文档介绍：The F uture of Quan tum Cosmology
S
W
Ha wking
Departmen t of Applied Mathematics
and Theoretical Ph ysics
Univ ersit y of Cam bridge
Silv er Street
Cam bridge CB
EW
United Kingdom
August
Abstract
This is a transcript of a lecture giv en b y Professor S
W
Ha wking for the NA TO ASI conference
Professor Ha wking is the Lucasian Professor at the Univ ersit yofCam bridge
England
In this lecture
I will describ e what I see as the frame w ork for quan tum cosmology
on the basis
of M theory
I shall adopt the no b oundary prop osal and shall argue that the An thropic Principle
is essen tial
if one is to pic k out a solution to represen t our univ erse from the whole zo o of solutions
allo w ed b y M theory
Cosmology used to be regarded as a pseudo science
an area where wild sp eculation w as uncon
strained b yan y reliable observ ations
W eno wha v e lots and lots of observ ational data
and a generally
agreed picture of ho wtheuniv erse is ev olving
But cosmology is still not a prop er science
in the sense that
as usually practiced
it has no
predictiv e po w er
Our observ ations tell us the presen t state of the univ erse
and w e can run the
equations bac kw ard to calculate what the univ erse w as lik e at earlier times
But all that tells us is
that the univ erse is as it is no w b ecause it w as as it w as then
T o go further
and be a real science
cosmology w ould ha v e to predict ho w the univ erse should b e
W e could then test its predictions against
observ ation
lik e in an y other science
The task of making predictions in cosmology
is made more di
cult b y the singularit y theorems
that Roger P enrose and I pro v ed
The Univ erse m ust ha v e had a b eginning if
Einstein
s General Theory of Relativit y is correct
The energy densit y is p ositiv e
The univ erse con tains the ammoun t of matter w e observ e
These sho w ed that if General Relativit y w ere