Craig Hogan believes that the world is fuzzy. This is not a metaphor. Hogan, a physicist at the University of Chicago and director of the Fermilab Particle Astrophysics Center near Batavia, Ill., thinks that if we were to peer down at the tiniest subdivisions of space and time, we would find a universe filled with an intrinsic jitter, the busy hum of static. This hum comes not from particles bouncing in and out of being or other kinds of quantum froth that physicists have argued about in the past. Rather Hogan’s noise would come about if space was not, as we have long assumed, smooth and continuous, a glassy backdrop to the dance of fields and particles. Hogan’s noise arises if space is made of chunks. Blocks. Bits. Hogan’s noise would imply that the universe is digital.
It is a breezy, early autumn afternoon when Hogan takes me to see the machine he is building to pick out this noise. A bright-blue shed rises out of the khaki prairie of the Fermilab campus, the only sign of new construction at this 45-year-old facility. A fist-wide pipe runs 40 meters from the shed to a long, perpendicular bunker, the former home of a beam that for decades shot subatomic particles north toward Minnesota. The bunker has been reclaimed by what Hogan calls his Holometer, a device designed to amplify the jitter in the fabric of space.