It's 12:50
pm, so simple right? One can look at his/her watch or computer screen or phone
to tell what time it is. But, how did human measure time a thousand or even a
million years ago? There was no such thing as watch, phone, or computer. The
old method is using the position of the sun on the sky; a new day begins with
the sun rises and the cycle continues for what seems to be infinite relative to
our life time. Another method used by Chinese calendar was the moon. One
revolution of the moon around the Earth was one lunar month. Then, there came
the mechanical clock, then scientists used speed of light to redefine the
definition of a second, and now they are using the radioactive property of
Caesium-133 to define the nature of 1 second. However, for some people, one
second is merely greater than the time it takes to blink, thirty minutes is the
time to get to work, five minutes is the time to brush ones' teeth, and as for
me seven minutes is the time it takes to ride my bike from my dorm to my class.
As we all see, time is compared/seen as distance between home and work, the
position of one celestial body relative to another, the time its take for one
photon to go 299,792,458 meters… If one has a hard time imagining the
"fourth dimension"-time, it is, in these cases, being estimated by
the other three dimensions. Nevertheless, why can't we "see" time nor
draw a world with four dimensions.
That's because we just simply can't. For example, if we could see the
famous, extra "fourth dimension," time, as any of the three other
dimensions, we would easily look back in time and even at the future as simply
looking down the road. I personally think it is really stupid of anyone to try
to understand the computer graphic of four, ten, or twenty dimensions, we just
can't PERIOD. As I just said, it's one reason for humans to use the three
dimensions to estimate time.
So, where
does time come from? People are discussing that the Big Bang created time, but
how come? Don't we have time before the Bang? It is hard to perceive not to
have time, isn't it? But think this way. The big Bang created stuffs which in
turn created the Stars, the Sun, the Earth, the Moon, photons, Cesium... They
are our instruments to measure time, aren't they? It's the creation of 3D space
that makes it possible to estimate time. Not fully persuaded/understood? Put it
this way, I am about to prove time backward. Assume that the Big Rip is true
(The Big Rip is a cosmological hypothesis first published in 2003, about the
ultimate fate of the universe, in which the matter of the universe, from stars
and galaxies to atoms and subatomic particles, is progressively torn apart by
the expansion of the universe at a certain time in the future). So particles
(photons, quarks...) will be infinitely away from each other. In other word, no
two particles will ever meet again. So, a photon (light particle) will be alone
in the universe, and it won't know that it is traveling at 300 million meters
per second because there is nothing around it (such as houses, planets, or
stars) to tell how far it goes. Or this photon is being confused by asking
"am I really moving? I don't see so." The 3D space is annihilated
into 0D space-a single point, and frankly time has disappeared because there is
no photon can tell the time or Cesium to decay. So the "rip"
of matter brings the disappearance of time. Now, we go back and say, the
creation of matter, the Big Bang, creates time.
