Using data from a new map of the baby universe, astronomers said yesterday that they had seen deep into the Big Bang, and had gotten their first detailed hint of what was going on less than a trillionth of a second after time began.

The results, they said, validated a key prediction of the speculative but popular cosmic theory known as inflation about the distribution of matter and energy in the Big Bang. The theory holds that during its first moments, the universe, fueled by an antigravitational field, underwent a violent growth spurt, ballooning from submicroscopic to astronomical size in the blink of an eye.