Are you mad that we called Pluto a planet? Did you click just because you were mad that we called Pluto a planet? We don’t think Pluto is a planet, we think it’s a dwarf planet. But we also think that dwarf planets are a kind of planet, so sometimes we drop the dwarf for brevity. It’s okay. Breathe in and out.
Wait, now you’re mad that we don’t think it’s a planet? Are you sure? Okay. That’s fine. We can agree to disagree. Now on with the post.
Pluto is one weird little world, that’s for sure. NASA’s New Horizons team has been openly giddy ever since the first results from July’s flyby started pouring in. There’s still months of data left to downlink back to Earth — and perhaps even a new target for the New Horizons spacecraft to reach in a few years — but scientists are starting to present some real, solid findings based on the initial results.
We’ve already heard lots of “flyby science” — the kinds of things the team felt comfortable speculating about immediately, as data first came in — but we’ve only had a few formally published papers highlighting research that’s been fully chewed up and digested.
In Thursday’s issue of Science, a whopping five new studies dropped to remind us just how crazy the results from New Horizons have been. Here are the highlights:
The first paper outlines some of the team’s first findings on Pluto’s atmosphere. “For several decades, telescopic observations have shown that Pluto has a complex and intriguing atmosphere. But too little has been known to allow a complete understanding of its global structure and evolution,” the authors write in the study. Not anymore.
It turns out that Pluto’s nitrogen-rich atmosphere leaks into space much, much slower than scientists had previously assumed. Some mechanism — scientists aren’t sure what — is keeping the atmosphere dense and cool, which has allowed Pluto to maintain its neat icy geological structures.
“It’s always fun to have your models validated, but it is way more fun to have them trashed,” lead author Randy Gladstone of the Southwest Research Institute told the Los Angeles Times. “Finding out you are completely wrong is a great part of science.”
Ugh, Pluto and Charon. Bae 1 and bae 2. Scientists already knew that Pluto and its largest moon had a weird relationship: At half Pluto’s size, Charon is the largest moon in the solar system relative to its host planet. And the pair twirl around a fixed point, locked toward each other, like ice dancers spinning — as opposed to the more typical orbital routine, where a moon orbits around the planet itself.
Initial results indicated that Charon was a surprisingly compelling little world in its own right — not just a crater-pocked rock that had been battered around as it clung to Pluto’s apron strings.
In the latest study on the pair, researchers analyzing the composition of each world’s surface ice suggest that Charon was once quite active but ran out of juice about 2 billion years back. The geological processes that once resurfaced the moon with canyons and peaks slowed as the body cooled down.
“Unlike Pluto, Charon’s surface is quite old and uniform. It’s covered with water ice with low amounts of ammonia mixed in, and is not as geologically active as Pluto,” SETI Institute scientist Cristina Dalle Ore, an author on the paper, said in a statement.
It’s possible that Charon’s fractured surface — part of it seems recently resurfaced, while the other is old and jagged — is due to a liquid ocean that busted out of its core as it froze, slicking down a clean layer of ice where it hit.
The study doesn’t announce any crazy new features on Pluto — we’ve seen these canyons and planes and glacial flows before. But the big takeaway is just how much variation there is. Some parts of the surface have been unchanged for ages, but others seem relatively recently renovated.
Pluto is host to a whole bunch of molecules that spend most of their time on Earth as gasses. When the temperature gets dialed down low enough for methane, carbon monoxide and nitrogen to become ice, things get weird. We’re finally seeing how all of those elements interact at that temperature.
“The expectation all along was that these things [molecules] would be there, but I think people didn’t really put one and one together and realize how these two different classes of materials could work together to create active geology even at really, really low temperatures,” study author Will Grundy told Mashable.
Some of the scientists are even suggesting that Pluto could maintain a liquid ocean under its surface, as we now know that many icy moons in our solar system do — but for now, this is pretty much pure speculation.
Here come the babies! We’ve reported before these little moons are super wonky, and now scientists have confirmed it.
Hydra, what are you even doing.
Scientists assumed that Styx, Nix, Kerberos and Hydra had formed at the same time Charon did — probably in the midst of some major collision.
“Consequently, we expected the small moons to resemble Charon,” study author Mark Showalter, senior scientist at the SETI Institute, said in a statement. “Instead, we find that their surfaces are much brighter and much older than that of their large sibling.”
That doesn’t necessarily discount the idea that a single collision produced all of the moons, and other evidence points toward that scenario. But it does suggest that something went differently for Charon than it did for the smaller guys. Their orbits are also a little special, and scientists aren’t totally sure what’s messing them up.
According to the last study of the bunch, Pluto barely interacts with solar wind — the high-energy particles jettisoned into space by our sun.
The same study used data from a student-built dust counter to look for signs of debris left over from collisions with Pluto or its moons — but the area is pretty pristine.
“The bottom line is that space is mostly empty,” study author and CU-Boulder Professor Fran Bagenal said in a statement. “Any debris created when Pluto’s moons were captured or created during impacts has long since been removed by planetary processes.”
There’s a lot left to learn from Pluto. Heck, there’s a lot of data left to download! But these papers already make it abundantly clear that it was a world worth visiting.