The Hubble Space Telescope has allowed scientists to peer into deep space, expanding our understanding of the universe. But there are still many gaps in that knowledge, including knowing how many galaxies are really out there.
Brian O'Shea is an associate professor of physics and astronomy at Michigan State and part of a team that has been working on that question.
The team has been using the Hubble Space Telescope to view galaxies that are billions of light years away.
When you're looking this far away it allows you to look back at what the universe was like in the beginning. O'Shea explains that because the speed of light is so fast we are actually looking backwards in time when viewing galaxies billions of light years away.
"And so, in that way telescopes are time machines. So, the further away you look the further back in time you look and you can see how galaxy populations change over time," he says.
The group has also been exploring these population changes in a simulation on a super computer to understand how the universe has changed.
"And what we're learning is there's actually way fewer galaxies near the beginning of the universe – so after the Big Bang – than we thought," he says.
The simulation has shown "it's a lot harder to make stars and make galaxies than we originally thought.”