In
the beginning
by Marcus Loane
24th September 2010
In
the beginning. No.
Not in the beginning. There always was, is and will be,
the quantum vacuum, a frothy seething chaos where cause and effect makes little
sense and where quantum uncertainty reigns. Out of this disorder, space-time
bubbles pop in and out of existence. Space and time twist and distort into
different geometric configurations and some of these expand into large bubbles
like our own universe (a Big Bang). The shapes that space-time twists into
determine the physical constants for each universe, for example the mass of the
sub-atomic particles or the strength of gravity and the strong nuclear force.
Particles and forces can be modelled as tiny strings or membranes vibrating at
different frequencies and wrapping themselves around the shapes that space-time
has taken on.
There are
many universes with different apparent laws of physics. Naturally we find
ourselves in a universe with physics suitable for the formation of galaxies,
stars, planets, carbon, water and the evolution of life. There will be many
universes unsuitable for life. There are approximately 10^500 (that is, a one,
followed by 500 zeroes) configurations for a universe.
Our universe
has one time dimension and 10 space dimensions. Only three space dimensions are
extended and obviously noticeable to us. They are up/down, left/right and
forward/backward, That is, a point in space can be denoted by three
coordinates. The other dimensions are curled up into tiny twisted shapes such
as that depicted below and it is these that the vibrating strings and M-branes curl themselves around giving rise to the particles
and forces we observe in experiments. Other universes will have different
numbers of dimensions and different shapes so their apparent laws of physics
will be different from ours.
There may be
an infinite number of universes which means there are an infinite number
without life and an infinite number with life and an infinite number with intelligent
conscious life like ours. In fact when you think about what infinity does to
probabilities there will also be an infinite number of universes almost
identical to ours except perhaps your hair colour may be different or Amy Winehouse lives to a ripe old age.
There are experiments
which can provide supporting evidence for these ideas. That is why ever larger
particle accelerators are being built. Astronomical observations can also be
used as evidence and it is possible that other universes may interact with ours
through gravitational effects which could be measured. For example see this story about a
possible imprint of other universes on our own.
All this will
profoundly change our worldview and our place within it. Even if we are the
only intelligent life in our own universe, and this is probably not the case,
there will be numerous other similar universes with beings who eventually
figure out how they came to exist.
What
would be evidence for string/M theory?
String theory
predicts that for each of the known particles there would be a superpartner particle due to something called supersymmetry. The particles will only exist at high
energies such as those created in the new breed of particle accelerators. If
any of these are discovered it would be good evidence for string/M theory. A
working quantum computer is also evidence
for multiple universes.
What
do we know?
What is
already well supported by evidence regarding our origins? We know that our
universe is expanding at an ever increasing rate because light from distant
galaxies is red-shifted more, the further away the
galaxy is (the way the sound of an ambulance siren changes tone if it is coming
towards or retreating from the observer). This means that if we wind the clock backwards, everything in the universe was
closer together which would have made it hotter and denser. We can work out
from known physics, what the universe was like at various stages, and we can go
back about 13.7 billion years when everything would have been compressed into a
small point. We have detected the radiation left over from the Big Bang. We can
work out how stars and galaxies and planets formed. We can view the development
of stars and galaxies at different stages of their life cycles by looking out
into space. The further out we look, the further back in time we are looking
because it has taken so many years for the light to reach us. Therefore when we
look at galaxies 500 million light years away we are looking at them as they
were 500 million years ago. You might wonder how we know how far away the
galaxies are (and hence how old they are). There are various methods for
measuring distances in outer space and some of them are described here.
A telescope is a time
machine.
When we peer
through telescopes we are looking back in time. A galaxy, named Abell 1835 IR1916, which is 13.23 billion light-years from
earth was observed in 2004. When we look at it we are looking at the universe
in its infancy, 13.23 billion years ago, because that is how long it has taken
for the light to reach us. Other evidence for the Big Bang comes from the ratio
of elements such as hydrogen and helium that we observe in the universe. If the
universe was denser and hotter in its early history it would have acted like a
nuclear fusion reactor and the theory predicts it would leave a universe
predominantly composed of hydrogen, 23% helium and some lithium. The heavier
elements like carbon from which we are formed would be formed later inside
stars. This ratio of hydrogen to helium is what we have observed (remember
stars are mostly hydrogen) so this is more strong evidence for the Big Bang.
We also have
at least tens of thousands of pieces of evidence for the evolution of life on
earth from a common ancestor. The categories of evidence for evolution are
detailed on the talk origins
web site. Each of these categories will have many thousands of individual
pieces of evidence.
Therefore, at
present, it is possible to see how our universe today with all its complexity
developed from simpler beginnings due to matter and energy obeying the laws of
physics, including the evolutionary algorithm kicking
in (obeying the same laws of physics) as soon as a molecule replicated itself.
It can be
difficult to grasp where the matter and energy arises from. However
gravitational energy is negative so it can cancel out the energy and matter
(which is another form of energy) in the universe so the whole universe can
have a net energy of zero. That is how something can come from “nothing” with
conservation of energy being maintained. A simple calculation of this is here.
What remains is the question of where the apparent laws of physics came from. If the ideas sketched out earlier are confirmed the laws of physics of our universe will also have developed naturally from the contortions of space-time and gravity. Even if that is the case, there had to be more fundamental laws concerning quantum effects, quantum gravity, energy of the vacuum etc. which physicists seem to attribute to the “nothing”. Nothing is not quite nothing. The effective laws of physics we construct for our own little patch (our universe) are probably emergent from more fundamental laws from which other universes could form with different apparent laws of physics. E-mail me your thoughts on any of this at contemplations@thebigwhy.com.
--
Marcus Loane
Why is there
something instead of nothing? Theory of nothing
by Marcus Loane
Quantum vacuum:
The words "nothing,"
"void," and "vacuum" usually suggest uninteresting empty
space. To modern quantum physicists, however, the vacuum has turned out to be
rich with complex and unexpected behaviour. They envisage it as a state of
minimum energy where quantum fluctuations, consistent with the uncertainty
principle of the German physicist Werner Heisenberg, can lead to the temporary
formation of particle-antiparticle pairs.
I found a
useful article here
which explains how “nothing” is not really nothing. Another article here
describes the multiverse ideas in ways that are easy
to visualise.
A creation story
inspired by modern physics by Thomas J. McFarlane – this was beautifully
written in 1997. It does not mention string theory or the multiverse.
It is closer to what we already have evidence for. However I would take issue
with the idea of mapping psychology over the processes in the universe which I
suspect is inspired by Eastern culture (Buddhism) - it is interesting but I am
not sure we can deduce much from it.
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