The Early Universe Was All About Galactic Hook Ups

Artist's illustration of the Andromeda galaxy and the Milky Way merging, based on data from the Hubble Space Telescope. Credit: NASA

In about 4 billion years, scientists estimate that the Andromeda and the Milky Way galaxies are expected to collide, based on data from the Hubble Space Telescope. And when they merge, they will give rise to a super-galaxy that some are already calling Milkomeda or Milkdromeda (I know, awful isn’t it?) While this may sound like a cataclysmic event, these sorts of galactic collisions are quite common on a cosmic timescale.As an international group of researchers from Japan and California have found, galactic “hookups” were quite common during the early universe. Using data from the Hubble Space Telescope and the Subaru Telescope at in Mauna Kea, Hawaii, they have discovered that 1.2 billion years after the Big Bang, galactic clumps grew to become large galaxies by merging. As part of the Hubble Space Telescope (HST) “Cosmic Evolution Survey (COSMOS)”, this information could tell us a great about the formation of the early universe.Previous research has shown that some 200 million years after the Big Bang, the universe was filled with pre-galactic clumps. These cold gas clouds were roughly one-hundred times smaller and one-million times less massive than modern galaxies. It is from these clumps of gas that the first stars and galaxies are believed to have formed.After the first small galaxies were formed, they began to merge together, forming the larger galaxies we see today – i.e. which contain hundreds of billions of stars and measure thousands of light years across. For some time, scientists have been trying to see galaxies as they existed in the early universe, at a time when they were still actively forming stars.Unfortunately, given the distances involved (13 billion light years) and the fact that most of the galaxies in the young universe were quite small, getting a sense of their detailed —> Read More