The Cosmos Is Cracked

If the prospect of an ever-expanding universe that eventually stretches into a vast emptiness isn’t depressing enough, there’s this: the universe may have cracks in it.

Cracks, called cosmic strings, are topological defects in spacetime that might have formed when the universe was young. Experiments haven’t found any proof that cosmic strings are even out there, but that hasn’t stopped physicists from calculating how many strings we might expect there to be if, in fact, they turn out to exist after all. And it’s a lot: cosmic strings would produce at least a billion loops throughout the visible universe today, researchers report. “Cosmic strings are these filaments which wind and sneak throughout the universe,” says study co-author Benjamin Shlaer of Tufts University. They are essentially one-dimensional fault lines in space, made not of mass but pure energy. Some could be infinitely long, and all are almost impossibly thin, much narrower than a proton.