Once upon a time (?), there lived
two legendary friends in Mars, called Bob and Jack. Bob was born in poverty,
while Jack in aristocracy. This is their story of birth and death, and the tale
of how Nature played them false. I will tell you all for their angels reported
me thus.
Mars is a different planet in a
different universe. The numbers that Nature plays with are a bit different
there. However, Nature is as cunning there as she is here. But since the
numbers are not the same, it happens to be that the Martians are well aware of
Nature’s deceitful nature. For instance, the speed of light – the universal
constant of Nature – is approximately 11.547 ms-1. As perhaps can be sensed from what has been
just said, Bob and Jack by mere chance happen to use units from the metric
system. But that is not the point. The point is, Bob and Jack happen to see
with their bare eyes the conspiracy that builds up from there.
The Martians live a long
perspicuous life of exactly a period of five seconds. That’s the way things are
in Mars. Wait! The statement is not complete yet. They live for five seconds if
they do not move, but stay at rest for their entire lifetime. Why is that?
Because motion increases their lifetime by several factors. And that is because
the decree of Nature is, “Thy shalt find moving clocks run slow.” Now
Nature does not care about the engineering abilities of the Martians, or what
dials and gears and wheels, in what order and arrangement, they use to
construct their clocks. What she knows is ‘time’ that they intend to measure
using devices they call clocks. Therefore, the decree is that time must run
slow in the first place. The Martians could use a bucket full of water (or
whatever liquid they drink) with a tiny pore in it that lets drops of water
fall periodically, as a way to measure time, as a clock. Or, they could use
their own pulses in their wrists. Or, perhaps atomic clocks. But the thing is,
whatever they look at as a clock, must run slow. Therefore, even biologically,
their metabolism slows down, they grow slowly, they talk slowly, and everything
is slow: even if a cup drops from their hands, it comes to the ground and
breaks and pieces fly apart, it is as if in a slow motion movie. But there is a
hitch, what does it mean to say that something slows down? Of course, the person
that is slow finds everything running at normal pace because his world slows
with him. Words like big, small, fast or slow have no meaning in the absolute
sense, they are used in comparison of two things. To say that moving clocks run
slow is to say that they run slow when compared with the clocks at rest.
Therefore, moving aliens live longer (although they themselves perceive it not)
according to those that remain motionless in the ground.
Having said that, there comes
this BIG question that why Nature must lay forward such a decree. The answer
lies in one of the cute natures of Nature that she is a cosmopolitan socialist.
To Nature, all are equal, all people, microbes, even dust or the different ways
they behave – equal as the tooth of a comb, irrespective of whether they are at
rest, or moving uniformly with some speed in some direction. No one is
preferred by Nature, in the sense that whether they are at rest, or moving
uniformly with respect to someone else. Now there is this another aspect of
Nature called electricity and magnetism that is a bit nasty. By the very nature
of the laws of electricity and magnetism, there comes into being a phenomenon
called light that travels at a certain tremendous amount of speed determined
exclusively by the product of two fundamental constants – one from electricity,
and the other from magnetism. Because Nature is one and the same for all (that
move with respect to one another), one must not be able to differentiate
between moving systems by an excuse in the name of the electric and magnetic
phenomena observed in them. And therefore, electromagnetic constants ought to
be constant. Therefore, the speed of light ought to be a natural constant
irrespective of one’s state of motion. And lo! It is.
So in some sense, Nature is now
squeezed a bit by the very things her own hands have put forth. So, she plays
around with a few numbers to make both ends meet and keep the speed of light a
constant, that is to say, make the person at rest and the one in relative
motion measure the same speed of light. The first of her strategy is slowing
down of time in the moving system with respect to the one who considers himself
at rest. What is so clever in that? Nature knows that she need not worry about
the thing called light, but about the speed of light that they measure. It does
not matter who or what has this speed called the speed of light, but if she can
arrange that everyone else (whether at rest or relatively moving) agree upon
this that his speed is always the same independent of who measures it, her job
is done. Take for instance, a bullet shot inside a ship, and the bullet travels
with the speed of light as seen from the ship. Now as seen from the ground, if
the ship catches a speed equal to the speed of light, time must appear to
freeze inside the ship, for only when it is so, the ground observer claims that
the bullet being frozen in air inside the ship, it travels with the same speed
as the ship, the speed of light. So you get the rough idea of what really
happens – time slows with motion, and at the extreme, freezes with the highest
possible motion, the speed of light – all to keep Nature cosmopolitan. That’s
not so hard to understand. The main fact is that moving aliens live longer.
Coming back to Bob and Jack, it
is worth mentioning that Bob’s parents were so stricken by poverty that they
decided they could not afford to have another child, so before he was even
born, his parents planned to murder him. These idiots become Wordsworth in
spring, and turn into Devil by winter. So they gave him birth in a railway
track. You perhaps got their intention. And with time, the train arrived. The
train came running with a crazy speed of almost the speed of light. Such
technology they had. The train had a speed of 10 ms-1. Crushed by
such a train, there is no chance of survival. The train rushed towards Bob.
Death awaited him as he was bound to the ground with indestructible chains.
But destiny was clever. When Bob
was born, the train was very far away, 50 meters from him. Coincidentally, Jack
the lucky rich was also born exactly the same time that Bob was born, but
inside the train. Since the train moved with a tremendous speed as seen from
the ground, time slowed inside the train, and Jack’s lifetime got doubled as
compared to Bob’s. Take my word for it, the mathematics of Nature’s conspiracy
resulted in this factor of 2. The train with the speed it had, took 5 seconds
to cover the 50 meters and finally come to Bob. And by that time, Bob had
already lived his full lifetime and died of old age. So the train only crushed
Bob’s dead, and he was spared from the tragedy.
By the time that Bob’s body was
crushed, Jack had lived only half his life, and there were 5 more seconds for
him to live. This is the description of all that happened as seen by an angel
standing on the ground.
But explanations are quite
different as given by an angel who saw the same thing from the train. From the
train, everything kept zooming past the ‘train at rest’ – the trees, the
buildings, the ground, the railway track, with this ominous speed of 10 ms-1.
It is true that Jack had lived only half his life when Bob came running under
the wheels of the train the time when he had just completed his natural
lifespan and died of ripeness. This is Nature being same to all. What Nature
really changed in this perspective are only a few numbers used to come to this
conclusion. The main thing is, since Jack was at rest according to this angel,
his lifetime was only 5 seconds now. However, since the planet moved past the
train with a speed of 10 ms-1, time slowed everywhere outside the
train because moving clocks run slow, and therefore Bob’s lifetime doubled to
10 seconds.
So how did Nature direct numbers
to change in the train for everything to make sense? First of all, simultaneity
broke down. Bob and Jack were not born at the same time. Bob was elder than
Jack by 7.5 seconds precisely (which was technically 0 seconds to those who
found Bob at rest). Nature exclaims, “This, because ye art born at places
that are not the same.” Secondly, the length scales changed. Looking back
into the past, 7.5 seconds before the birth of Jack, as Bob came into being, he
was 100 meters away from the train. So as the ground rolled below the train, it
dragged Bob with it and brought him to the wheels at a rate of 10 ms-1
which took exactly 10 seconds to cover the distance. This was the lifetime of
Bob. And only his corpse got crushed. It made sense.
But the strange thing was, as
seen from the train, out of these 100 meters of distance, Bob had traveled 75
meters without Jack. Only 2.5 seconds before the death of Bob, Jack was born.
So for the common time that they spent their life together, Jack found Bob
travel only 25 meters of the total journey. But recall, this common distance of
25 meters was 5o meters to Bob as he saw it from the ground. Therefore, the
angels noticed that 50 meters of the stationary railway track had shrunk to
just 25 meters when the perspective was changed where it was no longer
stationary but moved with a speed of 10 ms-1. They conclude, in
harmony with Nature’s commandment, “Moving rods, ye shall contract.”
Now the happy ending! Jack could
not live more than 5 seconds. He had lived 2.5 seconds when Bob died. Therefore
he had yet to live half of his life. So everything’s perfect for this one
moment.
Thus did the angels tell me, simultaneity
breaks, lengths contract and time dilates to make things sensible. These are no
fantasy but reality that has been observed in this world experimentally. Any
question that can be raised experimentally has a physical reality behind it
that cannot be denied as an answer. Nature wins this time and every time, for
she is cunning but not malicious. If you do not believe in the numbers that I
gave you, ask the angels – they are the Lorentz Transformations.