New Horizons for Pluto

Pluto and CharonThere is exciting Pluto news. Joseph Stromberg over at Vox reported, NASA’s New Horizons Probe Is Visiting Pluto — and Just Sent Back Its First Color Photos. New Horizons left Earth in 2006 and will come within one Earth diameter to Pluto on 14 July. This is very cool, because we really know almost nothing about this bit of solar system debris that many people like to call a planet. In fact, that image on the left is the best picture we’ve ever taken of the little bugger and its biggest moon, Charon. But over the next three months, the images are going to get better and better.

I’ve long been of the opinion that we make far too big a deal of Pluto. When I used to teach astronomy, I would compare it to asteroids and show that there was really nothing that distinguished it from asteroids. But now it just seems to be a notable object in the Kuiper belt — although not even the most massive of the ones we know about. As I said: solar system debris. But that doesn’t mean it isn’t cool. I now find the little stuff orbiting the sun to be the most interesting part of astronomy. It really does allow us to look way back in time.

Of course, the bigger of space debris are less interesting. Anything large enough to become spherical — Eris, 2060 Chiron, 1 Ceres — have their own internal environments. In fact, it is speculated that Pluto might have volcanic activity. I’m sure that (as is usual for these things) there will be complete surprises. As I said, we know so little about this dwarf planet that it could hardly be otherwise. But over the past forty years of unmanned space exploration, we’ve really had to change how we look at the solar system. It is not as we once thought. But that’s even true of the Earth itself.

In addition to imaging devices, New Horizons has other equipment. In particular, the probe will be looking at the gases escaping from the surface of Pluto. The planet is ridiculously cold: between 33 K and 55 K. Even at that upper temperature, nitrogen is a solid. But small amounts of it sublimates to create an incredibly thin atmosphere (roughly one-half-millionth of the Earth’s surface pressure). This atmosphere also contains methane and carbon monoxide. Methane has long been thought to be a marker of life, but we’ve found so much of it in the solar system, I’m not sure what that means anymore. Regardless, it would be hard to imagine life on Pluto, but I wouldn’t rule anything out. Regardless, we should know a lot more in the coming months.

After it flies by Pluto, New Horizons is going to continue on further out into the Kuiper belt. The investigators have not settled on which object they are going to head toward. But this is a very exciting time. In fact, this is certainly the best time yet for astronomy. The advances in our knowledge brought on by terrestrial telescopes really don’t compare to what we are learning today. And it just gets all the more amazing. We know so much more today than we knew just twenty years ago when I was teaching this stuff. Stay tuned!

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