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  3. Two teams of astronomers using the Hubble Space Telescope have overturned several decades of conjecture and theory by ruling out

Two teams of astronomers using the Hubble Space Telescope have overturned several decades of conjecture and theory by ruling out

admin2013-11-29  89
问题     Two teams of astronomers using the Hubble Space Telescope have overturned several decades of conjecture and theory by ruling out the possibility that small, dim stars make up most of the mass in the universe.
    Until now, small stars known as faint red dwarfs were considered ideal candidates for the so-called "dark matter" that is believed to account for more than 90 percent of the mass of the universe.
    All visible celestial objects, such as planets, stars and galaxies, are believed to account for only 10 percent of the mass of the universe. The rest of the "missing mass" is presumably invisible because it does not emit or reflect light, or the light is too feeble to be detected. But dark matter can be indirectly detected due to its gravitational influence on other visible objects.
    According to Bacall, professor of natural science at the Institute of Advanced Study in Princeton, New Jersey and leader of one of the teams, the nature of dark matter, and its abundance, are among the most important questions in modern cosmology today.
    The ultimate fate of the universe will be determined by the amount of dark matter present If there is not enough dark matter to bind the universe together gravitationally, it could continue expanding forever. If there is enough mass to hold the universe together gravitationally, the universe may slow down its expansion, come to a halt and begin to contract and eventually collapse.
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答案 两个天文学家小组用哈勃太空望远镜排除了宇宙暗弱的小行星构成宇宙主要质量的可能性，从而推翻了几十年来的推测和理论。 到现在为止，被称为淡红矮星的小星体一直被认为是所谓的“暗物质”的理想物质。天文学家认为，整个宇宙的百分之九十都是由这种暗物质构成的。 天文学家认为，行星、恒星和银河之类的所有可以看得见的天体只是构成了宇宙质量的百分之十左右。其他的“隐形质量”是不可见的，由于它们不自己发光，也不反射光，或者是发出的光太微弱，因而无法被探测到。但是由于暗物质对其他可见天体有引力作用，因此可以间接被检测到。 巴考尔是新泽西州普林斯顿高级研究所的自然科学的教授，也是两组天文学家中其中一组的学科带头人。按照他的说法。关于暗物质的本质和存在丰富性的讨论，是当代天文学上的重要研究课题之一。 宇宙的最终命运将由存在的暗物质的量来决定。如果没有足够的暗物质通过引力作用将宇宙粘合在一起的话，宇宙就会永远不停地膨胀。然而，如果能有足够的质量通过引力作用把宇宙拉合在一起的话，宇宙就有可能减速并停止膨胀，并开始收缩，并最终坍缩。
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