In the Perseus galaxy cluster, 240 million light years away, scientists have found a huge wave of gas about twice the size of the Milky Way. This gas has been expanding for over 2.5 billion years, and it burns so hot that it can only be seen in the X-ray band.
Expanding Gas Wave in the Perseus Galaxy Cluster
“Perseus is one of the most massive nearby clusters and the brightest one in X-rays, so Chandra data provide us with unparalleled detail,” said Stephen Walker, one of NASA’s lead scientist.
At 200,000 light years across, the gas wave is about twice the size of our own galaxy. The gas at the cooler center burns at around 54 million degrees Kelvin, while the outer regions are up to three times as hot. Scientists have dubbed it an “X-ray Tsunami”, which made its detection by Chandra all the more likely.
In the last 2.5 billion years, the gas has risen almost 500,000 light years from the center of the phenomenon. Then a smaller galaxy made a fly-by pass. This caused the gas formation to create a 200,000 light year wave that rolls for hundreds of millions of years before it finally fades away.
These waves operate similarly to Kelvin-Helmholtz waves which are caused by two liquids mixing at different velocities. This phenomenon seems to occur at almost every scale of the universe, from backyard puddles to a massive wave of gas larger than many galaxies.