In this series of lectures I
shall try to give an outline of what we think is the history of the universe
from the big bang 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 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 holes aren't as black as they
are painted.
In 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.