The Nature of Time
(Sheikh Imtiaz, Rawalpindi)
Space time
We know that time is universal.
We know that it is everywhere around us. We also know that it is regular and it
only moves in one direction. But these assumptions will not hold water as we
deepen our understanding of time.
It was Einstein who challenged the idea that time was regular. Einstein said
that time changes with the speed with which one moves. In other words, the
higher the speed with which an object moves the slower is the time for that
object vis-a-vis another, say at rest. Hence, time varies according to the speed
of an object. A concrete example is that of sub-atomic particles called Muons.
Muons are formed when cosmic rays collide with upper atmosphere.
The lifespan of a Muon is just two millionth of a second. Now how does this
particle travel miles to reach the Earth’s surface, whereas with such a short
lifespan it should only travel a few meters before dying out. The reason is that
since Muons travel close to the speed of light relative to the Earth, time slows
down for them and they manage to reach the surface of the Earth. Hence, time
stretches for these particles due to their speed.
In our normal life, time is orderly. And an object can exist only at one place
at one particular time. But this is not true at the sub-atomic level where time
becomes chaotic. An example is that of individual particles called Photons.
Light is made up of Photons. Now experiments have shown that a single Photon can
be at two different places and two different times simultaneously.
We also believe that time is always flowing and cannot stop. But even this is
not true! The black holes’ existence, which is extremely massive, has proven
that when the gravitational pull of an object is infinite, time slows down for
it. And for any object which is located at the centre of a black hole where
gravity is infinite, time will stop altogether or would cease to exist.
Another thing we experience in daily life is that time travels only in one
direction (forward) and cannot move backwards. But even that is not true. Can we
have a time machine? Perhaps yes! Theoretically it is very much possible! The
problem is with engineering. We still do not have the technology to build such a
sophisticated machine.
At the sub-atomic level the fabric of time and space become so unstable that it
assumes a kind of foam where tiny bubbles of space-time momentarily pop in and
pop out of existence. This is called space-time foam. Now objects called
wormholes (tiny passageways between two points in space and time) are contained
within this foam. Theoretically speaking we can stabilize these wormholes and
bring them into a permanent state by subjecting them to an enormous amount of
energy(inside an accelerator). After a wormhole is stabilized it can be plucked
out and enlarged through negative energy (a kind of energy with
anti-gravitational properties) inside a laboratory.
Once this objective is achieved, we can have two wormholes like two capsules.
Now by subjecting one end of a wormhole to a huge gravitational field we can
bring its clock almost to a stop. This way we have two wormholes existing at
same place but at different times. This can be the prototype of a time machine.
Is time eternal? We do not know!
But if our current model holds, then the passage of time will essentially cease
somewhere beyond
10,000-trillion-trillion-trillion-trillion-trillion-trillion-trillion-trillion
years down the road.
Finally we can say in the words of Bill Bryson that “Physics is really nothing
more than a search for ultimate simplicity, but so far all we have is a kind of
elegant messines