“In
1979, Alan Guth,a physicist working at the Stanford Linear Accelerator
Center in California, hypothesized that during its earliest moments,
the cosmos expanded at an incredibly rapid rate—so rapidly that
different bits of matter accelerated away from one another, reaching
speeds far greater than the speed of light. But
doesn't Einstein's theory of special relativity make the speed of
light a universal speed limit for all motion? Not exactly, Einstein's
limit applies only to objects moving within space and not the
expansion of space itself. During
the “inflationary epoch,” which lasted only about 10-37
second
to 10-34
second after the big bang, the cosmos expanded by a factor of about
1050.
“What
produced this enormous cosmic expansion? Guth speculated that all of
space must have undergone a “phase transition,” something
analogous to what happens when liquid water quickly freezes into ice.
After some crucial tweaking by his colleagues in the Soviet Union,
the United Kingdom, and the United States, Guth's idea became so
attractive that it has dominated theoretical models of the extremely
early universe for two decades.
“And
what makes inflation such an attractive theory? The inflationary era
explains why the universe, in its overall properties,looks the same
in all directions: everything that we can see (and a good deal more
than that) inflated from a single tiny region of space, converting
its local properties into universal ones. Other advantages, which
need not detain us here, accrue to the theory, at least among those
who create model universes in their minds. One additional feature
deserves emphasis, however. The inflationary model makes a
straightforward, testable prediction: space in the universe should be
flat, neither positively, nor negatively curved, but just as flat as
our intuition imagines it.
“According
to this theory, the flatness of space arises from the enormous
explosion that occurred during the inflationary epoch. Picture
yourself, in analogy, on the surface of a balloon, and let the
balloon expand by a factor so large you lose track of the zeroes.
After this expansion,the part of the balloon's surface that you can
see will be flat as a pancake. So too should be all the space that we
can ever hope to measure—if the inflationary model actually
describes the real universe.
“But
the total density of matter amounts to only about one quarter of the
amount required to make space flat. During the 1980's and 1990's,
many theoretically minded cosmologists believed that because the
inflationary model must be valid, new data would eventually close the
cosmic “mass gap,” the difference between the total density of
matter, which pointed toward a negatively curved universe, and the
critical density, seemingly required to achieve a cosmos with flat
space. Their beliefs carried them buoyantly onward, even as the
observationally oriented cosmologists mocked their overreliance on
theoretical analysis. And then the mocking stopped.”
(italics
added)
ORIGINS:
FOURTEEN BILLION YEARS OF COSMIC EVOLUTION,
by Neil deGrasse Tyson and Donald Goldsmith,pp.84-85 (W.W. Norton &
Co., NY, London:2004)
