The black hole is famously so dense, not even light can escape it. But something can, or at least it can linger at the edges. This is the centerpiece of Stephen Hawking’s new theory about black holes.

For a long time, the general theory about black holes explained that they have no particular features beyond mass, spin and angular momentum. In other words, black holes were considered featureless blobs of physics, with no way to tell just how they were formed. However, Hawking posited something different — that black holes “leak” radiation over time, eventually fading away. But that would leave an identical vacuum every time they left, so if you wanted to know what created that hole, you were back to square one.

A new theory, developed by Hawking, his colleague Malcolm Perry, and Harvard theoretical physicist Andrew Strominger, argues otherwise. If you introduce a “soft” photon — or a photon that has no energy — into that vacuum, it changes the angular momentum. In other words, there are ways to determine what formed a black hole and what might have gotten sucked into it. This would mean black holes have “hair,” long strands of zero-energy photons and gravitons that could tell us the history of that black hole. Strominger likens it to a hard drive that can store infinite data about the universe.

This is a bigger deal than you might at first think. Black holes are all over the universe, and if this theory holds true, it would mean we could read them like rings on a tree. In theory, if we got to and observed a black hole properly, we could determine a lot about the history of the galaxy in that particular neighborhood. So, in short, if Hawking and Strominger are right, black holes hold the entire history of the universe in their hair. We just need to unlock it.

(Via NBC News)