11/16/2018

Beneath The Ice, A Massive Crater

6:44 minutes

Researchers using specialized ice-penetrating radar have located a massive impact crater buried under a half-mile thick Greenland ice sheet. The crater is 31 kilometers wide, making it one of the 25 largest craters known on Earth.

The scientists believe the crater is the result of a collision with an iron meteorite at least one kilometer across—an impact capable of melting rock, as well as a significant part of the ice sheet,  potentially causing sea level rise and climate disturbances across the globe. The date of the impact is unknown, however—it could have been as recent as 12,000 years ago, or as old as three million years.

[Just when you thought you’ve seen every kind of cloud in the sky, researchers capture electric blue ones.]

Annalee Newitz joins Ira to talk about the discovery, and other stories from the week in science, including news about the thought processes of orangutans, violence in the Neanderthal world, and a look ahead to the landing of the Mars InSight mission later this month.

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Segment Guests

Annalee Newitz

Annalee Newitz is a science journalist and author based in San Francisco, California.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow, broadcasting today from the studios of WUSF at the University of South Florida in Tampa. 

OK, you’ve seen the horror movie, right? The bad guy is over there. The protagonists are hiding and waiting, and they whisper, be quiet. He’ll hear you. OK, the bad guy leaves. And when they hear them, then they make their quick getaway. It’s called displaced reference, being able to talk about something that is not actually right where you are. 

And it turns out it is not just a human thing. Researchers report this week in the journal Science Advances that orangutans can do a very similar thing. Here to tell us more about that and other selected short subjects in science is Annalee Newitz, science journalist and author based in San Francisco. Welcome back. 

ANNALEE NEWITZ: Hey, thanks for having me. 

IRA FLATOW: So what did the researchers actually see the orangs do? 

ANNALEE NEWITZ: So the best part about this study is how they did their research because they wanted to see if orangutans would talk about danger– not talk about, but communicate about danger that wasn’t there. So the researchers found some sheets that were patterned like tigers and other cat fur that was associated with predators in the orangutans’ habitat in Sumatra. And they walked on all fours underneath the trees where the orangutans were, put the sheet over them, and basically pretended to be tigers. 

And what they found was that the orangutans, which most of them were mothers with babies, would completely become silent during that time. But then about 20 minutes later, after the scientist wrapped in a sheet was gone, then they would issue distress calls and warning calls. So it was a very clear example of an animal other than a human talking about something that wasn’t within their immediate frame of reference. 

IRA FLATOW: And researchers say this is very significant? 

ANNALEE NEWITZ: It’s significant because we’ve never seen this in another primate. One of the only other animals we’ve seen do this are bees, actually, when bees do their waggle dance and communicate with each other about where to find honey when they’re back in the hive. So this is an incredible breakthrough. And we may find this happening in more animals, but we’re certainly learning more about what scientists will do to get answers when they put on sheets and crawl through the forest. 

IRA FLATOW: Must have been a graduate student. OK, in other anthropology news, there’s news out about just how dangerous the lives of Neanderthal were. 

ANNALEE NEWITZ: That’s right. So you know, there’s a lot of misinformation out there about Neanderthals, you know, that they were dumb or that they, you know, led incredibly dangerous lives. And so we already know that Neanderthals were basically the same intelligence level as Homo sapiens, and now we have evidence that they weren’t actually leading more dangerous lives either. 

A couple of researchers in Europe looked at a collection of fossils, about 800 examples of Neanderthal and Homo sapien skulls, to see how many of them had died violent or dangerous deaths. And the way they do that is basically looking at skull trauma. You know, did you die by being hit on the head? And they found no difference between the adult Homo sapiens and the adult Neanderthals. They were basically experiencing violent deaths at the same rate. A slightly elevated number of Neanderthal juveniles and children had died from head injuries, and there’s other reasons that that could be true. 

But what this means is that we’re not seeing Neanderthals engaging in a more dangerous lifestyle that might have led to their demise. So again, we’re left with questions about what actually led to their end. 

IRA FLATOW: Very interesting. And I want to get to another really interesting discovery, a new discovery about a huge crater that’s under the Greenland ice sheet? 

ANNALEE NEWITZ: I know, this is a fantastic story. So scientists using a relatively new form of ground penetrating radar that works really well for penetrating ice have discovered a 31-kilometer wide meteor impact under the ice sheet known as Hiawatha in Greenland. And the thing that’s super interesting is this is one of the 25 biggest impact craters on the planet. And we can tell that it came and hit when the ice sheet was still in place, which means it had to have been during the Pleistocene. So it was 2.5 million years ago or younger. 

So this is relatively recent. And it would have been such an enormous impact that it would have melted a huge part of the glaciers, probably resulting in sea level rise, and probably perturbing climates around the planet, certainly in the northern hemisphere. So this was a huge hit really recently in Earth’s history. So you know, this gives us a lot of insight into how often giant rocks from space hit the planet. 

IRA FLATOW: Wow. But it wasn’t big enough to wipe out Earth like– 

ANNALEE NEWITZ: It certainly wasn’t. To give you a comparison, you know, the meteorite that wiped out the dinosaurs, that impact crater is about 150 kilometers across. So it’s significantly larger. 

IRA FLATOW: Yeah. Let’s go to some other spacey kind of news. There’s another Martian landing coming up, right? 

ANNALEE NEWITZ: I know, this is so exciting. So Insight, which is going to be exploring Mars, is landing on November 26 in the afternoon, East coast time around 3:00 PM. 

And this is going to be a relatively easy landing. There’s no sky crane like when Curiosity landed. It’s just a parachute landing. And it’s going to be sitting in place. So it’s not going to be driving around. 

And it’s learning about the interior of Mars, which means it has a giant drill and it’s going to drill five meters into the Martian crust. And that’s going to tell us about the planet’s composition, it’s going to tell us about heat levels inside the planet, and give us just more information about how rocky worlds are formed. 

Second data point that we have on that. You know, Earth is a rocky body. We’ve studied that. Now we’re going to study it on Mars. And it’s also going to learn more about seismic activity on Mars. So we might actually learn about Mars quakes. 

IRA FLATOW: So what date should we circle on our calendar for this one? 

ANNALEE NEWITZ: So November 26. And if you go to NASA’s website, there’s going to be watching parties all across the United States, so you can get together with friends and and watch the landing. And like I said, it’s happening in the afternoon, so it’s actually a reasonable time. So get out and watch our space program go. 

IRA FLATOW: I love it. I love it. Thank you very much, Annalee. 

ANNALEE NEWITZ: Yep. Thanks for having me. 

IRA FLATOW: Have a happy holiday. Annalee Newitz is a science journalist and author based in San Francisco.

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