EPILOGUE 287
same everywhere, or whether the Universe is ultimately a tidy or an
untidy place... All the great questions about the nature of the Universe-from its beginning to its end-turn out to be unanswerable."
Barrow is correct in saying that we will never know, with absolute
certainty, the true nature of the universe, in all its glory. But it is possible to incrementally chip away at these eternal questions and come
tantalizingly close. Instead of representing the absolute boundaries of
our knowledge, these "impossibilities" may perhaps better be seen as
the challenges awaiting the next generation of scientists. These limits
are like piecrusts, made to be broken.
DETECTING THE PRE-BIG BANG ERA
In the case of the big bang, a new generation of detectors is being built
that could settle some of these eternal questions. Today our radiation
detectors in outer space can only measure the microwave radiation
emitted 300,000 years after the big bang, when the first atoms formed.
It is impossible to use this microwave radiation to probe earlier than
300,000 years after the big bang, since radiation from the original fireball was too hot and random to yield useful information.
But if we analyze other types of radiation we may be able to get
even closer to the big bang. Tracking neutrinos, for example, can take
us closer to the instant of the big bang (neutrinos are so elusive that
they can travel through an entire solar system made of solid lead).
Neutrino radiation could take us within a few seconds after the big
bang.
But perhaps the ultimate secret of the big bang will be revealed by
examining "gravity waves," waves that move along the fabric of spacetime. As physicist Rocky Rolb of the University of Chicago says, "By
measuring the properties of the neutrino background we can look
back to one second after the Bang. But gravitational waves from [the]
inflation area are relics of the universe 10
-35 seconds after the bang."
Gravity waves were first predicted by Einstein in 1916; they may
eventually become the most important probe for astronomy. Histori-
same everywhere, or whether the Universe is ultimately a tidy or an
untidy place... All the great questions about the nature of the Universe-from its beginning to its end-turn out to be unanswerable."
Barrow is correct in saying that we will never know, with absolute
certainty, the true nature of the universe, in all its glory. But it is possible to incrementally chip away at these eternal questions and come
tantalizingly close. Instead of representing the absolute boundaries of
our knowledge, these "impossibilities" may perhaps better be seen as
the challenges awaiting the next generation of scientists. These limits
are like piecrusts, made to be broken.
DETECTING THE PRE-BIG BANG ERA
In the case of the big bang, a new generation of detectors is being built
that could settle some of these eternal questions. Today our radiation
detectors in outer space can only measure the microwave radiation
emitted 300,000 years after the big bang, when the first atoms formed.
It is impossible to use this microwave radiation to probe earlier than
300,000 years after the big bang, since radiation from the original fireball was too hot and random to yield useful information.
But if we analyze other types of radiation we may be able to get
even closer to the big bang. Tracking neutrinos, for example, can take
us closer to the instant of the big bang (neutrinos are so elusive that
they can travel through an entire solar system made of solid lead).
Neutrino radiation could take us within a few seconds after the big
bang.
But perhaps the ultimate secret of the big bang will be revealed by
examining "gravity waves," waves that move along the fabric of spacetime. As physicist Rocky Rolb of the University of Chicago says, "By
measuring the properties of the neutrino background we can look
back to one second after the Bang. But gravitational waves from [the]
inflation area are relics of the universe 10
-35 seconds after the bang."
Gravity waves were first predicted by Einstein in 1916; they may
eventually become the most important probe for astronomy. Histori-