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 email@example.com.
Why is there something instead of nothing? Theory of nothing by Marcus Loane
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.
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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