Host: Benjamin Thompson

Welcome back to the Nature Podcast. This week, we’ll be hearing about atomic espionage during World War II…

Host: Nick Howe

And finding out more about the early Universe. I’m Nick Howe.

Host: Benjamin Thompson

And I’m Benjamin Thompson.

[Jingle]

Voiceover

I have taken occasion to speak to you tonight because we have reached one of the climacterics of the War.

Interviewer: Nick Howe

It’s June 1941, and Winston Churchill is addressing the people.

Voiceover

At 4 o’clock this morning, Hitler attacked and invaded Russia.

Interviewer: Nick Howe

This would be the beginnings of an alliance between the UK and Russia, forged at the height of the Second World War.

Voiceover

It follows therefore, that we shall give whatever help we can to Russia and to the Russian people. We shall appeal to all our friends and allies in every part of the world to take the same course and pursue it, as we shall, faithfully and steadfastly to the end. We have offered to the governments of Soviet Russia any technical or economic assistance that is in our power.

Interviewer: Nick Howe

These may have been the words that inspired a man later referred to as having ‘accomplished greater damage than any other spy in the history of nations’ – Klaus Fuchs, the spy who spilled the secrets of the atomic bomb. At least that is according to Frank Close, a physicist from the University of Oxford, who’s written a new book all about him. Here’s Frank.

Interviewee: Frank Close

One of the things that he had in his mind, he was told, ‘You must escape because when the Revolution comes, people like you will be needed to build the new Germany.’

Interviewer: Nick Howe

Fuchs fled Germany during Nazi rule. He and his family had ties to communism and when his father was arrested by the Gestapo, he escaped, finding refuge in the UK. There he studied physics and made a reputation for himself as someone who gets things done.

Interviewee: Frank CloseI wouldn’t want to give the impression that he was somebody in the league of Einstein or Fermi – he certainly wasn’t – but if you wanted a problem solving, Klaus Fuchs was the sort of person who could solve it.

Interviewer: Nick Howe

And one of the most high-profile problems in physics at the time surrounded the atomic bomb. Since the splitting of the atom two years before, it had been theorised that tremendous amounts of energy could be released from uranium, enough to make a devastating bomb. However, for a long time it was thought that such a bomb would require too much uranium to be practical in war. That was until 1940 when Rudolf Peierls, along with Otto Frisch, realised that if uranium could be enriched – that is to say the radioactive component could be increased – a bomb would be possible.

Interviewee: Frank Close

And Peierls was effectively leading the British efforts into working out how to do this in the initial stages. And by 1941, the problems to be solved were sort of mounting up. I mean he was doing teaching in the university, he was doing this in effect almost in spare time. He needed an assistant. He was impressed by Klaus Fuchs. He knew that Fuchs was an émigré like himself. He knew that Fuchs detested Hitler, which was also a good thing, and so arranged for Fuchs to become his assistant, working with him and the team on developing the theory behind how to enrich uranium to make a bomb.

Interviewer: Nick HoweThrough Peierls, Fuchs became intimately involved in the British effort to make a bomb, then the American effort, the Manhattan Project, and even the first test of a nuclear bomb, Trinity. Little did Peierls know, Fuchs had had another employer – the KGB. Fuchs was a spy, and had been passing information to the Russians from the start.

Interviewee: Frank Close

So, he was certainly passing information as early as August 1941 – I found documents that show that from KGB records – and he passed information continuously throughout the War from initially Birmingham, then from New York when they moved across to the United States, then from Los Alamos, where the bomb itself was being assembled, right the way through to the day the bomb was tested and shown to work. He passed all the data on that working bomb to the Russians, so now the Russians knew this was a bomb that works and I estimate that the amount of time that was saved for the Russians was probably between one and two years.

Interviewer: Nick Howe

Fuchs would take bus rides carrying nuclear notes that he would covertly leave on his seat for his Russian handlers to pick up. But it was those same handlers that would eventually let him down.

Interviewee: Frank Close

The weak link in this is you have to pass your information to a courier, the courier passes it on to the Russian Embassy and the Russian Embassy has to get the information back to Moscow, which they did by cables. Now, these cables were intercepted by the Americans, but the codes were uncrackable – they were using what’s called one-time pads. How these work is beyond this. The only thing you need to know is a one-time pad is absolutely uncrackable as long as you only use it once. For some reason, the Russians used some of these things twice, and in turns out that for cryptography, that gives enough chink in the armour that eventually, with enough expertise, you can crack it.

Interviewer: Nick Howe

And those decoded cables would give the British and American intelligence services enough to zero in on Fuchs. He was caught and confessed to spying in 1950. He served nine years in prison, but unlike many of the other spies caught during the war, he avoided the death penalty for espionage, as technically the Russians were Allies. He was released in 1959 and travelled back to his homeland in East Germany where he lived, according to Frank, with little remorse for what he had done.

Interviewee: Frank Close

I don’t think he had regrets. He claimed, after being arrested in Britain, that he was changing his mind and he was suspicious of the Soviets and so forth, but then after he’d been released from prison, he was interviewed by KGB people and he told them quite a different story. I think he told people what they wanted to hear.

Interviewer: Nick Howe

Fuchs lived out the rest of his life working as a physicist. As far as is known, he was never involved in any more military projects. But it seems he left an indelible mark on military history.

Interviewee: Frank Close

Well, the Korean war started in 1950 and imagine a world where the Americans were the only ones with an atomic bomb and the Korean War is taking place, and it is known now in historical records that there were very strong hawks in America who were wanting to use their atomic bomb in the Korean War and a reason why they did not was because the Russians had one, thanks to Fuchs.

Interviewer: Nick Howe

That was Frank Close from the University of Oxford. You can find a review of his new book Trinity, which is all about Fuchs, over at nature.com.

Host: Benjamin Thompson

Later in the show, we’ll learn how the culturing of a microbe might shed more light on how complex life evolved – that’s coming up in the News Chat. Now though, it’s time for the Research Highlights, read this week by Anna Nagle.

[Jingle]

Anna Nagle

While they may be a fun way to zip from A to B, the rentable electric scooters that now pepper the pavements of many cities might come with a high environmental cost. Battery-powered and emission-free, e-scooters are touted as a green way to roll in urban environments. To test this claim, a team of researchers in the US calculated the greenhouse gas emissions associated with the production and usage of the scooters and compared them to other modes of transport. They estimated that the materials and manufacturing involved accounted for half of the emissions produced during an e-scooters lifetime. Almost as high were the environmental costs associated with collecting and charging discarded scooters, a daily task often done by scooter company employees driving their own vehicles.

The research suggests there are other modes of transport, such as biking or taking the bus, that are less carbon-intensive and that rentable e-scooters are only really more environmentally friendly when people use them instead of driving their cars. Scoot over to Environmental Research Letters to read more.

[Jingle]

Anna Nagle

The endangered Goliath frog, an African amphibian that can weigh more than 3 kg, is quite the aquatic engineer, according to new research. A team of scientists heard rumours that these hefty hoppers heave heavy rocks to build circular nests. To find out if these tales were true, the researchers surveyed a 400-metre-long stretch of a river in west Cameroon. They found 19 frog nests that averaged 1 metre in diameter. While some of these nests were simple clearings, others were gravel beds encircled by carefully placed rocks weighing as much as 2 kilograms. It appears that these engineered nests provide an oasis for the frogs’ eggs and tadpoles, protecting them from fast-flowing water and predatory fish. This is the first nest-building behaviour seen in an African amphibian, and gives new insights into the reproductive strategies of the world’s biggest frog. Hop over to the Journal of Natural History to read more.

[Jingle]

Interviewer: Benjamin Thompson

Next up on the podcast, we’re going to be travelling back in time to learn a bit about the origin story of the Universe as we know it. Nature reporter Davide Castelvecchi has written a feature article looking at efforts to probe a billion-year period of the Universe’s history that began just after the Big Bang. Because light takes time to reach us, the further away you peer into the Universe, the further back in time you can see. But why do researchers want to learn about this period? Here’s Davide to explain.

Interviewee: Davide Castelvecchi

Basically, this is the transition from the age of the cosmic microwave background, which was this undifferentiated broth of elementary particles, to the more familiar age of galaxies and black holes and stars, and in between, you should be able to see how the Universe transitioned from one to the other. So, it’s a very consequential, very eventful period, but it’s also very difficult to observe.

Interviewer: Benjamin Thompson

Well, what does the Universe look like at this point? What’s there?

Interviewee: Davide Castelvecchi

There’s basically only two things – dark matter and individual atoms, mostly of hydrogen. And it’s that hydrogen which astronomers hope to observe in the process of falling into large clusters of galaxies and forming stars and so on.

Interviewer: Benjamin Thompson

Yeah, because I guess we know how the story ends, I mean galaxies and so forth exist, but it’s from this hydrogen then that everything comes together eventually. Why is it so difficult to observe this period of time?

Interviewee: Davide Castelvecchi

Because there was basically no light. If you were to travel back in time, if you were in a spacecraft, say, 5 million years after the Big Bang, you would see nothing. The only light that you would see is this afterglow of the Big Bang. Other than that, it’s just transparent gas. There’s nothing to see.

Interviewer: Benjamin Thompson

Which begs the question, if there’s nothing to see then, how are astronomers going about looking at this time period?

Interviewee: Davide Castelvecchi

Ah, because even if there are no sources of light, there are no stars, nothing, hydrogen – and this is neutral atomic hydrogen – will absorb or emit this very long wavelength radiation. It’s called the 21-centimetre line, and it’s extremely faint and it’s extremely difficult to tell apart from all of the rest of the radiation in the cosmos that has existed since then.

Interviewer: Benjamin Thompson

And it’s this 21-centimetre line then that you’ve written about in your feature that astronomers are so interested in.

Interviewee: Davide Castelvecchi

Yeah, and it has an interesting history because it’s been kind of a work-horse of radio astronomy for more than half a century. In the 1950s, it was the way that astronomers realised that the Milky Way has a spiral structure – it’s because they were able to observe this 21-centimetre emission from neutral hydrogen in our own galaxy. Soon, cosmologists realised that you could use it, not just to study our own galaxy or nearby galaxies, you could look all the way back into the primordial Universe, and the catch is because the Universe has expanded, everything has stretched, including the wavelength of these radio waves and so what was once 21-centimetre waves would be now several metres long. So, we’re talking about very, very long wavelength radio waves.

Interviewer: Benjamin Thompson

And are these quite difficult to sort of pick up then to measure?

Interviewee: Davide Castelvecchi

They are very hard. Well, for one thing, it’s part of the spectrum that overlaps with FM radio, so sometimes they see TV stations reflected back from overhead aircrafts passing by or even the International Space Station. It’s really difficult to be in a place where you have no radio interference from human activity.

Interviewer: Benjamin Thompson

Maybe before we get into some of the fairly extreme efforts that radio astronomers have gone to try and detect these wavelengths then, let’s maybe talk about what they could actually be used for specifically. I mean what sort of questions about the Universe could these signals answer?

Interviewee: Davide Castelvecchi

Cosmologists have calculated that there should be a number of different features in the radio spectrum from the early Universe. In particular, there’s three that they hope to detect, and the mechanism of what produced these features is different in different ages. So, the first one would come from the very, very early ages of the Universe before there was any kind of starlight and it was just from the interaction of hydrogen and the cosmic microwave background, and then later, there would be stars and the stars would light up and make themselves known by their effects on the hydrogen and then finally, stars and galaxies and black holes, they start emitting so much radiation that they strip hydrogen of its electrons, it becomes ionised and it stops interacting with these radio waves, so basically that part of the spectrum becomes dark.

Interviewer: Benjamin Thompson

So, a few theories about what might be going on then. Have there been any hints that these signals have been detected here on Earth?

Interviewee: Davide Castelvecchi

The first potential hint that we’ve seen is from an experiment in Australia called EDGES and it released its results in early 2018 and it caused a sensation but also a lot of controversy because the results seemed too good to be true. But if it is confirmed, it would be our first hint from this sort of cosmic dawn era when the first stars lit up the hydrogen.

Interviewer: Benjamin Thompson

Well, in your feature, you talk about some of the experiments trying to confirm these findings or maybe detect some of the other features of the 21-centimetre signal, and the lengths that researchers have gone to try and avoid this background radio noise that you mentioned earlier.

Interviewee: Davide Castelvecchi

One of my favourite experiments is one called SARAS, based in India, and it’s one single, small antenna the size of a coffee table and it looks a little bit like one of the flying saucers from The Jetsons, for those who know the cartoons. And this team of radio astronomers first experimented with putting it just in the countryside, but there was too much radio interference, and then they moved it to the Himalayas, to the Tibetan Plateau, and it was still very difficult, and now they are experimenting with putting it on a raft, on a lake, where they can get a better handle on the way that the radio waves interact with the water and the antenna, versus putting it in soil where it’s much more complicated.

Interviewer: Benjamin Thompson

Well, finally then Davide, what are researchers hoping we can ultimately learn about this mysterious period in the Universe’s history?

Interviewee: Davide Castelvecchi

The hope is to be able to see how we got here, basically, how the largest structures in the universe – galaxies and clusters of galaxies – formed. In particular, what was the role of dark matter? How much dark matter was there, which is what caused the clusters of galaxies and galaxies to form in the first place? How many black holes were there and what kind of black holes and what role did they play in accelerating or choking the formation of galaxies? And ultimately, this epoch of the early Universe, which goes from soon after the Big Bang to about a billion years later, comprises about 80% of the current volume of the Universe and basically, cosmologists see it as the richest trove of information about the basic properties of the Universe. It would be very difficult to get there, to extract all this information, but it’s very exciting.

Interviewer: Benjamin Thompson

That was Nature reporter Davide Castelvecchi. To read his feature article, head over to nature.com/news.

Interviewer: Nick Howe

Finally on the show, it’s time for the News Chat. This week, I’m joined in the studio by Nisha Gaind, Nature’s European Bureau Chief. Nisha, how are you doing today?

Interviewee: Nisha Gaind

I’m well. Thanks very much, Nick.

Interviewer: Nick Howe

Well, it’s good to have you here. So, as per, we’ve got a couple of stories to cover. For the first story, I thought we could talk about the Endangered Species Act in the United States. The Trump administration has made some revisions to the Act. Nisha, can you tell me why they’re changing it?

Interviewee: Nisha Gaind

So, the administration says that it will ease the burden of regulations and increase transparency into the decisions over whether species are protected, but it’s already drawn some pretty heavy fire from environmental groups and researchers who are worried that these changes will cripple the ability of this legislation to protect species, which it has done successfully for more than 40 years.

Interviewer: Nick Howe

So, what have they specifically changed about the legislation?

Interviewee: Nisha Gaind

So, there are three main changes that have been made to the Endangered Species Act and chief among them is a change that removes blanket protections for threatened animals and plants. So, under this act, a species can be listed as threatened and previously, any species deemed threatened received the same protections as the species deemed endangered. But now, those protections will be determined on a case-by-case basis and critics say that this is likely to reduce overall protections for species that are added to the threatened list.

Interviewer: Nick Howe

And is anyone challenging this legislation?

Interviewee: Nisha Gaind

Yeah, so it’s a pretty strong piece of legislation to mess with. It’s a very popular piece of legislation and there are some officials who have already said that they are going to sue the Trump administration over these changes. Those include the Attorneys General of California and Massachusetts who say that this overhaul is unlawful.

Interviewer: Nick Howe

So, when might we see these changes come into force?

Interviewee: Nisha Gaind

So, these changes were finalised by the Fish and Wildlife Service and the National Marine Fisheries Service on 12th August. They are expected to be published formally this week and they will then take effect 30 days after publication.

Interviewer: Nick Howe

From endangered species then, we’re moving on to ancient species, and for our second story we’re talking about the possible origin of complex life. So, as I understand it, there are three main domains of life: the single-celled bacteria and archaea, and then there’s the eukaryotes which includes us and all complex life, and now there’s a study that may help shed some light on how eukaryotes evolved.

Interviewee: Nisha Gaind

Yeah, that’s right. This is a really cool piece of research and biologists for the first time have essentially captured and grown a very elusive type of microbe that is similar to those that might have given rise to all complex life on Earth.

Interviewer: Nick Howe

Right, and I’m guessing that this wasn’t an easy thing to accomplish?

Interviewee: Nisha Gaind

Yes, this is not a simple task at all. It is in fact the culmination of 12 years of work by some scientists in Japan. Now, these scientists cultured something called a Lokiarchaea, and this is a type of microbe that they found in deep sea mud. But what’s special about it is that it gives scientists the first look at the kind of organisms that could have made the jump from these simple cells to eukaryotes which, as you say, are group of complex organisms that include plants, fungi and animals, including humans.

Interviewer: Nick Howe

And so how is having now a living culture of it able to give us insight into this origin of eukaryotes?

Interviewee: Nisha Gaind

So there’s a little bit of backstory here, and this group called Lokiarchaea, even though they are this very basic type of single-celled organism, the reason that they are suspected to be similar to the potential microbe that made the jump from archaea to eukaryotes is because they have elements of eukaryotic genetic fragments within their genetic sequence. And we know this from some work that was done in 2015 but this work was all to do with sequencing and it was all quite theoretical, so there were only so many questions that it could answer. The reason that this research is now really interesting is because it gives us a natural culture of Lokiarchaea in the lab that scientists can study.

Interviewer: Nick Howe

So, what is this culture going to help us understand?

Interviewee: Nisha Gaind

So, before when scientists were just working on the genetic sequences, there were some questions about whether these little bits of eukaryotic sequence in the Lokiarchaea were genuine. There were some researchers who suggested that it could be contamination from other types of microbes. This lab culture now, having it actually in the lab for researchers to study, should be able to answer those questions about contamination and should answer the questions about whether this is the ancient lineage of microbe that researchers have been searching for that means so much to complex life.

Interviewer: Nick Howe

So, this might answer some key questions about the origin of eukaryotes, but also, I have some other questions. Why is it called a Lokiarchaea?

Interviewee: Nisha Gaind

So, that is a great question and the answer to that lies in the work that was done in 2015, this sequencing work. Researchers created these genetic sequences from some mud that they found off the coast of Greenland. The mud was found close to Loki’s Castle and as we know, Loki is the trickster of Norse mythology, so they decided to name the archaea-like microbe that they found, Lokiarchaea.

Interviewer: Nick Howe

And what does this trickster god-named archaea look like?

Interviewee: Nisha Gaind

Well, now that we are able to look at it in the lab, thanks to this culture that took 12 years to make, it’s basically some round cells that are less than a micrometre wide, but they are cells with loads of information that are fantastically important to scientists.

Interviewer: Nick Howe

Thanks, Nisha. Listeners, for more on those stories, head over to nature.com/news.

Host: Benjamin Thompson

That’s it for this week’s show. Don’t forget, you can reach us on Twitter – we’re @NaturePodcast. Or if you need a few more characters, you can send us an email. That’s podcast@nature.com. I’m Benjamin Thompson.

Host: Nick Howe

And I’m Nick Howe. See you next time.