This artist's concept illustrates one possible answer to the puzzle of the 'giant galactic blobs'. These blobs (red), first identified early in the 21st century, are mammoth clouds of intensely glowing material that surround distant galaxies (white). Astronomers using visible-light telescopes can see the glow of the blobs, but they didn't know what provides the energy to light them up. NASA's Spitzer Space Telescope set its infrared eyes on one well-known blob located 11 billion light-years away, and discovered three tremendously bright galaxies, each shining with the light of more than one trillion of Earth's suns, heading toward each other.
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