Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, July 7, 1994 TAG: 9407070127
SECTION: NATIONAL/INTERNATIONAL PAGE: A6 EDITION: METRO
SOURCE: Associated Press
DATELINE: LENGTH: Medium
If scientists really have detected the ``intergalactic medium,'' as the gas is known, it would be the culmination of a search that began more than 30 years ago.
The Hubble found gas that is older than most of the stars, and the discovery provides more confirmation of the big-bang theory and new clues about the early history of the universe.
The finding is reported in today'sThursday's issue of the journal Nature by Peter Jakobsen, a scientist at the European Space Agency in Noorwijk, the Netherlands, with colleagues in England, France and the Space Telescope Science Institute in Baltimore.
The Hubble telescope observed the gas as it existed when the universe was only about 2 billion years old, compared with its estimated current age of 15 billion years, Jakobsen said. That is because the gas is so far away that light from it took a very long time to reach the Hubble.
The gas is 13 billion light-years away in the direction of the constellation Cetus. A light-year is the distance light travels in one year, or about 5.9 trillion miles.
Observations showed that the ancient gas contained helium, which corroborates the big-bang theory, Jakobsen said in a telephone interview. The theory says the helium was produced along with hydrogen in the first three minutes after big bang, the instant when the universe burst forth from a single point and began its expansion.
Helium atoms in the gas had been stripped of one of their two electrons, suggesting they had been blasted with ultraviolet radiation, Jakobsen said.
John Bahcall, a professor of natural science at the Institute for Advanced Study in Princeton, N.J., called the discovery ``very exciting for me. I can't imagine an astronomer alive who won't be excited by this.''
It will ``help us figure out ... the puzzle of how the galaxies, and therefore how we, got here,'' he said.
Bahcall said, however, he was not convinced that the newfound gas was really from the long-sought diffuse intergalactic medium, rather than from ancient clouds. Jakobsen said the Hubble found more helium than could easily be explained by the presence of known clouds.
The scientists detected the gas with the help of a quasar, a powerful celestial source of light, on the other side of the gas. Light from the quasar comes in a mixture of wavelengths, and as it passed through the gas, the helium absorbed light of certain wavelengths. So light reaching the Hubble was deficient in those wavelengths, revealing helium's presence.
by CNB