charles 2009-3-23 10:25
紅外線波段 <<銀河中心>>
The Galactic Center in Infrared
[img]http://i13.tinypic.com/2vnj4oj.jpg[/img]
Credit: 2MASS Project, UMass, IPAC/Caltech, NSF, NASA
[color=navy]Explanation:[/color]
The center of our Galaxy is a busy place. In visible light, much of the Galactic Center is obscured by opaque dust. In infrared light, however, dust glows more and obscures less, allowing nearly one million stars to be recorded in the above photograph. The Galactic Center itself appears on the right and is located about 30,000 light years away towards the constellation of Sagittarius. The Galactic Plane of our Milky Way Galaxy, the plane in which the Sun orbits, is identifiable by the dark diagonal dust lane. The absorbing dust grains are created in the atmospheres of cool red-giant stars and grow in molecular clouds. The region directly surrounding the Galactic Center glows brightly in radio and high-energy radiation, and is thought to house a large black hole.
[color=navy]說明:[/color]
我們銀河系的中心是個很忙碌的地方。在可見光波段，銀河中心受到塵埃的遮掩，基本上是不得見。不過在紅外光波段，塵埃變得較明亮且較透明，所以上面這幅影像能夠記錄將近一百萬顆恆星。銀河中心位在影像右端的半人馬座內，距離我們約有三萬光年遠。我們銀河系的盤面，同時也是太陽公轉軌道所在的平面，是斜貫過影像的黝黑塵埃帶。會吸收可見光的塵埃微粒是在低溫紅巨星的大氣中形成的，在分子雲內它們會逐漸增大。銀河中心周圍的區域在電波波段很明亮，而且也會發射強烈的高能量輻射，咸信其成因是中心的大黑洞。
[size=2]資料來源: Scientific American
Department of Physics, NCKU[/size]