BBC NEWS | Science & Environment | Black holes 'preceded galaxies'
A cosmic chicken-and-egg question has been solved by astronomers, who now say that black holes came before galaxies.
The findings were presented at a major astronomy meeting in California.
Most if not all galaxies, including our own Milky Way, are believed to have massive black holes at their cores.
It was unclear whether black holes came first, helping create galaxies by pulling matter towards them, or whether they arose in already formed galaxies.
"It looks like the black holes came first," said Dr Chris Carilli, from the US National Radio Astronomy Observatory in Socorro, New Mexico, who took part in the study. "The evidence is piling up."
The evidence was unveiled at the 213th American Astronomical Society meeting in Long Beach, California.
Earlier studies of nearby galaxies had revealed an intriguing link between the masses of black holes and the central "bulges" of stars and gas in galaxies.