Physics

Dark Matter Particles May be Massive Instead of Tiny

Catherine Griffin
First Posted: Nov 05, 2014 09:39 AM EST

Physicists have been searching for dark matter particles for years. Now, though, scientists have announced that researchers may want to consider looking for candidate particles that are far more massive than the tiny, exotic particles that are currently being studied.

Dark matter is unseen matter that, when combined with normal matter, could create gravity that prevents spinning galaxies from flying apart-among other things. Physicists calculate that dark matter makes up about 27 percent of the universe, while normal matter makes up just 5 percent.

In the past, scientists have examined tiny, exotic particles for evidence of dark matter. More specifically, they've been looking at weakly interacting massive particles (WIMPs), or axions, which are weakly interacting low-mass particles. Now, though, researchers have suggested that dark matter may be made of macroscopic objects.

"We've been looking for WIMPs for a long time and having seen them," said Glenn Starkman, one of the researchers, in a news release. "We expected to make WIMPs in the Large Hadron Collider, and we haven't."

While WIMPs and axions are still possible candidates for dark matter, there's a reason to search elsewhere. After all, excluding certain areas from search means that it's possible that scientists may be overlooking potential discoveries.

"The community has kind of turned away from the idea that dark matter could be made of normal-ish stuff in the late 80s," said Starkman. "We ask, was that completely correct and how do we know dark matter isn't more ordinary stuff-stuff that could be made from quarks and electrons?"

Although strange quarks are highly unstable, neutrons are also highly unstable. Yet in helium, bound with stable protons, neutrons remain stable.

"That opens the possibility that stable strange nuclear matter was made in the early universe and dark matter is nothing more than chunks of strange nuclear matter or other bound states of quarks, or of baryons, which are themselves made of quarks," said Starkman.

The findings are published online and can be found here.

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