|
D:\M J\Sanjit pers\4kids\httpdocs\sidebar.html
|
It's amazing to see a
star studded night sky. Those countless bluish-white twinklers are, as
if, sprayed across the black canopy up above. The longer you keep
looking up, the more of those twinklers bloom out from the dark
background. True, the night sky does not view the Sun. But it offers a
far greater view. The view of the Universe. The universe that comprises
billions and billions of such suns and their families. Our solar
system, to which the Earth belongs, is also a tiny member of this
universe. And like those twinklers it is tucked away, up there against
the vast blackness.
At the outset, though, all of them appear more or less the same, they
are not.
A little keener gaze, and you can tell the difference. Some are
twinkling with a glow, some are fader, yet, stay steady. Some are off
white, while some sport a shade bluish tinge. Some are closer, while
some are way far. Some of them are stars, some planets, and, moons or
satellites. The shooting ones are mostly meteors, while those with a
trailing light are mostly comets. Scientists or astronomers have made
us familiar with quite a few of them. Yet, there are countless of them
still unknown.
In fact, the star studded night skies are a window to the limitless
world of the unknowns.
However, what we see there with naked eyes reveals only a small glimpse
of a far more huge world. And there are just too many of those stars
and comets and planets and moons and meteors that we can imagine.
The larger bodies to which
we belong:
|
For a better
understanding, the whole of the universe can be said to be made of
certain smaller units of different sizes and shapes. The largest types
of these universal units are called star Clusters. In fact, there are
such millions and millions of star Clusters in the universe. And each
of these clusters contains a group of galaxies, the second largest
units of the universe. Again, these galaxies comprise a number of
star-systems, like that of the Sun. Our Sun is only one star of such a
galaxy, called Milky Way. And the Milky Way consists of about 100,000
million stars, along with clouds of dust and gas. So imagine the
vastness of our universe compared to our small planet. Or, just the
other way round - the smallness of our planet vis-a-vis the
universe.
top
The divine
discipline:
Anything you can think of to which we can compare this well ordered
vastness? It is fascinating to note that despite such huge
vastness, there is an inherent discipline and orderliness. It is that
orderliness that has bound everything inside it in their respective
place. It is like a strange endless elastic super-string. Thus each of
the insiders can move on freely in their path. But wherever they go the
super string keeps them bound by the rule of the universe. This
super-string like binder, that embraces all bodies in the universe, is
called gravitation.
In fact, all these stars and planets, which appear fixed up against the
night sky, follow certain course of motions. Yet, they are not
displaced or derailed from their course due to this gravitation. Like
the planets in the solar system, the Sun itself is in motion, Along
with it carries the whole system. But over a much longer period. And so
does all the star-systems like that of the Sun.
And, the galaxies made
up of these star systems, are also in motion. Many rotate about their
own axis, while the stars inside them move back and forth. Thus, rotate
or not, each galaxy is also moving along as a whole. Even so, the
distances between galaxies take a 1000 million years to move past each
other.
Besides, these individual motions, the distant galaxies have a rapid
motions, the distant galaxies have a rapid motion in common. They all
seem to be moving away from us. The farther they are, the faster they
appear to move away from us. So the distant ones move faster than those
nearer our own galaxy. These movement farther away points to the
concept or the universe being inflated like a balloon. And it is called
the expansion of the universe.
When the universe was first conceived of as an orderly unit, it was
called cosmos. Just as opposed to chaos. The movement of the star
against galaxy affects its light as seen by an observer. top
The expansion
and the Big Bang:
Well, is there an end to this kind of expansion?
This is where the theory of Big Bang came in. The idea holds that the
universe began in an immense explosion of space-time. The legacy of
that bang is the expanding universe, in which everything races away
from everything else like raisins in a rising tea-cake.
Abbe Georges Lemaitre, a Belgian astronomer-priest, explained this
process of expansion in the 'big bang' theory. He argued that billions
of years ago, cosmic matter or the universe, was in an extremely
compressed state. With all its energy and mass compressed into,
commonly termed, a super dense ball.
Then a kind of huge explosion took place. This
explosion, called the 'Big Bang' because of its hugeness,
spark-plugged the process of compression. This explosion broke
up the super dense ball and cast its fragments far out into the
space. There they are still traveling at thousands of
kilometers per second. It is from these speeding fragments of
matter that our galaxies
have been formed.
The formation of galaxies and stars has not halted the speed of
expansion. And as it happens in all explosions, the farthest
pieces are flying the fastest. |
 |
The explosion is of a
primordial type. Because it was the first of its kind known to the
universe. And this primordial explosion is the hallmark of the big bang
theory. And it is regarded as one of the most viable theories that
explain the birth and life of the universe. Based on this line of
thought, scientists now believe that the universe not only expands. But
it contracts as well. This expansion and contraction take place
alternately between periods running into tens of billions of
years. top
The next bang
and after:
Some scientists believe that it was about 12 billion years ago when the
great explosion occurred in the universe. And that the universe has
been expanding ever since. It is likely to expand for 29 billion years
more. Following this the gravitation will halt further expansion. From
then on all matters will begin to contract or collapse upon itself in a
process known as 'implosion'. This will go on for some 41 billion years
compressing matters into an extremely super dense state and then it
will explode once again.
|
