NASA 美国宇航局的每日一图 3月份
发布: 2009-1-14 17:53 | 作者: webmaster | 来源: 本站原创 | 查看: 171次
2008 March 26 
影像提供: FORS Team, 8.2-meter VLT Antu, ESO
说明: 恒星都跑到那儿去了？以前我们认为它是天空中的一个洞，现在则知道它是个暗分子云。 在这个分子云中，高密度的尘埃和分子云气几乎完全挡住了背景恒星所发出的可见光。 这个诡异暗分子云的内部，可能是宇宙中最阴冷且最孤独的地方之一。 上面这张照片里的星云是位于蛇夫座的巴纳德68，它是最著名的暗星云之一。 在星云的中心附近完全看不到任何的恒星，显示巴纳德68离我们不远，量测结果认为它离我们约有五百光年远，大小约有半光年。 我们现在还不是很清楚像巴纳德68这种分子云是如何形成的，但我们知道它们很可能是新恒星将形成的地方。我们可以用红外光透视这类云气，一窥星云内部的状态。
Explanation: An intriguing and beautiful nebula, NGC 3576 drifts through the Sagittarius arm of our spiral Milky Way Galaxy. Within the region, episodes of star formation are thought to contribute to the complex and suggestive shapes. Powerful winds from the nebula's embedded, young, massive stars shape the looping filaments. The dramatic false-color image also highlights the contributions of hydrogen, sulfur, and oxygen, energized by intense ultraviolet radiation, to the nebular glow. But the glow also silhouettes dense clouds of dust and gas. For example, the two condensing dark clouds near the top of the picture offer potential sites for the formation of new stars. NGC 3576 itself is about 100 light-years across and 9,000 light-years away in the southern constellation of Carina, not far on the sky from the famous Eta Carinae Nebula. Near the left edge of the picture is NGC 3603, a much larger but more distant star forming region.
Explanation: An intriguing and beautiful nebula, NGC 3576 drifts through the Sagittarius arm of our spiral Milky Way Galaxy. Within the region, episodes of star formation are thought to contribute to the complex and suggestive shapes. Powerful winds from the nebula's embedded, young, massive stars shape the looping filaments. The dramatic false-color image also highlights the contributions of hydrogen, sulfur, and oxygen, energized by intense ultraviolet radiation, to the nebular glow. But the glow also silhouettes dense clouds of dust and gas. For example, the two condensing dark clouds near the top of the picture offer potential sites for the formation of new stars. NGC 3576 itself is about 100 light-years across and 9,000 light-years away in the southern constellation of Carina, not far on the sky from the famous Eta Carinae Nebula. Near the left edge of the picture is NGC 3603, a much larger but more distant star forming region.
