[SOUND] How did it all start? An awesome question, certainly, but it appears there really was a beginning. Some scientists refer to this as the Big Bang. I like to call it the great flaring form. Imagine the universe beginning like this. [SOUND] 14 billion years ago, everything in the universe, all the bright matter of the stars in galaxies as well as all of the dark matter, no one has ever see. All of that existed in a single point. So energetic, it was trillions of degrees hot. [SOUND] Instantly, this micro-universal rushed apart even faster than the speed of light. [SOUND] The discovery that the universe has expanded, and is still expanding, is one of the greatest of human history. The common understanding had been that the universe is simply a vast space, a vast space in which things existed. Large things like galaxies and small things like atoms, scientists knew that matter changed form in the universe, but everyone assumed that the universe as a whole is not changing. But no. The universe is changing and has been changed dramatically. The universe has a start, a beginning, a middle where we are now, and perhaps in some far distant future, an end. [MUSIC] In the 1920s, the cosmologist, Edwin Hubble, trained his 100-inch telescope at the night sky. He was trying to determine if our Milky Way was the only galaxy in the universe. Not only did he discover the universe is filled with galaxies, he also determined that all of them are rushing away from each other. With Hubble's work, humanity learned that the universe began with a massive explosion that has been carrying the galaxies apart for billions of years. [MUSIC] Another special quality about the universe is the rate of expansion. If the rate of expansion had been slower [SOUND], even slightly slower [SOUND], even a millionth of a percent slower [SOUND], the universe would have recollapsed immediately. [SOUND] That would have been it. After a million years, the universe would have imploded upon itself and formed a massive black hole. On the other hand, if the universe had expanded a little more quickly [SOUND], even slightly more quickly [SOUND], even calculations show one millionth of 1% more quickly [NOISE], the universe would have expanded too quickly for structures to form, it would have simply exploded [SOUND]. There would have been no galaxies, no structure, no life, nothing but dust for all time. So what we've discovered is that we're living in the universe that is expanding at exactly the rate necessary for life and structure to come forth. It could be then that even though we can't call the early universe alive, we can understand it as life-generating. One of the physicists who was reflecting on this is the celebrated Freeman Dyson. And he mused that the more he reflected on the structures of the early universe, the more he became convinced that in some sense, the universe must have known from the very beginning that life was coming. [SOUND] The light, from the beginning of time, has been travelling for 14 billion years. [SOUND] Meanwhile, life has been evolving. With the recent emergence of advanced technology, we were at last able to see the story these photons tell about the birth of the universe and where we ultimately come from.
