New! Sign up for our email newsletter on Substack.

Galaxy’s 2 Million MPH Crash Creates Cosmic ‘Sonic Boom’

WEAVE data overlaid on a James Webb Space Telescope image of Stephan's Quintet, with green contours showing radio data from the Low Frequency Array (LOFAR) radio telescope. The orange and blue colours follow the brightness of Hydrogen-alpha obtained with the WEAVE LIFU, which trace where the intergalactic gas is ionised. The hexagon denotes the approximate coverage of the new WEAVE observations of the system, which is 36 kpc wide (similar in size to our own galaxy, the Milky Way).

WEAVE data overlaid on a James Webb Space Telescope image of Stephan's Quintet, with green contours showing radio data from the Low Frequency Array (LOFAR) radio telescope. The orange and blue colours follow the brightness of Hydrogen-alpha obtained with the WEAVE LIFU, which trace where the intergalactic gas is ionised. The hexagon denotes the approximate coverage of the new WEAVE observations of the system, which is 36 kpc wide (similar in size to our own galaxy, the Milky Way).

In a dramatic cosmic spectacle, astronomers have captured unprecedented details of a galaxy hurtling through space at an astonishing 2 million miles per hour, triggering a massive collision that creates shock waves comparable to a fighter jet’s sonic boom.

Published in Monthly Notices of the Royal Astronomical Society | Estimated reading time: 4 minutes

Using the newly commissioned 20-million Euro WEAVE telescope in La Palma, Spain, scientists observed this celestial crash occurring in Stephan’s Quintet, a group of five galaxies that has fascinated astronomers since its discovery in 1877. The intruding galaxy, designated NGC 7318b, is plowing through a complex field of galactic debris, reawakening ancient cosmic turmoil.

Dr. Marina Arnaudova of the University of Hertfordshire, who led the research, describes the collision as a “galactic crossroad” where past galaxy interactions have left their mark. “The shock created by this collision is so powerful it can strip electrons from atoms, leaving behind a glowing trail of charged gas that we can observe with our instruments.”

The research team, comprising over 60 astronomers, made a surprising discovery about the nature of these cosmic shock waves. When the supersonic disturbance encounters pockets of cold gas, it creates intense, glowing trails. However, its behavior changes dramatically when passing through hotter regions, where it compresses the gas and generates distinctive radio waves.

This dual nature of the shock front, previously unknown to astronomers, was revealed through the combined power of multiple cutting-edge instruments, including the Low Frequency Array (LOFAR), the Very Large Array (VLA), and the James Webb Space Telescope (JWST).

Glossary

Shock Front
A boundary where matter undergoes abrupt changes in properties due to supersonic collision impacts.
Spectroscopy
The study of how matter interacts with electromagnetic radiation, revealing its composition through light analysis.
Intergalactic Medium
The space between galaxies, containing various forms of matter and energy.

Test Your Understanding

How fast is the colliding galaxy NGC 7318b moving?

The galaxy is moving at an incredible speed of 2 million miles per hour (3.2 million kilometers per hour).

What happens when the shock wave encounters cold gas?

It travels at hypersonic speeds and strips electrons from atoms, creating a glowing trail of charged gas.

How does the shock wave behave differently in hot gas?

Instead of causing significant disruption, it becomes weaker and compresses the hot gas, generating radio waves detectable by radio telescopes.

What makes this observation particularly significant?

It’s the first time scientists have observed this dual nature of shock fronts in galaxy collisions, using the new WEAVE telescope alongside other cutting-edge instruments.

Enjoy this story? Subscribe to our newsletter at scienceblog.substack.com

Quick Note Before You Read On.

ScienceBlog.com has no paywalls, no sponsored content, and no agenda beyond getting the science right. Every story here is written to inform, not to impress an advertiser or push a point of view.

Good science journalism takes time — reading the papers, checking the claims, finding researchers who can put findings in context. We do that work because we think it matters.

If you find this site useful, consider supporting it with a donation. Even a few dollars a month helps keep the coverage independent and free for everyone.