Astronomers have spotted a massive disk galaxy, not unlike our own, that formed 12.5 billion years ago when our 13.8 billion-year-old universe was only a tenth of its current age. But according to what scientists know about galaxy formation, this one has no business being in the distant universe.
This discovery is challenging how astronomers think about galaxy formation in the early universe.
It’s known as Galaxy DLA0817g, but astronomers nicknamed it the Wolfe Disk after late astronomer Arthur M. Wolfe, former doctoral advisor to three of the study’s four authors. It represents the most distant rotating disk galaxy they have ever observed, thanks to the Atacama Large Millimeter/submillimeter Array of telescopes in Chile known as ALMA.
According to their observations, the galaxy’s disk has a mass of 70 billion times that of our sun. It’s also rotating at 170 miles per second, which is similar to our Milky Way galaxy. But galaxies with stable, well-formed disks, like the Milky Way, formed gradually and appeared later in the universe’s timeline, with some dated to 6 billion years after the Big Bang.