PARALLEL UNIVERSES 251
pouring in today from outer space from the WMAP and COBE satellites. It is, in fact, unquestionably the leading candidate for a theory of
the big bang.
Yet the inflationary universe theory raises a series of embarrassing
questions. Why did this bubble start to inflate? What turned off the expansion, resulting in the present-day universe? If inflation happened
once, could it happen again? Ironically, although the inflation scenario
is the leading theory in cosmology, almost nothing is known about
what set the inflation into motion and why it stopped.
In order to answer these nagging questions, in 1987 Alan Guth and
Edward Fahri of MIT asked another hypothetical question: how might
an advanced civilization inflate its own universe? They believed that if
they could answer this question, they might be able to answer the
deeper question of why the universe inflated to begin with.
They found that if you concentrated enough energy at a single
point, tiny bubbles of space-time would form spontaneously. But if the
bubbles were too small, they would disappear back into the space-time
foam. Only if the bubbles were big enough could they expand into an
entire universe.
On the outside the birth of this new universe would not look like
much, perhaps no more than the detonation of a 500-kiloton nuclear
bomb. It would appear as if a small bubble had disappeared from the
universe, leaving a small nuclear explosion. But inside the bubble an
entirely new universe might expand out. Think of a soap bubble that
splits or buds a smaller bubble, creating a baby soap bubble. The tiny
soap bubble might expand rapidly into an entirely new soap bubble.
Likewise, inside the universe you would see an enormous explosion of
space-time and the creation of an entire universe.
Since 1987 many theories have been proposed to see if the introduction of energy can make a large bubble expand into an entire universe. The most commonly accepted theory is that a new particle,
called the "inflaton," destabilized space-time, causing these bubbles to
form and expand.
The latest controversy erupted in 2006 when physicists began to
look seriously at a new proposal to ignite a baby universe with a
pouring in today from outer space from the WMAP and COBE satellites. It is, in fact, unquestionably the leading candidate for a theory of
the big bang.
Yet the inflationary universe theory raises a series of embarrassing
questions. Why did this bubble start to inflate? What turned off the expansion, resulting in the present-day universe? If inflation happened
once, could it happen again? Ironically, although the inflation scenario
is the leading theory in cosmology, almost nothing is known about
what set the inflation into motion and why it stopped.
In order to answer these nagging questions, in 1987 Alan Guth and
Edward Fahri of MIT asked another hypothetical question: how might
an advanced civilization inflate its own universe? They believed that if
they could answer this question, they might be able to answer the
deeper question of why the universe inflated to begin with.
They found that if you concentrated enough energy at a single
point, tiny bubbles of space-time would form spontaneously. But if the
bubbles were too small, they would disappear back into the space-time
foam. Only if the bubbles were big enough could they expand into an
entire universe.
On the outside the birth of this new universe would not look like
much, perhaps no more than the detonation of a 500-kiloton nuclear
bomb. It would appear as if a small bubble had disappeared from the
universe, leaving a small nuclear explosion. But inside the bubble an
entirely new universe might expand out. Think of a soap bubble that
splits or buds a smaller bubble, creating a baby soap bubble. The tiny
soap bubble might expand rapidly into an entirely new soap bubble.
Likewise, inside the universe you would see an enormous explosion of
space-time and the creation of an entire universe.
Since 1987 many theories have been proposed to see if the introduction of energy can make a large bubble expand into an entire universe. The most commonly accepted theory is that a new particle,
called the "inflaton," destabilized space-time, causing these bubbles to
form and expand.
The latest controversy erupted in 2006 when physicists began to
look seriously at a new proposal to ignite a baby universe with a