慧星上发现水 宇宙可能有生命，本文主要内容关键词为：慧星论文,宇宙论文,生命论文,发现论文，此文献不代表本站观点，内容供学术参考，文章仅供参考阅读下载。
Comets orbiting a distant star have been found to containwater,the first time the ingreclient considered key to lifehas been discovered in objects circling a star other than our sun.
The discovery,announced by scientists,adds weight to thetheory that other planetary systems may be similar to our ownand may contain chemicals that are essential to the formationof life as we know it.
Scientists have no way of knowing whether life ever existed onany comets or planets orbiting this particular star,known asCW Leonis and located some 3,000 trillion miles (4,800trillion kilometers)from Earth in the constellation Leo.
But they are certain that no life could exist there now.Thatis because as it burns out the last of its nuclear fuel,thestar has swelled and increased in luminosity,engulfing nearbyobjects and melting comets in orbits as distant as Neptune isfrom the sun- - releasing the water that astronomers spottedusing a radio telescope in other space.
"Ironically,the existence of these bodies is measured throughtheir destruction,"said Gary Melnick,chief scientist on the project and an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridger,Massachusetts.
Mr.Melnick said the discovery was of particular importance because if there was a reservoir of water farther from the star,there could have been water closer to the star,bolstering the idea that life may have existed outside our solar system.Comets are believed to have helped build life on Earth,Mr.Melniek and other scientists said.Besides bringing water to the oceans,they are also thought to have transported important chemicals as they hurtled through Earth's atmosphere in past eons.
"Comets are some of the smaller bodies in the solar system and form the seeds of planets themselves,"said Saavik Ford,a graduate student at Johns Hopkins University who initially suggested that the water may have come from evaporating comets."The fact that we found water is interesting because it is a necessary prerequisite for the formation of life."
［参考译文］最近，在围绕一颗遥远恒星运行的彗星上发现了水，这是首次在太阳以外的恒星周围物体上发现这种对生命有重要意义的物质。
科学家宣布了这一发现，使下述论述更具重要性，即其他星系很可能和我们的太阳系相像，可能含有我们已知的对生命组成有重要意义的化学物质。
该恒星是狮子座的CW星，距地球大约3000万亿英里（4800万亿公里），科学家还无法知道在这颗恒星周围运行的彗星和行星上是否曾经有生命存在。
但是他们可以确定的是该恒星现在不可能有生命存在。原因是当该恒星燃烧尽核燃料时，星体膨胀而且发光度增大，吞没周围物体，同时熔化与之距离像海王星和太阳那么远的轨道上的彗星，从而释放了水，这是天文学家用射电望远镜在太空中观测到的。
该项目的主管科学家格雷·墨尼克说：“具有讽刺意味的是，这些物体毁灭了才推测出它们存在过。”他是在麻省坎布里奇市哈佛史密森天体物理学中心工作的天文学者。
他说该发现有重大的意义，因为如果在距该恒星较远的地方有水储存，那么在距该恒星比较近的地方很可能也有过水的存在，从而支持了太阳系以外可能有生命存在的推断。墨尼克先生和其他的科学家还说彗星被认为是帮助地球产生生命的因素之一。人们认为远古时彗星通过地球大气层除了为海洋带来了水，也给地球带来了重要的化学物质。
沙维克·福德说：“彗星是太阳系中较小的天体，它们也是形成行星的根源。”他是约翰·霍普金斯大学的研究生，最早提出水有可能来源于蒸发的彗星。他说：“发现水这一事实很有意义，因为水是生命构成的一个必要的先决条件。”