Isotropy

Imagine being in a giant sphere filled with translucent beads. You look to the left, and you see a prism of distorted light, refracting as far as you can see into a uniform color and consistency. When you look to the right, it’s the same—no matter how far you peer, and no matter what direction you look in, everything looks the same.

This condition is called isotropy. It comes from the Greek words isos and trópos, which roughly mean “equal turn.” To say that something is isotropic is to say that everything is uniform in all directions.

Our universe is isotropic. No matter how many billions of light years away you look, and no matter the direction, space and its relationship to matter are identical—that is, once you get to a large enough scale. There’s no way to know if you’re peering out at the distant cosmos from Nigeria or from Bolivia, except for the stuff that’s close enough for us to have mapped.

Well… it’s very, very isotropic. But even at very big scales, there are regions of ani…