Ancient Milky Way-like galaxy discovered, surprising astronomers

Washington: Astronomers have observed a galaxy dating to an earlier epoch in the universe's history that surprisingly is shaped much like our Milky Way - a spiral structure with a straight bar of stars and gas running through its center - but far more massive, offering new insight into galactic formation.

The distant galaxy, called J0107a, was observed as it appeared 11.1 billion years ago, when the universe was about a fifth of its current age. The researchers used data from the Chile-based Atacama Large Millimeter/submillimeter Array (ALMA) and NASA's James Webb Space Telescope to study the galaxy.

They determined that the galaxy's mass, including its stars and gas, was more than 10 times greater than that of the Milky Way, and it was forming stars at an annual rate approximately 300 times greater. J0107a was more compact than the Milky Way, however.

"The galaxy is a monster galaxy with a high star formation rate and plenty of gas, much more than present-day galaxies," said astronomer Shuo Huang of the National Astronomical Observatory of Japan, lead author of the study published this week in the journal Nature.

"This discovery," said study co-author Toshiki Saito, an astronomer at Shizuoka University in Japan, "raises the important question: How did such a massive galaxy form in such an early universe?"

While a few galaxies that are undergoing star formation at a similar rate to J0107a exist in today's universe, almost all of them are ones that are in the process of a galactic merger or collision. There was no sign of such circumstances involving this galaxy.