Science: Background radiation deepens the confusion for big bang theorists

日期:2019-02-26 01:07:10 作者:皇杞愤 阅读:

By CHRIS VAUGHAN in WASHINGTON DC THE LATEST results from NASA’s Cosmic Background Explorer (COBE) satellite are continuing to mystify astronomers. They show that the matter of the early Universe was spread so smoothly that it is difficult to understand how galaxies and clusters of galaxies could have formed (New Scientist, Science, 19 December). Astronomers presented the results last week at a meeting of the American Physical Society in Washington DC. Although the results confirm those released earlier, they are from observations of the whole sky rather than from just a small portion (This Week, 20 January). COBE was launched earlier this year to observe the cosmic background radiation, the remnant radiation of the big bang in which the Universe was born 15 billion years ago. The radiation was created a mere 300 000 years after the big bang. By determining how smoothly that radiation is distributed across the sky we can learn how smoothly matter was distributed at that epoch. ‘These measurements are more and more puzzling,’ says Michael Hauser of the NASA-Goddard Space Flight Center. The COBE data show that 300 000 years after the big bang, the matter of the Universe had a density uniform to one part in 10 000. Many of the scientists at the meeting expressed concern that many accepted theories of galaxy formation will have to go if the data build up and continue to show there is no variation in the background radiation. Galaxies could only have condensed from the stuff of the big bang if it was lumpy. ‘We will be surprised if we don’t start seeing wiggles at the level of one part in 100 000 of accuracy,’ said David Wilkinson of Princeton University. ‘If COBE gets to (one part in a million) and still sees things smooth big bang theories will be in a lot of trouble.’ According to George Smoot of the University of California, Berkeley, the data from COBE are really more accurate than one part in 10 000, but the scientists are not revealing these data until they have a chance to correct for any systematic errors. They hinted, however,