出处:http://www.sai.msu.su/apod/ap080606.html
Two-Armed Spiral Milky Way
Illustration Credit: R. Hurt (SSC), JPL-Caltech, NASA
Survey Credit: GLIMPSE Explanation: Gazing out from within the Milky Way, our own galaxy's true structure is difficult to discern. But an ambitious survey effort with the Spitzer Space Telescope now offers convincing evidence that we live in a large galaxy distinguished by two main spiral arms (the Scutum-Centaurus and Perseus arms) emerging from the ends of a large central bar. In fact, from a vantage point that viewed our galaxy face-on, astronomers in distant galaxies would likely see the Milky Way as a two-armed barred spiral similar to this artist's illustration. Previous investigations have identified a smaller central barred structure and four spiral arms. Astronomers still place the Sun about a third of the way in from the Milky Way's outer edge, in a minor arm called the Orion Spur. To locate the Sun and identify the Milky Way's newly mapped features, just place your cursor over the image.
译文来源:
http://www.bjp.org.cn/apod/2008-06/06/content_8541.htm
说明:从银河系内往外看,很难辨认我们银河系的真实结构。但是,斯皮策太空望远镜的巡天计划,提供了一项令人信服的证据,那就是我们处于一个巨大旋涡星系内,其内有两条主要的旋臂(长形盾-半人马臂和英仙臂),出现在巨大的中央旋棒的末端。事实上,如果天文学家从一个有利的位置朝我们银河系观看,那么从遥远星系上看到我们银河系是一个具有两条旋臂的棒旋星系,就像这张艺术家的插图一样。先前的调查确认银河系具有一个较小的中央棒状结构及四条旋臂。天文学家仍然将太阳定位在从银河系外边缘进入内部的1/3位置上,也就是位于被称为猎户座的小旋臂上。为了定位太阳以及确认银河系内出现的新特征,就将你的鼠标上在影像上。
有标注大图下载,注:分卷压缩全部下载方可解压.
[ 本帖最后由 寻找拉玛 于 2008-6-6 18:52 编辑 ] |
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