Baby Galaxies Bloated With Stars

April 29, 2008 -- They may have been small, but some of the universe's first galaxies sure packed a wallop.

Astronomers have discovered nine baby beasts, each of which would fit quite contently in just the hub of our own rather modest Milky Way galaxy, stuffed with as many stars as galaxies of more recent vintage.

"Seeing the compact sizes of these galaxies is a puzzle," said Yale University's Pieter van Dokkum, lead author of a paper on the discovery appearing in this month's Astrophysical Journal Letters.

Scientists estimate the early galaxies would have needed to expand five times over to reach the stately proportions of their more modern kin. Colliding with each other might be one way to build up real estate, but that's probably not the whole answer, van Dokkum said.

"It is not yet clear how they would build themselves up to become the large galaxies we see today," he added.

Astronomers using the Hubble Space Telescope and the Keck Observatory on Mauna Kea, Hawaii, found nine compact galaxies that formed about 11 billion years ago, less than 3 billion years after the birth of the universe.