pretty as a picture

I've been into astronomy since elementary school, and the geek in me loves artwork like this:

But the dirty little secret of such NASA publicity stills is that space just isn't that photogenic. Even gorgeous telescope images—as opposed to artists' conceptions like the one above—often are not quite what they seem. Here, for instance, is one from the Spitzer Space Telescope, which figures prominently in the same NASA news release. (Note that both images are clickable.)

If somehow you were in a spaceship, close enough to the region pictured so that it occupied a good chunk of your field of vision, you would see nothing like this: Spitzer is an infrared telescope (indeed, its earlier name was SIRTF, the Space Infrared Telescope Facility). What shows in the image above as reddish/purplish is emission from hydrogen, though in actuality it is at wavelengths too long for human eyes to detect. In photographs such hydrogen emission is customarily (though falsely) represented in this fashion, most likely because one particular hydrogen emission wavelength—the H-alpha line—does fall in the visible spectrum, and is a most dramatic shade of red.

Some recent entries notwithstanding, this isn't a photoblog, and it's not as if these sorts of images are in short supply (NASA's Astronomy Picture of the Day is the best archive). So why this post?

Well, mostly because it isn't everyday that I see one of my former profs interviewed for Reuters.

The youngest planet ever detected — a baby less than 1 million years old — may have been discovered by NASA's Spitzer Space Telescope, scientists reported on Thursday.

The possible infant planet was spotted circling a star known as CoKu Tau 4, some 420 light-years away in the constellation Taurus, according to astronomer Dan Watson of the University of Rochester, New York.

A light-year is about 6 trillion miles, the distance light travels in a year.

Researchers have identified more than 100 so-called extrasolar planets — those found outside our solar system — but generally these objects were thought to be a billion years old or more. Earth and its immediate planetary neighbors are all about 4.5 billion years old, well into middle age.

This possible planet was detected by examining the dusty disk around the star CoKu Tau 4, where scientists found a donut-like hole in the dust. The putative planet may have formed by scooping together this dust, scientists said at a briefing at NASA headquarters.

“The object is only a million years old,” Watson said. “That probably makes it the youngest planet that we've ever seen, and young enough that it really causes problems for the major theories of planetary formation.”

If you can handle a bit more astro technobabble, the official Spitzer press release is here. One highlight:

“Preliminary data suggest that all 300 or more stars harbor discs, but so far we've only looked closely at two. Both were found to have discs,” said Dr. Ed Churchwell of the University of Wisconsin, Madison, Wis., principal investigator of the RCW 49 research, with Dr. Barbara Whitney of Space Science Institute, Boulder, Colo.

Planet-forming, or “protoplanetary,” discs are a natural phase in a star's life. A star is born inside a dense envelope of gas and dust. Within this envelope, and circling the star, is a flat, dusty disc, where planets are born.

“By seeing what's behind the dust, Spitzer has shown us star and planet formation is a very active process in our galaxy,” Churchwell said.

My physics master's thesis was on angular momentum transfer in protostellar accretion discs, which become protoplanetary once the central star begins hydrogen fusion. That was in the mid-90s, when the first indirect observations of planetary systems were still controversial.

Things have certainly progressed in the few years since.

but the colors are nice!