If you think Earth is a mess, consider the turmoil in the constellation Hydra, where astronomers have spotted two monster galactic clusters slamming together in one of the biggest collisions ever recorded.
The cosmic smash-up poses no danger to Earth — it is located about 800 million light-years away, and the galaxies involved tend to speed by each other without crashing — but our own Milky Way could be on a similar collision course in a few billion years.
Astronomers who observed the violent merger said Thursday it could be likened to the clash of two particularly strong weather fronts on Earth.
“Today’s cosmic weather report shows a cosmic storm that is one of the most massive objects in the universe,” Patrick Henry of the University of Hawaii, who led an international scientific team to make the observation, said at a telephone news conference.
“The long-term forecast is for fair weather, about 7 billion years in the future,” Henry said.
At 800 million light-years’ distance, the crash site is considered relatively close by cosmic standards. The crash itself extends about 3 million light-years across. A light-year is about 6 trillion miles (10 trillion kilometers), the distance light travels in a year.
The larger of the two galactic clusters probably contains 1,000 galaxies, while the smaller one has 300 or so. By comparison, the Milky Way does not belong to a galactic cluster, but is part of a group located on the outskirts of the Virgo cluster, which is about the same size as the smaller component of the big collision.
Henry and his colleagues reckon the two galactic clusters were separate objects 300 million years before the scientists spied it, and began slamming together after that.
X-ray observatory used
The scientists captured information on the violent merger with the European Space Agency’s XMM-Newton observatory.
Astronomers have known for decades that two clusters of galaxies were merging in the area of the sky near Hydra (The Water Serpent), and dozens of other such colliding galactic clusters have also been identified.
But this particular violent merger offers the best data yet of the process, which could help scientists learn more about how galaxies and everything in them developed in the early universe.