Mysterious Dark Force Is Killing Galaxies Across the Universe

Thousands of galaxies are dying throughout the vast universe and scientists embarked on a mission to find out how and why. A recent study published in the Monthly Notices of the Royal Astronomical Society finally solved the mystery, pointing to a phenomenon called ram-pressure stripping.

According to an official release from the International Centre for Radio Astronomy Research (ICRAR), ram-pressure stripping sucks away the gas from the galaxies, rendering them unable to create new stars and effectively dead. The global team of scientists observed data from 11,000 galaxies and discovered that this phenomenon is happening on a wide scale all across the universe.

Astronomers describe galaxies as enclosed in clouds of the mysterious dark matter dubbed as dark matter halos.

"During their lifetimes, galaxies can inhabit halos of different sizes, ranging from masses typical of our own Milky Way to halos thousands of times more massive," study leader Tony Brown explained. "As galaxies fall through these larger halos, the superheated intergalactic plasma between them removes their gas in a fast-acting process called ram-pressure stripping."

He added, "You can think of it like a giant cosmic broom that comes through and physically sweeps the gas from the galaxies."

Without the gas, galaxies can't make new stars. Existing ones will cool off and age, and Brown said this turns the galaxy into a dead object.

Ram-pressure stripping is fast-acting - at least relatively and in an astronomical scale - as it sucks up the gas in just tens of millions of years, compared to the much slower death it experiences with a process called strangulation. In the latter case, the galaxy consumes gas to create stars faster than the gas is being replenished.

From a human perspective, the millions of years it takes for a galaxy to die takes a seemingly infinite number of lifetimes. Besides, it's unlikely for the universe to run out of galaxies. According to a report from Phys Org, a recent study revealed there are at least 2 trillion galaxies that exist, a number that's ten times more than previously believed.