Detecting Dark Matter
For years, researchers have been hunting for dark matter, which is thought to make up about 27 percent of the entire known universe. Now, an innovative team of scientists says they may have figured out a new way to detect the elusive substance using an international network of atomic clocks.

In 1998, with observations from the Hubble Space Telescope, scientists found that the universe was expanding faster and faster, which contradicted the expectation that gravity wou