ANNIE MINOFF: A new study out this week suggests that around 2 to 3 million years ago, our solar system collided with a gigantic interstellar cloud. And it could have changed the trajectory of life here on Earth. Here to fill us in on that and other science stories of the week is Tim Revell, Executive Editor for New Scientist. Welcome back, Tim.

TIM REVELL: Hi. Thanks for having me.

ANNIE MINOFF: So explain what was going on with this giant interstellar cloud.

TIM REVELL: Yeah. So the first thing you need to know about this is that the sun has a protective bubble around it called the heliosphere. And that’s formed by solar winds pushing outwards. And this protective bubble extends to the edges of the solar system, and so it helps protect the planets within it from radiation. But researchers have now worked out that about 2 to 3 million years ago, the sun passed through this dense cloud of helium called the Local Ribbon of Cold Clouds.

ANNIE MINOFF: I love that it has a name. Just to pause on that– the Local Ribbon of Cold Clouds, all uppercase.

TIM REVELL: It’s an amazing name, isn’t it? It sounds like something from a fantasy novel or a sci-fi. It’s amazing. So it passes through this dense cloud of helium, the Local Ribbon of Cold Clouds.

And that caused the heliosphere to shrink so much that it no longer protected Earth. So it really shrunk in on itself. And then that meant that Earth was suddenly exposed to interstellar radiation in a way that it hadn’t been before.

ANNIE MINOFF: And do we know what impact that would have had to have all that radiation coming at us?

TIM REVELL: We can only really guess. It took about 10,000 years to return, so it had quite a long time to have an impact. And this was at a time where, on Earth, there was woolly mammoths and giant sloths walking on the planet.

And we know that radiation is often linked to mutations in DNA. And that’s also the driver behind evolution. And so potentially being exposed to a lot more radiation from interstellar space could have affected evolution in quite a significant way.

ANNIE MINOFF: And we’re going to stick with space for this next one because you’ve brought us a story about a study that looked at space tourists– so private citizens who’ve been on SpaceX flights. Tell us about that.

TIM REVELL: Yeah, so this is actually a story that’s not just space tourists, but also astronauts in general. And it’s about this thing called a space biobank. And that’s basically a big collection of blood samples, tissue samples, and medical information, with all of that coming from people who’ve been to space. And so, as you say, some of those have been private citizens, but also, some of them have been professional astronauts. And the idea of this space biobank is to really try and pin down the hazardous health effects of going to space, of which we already know there are quite a few.

So the study is initially about bringing all of this data together, but it has got some early findings that I think are pretty interesting. So one thing they found is that a lot of the changes recorded on a SpaceX mission that involved private civilians– the changes that were recorded to people’s immune systems and their DNA when they had immediately come back from space, within a few months, they’d actually returned back to normal. And one of the things that they were able to conclude from that is that actually maybe the risks to civilians of going to space are very similar to those of professional astronauts– so this highly trained, elite group. And so maybe as we explore the possibility of more civilian space trips, that’s something that’s super interesting to know.

ANNIE MINOFF: So for this next story, we’re going to head to the Australian Outback, where scientists have found an impressive dinosaur skeleton. Tell me about that.

TIM REVELL: Yeah, this is an amazing find. So strictly speaking, it’s a pterosaur, which is a type of flying reptile that inhabited Earth around the same time as the dinosaurs. And normally with these, we just find the odd bone or two. But what’s been found now in Australia is a 100-million-year-old pterosaur fossil that constitutes about a quarter of the animal, and it’s the most complete pterosaur ever found in Australia.

ANNIE MINOFF: I was reading that pterosaurs are sometimes called demonic pelicans. Is that what they looked like?

TIM REVELL: Yeah, demonic pelican is a good word for them. This one they found here, it’s a new species of pterosaur, one that we didn’t know about before. And they think it had a 15-foot wingspan–

ANNIE MINOFF: Wow.

TIM REVELL: –and, as you say, would have looked a bit like a pelican, but demonic pelican in the fact that it had a mouth full of spiky teeth. And then in particular with this new pterosaur, they think that it had a massive, muscular tongue that it would have used to catch and hold down prey, which personally does sound quite demonic to me.

ANNIE MINOFF: So to catch and hold down prey with the tongue and then get it with the bitey teeth? Is that the idea?

TIM REVELL: Yeah, the very fierce teeth. I mean, we think they probably ate things like slippery animals, like squid and fish. And so that double combo of having the extremely muscular, powerful tongue and a whole bunch of sharp teeth, I think, would have been quite hard to fight against.

ANNIE MINOFF: Yikes. OK. So from one slightly disturbing story to another, Tim, a lot of us have heard about this double cicada brood that’s happening in the US right now. But there’s this really odd fungus that is infecting some of these cicadas. Tell us about that.

TIM REVELL: Yeah, I read about this in The Washington Post. They’ve got this great story about this fungus. And in their words, they’re saying it’s leading to sex-crazed zombies.

ANNIE MINOFF: Fun.

TIM REVELL: Yeah, fun indeed. So this fungus, it’s been known about for some time, but it’s only really in recent years that we’ve begun to understand it. And there are some pretty outrageous details here. So I must warn you to brace yourself.

ANNIE MINOFF: OK.

TIM REVELL: The fungus itself, it grows inside cicadas, and then it causes their genitals and rear ends to fall off. The fungus then replaces these parts with itself and then produces mind-altering chemicals to make the cicadas continue to look for a mate, despite the fact that they can no longer reproduce. So the cicadas, they then attempt to mate with males and females. They pass on the infection to others that way. But also, as they’re beating their wings when flying about, they deposit powdery spores onto the ground that can then infect cicadas years later when they emerge.

ANNIE MINOFF: Wow.

TIM REVELL: Yeah, it’s really wild. And that particular part of the process has led to them gaining the nickname “flying salt shakers of death.”

ANNIE MINOFF: I mean, just to add insult to injury, not only do they eat away the genitals, but then they hijack the brain so that you keep trying to have sex. Is that right?

TIM REVELL: That’s right. They produce this kind of amphetamine that has that mind-altering effect. It’s really quite incredible.

ANNIE MINOFF: So on the one level, this is clearly horrifying to have a butt-eating fungus infect you, but you also have to Marvel at all of the different ways that species have developed to reproduce. I mean, it’s really kind of clever.

TIM REVELL: Yeah, it’s certainly inventive, I would say. I feel like with these things, often, if you wrote them in a horror novel, you wouldn’t believe it. And then nature has gone and done it anyway.

ANNIE MINOFF: So this might be my favorite story from this week. It turns out that elephants might have names for each other.

TIM REVELL: Yeah, I would also say this is my favorite story of the week. It is an absolutely incredible finding. We can now say that we believe that elephants give each other unique names, and that’s thanks to an analysis of the calls of African savanna elephants. In the analysis, it used machine learning, a type of AI, and the way they did it was that the AI was trained using a whole bunch of elephant rumbles. These are these low-frequency calls that elephants make.

And the AI was able to guess correctly which call responded to an individual elephant about a third of the time, which is not amazing, but it’s certainly better than chance. But the real clincher in this study was the researchers then used this new information to play those sounds that they thought corresponded to individual elephants out of a ANNIE MINOFF. And then they saw that the individual elephants responded very strongly to their own names, moving closer to the ANNIE MINOFF or responding with their own greeting rumbles. It’s just such an amazing finding.

ANNIE MINOFF: So they would play the name, like, “Henry,” except guess it’s a rumble, so it’s more like, [GRUMBLES]. And Henry would be like, “Yeah?” Is that the idea?

TIM REVELL: Yeah, that’s exactly the idea. And there would be a group of elephants, and it would be that one individual that would suddenly get up or turn its head and be interested in what was coming out of the ANNIE MINOFF, as if it was corresponding specifically to them.

ANNIE MINOFF: Is it possible that we could use this machine learning technique to find out other things about elephant language?

TIM REVELL: Yeah, absolutely. I mean, the hope is that we can unpick this even further. So one thing we don’t know yet is that if the elephants have a name that all the other elephants they use or whether it’s the individual elephants have individual names for other elephants, a bit like everyone having a nickname.

And perhaps that’s something that AI could work on. I mean, other than humans, elephants are the first species where we’re seeing that this could be the case. But to me, personally, it seems unlikely that it’s only elephants. AI could be key to us understanding whether this is something that is more widely distributed across the animal kingdom.

ANNIE MINOFF: Totally fascinating. And as our last story, we have some news for fans of the polar explorer, Ernest Shackleton, of which I am one. Some of you might remember that his famous, I guess, maybe I should say, infamous ship, The Endurance, was discovered recently. And now we have found another one of his ships, right?

TIM REVELL: Yeah, that’s correct. So this ship is called Quest, and it’s been found off the Coast of Newfoundland, Canada. And it was the ship that Shackleton actually died on, but not in Infamous way like on Endurance, the story around that. Instead, he suffered a fatal heart attack, and then the ship never quite reached its destination, which was meant to be the Antarctic.

And Quest then had a life after Shackleton. It continued to be used. It was used by the Canadian Navy for a period and then Norwegian sealers. And somewhat ironically, in the early ’60s, 1962, it then collided with some thick sea ice, piercing the hull and sending it to the deep, which was, I’m sure you remember the same thing that happened to Endurance.

A team now led by the Royal Canadian Geographical Society– they’ve been on the hunt for where this ship actually lays, and they use ship’s logs, navigation records, photographs, and documents to really narrow down where to look. And then when they got there, they used sonar. And amazingly, almost exactly where they had predicted, they found the ship about 1,200 feet underwater, though they are keeping that location secret for now.

I think what’s interesting often with these ships is just how intact they are afterwards. So they have taken some pictures of the ship and explored a little bit of it so far. And it seems to be sitting basically upright on the sea floor. Apart from having a fairly sizable hole in the hull, it’s got a mast that is a little bit broken hanging over one side. But other than that, it seems to be completely intact.

ANNIE MINOFF: Well, thank you so much for bringing us these stories, Tim.

TIM REVELL: My pleasure. Thanks for having me.

ANNIE MINOFF: Tim Revell is Executive Editor at New Scientist. And one last thing before the break, this week, Dr. Ed Stone passed away at the age of 88. He was the former director of NASA’s Jet Propulsion Laboratory and served as the project scientist for the Voyager missions for 50 years. We spoke with him in 2013 about the Voyager legacy.

ED STONE: Time after time, our view had to be so greatly expanded. And I think that’s the biggest, broadest impact of that part of the Voyager mission. Now we’re on a totally different, mission, which is the first to leave the solar bubble and begin to sail on the cosmic sea that’s between the stars because that’s what most of the Milky Way is, is the sea between the stars. It’s not the stars, but the sea between.

ANNIE MINOFF: That was Dr. Ed Stone, one of our many conversations with him over the years about Voyager. He died earlier this week.

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