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Archive for January, 2013

black bole

Black Holes: The Prima Donnas of Space Opera!

All the world is a stage
And all the men and women mearly players
They have their exits and entrances,
And one man in his time plays many parts.
(William Shakespeare)
The whole Universe is a stage all the planets stars are like the actors they too
have their exists and entrances..they form they disintegrate and reform.
There are unaccountable universes in the Cosmos
The huge collections of suns planets moon asteroids and physical debris of
all sorts we designate as galaxies. The galaxies are moving apart further
with great speed. The center of the galaxies is dark and possesses relentless
gravitational pull. They are called Black Holes. We cannot see black holes
but we can determine them from material falling into them.
The term black hole is ofrecent origin it was coined in 1969 by an
American scientist JohnWheeler. From where do these black holes emerge?
To understand , we must first see the life cycle of a star.
A star is formed when large amount of gas(hydrogen) starts to collapse
on itself due to gravity. As it contracts the atoms of the gas collide with
eachother. Heat is generated. The atoms coalease to form Helium then
Oxygen Carbon Iron etc etc elements are formed. Huge amount of energy
and heat is released during the nuclear reactions, explosions taking place
inside the star –is what makes the star shine.
The star remains stable for millions of years. It is a bit like a
Balloon. There is balance between the pressure of the air inside which is
trying to make the balloon expand and the tension of the rubber which
is trying to make he balloon smaller. The heat from the nuclear reaction
balancing the gravitational attraction.
When all the nuclear fuel is used up the star cools down and so it contracts.
What might happen to it then was first understood at the end of 1920.
Subramanyn Chandrashekhar: In 1928 an Indian graduate set sail for
England to study at Cambridge,with the British Scientist Sir Arthur
Eddington an expert in general relativity.
S. Chandrashekahar framed that when a cold star(dying star) who’s mass is more
than one and a half time the mass of the sun( this mass is known
Chandrashekhar Limit.) it would not be able to support itself against
its own gravity, it would collapse and form a stellar remnant(Neutron Star)
or a Black hole.
The boundry of the black hole is called the event horizon. The
point of no return. The light too cannot escape. Black holes of
Stellar mass are expected to form when very massive stars collapse
at the end of their lifecycle.
Eddington did not approve that a star shrinking to zero as per Chandrashekar. A lot of controversy sparked amongst the scientist.
Later in the year 1983 Chandrashekar was awarded Nobel Prize
for his work on the limiting mass of cold stars
There is a strong evidence of a black hole of more than four million solar masses at the center of our galaxy-Milky Way.
Endless process of destruction and regeneration is going on and on inside the black holes they indeed are the prima donna of Space Opera …..
Another and another cup to drown,
The memory of this Impertinence!
(Omar Khayyam)
By
Prajakta Dighe
My above article got published in The Hitavada dated 6/5/2012
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