Source: NY Times
By Dennis Overbye
Misconception: The universe started someplace.
Actually: The Big Bang didn’t happen at a place; it happened at a time.
“Where did the Big Bang happen?” I am often asked, as if the expansion of the universe was like a hand grenade going off and the solar system and our Milky Way galaxy were shards sent flying.
The universe didn’t start at a place, it started at a time, namely 13.8 billion years ago, according to the best cosmological data. It’s been expanding ever since — not into space because the universe by definition fills all space already, so much as into time, which as far as we know is open-ended.
It is true that everything we can see now, out to 13.8 billion years of light-travel time, was once the size of a grapefruit, buzzing with hideous energies, but that grapefruit was already part of an infinite ensemble with no edge, except one made up of time. When we look out, we look into the past, the farther we look, the more deeply into the past we see. At the center is the present. Alas there is no direction in which we can look to see the future — except perhaps into our own hearts and dreams. All we know is right now.
So where is the center of the universe? Right here. Yes, you are the center of the universe.
When Albert Einstein married space and time in his theory of relativity back in 1905, he taught us that our eyes are time machines. Nothing can go faster than the speed of light, the cosmic speed limit, and so all information comes to us, to the present, from the past.
We’re using the first week of April as an opportunity to debunk some of the misconceptions about health and science that circulate all year round.
And so Einstein’s relativity teaches us that the center of the universe is everywhere and nowhere. It is the present, surrounded by concentric shells of the past. History racing at you at 186,282 miles per second, the speed of light, the speed of all information. Your eyes are the cockpit of a time machine, filmy wet orbs looking in the only direction any of us can ever look: backward. Everything we see or feel or hear — now that gravitational waves have been discovered — took some time to get here, and so comes to our senses from the past. The moon, hovering over the horizon, is an image of light that left its cratered surface traveling at the speed of light a second and a half ago. The sun that burns your skin is eight minutes and nineteen seconds in the past.