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BLACK HOLE.....AND SPACE SCIENCE

BLACK HOLE B lack holes are some of the most interesting pathologies in space and time delivered by Einstein's general theory of relativity. They form when matter collapses gravitationally onto itself, such as when massive stars burn out. They are a region of space where the gravitational pull is so strong that nothing--not even light--can escape. Hence John Wheeler called them "black holes." There is more. They incorporate singularities in spacetime structure: points where Einstein's theory breaks down, since the curvature of spacetime becomes infinite. And they can supply bridges to new universes. S uch a star may become a white dwarf or a neutron star, but if the  star  is sufficiently massive then it may continue shrinking eventually to the size of a tiny atom, known as a gravitational singularity. A  black hole refers to the region in space in which the singularity’s gravitational force is so strong that not even light can escape its pull.
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THE THEORY  OF        EVERYTHING

 
THE ORIGINE AND FATE OF THE UNIVERSE
SPECIAL EDITION
THE THEORY OF EVERYTHING
THE ORIGIN AND FATE OF THE UNIVERSE

STEPHEN W. HAWKING
CONTENTS
Introduction.

FIRST LECTURE
IDEAS ABOUT THE UNIVERSE..

SECOND LECTURE
THE EXPANDING UNIVERSE.

THIRD LECTURE
BLACK HOLES....

FOURTH LECTURE
BLACK HOLES AIN'T SO BLACK

FIFTH LECTURE
THE ORIGIN AND FATE OF THE UNIVERSE

SIXTH LECTURE
THE DIRECTION OF TIME

SEVENTH LECTURE
THE  THEORY OF EVERYTHING.

INTRODUCTION
In this series of lectures I shall try to give an outline of what we think is the history of the universe from the  Bigbang   to black holes. In the first lecture I shall briefly review past ideas about the universe   and how we got to our present picture. One might call this the history  of the universe.  
In the second lecture I shall describe how both Newton's And   Einstein's theories of gravity  led to the conclusion that, The universe could not be static;  it had to be either Expanding or contracting. This, in turn, implied that there Must have been a time between ten and twenty billion Years   ago when the density of the universe was infinite. This is called the big bang.

It would have been the Beginning   of   the universe.
In the third lecture I shall talk about black holes. These are  formed when a massive star or an even larger body Collapses in on itself under its own gravitational pull.
According to Einstein's general theory of relativity, anyone foolish enough to fall into a black hole will be lost forever.
They will not be able to come out of the black hole again.
Instead, history, as far as they are concerned, will come to a sticky end at a singularity. However, general relativity is a  classical theory-that is, it doesn't take into account the uncertainty  principle of quantum mechanics.
In the fourth lecture I shall describe how quantum
Mechanics   allows energy to leak out of black holes. Black Hole s aren't as black as they are painted.
ViIn the fifth lecture I shall apply quantum mechanical
ideas to the big bang and the origin of the universe. This leads to the idea that space-time may be finite in extent but without boundary or edge. It would be like the surface of the Earth but with two more dimensions.
In the sixth lecture I shall show how this new boundary
proposal could explain why the past is so different from the future, even though the laws of physics are time symmetric.
Finally, in the seventh lecture I shall describe how we are trying to find a unified theory that will include quantum mechanics gravity, and all the other interactions of Physics. If we achieve this, we shall really understand the universe and our position in it.

         




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