Others attribute the Big Bang to what they call “a false vacuum” or “a scalar field” or “vacuum energy”-some quality or thing, at any rate, that introduced a measure of instability into the nothingness that was. It seems impossible that you could get something from nothing, but the fact that once there was nothing and now there is a universe is evident proof that you can. It may be that our universe is merely part of many larger universes, some in different dimensions, and that Big Bangs are going on all the time all over the place. Or it may be that space and time had some other forms altogether before the Big Bang-forms too alien for us to imagine-and that the Big Bang represents some sort of transition phase, where the universe went from a form we can’t understand to one we almost can. “These are very close to religious questions,” Dr. Andrei Linde, a cosmologist at Stanford, told the New York Times in 2001.

The Big Bang theory isn’t about the bang itself but about what happened after the bang. Not long after, mind you. By doing a lot of math and watching carefully what goes on in particle accelerators, scientists believe they can look back to 10^-43 seconds after the moment of creation, when the universe was still so small that you would have needed a microscope to find it. We mustn’t swoon over every extraordinary number that comes before us, but it is perhaps worth latching on to one from time to time just to be reminded of their ungraspable and amazing breadth. Thus 10^-43 is 0.000000000000000000000 0000000000000000000001, or one 10 million trillion trillion trillionths of a second.

Most of what we know, or believe we know, about the early moments of the universe is thanks to an idea called inflation theory first propounded in 1979 by a junior particle physicist, then at Stanford, now at MIT, named Alan Guth. He was thirty-two years old and, by his own admission, had never done anything much before. He would probably never have had his great theory except that he happened to attend a lecture on the Big Bang given by none other than Robert Dicke. The lecture inspired Guth to take an interest in cosmology, and in particular in the birth of the universe.