Astronomers have finally solved a cosmic mystery that has puzzled scientists for decades.
Using powerful observations from the Subaru Telescope in Hawaii, an international research team uncovered direct evidence of a massive, long-lost object that once crashed into the Perseus cluster—a huge group of galaxies located about 240 million light-years from Earth.
The Perseus cluster is one of the largest known structures in the universe, weighing about 600 trillion times more than our Sun.
For many years, scientists thought it was a peaceful, stable cluster because it showed no obvious signs of recent violent events. In fact, it was often used as the “textbook example” of a calm galaxy cluster.
However, newer, more detailed observations revealed strange patterns in the cluster’s gas and structure, hinting that a major collision had happened long ago.
But the big question remained: where was the object that smashed into Perseus?
To find out, the team studied detailed images taken with Hyper Suprime-Cam on the Subaru Telescope.
They used a technique called gravitational lensing, where the gravity of massive objects bends and distorts light from galaxies behind them.
This method allows astronomers to map invisible dark matter—the mysterious substance that makes up most of the universe’s mass.
The researchers found a huge clump of dark matter about 1.4 million light-years west of the cluster’s center.
This clump is around 200 trillion times the mass of the Sun. Even more exciting, they discovered a faint but real “dark matter bridge” connecting this clump to the core of the Perseus cluster, showing that the two had interacted in the past.
Simulations suggest that this dark matter structure collided with Perseus about five billion years ago. Although the visible galaxies and gas have changed since then, the fingerprints of the collision are still clear in the dark matter and the swirling shapes of gas today.
“This is the missing piece we’ve been searching for,” said Dr. James Jee, the lead researcher, whose team published the findings in Nature Astronomy. “Now, all the strange patterns we see in Perseus make sense.”
The discovery also shows how powerful gravitational lensing can be for uncovering hidden parts of the universe.
By combining cutting-edge imaging and new techniques, scientists are now able to reveal the secret histories of the universe’s largest structures—stories that have been hidden in the darkness for billions of years.
Source: KSR.
