Two words "black hole" . But the greatest mystery of the universe is hidden in this two words.This is the thoughts of world's greatest scientists from Einstein upto Stephen Hawking.During last three-four decades the fiction-writers are creating lots of utterances about this which may be possible or not.
A black hole is a concentration of mass whose gravitational field is so strong that nothing can escape.General Relativity not only says that black hole can exist , but in fact predicts that they will be formed whenever a sufficient amount of mass gets packed in a small region in space known as gravitational collapse.As the mass inside the given region of space increases ,it's gravity becomes stronger .Eventually gravity gets so strong that nothing can escape ; an event horizon is formed, & matter & energy must inevitably collapse to a density beyond the limits of known physics.
Surrounding a black hole , there exists few miles of pure stoicism .There is no existence of space.According to the scientists , in the surrounding of this holes , the amount of spinning objects & energy present , is few multiples of the Sun.But the presence of this particles can't be seen directly , though Hubble Space Telescope helps to feel it's effects.
The surface of a black hole is the so-called event horizon,an imaginary surface surrounding the mass of the black hole .Stephen Hawking proved that the topology of the event horizon of a non-spinning black hole is a sphere. At the event horizon , the escape velocity is equal to the speed of light.Particles outside this region can fall in , cross yhe event horizon, & will never be able to leave.
3.FRAME OF REFERENCE
Objects in a stronger gravitational field experience a slowing down of time than the lesser field known as time dilation.Near the eevent horizon , the time dilation increases rapidly. To he distant observer , a falling object's movement slows down , approaches but never reaches the event horizon.
At the centre of the black hole, well inside the event horizon, general relativity predicts a singularity, a place where the curvature of spacetime becomes infinite and gravitational forces become infinitely strong.
It is expected that future refinements or generalisations of general relativity (in particular quantum gravity) will change what is thought about the nature of black hole interiors.
5.BLACK HOLE IN LAB
After lots of thoughts the principal of St. Andreas University, Scotland, Ulf Leonhart & his colleague research-workers has claimed that in a few years they will be able to create a black hole in the lab. The size of the hole may be just like a rainwater drop.
To forming the black hole Prof. Leonhart is using an object known as Bose-Einstein Condensate, which is a particle neither liquid nor gaseous. Leonhart & his co-worker Puniki claimed that if light ray is passed through this condensate with a special treatment , the speed of the light will reduce to a few feet per sec. from 1,86,000 miles per sec. It is neccesary because artificial black hole can not attract normal light rays. To create this hole , they are using an object of tubular shape , inside which atoms are forced to whirl at a very low temperature. Though Leonhart described the whole process in a light mood as a "simple idea", the fiction writers are getting new thoughts from this experiment. Sir Arthur C. Clerk told that "the result of such high quality experiment nothing differs from a magic."
But very recently , scientists of Relativistic Heavy Iron Collider of Brookhaven National Laboratory , New York, created a fireball which posses a lots of characters similar to black holes. But the existence of this black hole is too small, a few thousand part of a second.
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