The universe is mostly a deep, dark black. But on a clear night, away from city lights, you can see a faint band of light arching across the sky. This is the Milky Way, our home galaxy.
The Milky Way may look like just another starry night to you, but it’s actually an enormous collection of more than 100 billion stars and planets — including Earth — located around one of the universe’s central supermassive black holes.
Moreover, The Milky Way contains billions of other galaxies as well — more than anyone has ever counted. These galaxies are much bigger than ours and contain many billions more stars than we have in our own galaxy. These galaxies are so far away that they appear as fuzzy patches of light in our telescopes.
Astronomers at Johns Hopkins University in Baltimore have been studying the Milky Way for years by observing its background radiation, which is light emitted by objects billions of years ago that we see now because it reflects off dust particles in our galaxy. Their most recent research was published in April 2019 in The Astrophysical Journal Letters.
“We’re trying to learn more about where we live,” said astronomer Terry Oswalt, who led the study along with his colleagues at Johns Hopkins University. “This is what goes on when we look at things behind us.”
Oswalt has spent his career studying how massive galaxies evolved over time; this latest paper focuses on how galaxies form stars and evolve into ellipticals or spirals.