Hundreds of millions of light-years from Earth, an uneasy place is observed where catastrophes of a galactic scale constantly occur. Stephan’s Galactic Five in the constellation Pegasus is the site of cosmic “car crashes.” In general, strictly speaking, this is a quadruple – only four galaxies are involved in the mass accident, and the fifth (NGC 7320) only seems to be involved with them, but in fact it is much closer and is not at all involved in the disparity occurring there.

Meanwhile, the “humble” galaxy NGC 7320c is a bit distant, as if it’s holding on to “nothing”. According to astronomical “surveillance cameras”, this is an ancient intruder: it crawled through the cluster hundreds of millions of years ago, wreaked havoc and is now hiding from the scene. The Hubble telescope found numerous “broken” galaxy fragments in the Stephan Quintet: clusters of stars scattered across intergalactic space.

But now attention is being drawn to a new “space accident” caused by NGC 7318b. It can be seen in the images together with the innocent NGC 7318a. To understand: the criminal is spiral, his arms are wide open, and the victim is elliptical.

It seems that these two galaxies are merging with each other, but in fact astronomers think otherwise: NGC 7318b is running too fast for this, compared to the surrounding galaxies, it literally flies away – its speed is estimated at almost 900 kilometers per second. That’s 120 times faster than the speed Earth ships need to enter space.

The “superaccelerating” galaxy NGC 7318b, among other things, emits a huge shock wave that spreads as a result of its collision with the elliptical NGC 7318a and extends for hundreds and thousands of light years. This is approximately the diameter of our Milky Way galaxy.

A team of astronomers from Great Britain, Spain and other countries recently examined this front using the WEAVE spectrograph on the William Herschel telescope on the island of La Palma. Scientists showed the resulting picture in an article. Monthly Notices of the Royal Astronomical Society.

Researchers explained that the accident pushed a large amount of interstellar gas into intergalactic space, and the shock wave was strong enough to eject electrons from hydrogen atoms. As a result, a cloud of charged plasma remains. At the same time, when the wave hits a substance that is already ionized, it becomes weaker.

According to calculations, a desperate racer entered the intersection only about 20 million years ago. They estimate that the crash will only last about 10,000 years. “The place where the event took place” is 270-280 million light years away from us, and we are observing events that old.