A gas cloud, spotted from 12.9 billion light-years away, could signal the earliest stages of galaxy formation back when the universe was just 800 million years old.
A light-year is the distance light travels in a year, about 6 trillion miles (10 trillion kilometers). An object 12.9 billion light-years away is seen as it existed 12.9 billion years ago, and the light is just now arriving
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Jeremy Hsu, staff writer
Wed Apr 22, 2009 3:22 pm ET