecchi

These hot and cold spots were first shown to the world 25 years ago by John's colleague, George Smoot. COBE measured variations in the temperature of the microwave background across the sky. The result: A baby picture of the universe, when it was a mere 400,000 years old. And the image left scientists gasping, yet again.

Interviewee: John Mather

So, Stephen Hawking said, if I remember roughly, that it was the most important scientific discovery of the century if not of all time.

Interviewer: Davide Castelvecchi

The map was so important because it showed how the primordial broth of elementary particles had clumped in denser regions. Those regions went on to form galaxies and stars millions of years later. John and George shared the Nobel Prize for Physics in 2006 and COBE’s discoveries made an impression on many young scientists. Among them was Jan Tauber who had just started a job at the European Space Agency.

Interviewee: Jan Tauber

I was a radio astronomer who had specialized in doing studies of our own galaxy which is, from a cosmological perspective, a very nearby object. And suddenly there was this guy talking about the very beginning of the Universe. It made an impact in the sense that this was clearly big science.

Interviewer: Davide Castelvecchi

Jan soon started an effort to build a European follow-up to COBE, called Planck.

Interviewee: Jan Tauber

Clearly COBE ushered in a new era where people tried to do better than COBE and this was one of the first attempts at that.

Interviewer: Davide Castelvecchi

Missions like Planck could take much sharper and more detailed pictures than COBE’s. But they also confirmed COBE’s results.

Interviewee: John Mather

I was really thrilled that we got the right answer the first time because in the places where they could measure the same that we measured, the answers agreed beautifully.

Interviewer: Davide Castelvecchi

Thanks to progress studying the cosmic microwave background, Cosmology has made giant leaps. It has uncovered everything from the universe’s age – 13.8 billion years – to signs of the enigmatic dark matter. So has the microwave background given away all its secrets?

Interviewee: John Mather

There’s still one wonderful secret that we might find.

Interviewee: Jan Tauber

We’re looking for gravitational waves.

Interviewer: Davide Castelvecchi

This is the question at the top of cosmologists’ list: whether the baby picture of the Universe contains an imprint of gravitational waves. These ripples could confirm that for a brief instant the Universe ballooned from microscopic to cosmic size – a theory called inflation. Cosmologists should be able to spot the imprint of these gravitational waves by measuring the polarization of the microwaves; this is the way the light is ordered together.

Interviewee: John Mather

So, if we could make that measurement, and if it matches or does not match the predictions, then we will have learnt something about those extreme conditions of the early universe.

Interviewer: Davide Castelvecchi

Planck’s final set of results is due out before the end of this year. And they will include the map of polarization. So Planck might have a shot at revealing the signature of gravitational waves. Here’s Jan again.

Interviewee: Jan Tauber

Planck is going to make a kind of unique contribution to that in the sense that it is able to measure this at the very largest scales across the whole sky.

Interviewer: Davide Castelvecchi

If Planck fails to spot this signal, other teams are hot on its heels, but even after so much progress that picture from 25 years ago is still as magical as ever.

Interviewee: John Mather

I still love looking at the picture. I am so thrilled that it has started off a cosmic exploration that tells us something about the Big Bang that we never guessed we could know.

[Music]

Interviewer: Kerri Smith

That was Jon Mather who’s at NASA’s Goddard Space Flight Center where he’s now senior project scientist currently on the James Webb Space Telescope. You also heard from Jan Tauber, project scientist for Planck at the European Space Agency.

Interviewer: Adam Levy

Stay tuned for the News Chat where we give you the low down on the March for Science. But now though, it’s Corie Lok with our top tit-bits in the Research Highlights.

[Jingle]

Interviewer: Corie Lok

The possibility of life on Saturn’s 6th largest moon, Enceladus, just got a little bit more exciting. Pictures of the moon often show geysers spraying out from the surface. These plumes are thought to originate from the moon’s ocean which lies just beneath the icy crust. In October, 2015, NASA’s Cassini spacecraft dove through one of these plumes. The geysers contain molecular hydrogen, probably formed from chemical reactions that are driven by geothermal processes at the interface between the moon’s ocean and its rocky core. These sorts of reactions also occur on earth, in hydrothermal vents at the bottom of the ocean, where life thrives. The discovery of hydrogen on Enceladus means that it might be a good place to search for life. You can learn more from the journal, Science.

[Jingle]

Interviewer: Corie Lok

Animals living in some North American lakes are in for a dangerously salty future. Researchers looked at data on salt concentrations in nearly 300 fresh water lakes in North America. They found a steady rise in salt levels in about a third of the lakes since the 1980s. Human activities, such as salting of roads, are to blame. Even having just one percent of nearby land covered with hard surfaces like asphalt increased the likelihood of salinization. By 2050, nearly 100 of the lakes will likely have salt levels that will put aquatic species at risk. You can find the study in the Proceedings of the Natural Academy of Sciences.

[Jingle]

Interviewer: Adam Levy

Before we get back to the show we’d like to ask a quick favour. You see, we love to get the most important science into your ears each week but there’s just one problem. We don’t really know whoyouare.

Interviewer: Kerri Smith

Help us for our quest for knowledge by filling in a quick online survey. It should only take a minute or so and will help us reach even more ears in future. Find the link via our website and on Twitter. We’re @naturepodcast. Right, no on with the show.

Interviewer: Adam Levy

Materials like graphene can be made in sheets that are just one atom thick. Physicists first made them by pulling single layers off a block of graphite with a simple piece of scotch tape. This flat structure gives graphene and other 2D materials like it some interesting properties. But one crucial property is missing, assumed impossible. Kerri spoke to one physicist who’s been looking for it.

[Music]

Interviewer: Kerri Smith

For centuries, people have speculated about a world without a third dimension. The ancient Greeks philosophized about it. In the 1800s a novelist wrote a story called Flatlandthat took place entirely in a two-dimensional world. This world would surely look quite different to our 3D playground. But would the physics be any different? Scientists have only been able to study this experimentally in the last decade or so.

Interviewee: Jing Xia

The scientific study of reduced dimensions is quite recent.

Interviewer: Kerri Smith

This is physicist, Jing Xia, from the University of California, Irvine.

Interviewee: Jing Xia

I have to say, it’s mostly promoted by the discovery of graphene, the first truly two dimensional material which now, we understand, it has very, very different properties – both electronic properties and optical properties from its three dimensional counterparts.

Interviewer: Kerri Smith

But one classic property is missing from the flat landscape of 2D materials: none of them is magnetic. In fact, a theorem from the 1960s called the Mermin–Wagner theorem suggests that it’s impossible for a 2D material ever to be magnetic.

Interviewee: Jing Xia

So our motivation is, so is that really true?

Interviewer: Kerri Smith

One more thing draws Jing’s interest in finding out if 2D materials can be magnetic: new gadgets. Where an electronic device depends on the movements of electrons through a material, another class of devices – spintronic devices – rely on the magnetic property of each electron: its spin.

Interviewee: Jing Xia

What we’re trying to do in spintronic devices in general is we want to use the magnetic bit, or the spin, to store information and at the same time we want to use much, much faster ways, methods, to change and process that information – much, much faster than what you can do in a hard drive.

Interviewer: Kerri Smith

This is very bold of you to go against a theory that’s been around for basically 50 years at this point.

Interviewee: Jing Xia

I would agree, yes.

Interviewer: Kerri Smith

Jing and his team – made up of theorists and experimentalists – realised that the original theorem, the Mermin–Wagner theorem – could be tweaked to predict magnetism after all. Then they had to experiment to see if the new version of the theorem was right. They chose to use a material based on chromium called CGT. When I spoke to Jing, I asked him to explain their magic addition to the theorem – something called magnetic anisotropy.

Interviewee: Jing Xia

If you look carefully at the proof of the Mermin–Wagner theorem, you realise that they ignored the so-called magnetic anisotropy. The magnetic anisotropy is basically the difference in magnetism along different directions. It would prefer to point to a certain direction, so what we did is that we made sure that the atomic structure of that material guarantees a difference between the north and the south – aka, magnetic anisotropy.

Interviewer: Kerri Smith

So, basically, you knew about this theorem, as everybody else in your field did, from the 60s, that said 2D materials will have trouble being magnetic but the trouble with the theory was they’d ignored this property of some materials which is that they have a definite way that their magnetism likes to point.

Interviewee: Jing Xia

Exactly, magnetic anisotropy.

Interviewer: Kerri Smith

So you thought well, we’ll use one of those and we’ll see if we can look at that and see if that’s magnetic?

Interviewee: Jing Xia

Exactly.

Interviewer: Kerri Smith

And how difficult was it to do that?

Interviewee: Jing Xia

I would say it’s actually quite difficult, both theoretically and experimentally. So theoretically, although this is a simple idea, this is a very familiar theorem that we physicists, we study in our introductory graduate courses so usually we would regard that as a law which you cannot break, so if we’re thinking about breaking some law, I think that’s very bold, theoretically. Experimental side, I would say it’s even more difficult for several different reasons – so, first, you have to reduce the material to two dimensions. Thanks to the invention of graphene, now we know we can use scotch tape, but to transfer that knowledge of scotch tape to this CGT material, we encountered many problems that we spent, I would say, more than 2 years solving. The second difficulty – experimental difficulty – which is even more challenging is, well you have this very tiny, one layer of thick material – how can you measure the magnetism? How do you locate this very tiny flake and then measure its very tiny magnetism simply because the volume is very tiny?

Interviewer: Kerri Smith

So having done all of this then – to tweak the theorem, to make the 2D material, to measure its magnetic property – you found it was indeed magnetic?

Interviewee: Jing Xia

Exactly. With our work we now understand not only that you can realise magnetism in two dimensions, but we realise that the magnetism in two dimensions is very, very different from the magnetism in three dimensions. You can basically engineer the magnetic property of two dimensional materials simply by using either an external magnetic field or by engineering the structure of the molecule to increase the magnetic anisotropy.

Interviewer: Kerri Smith

That’s very cool and that just gives you a lot more flexibility in what you can do with it.

Interviewee: Jing Xia

Yes, and with all these materials I think finally we have a very, very clear road map to achieve the so-called spintronic devices in two dimensions which can be integrated with the already existing electronic devices in two dimensions based on graphene.

Interviewer: Kerri Smith

That was Jing Xia of the University of California, Irvine. Next, he says, they’re exploring other materials to see if they can be 2D and magnetic, and they’re making devices that sandwich their material under a layer of graphene and then playing with ways to change and tune the magnetism. The paper can be found at nature.com/nature.

Interviewer: Adam Levy

Time now for this week’s News Chat and Ewen Callaway joins us in the studio. Hi Ewen.

Interviewee: Ewen Callaway

Hello there.

Interviewer: Adam Levy

So we already discussed, on Backchat, the science march that took place over last weekend – the pros, cons and all the various discussion that was going on about it. That was before the march. Ewen, you attended the march as a journalist. What was the actual reality of the march like?

Interviewee: Ewen Callaway

The reality of the march was – it was big. I was at the London march on Saturday morning. They went from the Science Museum, a couple of miles to Parliament where there was a rally. I think there were about 10 to 12,000 people there. Lots of people, lots of fun signs. Not a lot of like… the way I put it is overt party politics. I think there were a lot of people just saying, basically just pro-science messages: that we need to pay attention to knowledge-based enquiry of the world – that sort of thing. And not a lot of causes at least, from what I noticed.

Interviewer: Adam Levy

Because that was one of the big criticisms before the march – that it might make the notion of science political.

Interviewee: Ewen Callaway

Well, there were some. I ran into some representatives of the local Lib Dem party who pointed out that the other parties were too scared to show up. I don’t know if that’s actually true. There were some Greens there. I think I saw some socialists and some communists but really it was mostly people just saying we need to respect science as a way of understanding the world. There are pet issues: climate, I saw some anti-fracking folks, but by and large it was kind of just respect knowledge. That was the message that I got from people.

Interviewer: Adam Levy

And this wasn’t the only science march taking place by any means.

Interviewee: Ewen Callaway

I think there were hundreds of them. The biggest one I think was in Washington DC. I haven’t seen an official figure but I think it was tens of thousands – 40,000 or something like that. Paris had a pretty sizeable march, Berlin, Munich. You name it – they were all over the world.

Interviewer: Adam Levy

And what has the response been widely to these science marches?

Interviewee: Ewen Callaway

I haven’t seen a lot of opposition. I think there were a lot of people stuck in traffic, baffled, in central London. I can tell you that. I think people thought they were generally a good thing. I detected no opposition. I’m not convinced they made a huge difference to anything. Maybe scientists will feel more like they should be speaking out because their world view, or their way of seeing the world, is being questioned and devalued by politicians. I guess time will only tell.

Interviewer: Adam Levy

Well, on a more personal level… what were your favourite signs, the most stand out signs that you saw in the crowd?

Interviewee: Ewen Callaway

I like the ones that you had to read into. I think somebody had one that said, ‘Alternative facts are the square root of negative 1’ which we don’t need Davide Castelvecchi to tell us that means imaginary.

Interviewer: Adam Levy

Thank you for the clarification.

Interviewee: Ewen Callaway

There were a lot of people emphasizing the need for funding… ‘Girls just want to have funding.’ ‘WTF’: where’s the funding? A couple that I encountered… I ran into somebody dressed as Dolly the sheep who was a cancer biologist who told me her pet issue – no pun intended – was antibiotic resistance. So, say what you will about mixed messages at the science march but people were there for a lot of reasons.

Interviewer: Adam Levy

Moving on from one group of disgruntled scientists to another, this time in China. And there’s a location in China that’s under threat from mining. What’s so special about this place in the first place?

Interviewee: Ewen Callaway

So the site is called – I’m going to pronounce this slowly so I get it right – the Doushantuo geological formation which is in south-western China, in Guizhou province. And it’s a site that since about the early 90s, has revealed these microscopic or really small grain-sized fossils that some scientists think are the earliest animals on the planet. What’s important about them is that they’re tens of millions of years earlier than the so called Cambrian animals that we see from other formations that we think were the dawn of complex animal life. This suggests that maybe complex animals emerged a little bit earlier than we thought.

Interviewer: Adam Levy

So this amazing site, all these really interesting, unique fossils, but under threat from mining. Has this mining already started?

Interviewee: Ewen Callaway

Yeah, it’s been going on: phosphate mining. Phosphate is used in fertilizer. It was going on before scientists found the fossils and some people have said that the mining has in some way enabled the discovery of the fossils by exposing new sedimentary layers. But apparently the phosphate mining has really accelerated in the last few years and some researchers who have worked at this site have really been concerned that key areas where they’ve found really important fossils have basically completely vanished and so they’ve been trying to be more active about convincing local government that this is a site that needs preserving, while maybe mining goes on next to it, but the discoveries that flow out of this site are really important and they need protecting.

Interviewer: Adam Levy

Does it look like they might be able to convince officials? How’s it going so far?

Interviewee: Ewen Callaway

I think they actually had some success. So the scientists were actually shocked at how much of the site has been destroyed. They organised a meeting bringing paleontologists from all over the world to talk about the problem and advocate for a solution and days later the local government, at least temporarily, halted mining while they look for a solution. What that solution is, is unclear. The paleontologists have proposed that maybe you could have a field paleontologist there at the mining site just setting aside fossils, because these aren’t dinosaur bones. We’re talking about very small fossils and so you could just leave them aside and let the mining proceed. One of the organizers of these protests really wants to establish a geological national park to protect a really small area, I think, less than 2 kilometres squared from mining. So, we’ll see what actually happens there.

Interviewer: Adam Levy

If paleontologists aren’t able to stop the mining, and they can’t return to the digs at these sites, how much will be lost? How much have they already been able to excavate?

Interviewee: Ewen Callaway

Well one scientist estimated that just about 5% of the fossils in the site have been excavated so there’s a lot more out there, a lot more future Naturescience papers, all of which the site has yielded. Yeah, so a lot could be lost.

Interviewer: Adam Levy

Ewen, thank you for breaking down those two stories. For more on both of them and others head to nature.com/news.

Interviewer: Kerri Smith

That’s all for this week, but make sure to check out Backchat for more discussion of the science march. And keep an eye on you podcast feed for this month’s science fiction short. Futures will be out later this week.

Interviewer: Adam Levy

And don’t forget that the link to the survey is on our website and on Twitter. Until next time, I’m Adam Levy.

Interviewer: Kerri Smith

And I’m Kerri Smith.

[Jingle]

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