Universe may be less crowded than thought: study

There may be far fewer galaxies further out in the universe than thought earlier, according to a new study.
Over the years, the Hubble Space Telescope has allowed astronomers to look deep into the universe. The long view stirred theories of untold thousands of distant, faint galaxies.
The new research, led by Michigan State University, offers a theory that reduces the estimated number of the most distant galaxies by 10 to 100 times.
"Our work suggests that there are far fewer faint galaxies than we once previously thought," said Brian O'Shea, MSU associate professor of physics and astronomy.
"Earlier estimates placed the number of faint galaxies in the early universe to be hundreds or thousands of times larger than the few bright galaxies that we can actually see with the Hubble Space Telescope. We now think that number could be closer to ten times larger," said O'Shea.

O'Shea and his team used the National Science Foundation's Blue Waters supercomputer to run simulations to examine the formation of galaxies in the early universe.

The team simulated thousands of galaxies at a time, including the galaxies' interactions through gravity or radiation.
The simulated galaxies were consistent with observed distant galaxies at the bright end of the distribution - in other words, those that have been discovered and confirmed.
The simulations didn't, however, reveal an exponentially growing number of faint galaxies, as has been previously predicted, researchers said.
The number of those at the lower end of the brightness distribution was flat rather than increasing sharply, O'Shea added.

The study appears in the Astrophysical Journal Letters.