The Big Bang is generally considered to be the beginning of time, as the universe was created about 13.8 billion years ago, giving birth to the planets and the stars. And while there might have been, in theory, events that took place before our universe was born, physicist Stephen Hawking’s “no-boundary proposal” suggests that there is no way these events could be defined.
As noted by Popular Science, Hawking explained his theory in an interview conducted by fellow scientist Neil deGrasse Tyson on the latter’s National Geographic Channel program, StarTalk. Although the episode is scheduled to air on Sunday night at 11 p.m. ET, Popular Science posted a clip from the episode, and quoted some of the statements Hawking made about the Big Bang, and what could have possibly happened before our universe began to exist.
“Nothing was around before the big, big bang,” said Hawking.
Further expounding on his comments on the no-boundary proposal, Stephen Hawking added that if the universe really has no boundaries, time was in what he called a “bent,” distorted state prior to the Big Bang, though it incrementally smoothed out as the birth of the universe drew closer. According to News.com.au, this could mean that there was no such thing as a singular event where the universe was created from “nothing,” though it may look like that from the typical human perspective.
According to Live Science, Stephen Hawking’s appearance on Neil deGrasse Tyson’s StarTalk won’t be the first time for him to discuss the no-boundary proposal. Aside from a free documentary on YouTube where he explains the theory, he had also written and given out multiple lectures on the subject matter, including one where he wrote that all the events that might have happened prior to the Big Bang are “simply not defined,” as it’s impossible to measure when those events happened, or to determine what had actually taken place.
“Since events before the Big Bang have no observational consequences, one may as well cut them out of the theory, and say that time began at the Big Bang.”
As explained by Newsweek, the ideas of a single “Big Bang” giving rise to the universe some 13.8 billion years ago and the universe constantly expanding since its birth have been so widely accepted, but that hasn’t stopped scientists from speculating about the forces behind that expansion, or if there was such a thing as time before the Big Bang. Hawking’s no-boundary theory, however, suggests that ordinary time was, before the Big Bang, “replaced by imaginary time,” much like a “fourth direction of space.”
While Newsweek opined that Stephen Hawking’s no-boundary proposal may be a bit of a “brain teaser” at some points, the publication stressed that the main point is easier to understand, if one compares space-time to Earth’s poles or other curved surfaces that extend continuously.
“There is nothing south of the South Pole,” Hawking explained. “There was nothing around before the Big Bang.”