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 where 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.
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 is 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.
The Jupiter
we see, glowering orange at the zenith these nights, is about 414 million miles
out there as of this writing, or 37 minutes away in the past. The light from
the center of the Milky Way, hiding behind the thick star clouds and dust lanes
of Sagittarius, takes 26,000 years to get here. While it was on the way the
first primitive ice age villages grew into skyscrapers metropolises. If you see
a person brushing her teeth, it's been a nanosecond ago.
This is more than poetry.
Mathematically, in Einsteinian terms, all the information and history available
at any one place in the universe is known as a light cone. Everybody has one
and everybody’s is slightly different, which means in effect that everyone’s
universe is a little different.
As a result
every spot in the universe is unique. There will always be a piece of it you
haven’t seen yet and a piece that you have seen but that nobody else has. There
is no place to stand if you want to claim universal knowledge. We all need each
other in order to overlap our knowledge. We don’t have to stay in our prisons.
Working together and sharing, we can know much more.
OUR
PERSPECTIVE
No hay comentarios:
Publicar un comentario