Category Archives: Astronomy

07.22.10
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Where and how to look for extraterrestrial life?


The Benfords and a growing number of scientists involved in the hunt for extraterrestrial life advocate adjusting SETI receivers to maximize their ability to detect direct, broadband beacon blasts.

But where to look? The Benfords’ frugal-alien model points to our own Milky Way galaxy, especially the center, where 90 percent of its stars are clustered.

“The stars there are a billion years older than our sun, which suggests a greater possibility of contact with an advanced civilization than does pointing SETI receivers outward to the newer and less crowded edge of our galaxy,” Gregory Benford says.

07.20.10
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Lensing


According to Einstein’s general theory of relativity, if a large mass (such as a big galaxy or a cluster of galaxies) is placed along the line of sight to a distant galaxy, the part of the light that comes from the galaxy will split. Because of this, an observer on Earth will see two or more close images of the now-magnified background galaxy.

The first such gravitational lens was discovered in 1979, and produced an image of a distant quasar that was magnified and split by a foreground galaxy. Hundreds of cases of gravitationally lensed quasars are now known. But, until the current work, the reverse process — a background galaxy being lensed by the massive host galaxy of a foreground quasar — had never been detected.

Source: http://www.sciencedaily.com/releases/2010/07/100716085631.htm