Glowing Galactic Clouds
Astronomers have observed millions of galaxies in the universe. But of these vast conglomerations of stars, only a handful have been discovered with glowing green clouds of gas and dust. In images taken by NASA’s Hubble Space Telescope, the clouds appear as expansive blobs and warped halos on a galaxy’s outskirts. Their strange, colorful emission is believed to result from the interaction or merger of neighboring galaxies. In each galaxy’s core lies a massive black hole. When two galaxies zoom past each other or collide, the chaos propels material inward toward the black holes, generating intense but short-lived outbursts of energy. The energy radiates outward and takes thousands of years to reach the clouds. But when it does, the oxygen atoms in the clouds glow green, illuminating the surrounding gas and dust like lighthouses on a foggy night. Explore the images to learn more.
Please give credit for this item to:
NASA's Goddard Space Flight Center
Images courtesy of NASA/ESA/Galaxy Zoo Team/University of Alabama/W. Keel
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