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This week in science: Sneaky fish, shouting into space and waves getting taller

JUANA SUMMERS, BYLINE: It's time now for our science roundup from our friends at NPR's Short Wave podcast. Regina Barber and Berly McCoy are here. Hey, y'all.



SUMMERS: All right. So today I understand you've brought us three science stories that caught your eye. Can you just give me a little preview?

BARBER: OK. How about shouting into interstellar space...

MCCOY: A super-sneaky fish.

BARBER: ...And bigger waves off California because of climate change?

SUMMERS: OK. Regina, I can definitely identify with this idea of shouting into space a lot of the time, especially when I'm at home. Let's start there.

BARBER: Yeah, me, too. So a couple weeks ago, NASA lost contact with Voyager 2. This is the spacecraft that launched in 1977 and has traveled well beyond our solar system and is still sending back data. And they were worried they'd lost contact for good, but they reconnected to it last week by shouting at it across 12 billion miles or so.

SUMMERS: OK. And what exactly do you mean by shouting?

BARBER: Yeah. So NASA periodically sends messages to make sure Voyager 2 is pointing its receiver towards Earth. And a few weeks ago, there was an error in a code that was sent out that resulted in the receiver pointing the wrong way, just two degrees. And that error was kind of like sending an email with the wrong attachment. And because of that slight shift, they lost contact. The team was in emergency mode, but they were eventually able to send another message using the strongest signal they could, which was over twice as powerful as the original message. Linda Spilker, the Voyager mission scientist I talked to, called it shouting at Voyager 2.

LINDA SPILKER: And it worked. We shouted at Voyager, waited a day and a half. And Voyager came back and said, hi. I'm fine. Everything's great.

SUMMERS: Well, that sounds like a relief. But wait. There are two Voyager spacecrafts, right?

BARBER: Yeah. So there's Voyager 1 and Voyager 2. And they were both made to study the planets in our solar system. And Voyager 2 is actually the only spacecraft to study Uranus and Neptune. But since everything was still working after the initial four-year mission, scientists decided to give them a new mission to study interstellar space.

SUMMERS: "Interstellar." Isn't that a Matthew McConaughey film?

BARBER: Yes. But in real life, we're talking about the space beyond our solar system, between star systems, a place we haven't really explored. And that's where the Voyager spacecrafts are now. And this makes them the farthest human-made objects from Earth. Also, just in case they encounter intelligent life, Voyager 1 and 2 are carrying Golden Records. And these Golden Records have images, music and greetings from all over the world.

SUMMERS: OK. Now for our second science story, we are leaving space, and we're diving right into the ocean. Berly, tell us about these sneaky fish.

MCCOY: Yeah. So this discovery is in trumpet fish, which are these long, stick-like fish. And they do this thing called shadowing when they're hunting other fish, which is basically when one fish follows another fish closely. And there was some mystery as to why they would do that. Maybe they do it because it helps them sneak up on their prey, but they could also do it because they encounter less drag when they swim in the shadow of another fish. Researchers didn't really know.

SUMMERS: OK, so how did the scientists get to the bottom of it all?

MCCOY: So this is the really fun part. First, the researchers made these 3D-printed models of trumpet fish and the fish they tend to hide behind called parrotfish. Then the lead researcher spent weeks painting them - he said he felt like Bob Ross - and then took them out to a coral reef in the Caribbean where divers had seen this trumpet fish shadowing behavior before. And so two researchers would dive down, find a colony of trumpet fish prey and then set up two tripods with a nylon line between them. They attached 3D-printed trumpet fish and parrotfish to that nylon line, kind of like an underwater clothesline. And then they'd put on this underwater puppet show with the fake fish swimming across the reef and watch how the trumpet fish's prey responded.

SUMMERS: OK, so what did the prey do? How did they respond to these decoys when it looked like one fish was hiding behind the other fish?

MCCOY: Yeah. So this illusion that the researchers set up with the fake trumpet fish hiding behind the parrotfish - it seemed to trick the prey. The prey didn't dart out of the way as urgently as they did when they encountered the trumpet fish on its own.

SUMMERS: So it seems the scientists got closer to answering the question of why these fish do this then, right? It seems to help them get closer to their prey while hunting.

MCCOY: Yeah, that's what the researchers concluded, which means this is the first time researchers showed that a predator outside of humans can conceal themselves from their prey by hiding behind another animal. And since coral reefs are disappearing, there's less coral to hide behind. So hiding behind other fish could end up being an even more important strategy for trumpet fish in the future.

SUMMERS: For our third and final story, we are staying in the ocean. The waves along the California coast are getting bigger over time, and that's due to global warming.

BARBER: Yeah. So our NPR colleague Nate Rott wrote about this recently for npr.org. Apparently, California's winter waves have gotten about a foot taller on average since 1969. And the number of storms that produce waves greater than 13 feet tall have also become more common off California's coasts. So this is from a study published last week in the Journal of Geophysical Research Oceans.

SUMMERS: I mean, when you're talking about a foot taller waves - I'm not the best swimmer. That doesn't sound like good news for me. Maybe if you like to surf, it's a good thing.

MCCOY: Yeah, I think for the surfers, it might be a better thing for the rest of us. Surfers in California earlier this year said they saw the best swell in decades.

BARBER: Yeah, but like Juana said, there are plenty of downsides that come with massive waves, like damaged piers, crumbled sea cliffs, flooded coastlines. And when you combine that with rising sea levels, we're talking billions in damage to California's coast within the next few decades.

SUMMERS: OK, that's no good. So how did they figure out that California's waves were getting bigger?

BARBER: Peter Bromirsky, the study's author, used seismic records going back to 1931.

SUMMERS: I mean, I feel like when I hear the word seismic thrown around, I'm usually thinking about earthquakes, not waves.

MCCOY: Yep, yep, totally. But it is connected. We swear. So basically, when waves ricochet off the coast, they send energy back towards the sea. And when that energy hits incoming waves, it pushes energy downward. That creates a seismic signal that can be detected like earthquakes. So Bromirski was able to use that information to estimate the size of the waves.

BARBER: And this part is actually really cool. So we have data on wave height along the West Coast from buoys, but they've only been measuring this since 1980. So by using this older seismic data, Bromirski was able to go back further in time to activity patterns back to the 1930s.

SUMMERS: OK. And we mentioned earlier that these higher waves off California are linked to global warming. What's the connection?

BARBER: Well, this new study adds to research suggesting storm activity in the Northern Pacific Ocean has increased as human activities have caused the world's temperatures to warm. That storm activity is the main source of California's winter swells.

MCCOY: Plus, we know that climate change makes storms more powerful and dangerous. It makes storm surge and inland flooding more severe. So even though this study was focused on a specific region, the concern goes way beyond the California coast.

SUMMERS: That's Berly McCoy and Regina Barber from NPR's science podcast Short Wave, where you can learn about new discoveries, everyday mysteries and the science behind the headlines. Regina, Berly, thank you.

BARBER: Thank you.

MCCOY: Thanks, Juana.


NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.

Regina G. Barber
Regina G. Barber is Short Wave's Scientist in Residence. She contributes original reporting on STEM and guest hosts the show.
Berly McCoy
Kimberly (Berly) McCoy (she/her) is an assistant producer for NPR's science podcast, Short Wave. The podcast tells stories about science and scientists, in all the forms they take.