You are here

Dark Alternatives

August 29, 2016

So far, the leading candidate in the search for dark matter has wimped out. No one is giving up on it, but scientists are pondering some other possibilities just in case.

Dark matter emits no detectable energy. Yet astronomers “see” it by measuring its gravitational pull on the visible matter around it. Those observations tell us that there’s a lot more dark matter than normal matter.

The leading explanation for dark matter is a heavy subatomic particle known as a WIMP. But years of searches haven’t produced a single confirmed WIMP, and none have been seen in the experiments with the Large Hadron Collider. A gamma-ray glow from the center of the Milky Way galaxy could be produced by colliding WIMPs, but there are other possible explanations as well.

So researchers are looking for particles that would be much less massive than WIMPs, which makes them even more difficult to detect. And others are going in the opposite direction — looking for enormous numbers of black holes.

When black holes merge, they emit gravitational waves, which create “ripples” in space. Detectors have seen waves from two such mergers, between black holes that are up to about 30 times heavier than the Sun. A recent study said that the number of such mergers could tell us the total number of these black holes, which were formed in the early universe. If there are enough of them, they could account for all or part of the dark matter — leaving WIMPs in the dark.


Script by Damond Benningfield

Get Premium Audio

Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.