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New Horizons is teaching us all about Pluto! And it’s definitely not what we were expecting.
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NASA TV press briefing on July 15, 2015:

[Intro music]

(00:03) Since the New Horizons probe made its historic flyby of Pluto on July 14th, we’ve learned more about that dwarf planet and its moons than we did over the entire 85 years than we knew it existed. Just in the first few images and pieces of data sent back by New Horizons, there’s a ton of stuff to unpack and analyze. Days before the probe even got there, we got a much better estimate of Pluto’s size and the great picture of the adorable heart-shaped region on its surface.

(00:29) But now we know so much more! And from what we’ve seen so far, at least one thing’s for sure. We’re going to have to completely change the way we think about planetary geology. Take a look at this picture of Charon. There’s something about it that’s really strange. It’s not covered in nearly as many craters as we would’ve expected. Pluto and Charon’s hangout is in the Kuiper Belt, which is full of other objects. They definitely knock into them from time to time. The only way Charon could have a smooth surface like that is if it’s been geologically active, with some kind of process smoothing out the surface.

(1:00) Then, there’s that dark region near its dark pole, which apparently the mission team has been calling Mordor. They still aren’t sure why that area is darker than the rest but its fizzy boundaries means that it’s probably a veneer: a thin layer of something spread across the surface. You can actually see a brighter spots where small impacts might have punched through the veneer slightly.

(1:20) And Charon has canyons. You can see a couple of them in this image, with one at the top-right that’s about 6 to 10 kilometers deep and another on the opposite side that’s about 5 kilometers deep. Not bad for a 1,200-kilometer-wide moon.

(1:33) But there’s even more weird stuff on Pluto itself. New Horizons took lots of high resolution photos that the team will assemble into a mosaic. This is first one the probe sent back which is sharp enough to show features smaller than a kilometer, and you might notice that there are no craters in this picture either.

(1:50) But you know what the image does show? 3-kilometer-high mountains. Of ice! And those mountains are challenging everything we thought we knew about the way surface features form on other worlds. The only material on Pluto that’s strong enough to make such tall mountains without collapsing is water ice. At Pluto’s temperatures, scientists said that frozen water behaves more like rock than ice as we know it. So know we know that the dwarf planet probably has tons of ice coated in a layer of frozen nitrogen and methane.

(2:19) But we don’t know what process could have possibly formed ice into those mountains. Usually we attribute these kinds of features to tidal heating: where the gravity of a large, nearby object makes a moon’s insides shift around as it orbits, generating heat. The heat can then drive surface activity, like the formation of mountains. But Pluto and Sharon are tidally locked, meaning they orbit with the same sides always facing each other. Just like the Earth does with The Moon. That means they can’t be churning each other’s insides around. So there must be something else at work.

(2:49) And then there’s the matter of Pluto’s…leaky atmosphere. New Horizons’s scientists said that the dwarf planet is losing its atmosphere, which is mostly made of nitrogen, to space on the order of tons of gas per second. And yet there seems to be only a frosting of frozen nitrogen on its surface. Where’s all that nitrogen coming from? Something must be dragging more nitrogen out from inside the dwarf planet to keep reforming that thin layer on top. Again, researchers don’t know yet what that process could be. But it’s strong evidence that Pluto might have features, like geysers or volcanoes, that spew out frozen nitrogen.

(3:23) And the fact that Pluto is losing its atmosphere makes it a great place to learn about Earth’s history. Millions of years ago, Earth had a very different atmosphere, full of hydrogen and helium. But we lost it over time. Scientists think that Pluto’s atmosphere is undergoing a similar process. By studying the conditions on Pluto right now, researchers hope to learn more about what Earth was like back when our hydrogen-helium atmosphere was escaping.

(3:46) And this is just some of what we found out from just the first days’ worth of New Horizons’s data. There’s so much more data packed away on that probe’s hard drive. So, look out for future episodes of SciShow Space News, where we’ll definitely be covering the data and images as they come in. And thanks for watching episode which was brought to you by our patrons on Patreon. If you want to help support this show, just go to and don’t forget to go to and subscribe.

[Outro music]