Article Correctness Is Author's Responsibility: Seeing double could help resolve dispute about how fast the universe is expanding

How fast the universe is expanding has been puzzling astronomers for almost a century. Different studies keep coming up with different answers -- which has some researchers wondering if they've overlooked a key mechanism in the machinery that drives the cosmos. Now, by pioneering a new way to measure how quickly the cosmos is expanding, astronomers have taken a step toward resolving the debate.