Was There A
Yes, there was a beginning to time. However, a cautionary note is
Although our psychological sense of past, present, and future is strong, time may not
be a fundamental physical entity at all. Rather, it may simply express the numerical order of
For example, when a photon of light moves from position 1 to
position 2, position 1 doesn't exist before
position 2 in time, only in numerical order.
In this sense, the universe is timeless even though we use the word "spacetime"
to describe it. The universe isn't 3D in space and 1D in time, but
rather 4D in space.
Time plays an important role in comparing durations and in
describing physical systems but it may describe only how space
is quantum-networked and entangled, rather than describing something apart
That being said, our real time began when our universe did, in an
inconceivably hot, dense, tiny spot just after the "Big Bang".
wasn't an explosion in the usual sense of the word but rather the
sudden appearance of expanding space. Since then, a duration
equal to about 13.82 billion Earth years has elapsed.
"Big Bang" is a term
coined somewhat mockingly by Fred Hoyle, a 20th century English astronomer,
science fiction writer, and big-bang denier. In 1948, he argued against a beginning of time, proposing instead a
"steady state" universe with infinite time. He
rejected both the Big Bang theory and the Book of Genesis as
pseudoscience that suggests a creator.
But the challenge for Hoyle's theory was the observed expansion of our
universe over time, hardly a steady state. To explain the
expansion, confirmed in 1927 by Edwin Hubble, Hoyle postulated Mini Bangs
in between the galaxies that keep the outward flow of matter
constant, like a steadily flowing river.
But Hoyle's job got more difficult in the early 1960s when radio
sources were found to be more prevalent in the early (far away)
universe than in more recent times, once again contradicting a steady-state universe. In 1963, quasars, which almost only occur in the distant past, were discovered.
Then, in 1965, the observation of the cosmic microwave background (CMB), a
radiation with no discernable source, pretty much killed the Steady State theory.
What's more, the Big Bang
theory had predicted just such a background radiation.
When physicists try to extrapolate back in time from the earliest
well-understood state of the universe, a miniscule fraction of a
second after the big bang, they quickly hit a gravitational (a curvature) "singularity" where
classical laws break down: gravity, material density, and temperature
become infinite and spatial dimensions shrink to zero.
To the rescue comes imaginary time, which treats time like a dimension of
space and successfully predicts quantum behavior. The state of
our universe in real time can be calculated from the state of our universe in
Moreover, singularities like the big bang don't interrupt the flow of
imaginary time. Therefore, a beginning to real time doesn't
violate any physical laws
or call for a creator.
Steven Hawking has shown that the Big Bang could've been an ordinary point on
surface of spacetime just like the North Pole is an ordinary point on
2-dimensional surface of
The sudden expansion of such a singular point and the rapid inflation
universe could borrow energy from the intense gravitational field to create
In imaginary time, no physical laws would be violated and the gravitational debt
could be repaid at the end of
In 1994, when a Big Bang renaming contest in Sky and Telescope
magazine failed to pick a winner, Fred Hoyle said of the Big Bang, "Words are like
harpoons...Once they go in, they're very hard to pull out."