NASA’s Hubble Discovers Wobbling Galaxies That Could Reveal Nature of Dark Matter

Dark matter is a mysterious, cosmic material that has perplexed astronomers for years. Despite being invisible, researchers are certain that this celestial ingredient—which occupies nearly a quarter of the universe—exists. But new findings indicate that it moves in a different manner than originally thought.

Previously astronomers observed steady movements among the “brightest cluster galaxies (BCGs),” which—as the name implies—are the “most luminous galaxies in the universe.” According to new observations by NASA and the ESA’s Hubble Space Telescope, though, these bright galaxies may not be all that steady. Rather, they are a bit jiggly. 

“We found that the BCGs wobble around the center of the halos,” David Harvey, an astronomer at École Polytechnique Fédérale de Lausanne (EPFL), said in a statement. “This indicates that, rather than a dense region in the center of the galaxy cluster, as predicted by the cold dark matter model, there is a much shallower central density. This is a striking signal of exotic forms of dark matter right at the heart of galaxy clusters.”

10_27_Hubble Space Telescope The Hubble Space Telescope is grappled to space shuttle Atlantis STS-125 by the shuttle’s Canadian-built remote manipulator system, on May 13, 2009. According to new observations by the Hubble Space Telescope, bright galaxies may not be all that steady. Rather, they are a bit jiggly.  NASA via Getty Images

The wobbling was seen among 10 different galaxy clusters. It’s unknown exactly what causes the movement, but if it’s confirmed to be a new phenomenon, researchers may have to rethink how they study dark matter, European Space Agency (ESA) officials note in a release.

“We’re looking forward to larger surveys—such as the Euclid survey—that will extend our data set. Then we can determine whether the wobbling of BGCs is the result of a novel astrophysical phenomenon or new fundamental physics. Both of which would be exciting!” Frederic Courbin, a professor at EPFL, said.

Euclid “will provide thousands of relaxed clusters with strong lensing information,” the authors concluded in their paper, published in the Proceedings of the Royal Astronomical Society.

The ESA is currently preparing for its Euclid mission, which is set to launch in 2020 at the Cape Canaveral Air Force Station in Florida. In addition to studying dark matter, the mission is designed to provide new information about dark energy, according to NASA’s Jet Propulsion Laboratory at the California Institute of Technology.

Earlier this year, scientists published a detailed dark matter map using images from the Hubble Space Telescope. Because the instrument can’t directly observe dark matter, astronomers relied on gravitational lensing. 

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