12 Issues for the Future
241
itself had no existence “before”. We cannot ask what its cause was, because a
relationship of cause-effect requires time in order to exist.
At least this was the picture of the universe held by cosmologists since
Einstein staggered the world by overturning Newton’s theory of gravity.
Around the turn of the Twenty-first Century, however, there were new
proposals put forward that modify our conception of the earliest moments
of the universe. They are controversial, and certainly not accepted by all, but
have in recent years garnered increasing currency. We present some of the
basic concepts here.
In Chap. 10, we explored the beginning of the universe as far back as we
can reasonably go. As we emphasised there, the first 380,000 years of our
world’s existence remains shielded from our view, due to the impenetrability
of this region to electromagnetic radiation. The newly discovered gravitational waves are currently the only foreseeable possibility of direct observation
of this period in the future.
Although direct observation is not possible, there are residual effects from
this period that linger into the later development of the universe, and provide
us with some idea of what may have gone on before. Indeed, we find ourselves
very much in the same position as Plato’s slaves (see Chap. 1), whose observations of the shadows on the cave wall were all they had to provide them
with an inkling of the reality in which they were immersed. An example
of these residual effects is the incredible isotropy of the Cosmic Microwave
Background, and the nature of the few remaining inhomogeneities. As we
saw in Chap. 10, a period of very rapid inflation, lasting from 10 −36 s to
10 −32 s after the Big Bang, has been widely accepted as an explanation of
these effects.
Nevertheless, there will always remain a desire to explain the inexplicable.
Our universe appears to be tailored for the evolution of life. This is one of
the outstanding enigmas facing us as intelligent humans. It may be of little
importance in our daily lives. It has no impact on climate change, the international economy, or who will win the hundred-metre sprints at the next
Olympics. It is just a question that nags at us, and refuses to be put aside.
Naturally, there are theories that have been constructed to address this
issue. They also attempt to explain the preponderance of matter, compared
with anti-matter, in our universe; the laws of physics; and the possible unification of the four fundamental physical forces. Most of these theories involve
a multiverse, in one form or another. We shall discuss the multiverse, which
is a whole swathe of parallel universes, in Sect. 12.7. For the moment, let us
discuss the very early universe.
241
itself had no existence “before”. We cannot ask what its cause was, because a
relationship of cause-effect requires time in order to exist.
At least this was the picture of the universe held by cosmologists since
Einstein staggered the world by overturning Newton’s theory of gravity.
Around the turn of the Twenty-first Century, however, there were new
proposals put forward that modify our conception of the earliest moments
of the universe. They are controversial, and certainly not accepted by all, but
have in recent years garnered increasing currency. We present some of the
basic concepts here.
In Chap. 10, we explored the beginning of the universe as far back as we
can reasonably go. As we emphasised there, the first 380,000 years of our
world’s existence remains shielded from our view, due to the impenetrability
of this region to electromagnetic radiation. The newly discovered gravitational waves are currently the only foreseeable possibility of direct observation
of this period in the future.
Although direct observation is not possible, there are residual effects from
this period that linger into the later development of the universe, and provide
us with some idea of what may have gone on before. Indeed, we find ourselves
very much in the same position as Plato’s slaves (see Chap. 1), whose observations of the shadows on the cave wall were all they had to provide them
with an inkling of the reality in which they were immersed. An example
of these residual effects is the incredible isotropy of the Cosmic Microwave
Background, and the nature of the few remaining inhomogeneities. As we
saw in Chap. 10, a period of very rapid inflation, lasting from 10 −36 s to
10 −32 s after the Big Bang, has been widely accepted as an explanation of
these effects.
Nevertheless, there will always remain a desire to explain the inexplicable.
Our universe appears to be tailored for the evolution of life. This is one of
the outstanding enigmas facing us as intelligent humans. It may be of little
importance in our daily lives. It has no impact on climate change, the international economy, or who will win the hundred-metre sprints at the next
Olympics. It is just a question that nags at us, and refuses to be put aside.
Naturally, there are theories that have been constructed to address this
issue. They also attempt to explain the preponderance of matter, compared
with anti-matter, in our universe; the laws of physics; and the possible unification of the four fundamental physical forces. Most of these theories involve
a multiverse, in one form or another. We shall discuss the multiverse, which
is a whole swathe of parallel universes, in Sect. 12.7. For the moment, let us
discuss the very early universe.