The Coma Cluster of Galaxies
影像版權與提供: Jim Misti (Misti Mountain Observatory)
Explanation:
Almost every object in the above photograph is a galaxy. The Coma Cluster of Galaxies pictured above is one of the densest clusters known - it contains thousands of galaxies. Each of these galaxies houses billions of stars - just as our own Milky Way Galaxy does. Although nearby when compared to most other clusters, light from the Coma Cluster still takes hundreds of millions of years to reach us. In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other! Most galaxies in Coma and other clusters are ellipticals, while most galaxies outside of clusters are spirals. The nature of Coma's X-ray emission is still being investigated.
說明:
上面影像中的天體幾乎全是星系。這幅影像中的后髮座星系團 (Coma Cluster of Galaxies)是現知最緻密的星系團，它擁有數千個成員星系，每個星系都和我們的銀河系相當，是數十億顆恆星的家園。和大多數的星系團比起來，后髮座星系團算相當鄰近的，不過光還是得用上數億年才能傳到我們這裡。事實上后髮座星系團非常龐大，光要從這端傳到另一端也要花上數百萬年。后髮座星系團及其他星系團內的成員則大多是楕圓星系，然而非星系團成員的星系大多是螺旋星系。后髮座星系團內有非常高溫的X射線輻射，它的本質為何仍然正被探索之中。
資料來源: Scientific American
Department of Physics, NCKU
