A disk galaxy in the early universe, just 1.5 billion years after the Big Bang, somehow formed during a time of chaotic cosmic conditions. According to previous estimations, disk galaxies should take 6 billion years to form, reports VICE.

The galaxy DLA0817g is informally known as the Wolfe Disk

Disk galaxies, like our own Milky Way, take the shape of a rotating disk stretching across 100,000 light years. Scientists have thought that to achieve a size of this scale, it must take galaxies around 6 billion years.

However, with the discovery of the Wolfe Disk, our understanding of how galaxies are formed is being challenged. Due to hot clouds of gas being absorbed into the galaxies during their formation, it took them a long time to cool down and becoming rotating disks. But evidence has proven that the Wolfe Disk formed only 1.5 billion years after the big bang.

The study was conducted by Marcel Neeleman, a cosmologist at the Max Planck Institute for Astronomy in Germany. It states that “recent numerical simulations suggest that such galaxies could form as early as a billion years after the Big Bang through the accretion of cold material and mergers.” The study further explains that “observationally, it has been difficult to identify disk galaxies [in the early universe] in order to discern between competing models of galaxy formation.”

As such, with the discovery of the DLA0817g, scientists have had to reevaluate their understanding of how galaxies are formed and this includes revisiting the history of our own galaxy – the Milky Way.