Universe may have fewer galaxies than expected

A new study has shown that Universe may contain fewer galaxies than what was expected.

According to Michigan State University associate professor Brian O'Shea, earlier estimates had placed the number of faint galaxies in the early universe to be hundreds or thousands of times larger than the few bright galaxies that they could actually see with the Hubble Space Telescope.

However, now they think that number could be closer to ten times larger, he added.

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. The number of those at the lower end of the brightness distribution was flat rather than increasing sharply, O'Shea added.

These simulations will be tested further when the much-anticipated James Webb Space Telescope comes online in late 2018.

The study is published in the Astrophysical Journal Letters.