Copyright:
Robert Gendler
原文:
Why do many galaxies appear as spirals? A striking example is M101, shown above, whose relatively close distance of about 27 million light years allows it to be studied in some detail. Observational evidence indicates that a close gravitational interaction with a neighboring galaxy created waves of high mass and condensed gas which continue to orbit the galaxy center. These waves compress existing gas and cause star formation. One result is that M101, also called the Pinwheel Galaxy, has several extremely bright star-forming regions (called HII regions) spread across its spiral arms. M101 is so large that its immense gravity distorts smaller nearby galaxies.
中文翻譯:
為什麼許多星系呈螺旋狀呢？一個引人注目的例子是 M101，距離我們約 2700 萬光年，使得我們可以對它進行深入研究。觀察證據顯示，與鄰近星系的近距離重力互動產生了高質量和稠密氣體的波浪，這些波浪繼續繞著星系中心運行。這些波浪壓縮了現有氣體，並引發了恆星形成。結果，M101（也稱為 Pinwheel Galaxy）在其螺旋臂上散布著幾個極為明亮的恆星形成區域（稱為 HII 區域）。M101 巨大的重力甚至扭曲了附近較小的星系。
#M101 #PinwheelGalaxy #螺旋星系 #星際探索 #星雲 #HII區域 #天文學 #宇宙奧秘
來源:NASA每日圖片
