The Inflationary Universe

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The Inflationary Universe
By Josh Heller Sarah Breid Jesse Zellmer
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Inflation Theory-
The phenomenon by which the universe is driven
into exponential expansion by the repulsive
gravitational field created by a false vacuum.
Inflation would end with the decay of this false
vacuum. Although the inflation would occur in
far less than a second, it could account for the
bang of the big bang theory, it could explain
the origin of essentially all of the matter in
the observed universe, and it can solve the
horizon problem and the flatness problem. It
could also generate the density perturbations
that would later become the seeds for galaxy
formation.
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Alan H. Guth
Alan H. Guth is V.F. Weisskopf Professor of
Physics at the Massachusetts Institute of
Technology. In addition to receiving many
distinguished academic awards, Newsweek has
called him one of "The 25 Top American
Innovators," and Science Digest has ranked him
among the "100 Brightest Scientists Under 40." He
lives in Brookline, Massachusetts, with his wife
and two children.
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Alan Guth and inflation
The classic big bang theory is great at
describing what happened after the bang. Yet
until recently, particle physicists and
cosmologists were stuck on many questions that
the big bang theory couldn't answer, including
What made the big bang BANG in the first place?
If matter can be neither created nor destroyed,
how could so much matter arise from nothing at
all? Why can we only see a minute part of the
mega-universe? In 1979, a young particle
physicist named Alan Guth answered these
questions and made front page news with one of
the greatest discoveries in modern cosmology
cosmic inflation. This is the compelling,
first-hand account of Guth's paradigm-breaking
discovery of the origins of the universe and it
is a fascinating chronicle of his dramatic
struggle to justify it.
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Why the theory of inflation is needed
There are gaps in the Big Bang theory about how
all the matter exploded into what is now the
universe. Inflation expands upon the theory and
describes what was happening before the Big Bang.
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Inflation begins
Inflation not only explains the uniformity
that we see in the cosmic background radiation,
but it also explains the statistical properties
of the very faint nonuniformities that have been
observed with instruments so sensitive that they
can measure minute variations of less than 1/1000
of a percent.
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The old theory
In the early 1900's Edwin Hubble noticed that not
only are most galaxies are red-shifted (meaning
that they are moving away from us, but that the
ones further away from us (with light from much
further back in time) were moving faster than
those moving closer to us. Crunching the numbers
from this he concluded that everything was
expanding away from each other at a steady rate,
and had been doing so as far back as one could
see. Not only were the galaxies moving apart from
each other, but space itself was getting bigger.
So if you went back far enough in time,
everything would be very, very close together
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Old theory continued
And if everything were very, very close together
things would get very very dense, very very hot,
and particles would be very very energetic. So
energetic, in fact, that if you go far enough
back, we haven't observed things with those
energies, so our laws of physics don't cover what
happened if we go back too far - we have to make
educated extrapolations. But before that
happens, other weird things happen, like it
becomes too hot for atoms to hold together, or
the forces of electricity and magnetism start
acting like the forces that hold atomic nuclei
together. This very early time period, is
governed by laws of a branch of physics called
particle physics, which is related to quantum
mechanics.
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Big Bang and Inflation
The inflation theory builds on particle physics
and gets its name by concluding that during the
earliest period of the universe's expansion, it
wasn't expanding at a steady rate, but had an
accelerating rate of expansion - i.e., things
started expanding slowly but sped up. Then, after
not terribly long things had a steady rate of
expansion.
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The End