“You may speculate from the day that days were created,
but you may not speculate on what was before that.”
—Talmud, Tractate Hagigah 11b, 450 A.D.
To go back to the beginning, if there was a beginning, means testing the dominant theory of cosmogenesis, the model known as inflation. Inflation, first proposed in the early 1980s, was a bandage applied to treat the seemingly grave wounds cosmologists had found in the Big Bang model as originally conceived. To call inflation bold is an understatement; it implied that our universe began by expanding at the incomprehensible speed of light … or even faster! Luckily, the bandage of inflation was only needed for an astonishingly minuscule fraction of a second. In that most microscopic ash of time, the very die of the cosmos was cast. All that was and ever would be, on a cosmic scale at least—vast assemblies of galaxies, and the geometry of the space between them—was forged.
For more than 30 years, inflation remained frustratingly unproven. Some said it couldn’t be proven. But everyone agreed on one thing: If cosmologists could detect a unique pattern in the cosmos’s earliest light, light known as the cosmic microwave background (CMB), a ticket to Stockholm was inevitable.