By Richard Panek
The views expressed are his own.

For the first time in history our species has begun to answer some of the eternal questions about the universe: Where did it come from? Where is it going? We’re able to do so in part because of the discovery that is being recognized by this year’s Nobel Prize in Physics.

Before Galileo published the first discoveries he made with a primitive telescope, in 1610, cosmology—the study of the structure and evolution of the universe—was equal parts speculation and superstition. Even the subsequent, centuries-long discoveries of new planets, new moons, new stars, and new galaxies didn’t address the evolution of the universe. Not until Edwin Hubble’s 1929 discovery that, on a cosmic scale, galaxies appear to be receding from one another, carried along by the expansion of space itself, did the universe begin to acquire a narrative—a story that changes over time.

Even then theorists split into two camps: those who posited a universe that emerged in a “big bang,” and those who preferred a universe poised in a “steady state” through the continuous creation of matter. And there the theoretical divide, as theoretical divides must do in the absence of evidence, rested.

That evidence arrived in 1964, with the discovery of a remnant radiation that matched a prediction of the Big Bang theory. The answer to the question of where the universe had come from was beginning to find its answer—and cosmology was beginning its passage from metaphysics to physics, from speculation to science.

And what of the fate of the universe? Throughout the 1990s, two international teams of scientists raced each other to find out the answer. They reasoned that if the universe is expanding, and all the matter in the universe is attracting all the other matter in the universe through gravity, then the cumulative gravitational drag of all that matter on all that other matter would be slowing the expansion. The question was, How much? So much that the universe will eventually stretch as far as it can go, reverse direction, and collapse back on itself? Or so little that the universe will keep cruising, more and more slowly, until it reaches a virtual standstill?