Friday, October 17, 2008

Our Vast Universe

For eight years astronomer Dan Long and his colleagues have been mapping the universe in the most comprehensive effort of its kind to date. The Sloan survey, as it is called, has brought order to the universe in terms of understanding what is out there and where it is. The numbers boggle the mind:
In its five terabytes of data are 217 million individual objects, including 800,000 galaxies (which themselves contain billions of stars and planets) and 100,000 quasars, objects once so rare and strange that they weren't detected until 1962.
What have they learned about the universe that they didn't already know? Apparently not much:

Despite all the Sloan discoveries, none has challenged the prevailing theories about how the universe got started and how it operates today, he said. Could it be that humankind actually understands the structure of the universe? Or could all the labor and thought behind Sloan still be too primitive to pierce the real mysteries of the cosmos?

The questions haunt him. "We discovered lots of things, but I don't think we found much that we didn't expect," he said. "I'm not sure what that says."

Somehow I doubt that we understand very much yet.

(Photo: X-ray (left) and Optical (right) Images of Veiled Black Hole. The left hand panel shows the Chandra X-ray Observatory image of a powerful point-like source of X rays. The Hubble Space Telescope image (right panel) shows the spiral galaxy with which the X-ray source is associated. The X-ray source is located at the center of the galaxy, and has a deficit of low energy X rays, consistent with absorption by a thick cloud of gas. The combination of powerful X-ray emission, absorption of low energy X-rays, and the relatively normal optical appearance of the galaxy suggests that the source is a rare type of black hole called a Type 2 quasar.)

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