By Devin Powell
An invisible web thought to span the cosmos has now revealed one of its strands.
That thread is spun of dark matter and connects two titanic clusters of galaxies, some of the most massive objects in the universe. Its discovery supports the idea that galaxy clusters grow at the intersections of such filaments, and its heft backs the claim that filaments hide more than half of all matter.
“Filaments of dark matter have never been seen before,” says Jörg Dietrich, an astronomer at the University Observatory Munich in Germany, whose team reports the finding online July 4 in Nature. “For the first time, we successfully mapped one.”