Does inflation theory govern the universe?
Does inflation theory
govern the universe?
Ever since the Big Bang theory of the origin of the universe was proposed in 1927, the idea has had its skeptics. The radical concept stated that the
universe is expanding; run time backwards, and al! matter and energy intersect at a point in time 13.7 billion years ago, the moment of the "bang."
Big Bang cosmology has received enormous support from observational tests. In 1929, American astronomer Edwin Hubble observed galaxies generally recede from us; that was the lynchpin of the evidence.
In 1964, Bell Laboratories physicists Arno Penzias and Robert Wilson discovered the faint echo of the Big Bang — the cosmic microwave background radiation (CMB).
Along with the expansion of the universe and the CMB, nucleosynthesis, the process by which light elements formed in the early universe, is explained by the Big Bang model.
But the Big Bang does not yet explain it all. Although by the
MINUSCULE TIME. How much is 10 34 second? To get an idea, compare 1 second to the 13.7-billion-year age of the universe. Next, divide that 1 second into an equivalent number (13.7 billion) of parts to get 10” second. Repeat that step one more time, and you'll get back to inflation's beginning.
How quickly 0 did inflation | take place?
1 second
OnDnODDDDDDDaDDDDODOD I
10~17 second
1970s the Big Bang seemed to outweigh competing ideas about the formation of the cosmos, it left some problems unsolved.
The first was causality. To astronomers' amazement, they found the CMB's temperature was uniform everywhere they looked, to a high level of precision. If the universe began as a hot, primeval fireball, why would temperatures everywhere be so uniform? Leaving this enigma unsolved would threaten the Big Bang idea.
Second came the flatness problem. The cosmological number Omega (£2) describes
13.7 billion years
A TINY COSMOS. This artist's conception shows the universe at actual size, immediately after the period of hyperexpansion known as inflation, astronomy-
-
f: ' *
ROEN KELLY AND CHUCK BRAASCH
1 second
lO^^tsecond
10-17 second
both the universe's shape and fate.
Astronomers found Omega's value equals 1, which seemed highly coincidental.
A number less than 1
would mean space is open and will expand forever; greater than 1 would mean a closed universe and an eventual "Big Crunch," with the cosmos falling back on itself.
Third was the magnetic monopole problem. The cosmos is filled with electric monopoles, particles like electrons and protons. But astronomers have not observed any magnetic monopoles. The lack of these particles bothered particle physicists.
In 1981, to solve these problems, scientists presented a new idea that expanded the Big Bang theory and added weight to it. Alan Guth of the Massachusetts Institute of
62 50 GREATEST MYSTERIES
it up by a factor of 10s0/' Inflation resolves some questions surrounding the Big Bang.
Guth and his colleagues imagined a huge energy field in the early universe, which they called the false vacuum. As it expanded, the false vacuum was in a perilous state of equilibrium, and it had to decay into a real vacuum, leading to an enormous release of energy. Inflation resulted from the
Technology wrote a paper that described the "inflationary" model of cosmology, developed with his colleagues Andrei Linde, Paul Steinhardt, and Andy Albrecht.
Inflation proposes a short period of expansion — 10-34 second — in the early universe. As Mario Livio of the Space Telescope Science Institute says, "All inflation theories ... grab a speck of space and blow
BIG BANG ECHO. The cosmic microwave background radiation is a relic of hot radiation emitted when atoms first formed and light could travel freely, 380,000 years after the Big Bang. The smoothness of this radiation suggests the universe expanded at breakneck speed in the first fraction of a second. (Different colors show temperature differences of a few millionths of a degree.)
NASA/WMAP SCIENCE TEAM
decay. The released energy acted as an antigravity force, giving the universe a kick. The universe exploded by many factors in an instant.
Viewed as a radical concept when Guth's paper was published, the idea has received substantial support from a vast number of astrophysicists since. And observational tests of the Big Bang all have supported the theory. In 1992, the Cosmic Background Explorer (COBE) satellite discovered temperature fluctuations in the CMB, further evidence of the Big Bang. Later, the Wilkinson Micro- wave Anisotropy Probe (WMAP) refined this picture, adding weight to it. Other verifications of the Big Bang have helped convince skeptical astronomers that it occurred.
In the first years of a new century, evidence suggests the Big Bang occurred and that inflation was a key component of the cosmos'earliest moments. ED
INFLATIONARY STEP. Inflation made the universe flat. Here, a curved surface expands by a factor of 3 in each panel, appearing nearly flat by the end. To relive cosmic inflation, repeat this expansion 87 more times.
WWW.ASTRONOMY
govern the universe?
Ever since the Big Bang theory of the origin of the universe was proposed in 1927, the idea has had its skeptics. The radical concept stated that the
universe is expanding; run time backwards, and al! matter and energy intersect at a point in time 13.7 billion years ago, the moment of the "bang."
Big Bang cosmology has received enormous support from observational tests. In 1929, American astronomer Edwin Hubble observed galaxies generally recede from us; that was the lynchpin of the evidence.
In 1964, Bell Laboratories physicists Arno Penzias and Robert Wilson discovered the faint echo of the Big Bang — the cosmic microwave background radiation (CMB).
Along with the expansion of the universe and the CMB, nucleosynthesis, the process by which light elements formed in the early universe, is explained by the Big Bang model.
But the Big Bang does not yet explain it all. Although by the
MINUSCULE TIME. How much is 10 34 second? To get an idea, compare 1 second to the 13.7-billion-year age of the universe. Next, divide that 1 second into an equivalent number (13.7 billion) of parts to get 10” second. Repeat that step one more time, and you'll get back to inflation's beginning.
How quickly 0 did inflation | take place?
1 second
OnDnODDDDDDDaDDDDODOD I
10~17 second
1970s the Big Bang seemed to outweigh competing ideas about the formation of the cosmos, it left some problems unsolved.
The first was causality. To astronomers' amazement, they found the CMB's temperature was uniform everywhere they looked, to a high level of precision. If the universe began as a hot, primeval fireball, why would temperatures everywhere be so uniform? Leaving this enigma unsolved would threaten the Big Bang idea.
Second came the flatness problem. The cosmological number Omega (£2) describes
13.7 billion years
A TINY COSMOS. This artist's conception shows the universe at actual size, immediately after the period of hyperexpansion known as inflation, astronomy-
-
f: ' *
ROEN KELLY AND CHUCK BRAASCH
1 second
lO^^tsecond
10-17 second
both the universe's shape and fate.
Astronomers found Omega's value equals 1, which seemed highly coincidental.
A number less than 1
would mean space is open and will expand forever; greater than 1 would mean a closed universe and an eventual "Big Crunch," with the cosmos falling back on itself.
Third was the magnetic monopole problem. The cosmos is filled with electric monopoles, particles like electrons and protons. But astronomers have not observed any magnetic monopoles. The lack of these particles bothered particle physicists.
In 1981, to solve these problems, scientists presented a new idea that expanded the Big Bang theory and added weight to it. Alan Guth of the Massachusetts Institute of
62 50 GREATEST MYSTERIES
it up by a factor of 10s0/' Inflation resolves some questions surrounding the Big Bang.
Guth and his colleagues imagined a huge energy field in the early universe, which they called the false vacuum. As it expanded, the false vacuum was in a perilous state of equilibrium, and it had to decay into a real vacuum, leading to an enormous release of energy. Inflation resulted from the
Technology wrote a paper that described the "inflationary" model of cosmology, developed with his colleagues Andrei Linde, Paul Steinhardt, and Andy Albrecht.
Inflation proposes a short period of expansion — 10-34 second — in the early universe. As Mario Livio of the Space Telescope Science Institute says, "All inflation theories ... grab a speck of space and blow
BIG BANG ECHO. The cosmic microwave background radiation is a relic of hot radiation emitted when atoms first formed and light could travel freely, 380,000 years after the Big Bang. The smoothness of this radiation suggests the universe expanded at breakneck speed in the first fraction of a second. (Different colors show temperature differences of a few millionths of a degree.)
NASA/WMAP SCIENCE TEAM
decay. The released energy acted as an antigravity force, giving the universe a kick. The universe exploded by many factors in an instant.
Viewed as a radical concept when Guth's paper was published, the idea has received substantial support from a vast number of astrophysicists since. And observational tests of the Big Bang all have supported the theory. In 1992, the Cosmic Background Explorer (COBE) satellite discovered temperature fluctuations in the CMB, further evidence of the Big Bang. Later, the Wilkinson Micro- wave Anisotropy Probe (WMAP) refined this picture, adding weight to it. Other verifications of the Big Bang have helped convince skeptical astronomers that it occurred.
In the first years of a new century, evidence suggests the Big Bang occurred and that inflation was a key component of the cosmos'earliest moments. ED
INFLATIONARY STEP. Inflation made the universe flat. Here, a curved surface expands by a factor of 3 in each panel, appearing nearly flat by the end. To relive cosmic inflation, repeat this expansion 87 more times.
WWW.ASTRONOMY
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