Up until a couple of days ago we were shivering under some pretty cold temps up here in New England. The other night we took the trash out and it was about 10 below zero (F)—cold enough to literally take your breath away. The sky was quite clear that night, and the stars were stunningly beautiful. Mars was like a red beacon…The next day I walked out to get the mail and noticed the ice in the driveway. It reminded me of pictures I’d seen of ice fields on the worlds of the outer solar system. Out there ice doesn’t so much melt off the surfaces of those worlds, but it sublimates—it turns from ice crystals into a gas without going through that pesky liquid phase we see here on Earth.
Oh, there is liquid water out there at the outer worlds. At least, that’s the working hypothesis deduced from various observations. And, how else do you explain what looks like deposits of fresh ice that have somehow oozed up through cracks on the surfaces of places like Enceladus, Europa and Pluto’s moon Charon? It’s only a matter of time before the existence of all those cold oceans are confirmed. And, when I read about them, I can certainly sympathize with the idea of cold—especially after the bitterly cold weather we had last week. However, I am reminded that 10 below zero here on Earth would be a pretty warm day on Mars or Enceladus or Tethys or Pluto or Charon— so we have it pretty good here at home.
Speaking of cold and ice and outer solar system, here’s the latest installment of my ongoing vodcast series. It features an observation made at Gemini Observatory that I wrote about a few months ago, and an image I worked on with the PR folks at Gemini. Come on—let’s go visit some ice worlds!
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Ever hear of 2007 WD5? It’s all over the news right now, so I’m probably not telling you anything new about it, but just in case you’ve been out holiday shopping or traveling or hiding under a rock, here’s the scoop. 2007 WD5 is a 164-foot-wide asteroid that is moving in an orbit that will cross Mars’s orbital path in late January. It comes close enough to Mars that it will pass within 30,000 miles (48,000 kilometers) of the planet. It’s possible, although not likely, that this thing could actually smack into Mars’s surface. The chances are about 1 in 75. If it did, this rock (traveling at 30,000 miles per hour) would dig out a crater about the same size as the one that the Opportunity rover is exploring right now.
Victoria Crater on Mars
Over the next few weeks astronomers will get a better idea of the asteroid’s orbit and whether it will actually hit Mars or sail on by. You can follow the action by visiting NASA’s Near Earth Object Program web page for updates.
