AILSA CHANG, HOST:
It's time now for our regular science news roundup with our friends at NPR's Short Wave podcast, Regina Barber and Berly McCoy. Hey to both of you.
BERLY MCCOY, BYLINE: Hey.
REGINA BARBER, BYLINE: Hey, Ailsa.
CHANG: So you guys have brought us three science stories that caught your attention this week. Let's hear it. What are they?
BARBER: How sea lions are helping scientists map the ocean.
MCCOY: What you need to know about the Perseid meteor shower this weekend.
CHANG: OK.
BARBER: And where the moon's barely there atmosphere comes from.
CHANG: All right. Well, I want to start with the sea lion cartographers.
MCCOY: Yes. So researchers glued underwater cameras onto Australian sea lions, and then they used that footage to look at where they spent their time.
CHANG: Wait. They glued the cameras onto the sea lions?
MCCOY: Yes.
CHANG: Was that totally uncomfortable?
MCCOY: So these cameras are super lightweight, and the researchers are very gentle with the animals, and they get them back in the water as soon as possible.
CHANG: Well, what do we want to know about where sea lions are hanging out all the time?
BARBER: Well, the Australian seaons are an endangered species, and their population has declined by more than 60% in the last 40 years. And even though researchers have a broad sense of, like, where these sea lions spend their time hunting, there's a lot of specifics researchers don't know.
CHANG: OK. Well, how common is it for scientists to attach cameras to animals? Like, I see people do this with their dogs all the time, not me because Mickey (ph) is really sedentary, but, like, how common is this?
MCCOY: Yes. I would actually like to see Mickey's footage. But for marine animals, it's actually not that uncommon.
CHANG: Oh, really?
BARBER: Well, researchers had attached suction cameras to whales to do things like understand their behavior and acoustics, but it's rare to map the animals', like, habitat using these cameras. And they also use the footage to explore unmapped areas of the ocean.
CHANG: So neat. So, like, they can script these sea lions into becoming soldiers for science?
MCCOY: Kind of, yeah. But for the area that they mapped, it's a cheaper and less time-intensive way than sending divers down or remotely operated vehicles.
CHANG: That totally makes sense. All right. So how did they get these cameras back from the sea lines after gluing them on?
MCCOY: Well, because the researchers also attach trackers to the sea lions, they could monitor their location, wait until they came back to land and then gently remove the cameras.
BARBER: And once they get that video footage back, they identified six different habitats on the sea floor. And the scientists use this habitat data to build a computer model that can predict sea lion habitats in other areas. And this work was published this week in the journal Frontiers In Marine Science.
MCCOY: And, Ailsa, this is potentially a new way for other scientists to study the ocean. I talked with a whale researcher who was not involved in this work, whose name, out of respect, I will let him say...
MAEVE HACINBAJANAGH: My name is Maeve Hacinbajanagh (ph).
MCCOY: So Maeve said it inspired him to go back through the video footage that he's collected from humpback whales to see what else he could learn about their environment.
HACINBAJANAGH: And I think it would complete a lot of missing information on the underwater environment in general.
MCCOY: And he thinks it could encourage other researchers to do the same. But for me, the videos are just really fun to watch.
CHANG: All right. I'm going to switch gears a little bit right now and talk about the Perseid meteor shower. Should I be out in my backyard star gazing pretty soon?
MCCOY: Well, I don't know about your back yard because, like, light pollution, but it might be worth venturing outside of LA for. So this weekend is the peak of the Perseids, which NASA calls the best meteor shower of the year. Because sometimes people have reported seeing 90 or more every hour.
CHANG: Wow.
BARBER: Yeah. The Perseids are known for leaving these, like, long trains, kind of like the wake of a motor boat but in the sky.
CHANG: That's so cool.
BARBER: And these are ionized molecules left behind in the Earth's atmosphere as the meteor heats up the air in its path.
CHANG: Whoa. Well, can you remind us, like, what are the Perseid meteor showers caused by?
MCCOY: Yeah, so the Earth orbits around the sun every year, right? So that means every year around July or August, we pass through these clouds of ice and dust left over from the comet Swift-Tuttle or 109P. And when that debris hits our Earth's atmosphere, it usually burns up, which creates these bright shooting stars that we see in the sky, like the Perseids.
CHANG: Pretty. OK. I'm convinced. I'm totally going to check this out. What is the best time for me to watch?
BARBER: Your best time to spot a shooting star is going to be this Sunday night, like, after the moon sets around midnight and the sky is really dark. But even then, even if it's dark, you still need to have, like, 30 minutes to let your eyes adjust to that darkness. And be patient. Like, at best, you'll see like two a minute.
CHANG: Oh, my God. So slow. But I'll try.
BARBER: Yeah, exactly. Yeah. People expect there to be, like, showers, and it's not quite that.
CHANG: I think my eyes are going to dry out from staring so continuously. But OK. Let's stay in space and talk about this barely-there atmosphere of the moon. Like, what does that even mean for an atmosphere to be barely there?
BARBER: Yeah. It means the moon has, like, a very thin atmosphere, and it's composed of atoms that are, like, so spread out, they barely interact. It's like the tiniest wisp of an atmosphere. Because unlike Earth, which has active volcanoes that spew out gas, and Earth has enough gravity to, like, hold on to all that gas and make an atmosphere, the moon has no active volcanoes and, like, very little gravity.
MCCOY: But a new paper out this week helps to explain some of the mystery of how that tiny atmosphere got there.
CHANG: Oh, I love mysteries. So how did the moon's atmosphere get there?
MCCOY: OK. Well, I should first give you a little bit of a back story. So scientists have been debating this for decades. They even sent a lunar orbiter called LADEE up 11 years ago to investigate this, and it couldn't come up with a definitive answer. But there are two working ideas for how this atmosphere formed. So, OK, the first one is meteorite impacts. So when meteorites, even tiny ones, hit the moon surface, the energy from that impact vaporizes the soil, and the atoms from that collision go up into the air and create this thin atmosphere.
BARBER: Yeah. The other process involves solar winds, so that's the other part of the debate. Solar winds are just high-energy particles, like, flowing from the sun. And these particles are going so fast that they hit the lunar soil and that knocks particles out, and those particles go up and create an atmosphere.
CHANG: Dang. OK, solar winds or meteorites crashing into the moon.
BARBER: Yeah.
CHANG: I mean, that's wild. Which one ended up being right?
MCCOY: Well, that's where this new paper comes in. Scientists looked at actual lunar soil and rocks brought back by the Apollo astronauts for answers.
BARBER: Yeah, and these samples are very precious. Humans have only gone to the moon a handful of times. The lead author of this paper, Nicole Nie, told me that she was pretty nervous.
NICOLE NIE: Before I started to work on lunar samples, I spent three years to develop the chemical method to make sure that I can do it right.
MCCOY: She and her colleagues published the results of these chemical analyses in the journal Science Advances, and they determined that the majority of the moon's atmosphere, about 70%, was because of meteorite impacts.
CHANG: OK. So the moon's unsolved mystery is solved.
BARBER: Right. So the big deal is that this might actually tell something about other planetary bodies, like things beyond the moon, maybe the atmosphere around Mercury or even planets outside of our solar system.
CHANG: That is very, very cool. And that is Regina Barber and Berly McCoy from NPR's science podcast, Short Wave. If you liked the stories they brought us today, then every Tuesday this summer, you can hear their Space Camp series. It's awesome. It looks at all the things in outer space, all the things. Thank you to both of you.
MCCOY: All the things.
BARBER: Thank you so much.
MCCOY: Thanks, Ailsa.
CHANG: And special thanks to the U.S. Space and Rocket Center, home of Space Camp. Transcript provided by NPR, Copyright NPR.
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