In July of 2012, astronomers observed a spiral galaxy in the early universe, billions of years before many other spiral galaxies formed while using the Hubble Space Telescope. They were taking pictures of about 300 very distant galaxies in the early universe to study their properties. This distant object existed roughly three billion years after the Big Bang, and light from this part of the universe has been traveling to Earth for about 10.7 billion years.
“The fact that this galaxy exists is astounding,” said David Law, lead author of the study a fellow at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics. “Current wisdom holds that such ‘grand-design’ spiral galaxies simply didn’t exist at such an early time in the history of the universe.” A ‘grand design’ galaxy has prominent, well-formed spiral arms.
“As you go back in time to the early universe, galaxies look really strange, clumpy and irregular, not symmetric,” said Alice Shapley, a UCLA associate professor of physics and astronomy, and co-author of the study. “The vast majority of old galaxies look like train wrecks. Our first thought was, why is this one so different, and so beautiful?”
“BX442 looks like a nearby galaxy, but in the early universe, galaxies were colliding together much more frequently,” she said. “Gas was raining in from the intergalactic medium and feeding stars that were being formed at a much more rapid rate than they are today; black holes grew at a much more rapid rate as well. The universe today is boring compared to this early time.”
Galaxies in today’s universe divide into various types, including spiral galaxies like our own Milky Way, which are rotating disks of stars and gas in which new stars form, and elliptical galaxies, which include older, redder stars moving in random directions. The mix of galaxy structures in the early universe is quite different, with a much greater diversity and larger fraction of irregular galaxies, Shapley said.
The galaxy, which goes by the not very glamorous name of BX442, is quite large compared with other galaxies from this early time in the universe; only about 30 of the galaxies that Law and Shapley analyzed are as massive as this galaxy.
via Did Astronomers Find the Oldest Spiral Galaxy in the Cosmos?.