Until the End of Time: Mind, Matter, and Our Search for Meaning in an Evolving Universe

by Brian Greene

Although I described the inflaton’s value as being uniform, taking on the same value at all locations within the inflating patch of space, quantum uncertainty fuzzes this out. Uncertainty overlays quantum jitters on the classical uniformity, resulting in the field’s value, and hence its energy, being a tiny bit higher here and a tiny bit lower there. When inflationary expansion rapidly stretches these minute quantum energy variations, they spread across space making the temperature a touch hotter over here and a touch cooler over there. Not by much. Mathematical analyses, first carried out by physicists in the 1980s, showed that the temperatures of hot and cold spots would differ by as little as one part in a hundred thousand. But the mathematical analyses also suggested that the tiny temperature variations would be visible if you knew how to look for them. The calculations revealed that the stretched-out quantum jitters result in a distinct pattern of temperature variations across space, a cosmological fingerprint available for astronomical forensics. Indeed, since the early 1990s, a sequence of telescopes deployed above the distortions caused by earth’s atmosphere have confirmed the predicted pattern of temperature variations with ever-greater precision.