When galaxies collide: Stunning insights into 3.2 million kph crash

The impact has left some striking phenomena in the universe

The hexagon denotes the approximate coverage of the new observations. Photo: University of Hertfordshire

An incredible collision of galaxies that sent shock waves across the universe has been captured by modern telescopes and given new insights into the explosion, scientists have said.

The 3.2 million kph collision was captured in stunning detail by some of the planet’s most powerful telescopes.

The impact sparked an immensely powerful shock similar to a sonic boom from a jet fighter on Earth – and has left striking phenomena now seen in the universe, researchers said.

The smash was observed in Stephan's Quintet, a group of five galaxies, findings published in the Monthly Notices of the Royal Astronomical Society journal show.

Dr Marina Arnaudova said: “Since its discovery in 1877, Stephan’s Quintet has captivated astronomers, because it represents a galactic crossroad where past collisions between galaxies have left behind a complex field of debris.

Radio observations of Stephan's Quintet. University of Hertfordshire

“Dynamical activity in this galaxy group has now been reawakened by a galaxy smashing through it at an incredible speed of over two million miles per hour, leading to an immensely powerful shock, much like a sonic boom from a jet fighter.”

Scientists led by the University of Hertfordshire captured the event using the new €20 million ($21m) William Herschel Telescope Enhanced Area Velocity Explorer (Weave).

They uncovered a dual nature behind the shock front, previously unknown to astronomers.

They found that as the shock moves through pockets of cold gas, it travels at hypersonic speeds, powerful enough to rip apart electrons from atoms, leaving behind a glowing trail of charged gas.

However, when the shock passes through the surrounding hot gas, it becomes much weaker, according to PhD student Soumyadeep Das, of the University of Hertfordshire.

The WEAVE prime-focus corrector and positioner at the William Herschel telescope in La Palma, Spain. Photo: ING

He added: “Instead of causing significant disruption, the weak shock compresses the hot gas, resulting in radio waves that are picked up by radio telescopes like the Low Frequency Array.”

The insight and unprecedented detail came from Weave, combining data with other cutting-edge instruments, and the James Webb Space Telescope.