Magazine article Science News

Galaxy Survey Shows That Color Matters. (Red Team, Blue Team)

Magazine article Science News

Galaxy Survey Shows That Color Matters. (Red Team, Blue Team)

Article excerpt

Using the largest survey of galaxies ever compiled, astronomers have found that the cosmos divides sharply along color lines. Old, red galaxies clump tightly, while young, blue ones are more spread out. Although the standard theory of galaxy formation predicts the same general trend, it permits a continuum, from very tight to very loose clustering. The survey, however, denies the middle ground.

There's no ready explanation for this great divide among galaxies, says Alex S. Szalay of Johns Hopkins University in Baltimore. His Johns Hopkins colleague Tamas Budavari presented the findings this week at a meeting of the American Astronomical Society in Nashville.

The astronomers have analyzed 2 million of the roughly 50 million galaxies observed so far by the Sloan Digital Sky Survey. The survey, which uses a telescope at Apache Point, N.M., is scheduled to view some 100 million galaxies over the northern sky by 2005.

According to theory, the very first galaxies condensed from regions in the early universe where the density of matter was the highest. This material consisted mainly of invisible, mystery material dubbed dark matter. As time went on and gravity continued to pull material together, more ratified regions of the universe also began to form galaxies.

The first galaxies, which condensed less than a billion years after the Big Bang, are now elderly. They appear red because they stopped forming stars long ago and the longest-lived stars radiate most of their light at red or infrared wavelengths. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.