Column Cosmology

A century ago, Alexander Friedmann envisioned the universe’s expansion

He saw that Einstein’s equations predicted multiple cosmic scenarios, including a Big Bang

By Tom Siegfried

Contributing Correspondent

black and white photo of Alexander Friedmann

In 1922, Alexander Friedmann (shown) outlined multiple possible histories of the universe. Cosmic expansion was among those possibilities.

Leningrad Physico-Technical Institute, courtesy AIP Emilio Segrè Visual Archives

For millennia, the universe did a pretty good job of keeping its secrets from science.

Ancient Greeks thought the universe was a sphere of fixed stars surrounding smaller spheres carrying planets around the central Earth.