Half of Universe's Missing Matter Found

Researchers used the light from 28 qasars, the brilliant hearts of distant galaxies which still have a black hole at their center, in order to illuminate these structures, a bit like torches shining on fog.

Using the space telescope imaging spectograph on board the Hubble and NASA's far ultraviolet spectroscopic explorer (FUSE), they found hot gas and spectral "fingerprints" of intervening oxygen and hydrogen superimposed on the light from the qasars.

Probing this cosmic web of normal matter will be a task taken on by the new Cosmic Origins Spectograph (COS), due to be installed on the Hubble later this year.

"We predict that COS will find considerably more of the missing baryonic matter," said Shull.

"Our goal is to confirm the existence of the cosmic web by mapping its structure, measuring the amount of heavy metals found in it, and measuring its temperature. Studying the cosmic web gives us information on how galaxies built up over time."

Related Links:

Discovery News blog: Free Space

NASA on Baryons

Cosmic Origins Spectograph

How Stuff Works: Stars