Scientists find some of universe's missing matter

0 Comments | AFP, February, 2005

PARIS (AFP) — Some of the universe's missing "normal" matter has been found hiding in clouds of hot gas between galaxies, according to research published in the British scientific journal Nature.

Just five percent of the universe is believed to be made up of "normal" matter such as atoms and molecules, but scientists have only be able to find about half the expected amount.

Fabrizio Nicastro of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and his colleagues looked at X-rays from a distant quasar called Markarian 421 as they passed through a region of warm gas.

The X-rays were absorbed by ionized oxygen and nitrogen atoms there that are normally "invisible," and the scientists say there is enough matter in the gas to account...