Pluto Rolls Over (the Dwarf Planet, Not the Dog)

6:23 minutes

Keane - Animation of Pluto Reorienting - annotated
This animation shows how Pluto reoriented in response to volatile ices filling Sputnik Planitia (the left lobe of Pluto’s “Heart”). Sputnik Planitia started northwest of its present position, and as it filled with ices, the tides from Charon (Pluto’s largest moon) caused the entire dwarf planet to reorient, and align Sputnik Planitia with Pluto’s tidal axis (the line running through Pluto and Charon). If Sputnik Planitia is still accumulating ice, then Pluto may still be reorienting. Credit: James Tuttle Keane. Maps of Pluto and Charon by NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

One of the most recognizable features on Pluto’s surface is a massive, heart-shaped basin. Now researchers say that as ice accumulated in part of that basin, it appears to have tipped the dwarf planet on its axis. Sophie Bushwick of Popular Science discusses the finding, plus news of the first human use of CRISPR gene-editing technology, and how children can now sue the U.S. government for not doing enough to fight climate change.

Segment Guests

Sophie Bushwick

Sophie Bushwick is senior news editor at New Scientist in New York, New York. Previously, she was a senior editor at Popular Science and technology editor at Scientific American.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. A bit later in the hour, we decode your cold remedies. You know the tea, the zinc, the vitamin C– to see if there’s really any science backing them up. But first, when New Horizons whizzed past Pluto last summer, it sent back wonderful pictures of the planet, or the dwarf planet as you wish.

Remember that cold, icy heart that stretched across the Plutonian surface? Beautiful stuff. But those pictures were only the beginning of a huge trove of data trickling through space back to Earth.

We only received the last of that data a month ago and more than a year after the flyby happened. And this week, scientists announced that something strange may be lurking under that icy heart. Sophie Bushwick is here to talk about that and other selected short subjects in science. She’s senior editor at Popular Science here in New York. Welcome back, Sophie.


IRA FLATOW: Something strange in the neighborhood going on there? In Pluto?


SOPHIE BUSHWICK: Yeah. It’s really interesting. So the whole western part of the heart is this area called Sputnik Planitia. It’s this enormous basin formed from an impact that then filled up with ice. And researchers have realized that since it’s formation, it’s moved about 750 miles away from its original location, and it’s moved over to align with the tidal axis of Pluto.

This is the point where the pull from Pluto’s largest moon is strongest. It’s been dragged over there by this force, and it’s also, as it moved, drag the whole crust of Pluto with it. So Pluto’s almost rolled over.


SOPHIE BUSHWICK: And they think that one of the things that facilitated this movement was the existence of a subsurface ocean. There’s, under all that, is an underwater ocean?

SOPHIE BUSHWICK: Yeah. Under the crust, there’s like a slushy, liquid-y ocean, which is really surprising, because Pluto shouldn’t be warm enough to support an ocean like that. How so then it must be warm enough right?

SOPHIE BUSHWICK: Yeah, must be.

IRA FLATOW: Something going on under there keep it melted?


IRA FLATOW: Something, who knows?

SOPHIE BUSHWICK: Something that’s going to give them a lot more to delve into that makes them happy to have the New Horizons data.

IRA FLATOW: And yeah, who thought when they did this, when they launched this probe to Pluto, we’d find all this kind of stuff?

SOPHIE BUSHWICK: It’s really amazing, because they found this by looking at fault lines on the surface. The fault lines look cracks in the surface ice– those were the things that indicated to them that this Sputnik Planitia area had moved, and it also suggests that what they think happened is in order for it to move, it probably was because it’s heavier there than the rest of the surface. That’s why that heavy area got gravitationally drawn to the tidal axis. So that could be because when it formed a basin– early in its formation, it was a basin– the ocean beneath the surface pushed up into a bulge underneath that basin, because there was less weight on top of it there. And that bulge increased the weight in the area and dragged it over.

IRA FLATOW: Wow. So much stuff coming back from there. Great photos. All this data.

SOPHIE BUSHWICK: It’s really exciting.

IRA FLATOW: We have to look at that planet– minor planet–

SOPHIE BUSHWICK: Dwarf planet?


SOPHIE BUSHWICK: There’s always going to be someone who will fight you on the name.

IRA FLATOW: That’s true. Alright. Well, let’s move on to the next topic. We’ve talked a lot about the gene editing technique CRISPR on this show and how it might be used in the future to edit human cells. And now it looks like the time is upon us already with a clinical trial in China on a human?

SOPHIE BUSHWICK: That’s right. Chinese researchers took the cells of the immune system of one patient who had lung cancer that had spread through the body. They took the immune cells, and then they used CRISPR to genetically modify them to cut out a certain kind of protein that sort of slows down the immune system and was allowing the cancer to spread. And then once they had this cell, they cultured it to make lots of copies and put it back in the patient’s body. And there they felt that it was a really promising technique, and so they’ve moved on to a clinical trial, a larger trial.

IRA FLATOW: And of course, everybody is going to wonder hey, how soon is this available?

SOPHIE BUSHWICK: Oh my god. Yeah. Probably not for a while. Some researchers have pointed out that this isn’t the best way to treat this type of cancer, that there are other treatments that could be more efficient. But the thing about the trial is what it’ll show them is are there side effects? So is there a downside to using this treatment in the human body is one of the things it’ll investigate.

IRA FLATOW: Will it also spur other people or other countries to try to do this now that China has opened the door? I certainly think it will spur American researchers. I think that Chinese researchers do tend to be more forward in using CRISPR with humans, but I think that this could set off more of a competition between American and Chinese researchers to use CRISPR.

IRA FLATOW: Let’s move on to this other interesting story, and that’s President-elect Trump says he wants to cancel the Paris Climate Agreement, but now it looks like he and the federal government might face legal action if they do so and from an unusual plaintiff.

SOPHIE BUSHWICK: That’s right. A group of about 20 children has gained the right to sue the federal government over climate change. They say that because the federal government hasn’t taken enough steps to reduce the impact of climate change that these kids and their children are going to be the ones who bear the brunt of all the effects of climate change. More severe storms, more wildfires, more droughts, a lot of problems.

And they’re saying, well, this is impeding on our right to life, liberty, and the pursuit of happiness, and they wanted to bring this to court. But the fossil fuel industry and the federal government itself filed a motion to dismiss the case. And what happened most recently, as a judge in Oregon said, you can’t dismiss the case, it’s going to court.

IRA FLATOW: Wow. That’ll be interesting to keep track of what’s going on there.


IRA FLATOW: And the last story is about bird poop might be a good thing for the climate.

SOPHIE BUSHWICK: Yeah. Bird poop is actually good for the Canadian Arctic. Researchers noticed that every summer, there was a spike in ammonia levels, and that’s when the birds are coming to the Canadian Arctic. That’s when they migrate there. And so it’s their poop that’s causing this ammonia spike. And the ammonia actually helps combine with other materials and it seeds clouds in the air, so it creates these low-lying clouds, encourages them to form, and the clouds reflect sunlight, which actually causes a cooling effect.

IRA FLATOW: Wow. Who’d ever thought?

SOPHIE BUSHWICK: I definitely wouldn’t have.

IRA FLATOW: Must be happening on a great scale here in New York with all the pigeon.

SOPHIE BUSHWICK: Who knew bird poop was a good thing?

IRA FLATOW: That’s it. Sophie Bushwick, a senior editor with Popular Science here in New York. Always good to have you. Thanks for joining us.

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