The Telescope Aimed at Nothing

In 1995, astronomer Robert Williams made a decision his colleagues called a waste of time. He pointed the Hubble Space Telescope at a tiny patch of sky near the Big Dipper — a sliver no larger than a grain of sand held at arm's length — where, as far as anyone could tell, absolutely nothing existed. Just blackness. He kept the shutter open for ten consecutive days, collecting ancient light photon by photon.…