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原文:
This dance is to the death. Along the way, as these two large galaxies duel, a cosmic bridge of stars, gas, and dust currently stretches over 75,000 light-years and joins them. The bridge itself is strong evidence that these two immense star systems have passed close to each other and experienced violent tides induced by mutual gravity. As further evidence, the face-on spiral galaxy on the right, also known as NGC 3808A, exhibits many young blue star clusters produced in a burst of star formation. The twisted edge-on spiral on the left (NGC 3808B) seems to be wrapped in the material bridging the galaxies and surrounded by a curious polar ring. Together, the system is known as Arp 87 and morphologically classified, technically, as peculiar. While such interactions are drawn out over billions of years, repeated close passages should ultimately result in the death of one galaxy in the sense that only one galaxy will eventually result. Although this scenario does look peculiar, galactic mergers are thought to be common, with Arp 87 representing a stage in this inevitable process. The Arp 87 pair are about 300 million light-years distant toward the constellation Leo. The prominent edge-on spiral at the far left appears to be a more distant background galaxy and not involved in the on-going merger.
中文翻譯:
這個舞蹈是至死方休。在這個過程中，這兩個龐大的星系正在交鋒，一座由星星、氣體和塵埃組成的宇宙橋梁目前延伸超過75,000光年，連接著它們。這座橋本身強烈地證據顯示，這兩個巨大星系曾經彼此接近，並因互相重力引發了劇烈的潮汐運動。作為進一步的證據，位於右側的面對面螺旋星系，也被稱為NGC 3808A，展現了許多幼小的藍色星團，這是因為一場星星形成的爆發所致。而左側扭曲的邊緣螺旋星系（NGC 3808B）似乎被連接兩個星系的物質所包裹，並且環繞著一個奇特的極環。這個系統統稱為Arp 87，並在形態上被技術性歸類為”奇特”。儘管這種相互作用的過程持續了數十億年，但反覆的近距離接觸最終應該會導致一個星系的消亡，意即最終只會剩下一個星系。雖然這個情景看起來很奇特，但星系合併被認為是非常普遍的現象，Arp 87代表了這一不可避免過程的一個階段。Arp 87雙星系距離地球約3億光年，朝向獅子座。而最遠左側的明顯邊緣螺旋星系似乎是一個更遙遠的背景星系，並不參與這次正在進行的合併。
#星系交鋒 #宇宙的舞蹈 #Arp87 #NGC3808A #NGC3808B #星際合併 #神秘的宇宙 #星系演化 #天文學 #獅子座 #星際橋梁
來源:NASA每日圖片
