The Really Big Picture

By Kathy A. Svitil|Saturday, September 01, 2001

If you want to know where you are and how you got there, you need a map. Taking that logic to a cosmic extreme, two astronomy collaborations are conducting the deepest-ever sky surveys. Both recently released their first major results.

The universe is lumpy. Astronomers with the Two-degree Field (2dF) Galaxy Redshift Survey, carried out at the Anglo-Australian Observatory in New South Wales, found that quasars and galaxies are unevenly spread across the sky. The pattern appears to be a relic of the way matter and radiation linked together immediately after the Big Bang. "The interaction produced oscillations in the density of matter, which we now detect in the distribution of galaxies," says 2dF coleader Matthew Colless of the Australian National University.

Galaxies attract. The 2dF team also measured the locations of 100,000 galaxies and found them falling toward each other even when separated by as much as 75 million light-years. That motion demonstrates how gravity built up the biggest structures in the universe.

Galaxies formed early. The Sloan Digital Sky Survey, an $80 million effort at New Mexico's Apache Point Observatory, detected a quasar 13 billion light-years from Earth. It was shining when the universe was about 800 million years old. "Quasars are black holes at the centers of galaxies, so this tells us galaxies were already forming at that time," says Xiaohui Fan of the Institute for Advanced Study in Princeton, New Jersey.

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