* Astronomy

Little Telescope Spies Gigantic Galaxy Clusters

The rarest and largest of galaxy groupings, called galaxy clusters, can be the hardest to find. That's where NASA's Wide-field Infrared Survey Explorer (WISE) can help. The mission's all-sky infrared maps have revealed one distant galaxy cluster and are expected to uncover thousands more.
These massive structures are collections of up to thousands of galaxies bound together by gravity. They were born out of seeds of matter formed in the very early universe, and grew rapidly by a process called inflation.
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