[SciShow Intro Plays]

Hank: A new set of crew members is blasting off to the International Space Station! The launch is planned for today, March 18: Jeffrey Williams, Alexey Ovchinin, and Oleg Skripochka are heading off to join the team onboard the ISS, where they’ll continue work on Expedition 47. One of the main focuses of their mission will be new research into the bone and muscle loss that happens in orbit.

When they’re in space, astronauts can quickly lose their bone and muscle mass because they aren’t using their bodies to fight the pull of gravity the way we do here on Earth. As the saying goes, if you don’t use it, you lose it. Astronauts spend hours every day exercising to try and avoid this problem, and that exercise does help -- but they still lose a lot of bone density and muscle mass. So, on this mission, the crew will be testing an antibody that may be able to to prevent muscle and bone loss. The antibody has already worked with mice on Earth, and now they’ll be testing it on mice in space. Mice lose muscle and bone just like we do in space, so they’re a good model.

And in both mice and humans, the key to preventing muscle loss may be stopping the production of a protein called myostatin. Myostatin is helpful to us on Earth, because it stops our muscles from growing and growing and growing. But in space, it’d be handy to inhibit myostatin, at least a little bit, so that more muscle will grow. So, the crew will be taking mice up to the ISS and injecting them with an antibody that’s been shown to stop myostatin in mice on Earth. The hope is that the mice will be able to keep their muscles even while they’re in space.

The crew will also be trying out some new exercise equipment. See, the exercise machines that astronauts use now are pretty big and bulky, and take up lots of the limited space on the ISS. NASA hopes to shrink down the exercise equipment with the new Miniature Exercise Device II -- or MED-2, for short. It’s basically a small and light rowing machine, with a motor that resists the astronaut’s pull. It can also be used to simulate a deadlift. And it’s pretty tiny, as exercise machines go. Expedition 47 ends in June, but all three crew members will stay on for Expedition 48 -- and the new series of experiments that will come with it -- until they come back to Earth in September.

Meanwhile, it’s been more than 8 months since New Horizons flew past Pluto, and we’re still learning new things from the images we’re getting back. Like last week, when NASA released a photo of one of Pluto’s mountain ranges, capped with methane ice. The image shows the bright peaks of a 400-kilometer-long mountain range in a dark red region known as Cthulhu. And these peaks might look like fresh fluffy snow, but based on the way they absorb infrared light, we can tell that they’re actually methane.

Like water on Earth, the methane on Pluto condenses and freezes at high altitudes, forming methane ice. And we’ve been finding the stuff all over Pluto. Take a look at a picture, for example, of an area known as the Tartarus Dorsa region. Pluto’s surface looks all steep and scaly, with crack and cliffs hundreds of meters deep -- and those bumps are mostly made of methane, with a little bit of water.

Which is weird. From what we know about methane, it should be too -- well, mushy -- to make such sharp cliffs. In fact, Pluto’s gravity should be able to squish these structures down flat in just a few decades. So it’s possible that this isn’t just regular methane. Instead, the methane might have combined with the water to create what’s known as a clathrate.

A clathrate is basically a cage, where one molecule surrounds another -- and in this case, astronomers think there might be water surrounding the methane. We haven’t directly observed clathrates on Pluto, but we do know that they’d be strong and stable enough to form Pluto’s steep cliffs.

The clathrates would’ve formed very early in the solar system’s history, when it was a disk of gas and dust that was just starting to cool. Astronomers think that there are methane clathrates all over the solar system, and they may have been some of the main building blocks of comets and other icy worlds. So by studying these molecule cages, we might be able to learn more about what it’s like on Pluto -- and about how the solar system formed.

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