This isn’t the Nature Podcast — how deepfakes are distorting reality

Nick Petrić Howe

Welcome back to the Nature Podcast, this week: how to tackle the rise of AI generated deep fakes...

Benjamin Thompson

...uncovering evidence of the earliest known wooden structure...

Nick Petrić Howe

...and how NASA's OSIRIS-REx brought asteroid samples back to Earth. I'm Nick Petric Howe...

Benjamin Thompson

and I'm Benjamin Thompson.

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AI Deepfake Nick

Coming up on the show is a story about things that are not real.

Nick Petrić Howe

That was not my voice. It's a computer generated copy.

AI Deepfake Nick

I can say anything. What would you like me to say?

Nick Petrić Howe

I created this voice using an artificial intelligence tool called Overdub, the tool that's part of an application called Descript, for free.

AI Deepfake Nick

It is very straightforward to make a voice like this.

Nick Petrić Howe

This is what is called a deepfake, and they are becoming evermore prevalent. Deepfake videos of Kamala Harris speaking gibberish have been circulated on social media, fake pictures of Donald Trump hugging Tony Fauci have been weaponized online. And you may well have seen a faked picture of the pope in a puffer jacket. With AI at everyone's disposal, the age of the deep fake is upon us.

Nick Petrić Howe

Deep fakes are a way of manipulating reality. They could be an edited photo, an altered bit of audio, or even a fake video call. Long has it been possible to fake images using Photoshop or more analogue methods, but now it has become easier than ever.

Nicola Jones

So what happened is it just became more available to the consumer.

Nick Petrić Howe

This is Nicola Jones, a freelance science reporter who's been writing about deep fakes for Nature.

Nicola Jones

So now you can create an image or create a video or create whatever it is you want using generative artificial intelligence technologies. And a lot of it is free and easy to use, and anybody can do it.

Nick Petrić Howe

So easy is it to do that I'm not the only one in this podcast who has created an AI Alter Ego.

AI Deepfake Nicola

This is not me saying this sentence. This is a made up copy of my voice. How does it sound?

Nick Petrić Howe

That was Nichola's deep fake. It isn't as high quality as mine. But bear in mind that I used over half an hour of studio quality audio. It just so happens that given my job, there was a lot of that about, but Nicola trained hers with just 10 minutes of her voice, which she recorded with the low quality microphone on her laptop. And it was still good enough that even her kids thought it sounded just like her. This highlights one of the dangers surrounding deep fakes like this. Here is real Nicola, again.

Nicola Jones

People have used that to make a phone call to someone, maybe an elderly person and imitate the voice of say their grandchild. So they answer the phone and their grandchild is there saying I'm in trouble, I need money, you have to wire me money. And you can do this in real time. So you can like have a conversation in this person's voice. And people have definitely been fooled by this and lost 10s of 1000s of dollars.

Nick Petrić Howe

And it's not just your savings that can be put at risk by deepfakes, a faked photo of an explosion at the Pentagon, which went viral on X, then Twitter, briefly caused the stock market to dip before it was shown to be a deep fake.

Nick Petrić Howe

And that is the other side of the equation here. Deepfakes have not only become easier to make than in the past, they're also much easier to share and spread around through social media. And that has real world impacts. So what can be done about deepfakes? Well, AI researchers and companies have not been slouching. They've been hard at work coming up with solutions.

Nicola Jones

There's kind of two main technological solutions to the problem that deep fakes. One is to tag contents like pictures or videos at generation with some kind of way that shows what it is. And the other way is to try and develop algorithms that can detect whether something has been synthetically generated after the fact after it's been published.

Nick Petrić Howe

We are going to explore both of these technological solutions. But we're going to start with the second one. Algorithms can be used to detect deep fakes trained to quickly pick them out of a lineup. In essence, AI's may be part of the solution to exposing AI deepfakes. But we also need to stop deepfakes spreading. After all, it is hard to undo misinformation once it has gone viral. And that's where the first solution, Nicola mentioned comes in. Tagging, adding some kind of marker, which makes it clear that something is AI generated. I reached out to Hany Farid, an AI researcher that advises companies and governments on how to handle deepfakes.

Hany Farid

And so you insert a signal into the very content that you are now about to unleash into the wild. And then your browser or the social media companies are aware of those watermarks and will simply read them and notify you that when you view the image that a watermark has been detected, and that this has been generated by open AI on this date. And it's important to understand, we're not saying what you should or shouldn't do with the content, we're simply saying, label it, please. So it's a very low bar.

Nick Petrić Howe

For example, this could be accomplished by imperceptibly changing the colour of pixels in an image so that every 10th pixel has an even number associated with it. Hard for a human to see but easy for a computer to pick up as a signal that this has been AI generated. Another technique is called fingerprinting, where a distinct piece of traceable information is made and secret of the way every time an AI is used to generate a piece of content, which can then be read later.

Hany Farid

Fingerprinting, says extract from this piece of content and identifying distinct digital signature and hold that server side. Hold that so that nobody else has access to it. And then when that piece of content is out there, my browser can say, you know, I'd like to know if this is generated by open AI I will query their database and ask, is this something that you created?

Nick Petrić Howe

However, neither of these solutions are perfect. They could certainly help, but in this area, like a lot of cybersecurity, it's an Arms Race, when you find a good way to tag a piece of content as AI generated, someone will find a way to get around that. So regulators also need to step in. These can help put the pressure on companies that are creating these AIs, in turn, making it more difficult for would be bad actors to generate deepfakes for malicious purposes.

Hany Farid

So I think what regulations do is they force companies to abide by a certain set of basic fundamental safety standards, it's perfectly reasonable. And then for example, if they don't, well, then Apple and Google appstore won't allow you on their platform. GitHub won't allow you to host your services. So we have downstream pressure that can be placed if you are not complying with basic safety measures.

Nick Petrić Howe

The other way to fight deep fakes is to listen to podcasts, like the Nature Podcast, okay, I'm taking a little bit of a liberty here. But Hany and Nicola did tell me that education about what is out there and what can be faked is going to be crucial to help people recognise and not be fooled by deep fakes. But that's not to say it won't be challenging.

Hany Farid

There's always a little tension here, because on the one hand, you want to educate people that people are starting to get phone calls with fake voices, and they should be careful. You want to educate people that images can be manipulated, videos can be manipulated, but you don't want to go so far, that every time somebody sees an image, or audio or video, they're sceptical, every time they get a phone call from the husband and wife, they hang up the phone because they're scared. So I think what's important is to understand what is the technology? How does it work? Where are the limits of it currently? Where are we seeing weaponization of it? And then what are some of the things that you can do to protect yourself? Here's my favourite one. Because it's so simple. We know that people are now able to spoof your voice from a minute or two minutes of audio recording of you and most people have a couple of minutes of audio recording them somewhere. And so what happens when you get a phone call and it's your spouse or your your daughter or your son? Do you just panic? Or what we do, my wife and I do we have a passcode. So when I get a phone call from her and it sounds a little funny, I asked her, what's the password, and we have an agreed upon word. And this is easy. This is so old school, right? So there are simple things you can do to protect yourself against fraud.

Nick Petrić Howe

A lot of deepfake technology can be used for beneficial purposes, such as anonymizing people in group therapy, or allowing for more controlled social science studies. So this may not be a technology that we want to lock down altogether. Also, we alter images all the time to make colours pop, or to erase out that annoying person who wandered into frame. And that kind of use is not commonly referred to as a deepfake. So maybe it comes down to intent. What are these images or videos or audio going to be used for? Here's Nicola, real Nicola, again.

Nicola Jones

So a lot of people are thinking, well, it's it's going to become not a question of is this photo synthetic or not? It's more a question of what is the intent of this photo? What is the intent of the modifications that are made? So, these things that tag them with provenance information, they track all these things, you know, this, this was originally a photo it has had a colour filter applied, it has had some distracting objects in the background taken away, and then you can see all of that when the photo was published. So maybe more important is not just is this photo synthetic, but rather, who made it and why did they make it?

Nick Petrić Howe

That was Nicola Jones, freelance reporter based in Pemberton, Canada. You also heard from Hany Farid, from the University of California, Berkeley, in the US. For more on this story, check out the show notes for a link to Nicola's feature.

Benjamin Thompson

Coming up what ancient stacked timbers could reveal about hominin woodworking roughly half a million years ago. Right now, though, it's time for the Research Highlights read by Shamini Bundell.

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Shamini Bundell

Exactly how long is a day? Here on Earth, 24 hours is usually a good enough approximation. But sometimes researchers and engineers need a more precise answer. The problem is, the rotation of the Earth isn't constant, it can be slightly sped up or slowed down by things like the tides or the weather or events like El Nino. One way of measuring these subtle changes is to compare Earth's position with that of distant stars, a so called Star Compass that uses networks of satellites across the world. But now, researchers have created a device that can measure these changes from a windowless room in a lab in Germany. The ring laser interferometer is a four metre wide track inside which two lasers travel round in opposite directions. As the Earth rotates, the two lasers have slightly different distances to travel. And that difference can be seen in the interference patterns between them. This device can measure variations in the Earth's spin, allowing the team to calculate changes in the length of a day as small as just a few milliseconds without even needing to look out of a window. Read more on that in Nature Photonics.

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Shamini Bundell

Snow flies are small six legged insects which live on snow and ice and cannot in fact fly. But what they can do to help them survive in extremely cold conditions is to amputate their own legs. This unusual behaviour was discovered by researchers in Seattle in the US who were using thermal imaging to study these elusive creatures in more detail. They observed flies moving around on cold plates in the lab at temperatures as low as minus nine degrees celsius. The flies can certainly survive much colder conditions than their crane fly relatives. But if it gets too cold, eventually their internal fluid will start to crystallise and freeze which would usually be fatal. To avoid this, the flies could sometimes be seen detaching one, two or even three of their own legs to stop the freezing process from reaching their vital organs. Indeed, snow flies in the wild were often observed with missing limbs. Read more on this extreme survival tactic in Current Biology.

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Nick Petrić Howe

Up next reporter Anand Jagatia hears about an archaeological find from Zambia, which could be the earliest known example of a wooden structure made by early hominins.

Anand Jagatia

You've heard of the Iron Age and The Stone Age. But what about the Wood Age? Early hominins might have worked extensively with wood. But it's hard to know that much for sure, because it doesn't preserve very well. The oldest known example is a polished wooden plank from a site in modern day Israel, dating back to around 780,000 years ago. But then the archaeological record is empty for the next 400,000 years or so. But now a team of scientists have uncovered evidence of ancient woodworking from within this empty period around 476,000 years ago, from a site in Zambia.

Larry Barham

Conditions that this site, Kalambo Falls, are permanent wetness. So these are waterlogged deposits, things are not rotting. And remarkably, they have remained waterlogged for hundreds of 1000s of years, which makes this site unique.

Anand Jagatia

This is Larry Barham from the University of Liverpool who led the excavation back in 2019. A waterlogged site like this is a dream for archaeologists like him, because it can preserve wooden artifacts from the past. And that is exactly what Larry and his team found.

Larry Barham

The archaeological deposits were found behind what's called the lip of the fall where the water enters a chute and then drops 230 metres down below a gorge. And when that first day, we dropped down the cliff to tumble down onto this little beach on the edge of the Kalambo River. And there are artefacts, stone artefacts, and there was wood. I thought, oh my goodness, you could see wood sticking out of the section. And so we started to carefully excavate around the wood with a wet, mucky place a lot of clay, preserving the wood beautifully.

Anand Jagatia

The team discovered several wooden objects buried in this muddy location, but one in particular stood out, because it may be the earliest example of a very particular kind of artefact, a wooden structure.

Larry Barham

The definition of structure is the combination of two elements to make something new. In this case, this object, which is two logs, joined by a notch in the middle could be the foundations of a platform, foundations of a walkway, or maybe even the foundations of some kind of hut. But I can use the word construction because there are marks on the wood of the overlying piece, marks in the niche which sits on top of the underlying wood, and stone tool marks on the wood beneath it is planned.

Anand Jagatia

Well, we can't know for sure what this structure was actually used for the markings on it provide evidence it was made with tools. If this is the case, it would show unprecedented woodworking abilities in hominins that predate our own Homo sapien species. To investigate this, Larry worked with a Zambian ethnographer and they compared the finds with markings left by traditional woodworking techniques in the same area today.

Perrice Nkombwe

The project looks at preservation or maybe just trying to keep a record of woodworking tradition.

Anand Jagatia

This is Perrice Nkombwe, who works for the Zambian National Museums board.

Perrice Nkombwe

Some of these traditions that we have going on right now are deep rooted in ancient history. So there has been a passing on certain skills and knowledge, the marks that are made from tools when they're trying to cut the trees, trying to remove the back and things like that, that looked very close to one of the planks that was found at the Kalambo excavation.

Anand Jagatia

So if the structure had marks that suggests it was intentionally modified in a way that resembles woodworking that still goes on in the region today. But determining the age of the structure, and the other artefacts at the site was no mean feat. Excavations from the 50s and 60s also yielded wooden finds, but with no way to date them accurately. Now, though, Larry and his team have more modern tools at their disposal.

Larry Barham

The team used a form of what's called luminescence dating, which examines the last time sediments were exposed to sunlight. The oldest part is more than 477,000 years old. But we found other pieces in younger levels up to about 330,000 years ago. That's that's still really old and still really amazing to find them. There's one piece which is kind of wedge shaped. And you can see this kind of big crack in its top where somebody had hit it with a stone tool that's never been seen before. There was a digging stick just over a metre piece of wood, which has been shaped to a tapered point, there is a piece of a log, it has big, deep chop marks at either end, they chop that tree down, I'm sure.

Anand Jagatia

So what can objects like this tell us about the ancient human relatives that created them? Well, Larry has some ideas.

Larry Barham

It opened my mind all of this stuff, but particularly the big pieces, the fact that these early humans had the technological know how to work trees. And until this point, all we know about really is people using sticks for firewood or digging sticks, or throwing sticks. This is a conceptually new way of thinking of trees as a resource. Understanding the properties of the materials used to make a tool, understanding how the tool is going to be used, but also includes learning all those properties and uses. And I think there's something else I didn't talk about this in the article, but it's language. The structure is an abstract thing, a shared piece of knowledge, which I think was aided by language. It's a level of abstraction that really would only made sense if you could communicate with others in the shared purpose.

Anand Jagatia

Given the rarity of wooden artefacts in the archaeological record, Kalambo Falls is a site of great significance. And it raises a tantalising question, could there be more objects like this buried in the mud beneath the falls?

Larry Barham

Oh you know, the temptation is just to get back out there? Pull back more sediment find the rest of this structure in the other pieces. But I think that may be kind of searching for smoke because they think these people were reusing, they were carrying those logs around them, because they had invested time in them. But before I go back, I really want to see if we can get this site protected as a World Heritage Site. There's nowhere else like it.

Anand Jagatia

And Perrice agrees that Kalambo Falls should be protected for science, but also for future generations.

Perrice Nkombwe

It sits as the only evidence of well preserved wooden structure from that age. And so we should preserve the site, but just also to allow the local people to feel a sense of national pride and identity, knowledge sharing and also contributing to our understanding of the past to an international audience is something so significant, and that should be something that should move us to wants to preserve the site.

Nick Petrić Howe

That was Perrice Nkombwe from the Zambian National Museums board. You also heard from Larry Barham, from the University of Liverpool here in the UK, both of whom spoke to Anand Jagatia. For more on that story, check out the show notes for some links.

Benjamin Thompson

Last Sunday was a big day for space science. It saw the combination of NASA's $1.2 billion mission known as Origins Spectral Interpretation, Resource Identification, Security Regolith, Explorer, or to its friends, OSIRIS-REx, the mission centre craft hundreds of millions of miles to the asteroid Bennu, where it collected some samples of dust and rock, and after a year's long journey through space successfully brought them back. It's the first time NASA has ever brought material from this type of celestial object back to Earth. The sample landed in Utah, and on the ground, there was reporter Alex Witze, who's been covering the story for Nature. I gave her a call at the start of the week to chat about the mission and what the samples had collected could reveal about the solar system secrets.

Benjamin Thompson

Alex, how you doing? Thank you so much for joining me today.

Alex Witze

Thanks for having me. It's great to be here.

Benjamin Thompson

So yesterday, then you are in the desert in Utah remote military base, where the capsule portion of the OSIRIS REx mission serenely landed in the middle of the desert, what was the mood there like?

Alex Witze

The mood was, I would say euphoric and ecstatic. But first, it was nailbiting because this sample was coming in from deep space and had to deploy all these parachutes. So it had to slow down to a gentle landing, and just drop quietly onto the desert plains. And there have been times in the past, but this hasn't worked in 2004, there was another sample return that just went crash in the very same desert. So everybody was crossing their fingers. We saw footage, we knew this capsule was incoming, we were waiting and waiting and waiting. And then suddenly, these beautiful orange and white parachutes opened, and it was suddenly like... phew, it's gonna make it.

Benjamin Thompson

And were there researchers there with you? Were they cheering and punching the air?

Alex Witze

There were VIPs in a tent next to the media tent, they had us kind of corralled away. But you could hear cheering from the tent with all the NASA officials in the aerospace officials next door. Yes, it was a very exciting moment.

Benjamin Thompson

What's interesting is this is like a working military base. So they had to check there was no live ordinance or shells or things when the sample landed.

Alex Witze

Yeah, so the very first person who went up to the capsule was a military safety representative who needed to make sure it hadn't landed on a bit of grenade that might have been lying around. And the reason, if you're wondering, why it came into this military range is it's the largest restricted airspace in the US. So there's a lot of space for it to land, it's very well controlled, and the military has lots and lots of tracking, so they can watch it very precisely coming in. So that's why they wanted to go ahead and lay it out here, even if they had to go and make sure there wasn't a grenade that it landed on.

Benjamin Thompson

Well, before we talk about the sample. Let's just back up a bit because this was a big mission for NASA. And it's been going since its launch in 2016. Maybe you can give us just a very brief list of overviews.

Alex Witze

Yeah, so the point of this mission was to go to this asteroid called Bennu, gather asteroid samples and bring them back to Earth. And it seems to have worked out really well. They've got a cup full of rocks, which doesn't sound like a lot to go all the way to an asteroid hundreds of millions of miles and then back. But it's quite a lot of material for scientists to study back on Earth.

Benjamin Thompson

But why Bennu? What was it about this asteroid that NASA was so interested in?

Alex Witze

There are a couple of reasons. Number one, they could get to it with the spacecraft and back. Another thing is that Bennu is considered a near Earth asteroid, it's got actually a tiny, tiny chance of hitting Earth in the future, although it's probably not going to. And thirdly, it's just got really interesting chemistry. It's carbon rich, it's dark and probably contains materials from the start of the solar system 4.6 billion years ago.

Benjamin Thompson

And the actual spacecraft spent a good couple of years having eyes on this asteroid then before the sample was collected, what was learned about it in that time?

Alex Witze

They did a lot of taking pictures and studying it and trying to figure out why it is this funny kind of diamond shape. But it turns out to probably be this way because it's a rubble pile, is what they call them, basically a whole bunch of pebbles held together by gravity. And that turned out to be really surprising when this spacecraft OSIRIS-REx went in, in 2020, to try to grab this sample, it kind of went in for this fist bump and the rocks kind of flew everywhere because they were this rubble barely bound by gravity. And in fact, some of the spacecraft robotic arm that was trying to grab the rocks got a bit stuck because there was so many pebbles flying around. So even though they'd been orbiting this thing for two years looking at it, trying to figure out what it was made of when they went in, they were still surprised.

Benjamin Thompson

I mean, that's gonna be heart in the mouth time for the folk back in Mission Control. But it's worth saying that this isn't the first sample return mission from an asteroid. Japan's Space Agency, JAXA, previously collected samples from two different asteroids, but only a very tiny amount, a milligramme from one and about a teaspoon from the other. But in your article, you say that OSIRIS-REx was able to collect about 250 grams of rocks and dirt.

Alex Witze

Yeah, and they won't know for sure until they get it open. So this spacecraft landed in Utah and what happened right after that was they whisked it into a cleanroom. We, the reporters, couldn't see that we could see this helicopter from far away, take it to the cleanroom and then unwrapped it, they put it on it sort of a cart looked like a cafeteria cart, and wheeled into this cleanroom with everybody in bunny suits, you know, those big white suits, and they started taking it apart. And it turns out, it was intact, this kind of saucer shaped capsule was in great shape. They took the lid off, everything looks great inside. So now it's all packaged up and flying back to Houston where the scientists can really get it into the laboratory and start working with it.

Benjamin Thompson

And this is where they'll start disassembling things and ultimately getting to the contents of the sample container within the capsule. And this is very much a very specialist laboratory to make sure that no contamination can come in. And I think, am I right in saying, that this is one of the buildings where the Apollo moon samples were studied as well.

Alex Witze

Yeah, yeah, this is the Astro Materials facility, they call it at Johnson Space Centre in Houston. So it's right next to where they studied the Apollo samples, they actually built a special purpose lab for this material from the asteroid from Bennu. Because it's so important to keep it so pristine.

Benjamin Thompson

And what sort of questions then could this dust and rock help to answer?

Alex Witze

I could answer all sorts of questions about what our solar system was made of from the very beginning. So obviously, on Earth, we don't have rocks that are sitting around from 4.6 billion years ago with like, pristine chemistry. But this material from Bennu can tell us like what are the raw ingredients? Are there chemical compounds that are intriguing in terms of how life might have gotten started? How water might have gotten delivered around the solar system? What are the building blocks of life? And how common were they in other worlds?

Benjamin Thompson

I mean, some pretty big questions, then I'm sure researchers are kind of hyped to get a look at this. What's the timeline moving forward, then?

Alex Witze

Well, we're talking today on Monday, the 25th of September, and they could open the package as soon as tomorrow. So it's flying down to the Johnson Space Centre. And this week, we anticipate that the curators, especially trained people, we'll open it up and take a look. There's a couple of designated scientists who get the lucky first shot at it, there'll be looking at sort of a dust that comes off the outside of the capsule. And then in the coming weeks and months, there'll be opening the real Christmas gift, the large sample container in the centre, and they'll start to distribute that out. So we may know in a couple of weeks, the initial things of what they're finding, the longer science, of course, takes months to years, like it always does.

Benjamin Thompson

As we've discussed, you were on the ground. And you've been talking to researchers, what have they said about the accomplishment? And where we go from here?

Alex Witze

Yeah, the scientists I've talked to have been really excited just to start getting their hands on this material. I talked to one of the curators at the Johnson Space Centre yesterday, and she says, everything looks great. They're really surprised at how clean the package looks after having come in through the atmosphere. So it seems everything held together really well. Other scientists I've talked to are just really excited to start comparing and contrasting the meteorites and other asteroid bits that we have back here on Earth.

Benjamin Thompson

And it has to be said that while this is the end of the OSIRIS-REx mission, the sample has landed safely. The actual spacecraft that flew back and dropped the sample off, it's still trucking, it's still on its merry way through the universe.

Alex Witze

Yeah, NASA decided to repurpose it. So it dropped off the package that flew down here to Utah, and it is heading off to visit another asteroid. And the one that's going to here is actually a really cool asteroid called Apophis, which is kind of famous for in 2029, it's gonna whiz really close past Earth. So it's considered one of these, quote, unquote, dangerous near earth asteroids, although it will miss us. But it's going to come to a close we'll be able to take a lot of looks at it. And so OSIRIS-REx changed its name. It's now OSIRIS-APEx because the A stands for Apophis, and it's off to Apophis.

Benjamin Thompson

Very nice. Okay. And we've talked a bit about there that there haven't been a great many sample return missions. And it strikes me that these are very expensive and very complicated missions to undertake and to pull off what sense are you getting of the future of missions like this to try and bring things back? Because of course, Mars is the big one, for example.

Alex Witze

Yeah, Mars is definitely the big one. Kind of in more near future, Japan is sending a sample return mission to the Martian moon Phobos in the next couple of years. And then the big elephant in the room, as you mentioned, is Mars sample return. So NASA has been collecting rocks on the surface of Mars. It's got a rover called Perseverance that's been travelling around this ancient riverbed and putting them down on the surface for someone to come get some day. And now the giant question is, can we afford to go get those rocks? And NASA and the European Space Agency want to go, it's big, it's expensive. It would be scientifically really amazing, scientists say, because to have again, this kind of material where you know where it comes from unaltered would be really rewarding.

Benjamin Thompson

Alex Witze there. To read more about the OSIRIS-REx sample return, look out for a link to Alex's article in the show notes.

Nick Petrić Howe

And that's all we've got time for this week. As always, you can keep in touch with us on X. We're @naturepodcast, or you can send an email to podcast@nature.com I'm Nick Petric Howe...

Benjamin Thompson

...and I'm Benjamin Thompson. Thanks for listening.