Tag: apod

Astronomical crowdsourcing and Hanny’s Voorwerp

I once heard an interesting story about a group of scientists that had written some improbably small thing on a metal platter, something like the IBM logo written in individual xenon atoms. And here’s what they learned: it was easy enough to write something tiny, but having written it, it took them several hours to find it again so they could image it for their press release. I love the idea of something being lost at the nano scale. It may be just at the tip of my tongue, but if it’s only a few angstroms wide, it’s as good as gone.

There’s a similar problem with astronomy research. We have, via programs like the Sloan Digital Sky Survey, imagery that packs 120 megapixels into 1.5 square degrees of sky. How do you find the good stuff? If you can teach a computer to find good stuff, that’s great, but if not, you’ve got a real problem. That’s where the Galaxy Zoo project comes in. Web-organized volunteers are helping to classify galaxies, something that is, apparently, still very difficult for computers to get right. And every now and then people like the Dutch schoolteacher Hanny van Arkel find weird stuff that you can’t tell a computer to look for anyway, precisely because it’s unexpected. This is Hanny’s Voorwerp

I love the fact that there’s a green goblin in the sky named after a Dutch schoolteacher and volunteer astronomer. Also, it’s fun to learn what voorwerp means in Dutch.

Two faces of a moon

“Japetus is unique in the Solar System—you know this already, of course, but like all the astronomers of the last three hundred years, you’ve probably given it little thought. So let me remind you that Cassini—who discovered Japetus in 1671—also observed that it was six times brighter on one side of its orbit than the other.

“This is an extraordinary ratio, and there has never been a satisfactory explanation for it. Japetus is so small – about eight hundred miles in diameter—that even in the lunar telescopes its disk is barely visible. But there seems to be a brilliant, curiously symmetrical spot on one face, and this may be connected with TMA-1. I sometimes think that Japetus has been flashing at us like a cosmic heliograph for three hundred years, and we’ve been too stupid to understand its message.”

Arthur C. Clarke gave these words to his fictitious astronomer Heywood Floyd near the climax of his book 2001: A Space Odyssey. Like a lot of people, I read those words years ago and thought to myself: what is the dang deal with Japetus? Clarke wasn’t making up the part about the two-faced nature of Iapetus (as it is more commonly called), an oddball Saturnian moon.

The two-toned satellite is still mysterious, but now we have some quality snapshots from the visiting Cassini spacecraft. And, hoo boy! they do not disappoint. I find this APOD picture astounding: The Strange Trailing Side of Saturn’s Iapetus. Great Clarke! Look in the sky! It’s a cosmic snowball rolled in dirt… it’s a sugar-frosted chocolate space truffle… it’s… it’s a much better investment than the International Space Station. You know what we need? I’ll tell you what we need: more space robots with cameras and fewer accident-prone gold-plated Tang-sucking astro-cosmo-taikonauts.

Come fly with me

More joys of the Astronomy Picture of the Day, a.k.a. APOD. I think this must be one of the best (and most cost effective) public relations efforts ever managed by NASA. I used to work at NASA Ames Research Center, and I remember how important PR was, given their steady diet of taxpayer’s cash. It’s a good arrangement… I want to see cool space pictures, and NASA wants to show them to me for free. Last week APOD featured this: Liftoff With the Space Shuttle, which led me to a bonanza of online video here: STS – 112 Video Index (which is to say, videos from space shuttle mission 112, the most recent one). I really must insist that you take the time to download the movie that shows the view looking down from the external fuel tank as the shuttle takes off. You get an unbroken visual record as the shuttle moves steadily from one world to the next. First there is the familiar view as from an airplane of grasslands, beach, and ocean. Then after only 90 seconds (17 miles high! 2800 miles per hour!) the scene has become a view from space, with tiny clotted splotches of cloud painted flat against a dim Florida coastline. The last frame seen from this camera shows the soft curvature of the earth clearly highlighted against the black void beyond.

Before I leave the topic of APOD, I have to mention another title that caught my eye: October 24 – Gullies on Mars. Since my last name is Gulley, you can imagine I looked long and hard for a peek at my Martian cousins, but to no avail. Still, if their house is somewhere in the picture, they must have a marvelous view from their back yard.