The new research discovered something different. The authors found a substantial number of very massive galaxies—more than 10 times the mass of the Milky Way—at a much earlier time than expected. (I have to say that the image accompanying that press release is among the more … embarrassingly dorky examples I’ve seen.) Not only that, these galaxies were busily making new stars, with bigger galaxies giving birth faster than those with lower mass.
That’s consistent with what astronomers have seen for closer galaxies. But early galaxies—at least very high-mass ones—should drop off in star formation at some point. That expectation depends on galaxies merging from smaller chunks, and depleting some of their available star-making fuel. [read more…]