The Economist - August 13, 2009
IN THE crazy world of Dr Seuss, an American children’s author, a bird called a Pelf lays eggs that are three times as big as herself. At this week’s meeting of the International Astronomical Union, astronomers were asked to entertain equally odd thoughts when they were presented with the latest evidence that some early galaxies, although smaller than their more recent counterparts, contain much more mass. It is like being handed a baby that weighs three times as much as its mother.
The objects in question are “red compact” galaxies, in particular a well-studied one called 1255-0 that formed just 3 billion years after the Big Bang. As the universe is thought to be 13.7 billion years old, the light reaching Earth from this galaxy shows what it was like some 10.7 billion years ago, when it was the equivalent of a newborn. Images suggest that the galaxy is 3,000 light years across—just a fifth of the size of the Earth’s home galaxy, the Milky Way—but about four times as massive.
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