We still can't see dark matter. But what if we can hear it?

The most mysterious and yet ubiquitous stuff in the cosmos, dark matter is effectively invisible. This is simply because it doesn't interact with light. But what if instead of trying to see dark matter, scientists attempted to hear it instead? New research suggests dark matter could leave a tiny but discernible imprint in the cacophony of ripples in spacetime called " gravitational waves " that ring through the cosmos when two black holes slam together and merge. …