Gravitational-wave discovery could open up new window on the universe

New Scientist : Following the historic first direct detection of gravitational waves, scientists are looking forward to using those waves and many more to come to explore fundamental physics and solve cosmological mysteries. New Scientist mentions four areas of potential study. Some scientists hope to probe the effect of dark energy by combining gravitational-wave signals from multiple black hole mergers and measuring how space has expanded over time. Other researchers want to see whether gravity behaves over large distances as predicted by general relativity. Cosmologists hope that gravitational waves will provide a window to the distant past, including cosmic inflation. In a dream scenario, gravitational waves would lead physicists to a grand unified theory of the universe by providing a peek at the early universe when the four fundamental forces were not yet distinct.