本帖最后由 gohomeman1 于 2009-8-2 11:47 编辑
貌似中美海底光缆出问题了，或者是我国又对NASA主页在动手脚，反正当前的APOD慢得不得了。NASA图集索性过2天再更新吧。
http://apod.nasa.gov/apod/ap090801.html
2009 August 1
SN 1006 Supernova Remnant
Image Credit: NASA,ESA,Zolt Levay (STScI)
Explanation: A new star, likely the brightest supernovain recorded human history, lit up planet Earth's sky in the year 1006 AD.The expanding debris cloud from the stellar explosion,found in the southerly constellationofLupus,still puts on a cosmic light show across theelectromagnetic spectrum.In fact, thiscomposite view includesX-ray data in blue from the Chandra Observatory,optical data inyellowish hues, and radio image data in red.Now known as the SN 1006supernova remnant, the debris cloudappears to be about 60 light-years across and is understoodto represent the remains of a white dwarf star.Part of a binary star system,the compact white dwarf gradually captured material from its companion star.The buildup in mass finally triggered athermonuclearexplosion that destroyed the dwarf star.Because the distance to the supernova remnant is about 7,000 light-years, that explosion actually happened 7,000 years before the light reached Earth in 1006.Shockwaves in the remnantaccelerate particles to extreme energies and arethought to be a source of the mysterious cosmic rays. |
置顶卡
变色卡
千斤顶
显身卡
