A pair of scientists from the UK recently published a pre-print research
paper discussing the theory of a universe with no beginning.
Imagine it: our universe has always existed. The Big Bang either never
happened or it was simply another event in the infinite history of… itself.
On the surface it sounds counter-intuitive. According to the researchers, a
quantum physics paradigm called a “causal set” structure makes it possible
for the universe to exist beyond its perceived origin.
Per the duo’s
paper:
- Did time ever begin? It is hard to decide which answer is more unsettling: the idea of an infinite past with no beginning or the concept of such a beginning—the birth of the Universe.
- Stephen Hawking proved that General Relativity (GR) breaks down at a Big Bang singularity, but left open the possibility that the Big Bang is not the beginning of time but rather that it was preceded by a quantum gravity era which cannot be captured by GR.
- The question of the beginning of time must therefore be addressed within a theory of quantum gravity.
So what is quantum gravity and what does it have to do with time travel?
Well, the answer to the second question is: everything. But the first
question’s a bit more complicated.
Quantum gravity, at its most basic, is what scientists think occurs when
classical physics become mathematically nonsensical around quantum phenomena
such as black holes.
Time travel
The only surefire way to travel through time is to move through space at
near light speed. Theoretically speaking, a person traveling at such a speed
would physically experience time at a slower rate than someone standing
still on a planetary body. The same would ring true for someone caught in
the quantum gravity of a black hole.
However, all three persons would observe time at the “normal” rate. If you
were on a spaceship traveling at light speed your watch would still appear
to be ticking off seconds normally.
Obviously this doesn’t help us much if we want to go back in time and invest
in Microsoft or flash forward a hundred years to see what Grand Theft Auto 8
is like.
But that might be the best we can muster. If the universe has no beginning,
it’s conceivable that time travel isn’t possible because time and space are
essentially the same thing.
Stopping time
Let’s break down time into some easy-to-chew concepts. What if we could stop
time? What would that mean?
We’ll almost certainly never know. Time, as a measurement, effects all
things. The reason you’re capable of having a glass of water with ice in it
is because molecules move at different speeds during different phases. When
heat is applied to a substance its molecules move faster. And you can’t
measure speed without time.
So, if you pushed a big red button that said “STOP TIME,” you’d probably die
instantly because your brain, heart, and lungs all rely on the motion of
molecules.
Even if you were immune to the time-stoppage effects, you wouldn’t be able
to move through the air molecules because they’d be stuck. Anyone who’s ever
had an umbrella yanked out of their hands by a gust of wind knows that air
has mass.
Neither classical nor quantum physics appear to provide a viable scientific
path towards external time management. Stopping time like a supervillain or
moving through it like Doctor Who or Marty McFly remains solely in the realm
of science fiction.
But time is its own dimension, right?
Where things start to get interesting is when you stop playing by the rules
of classical physics and instead use quantum mechanics.
If the universe has no beginning, as the UK researchers posit, then it
follows that beginnings and endings are purely relative. We can’t imagine
time as a line or circle with an arrow indicating passage anymore.
We’re forced to view time as something inextricable from space. In other
words: space and time aren’t separate concepts. They combine to make up the
individual, discrete units which make up the bedrock of our universe.
This may sound counter-intuitive. But, if you think about it, you can’t hand
someone an inch or a minute. You can take a minute to go grab an inch of red
fabric. But measurements of time and space exist only to describe our
observations. If you take away the observations, the inches, and the
minutes, the universe still stays fundamentally the same.
The universe, arguably, makes no observations. Yet by all accounts it
exists. So the question becomes: does time exist if it is unobserved?
The answer’s an unequivocal “yes,” if we take the “timespace” view of time.
Timeless travel
If we can’t travel through time, or stop time to travel, perhaps we can
exploit quantum mechanics for timeless travel.
Scientists have long believed that the universe may contain hidden features
that allow us to turn our classical understanding of physics on its head.
One such wacky prospect is the idea of teleportation. The big idea there
usually involves wormholes that connect two points separated by distance.
These theories posit a method by which humans could potentially bend or
breach the fabric of the universe in order to travel great distances
instantly.
But, a universe that’s always existed may not actually have points that can
be bent or breached. Theories involving a “causal set” paradigm intimate
that the universe isn’t a big bowl of space that’s expanding at the edges,
but a discrete set of units that are multiplying.
It’s like someone took String Theory and said “yeah, but let’s do it without
the strings.”
In such a universe time wouldn’t affect our ability to actually travel
through space, just our observations on such travel.
Effectively, this could remove the speed limits put in place by Einstein’s
theory of relativity. An object capable of achieving a speed greater than
that of light itself would, theoretically, be capable of superseding
timespace itself.
In this form of timeless travel you wouldn’t teleport, you’d actually
traverse a measurable distance. But it wouldn’t take any time for you to
reach your destination because, essentially, you’d be sliding across the
space part of timespace by outrunning the time part.
Source: Link
Tags:
Physics