September 7, 1996
Galaxies were colliding long before you were born, and they will keep colliding long after us all.
Two Billion Years After the Big Bang
Birthday · September 7, 1996
A little universe, just for you
Your date.
Ready to give.
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APOD published September 7, 1996. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
What did the universe look like two billion years after the Big Bang? According to this computer model, the universe was filled with irregular looking objects like the ones shown above. The simulation then predicts that these blobs of stars and gas collide to form galaxies more similar to the ones we see today. In fact, this simulation bears much resemblance to recent pictures of distant galaxies taken by the Hubble Space Telescope. Galaxy formation is a complex phenomena which only now is becoming understood. Did most galaxies form 5 billion years ago - or 10 billion? Did galaxies fragment from larger sheets of matter, or are they conglomerations of many smaller clumps? Simulations like this one are helping to determine the answer.