New models for the Universe

New Models for the Universe

In recent years some theoretical physicists have written books that are eminently readable by the average human being. I regard the theoretical physicists as the true philosphers and mystics. Their academic theories deliving into the true nature of the universe are stranger than many of the themes of science fiction movies (indeed, their theories inspire the science fiction writers!).

Two books I recommend are:

Warped Passages by Lisa Randall (2007)
The Elegant Universe by Brian Greene (1999)

Neither book uses any mathematics, and both begin by explaining Einsteins theories of General and Special Relativity. They then proceed to explain how little we actually know about the universe and the models that have been proposed to try and explain the problems that arise. When I went to school I learnt that the fundamental particles were atoms composed of electrons, protons and neutrons. This has since been refined, and the three most fundamental particles in our familiar world are electrons, up-quarks and down-quarks (a proton is two up and one down quark, and a neutron is two down and one up quark). There are actually many fundamental particles, and each of these fundamental particles have their opposite (eg opposite of an electron is a positron).

There are three fundamental families of particles:

Family 1	Family 2	Family 3
Electron	Muon	Tau
Electron-neutrino	Muon-neutrino	Tau-neutrino
Up quark	Charm quark	Top quark
Down quark	Strange quark	Bottom quark

We don't encounter particles in families 2 or 3 because they existed much ealier in time shortly after the big bang. As the universe has cooled the conditions have changed and only those in family 1 occur naturally around our planet. To create these heavier particles the physicists need to to use particle accelerators, and are eagerly awaiting the Large Hadron Collider (LHC) in full working condition to enable bigger and more energetic collisions to occur and the discovery of new particles.

Some of the current theories are based around Supersymmetry and String Theory. Read the books above for understandable explanations of these theories. I won't try to do that here, but suffice to say the 11 dimensional M-theory and Branes. Strings are one-dimensional oscillating lines of the fundamental (Planck) length - the strings may be open or looped. The strings are short: about 1.6 and 10^-33 cm, which is very small considering atoms are about 10^-10 m. The extension of strings into multiple dimensions lead to Brane theory. Without going in to a lot of detail, current theories are that there are indeed 11 dimensions (10 plus time), but where we live in the universe the 7 higher dimensions are curled up (< 10^-16 m length) so we do not encounter them. Nobody is quite sure why.

Some of the problems physicists still face are:

Why does mass exist? The LHC will look for the Higgs Boson, which is the particle hypothesized to account for mass. Particles similar to the Higgs Boson may not exist in other Branes or dimensions - other dimension may be entirely energy. Our particular dimension could be unusual in having mass.
Why is gravity so weak compared to the other particles? This has been very puzzling, and one way it can be explained supports the theory of additional dimensions.
Where has 90% of the mass of the universe gone?

One theory proposed by Lisa Randall (and this is a theory, one of many that will be tested when the LHC comes online) is that there exists at least one additional Universe or Brane. This could be a 4 dimensional universe similar to ours, and very close to ours. Calculations show that a parallel universe could exist with a similar set of particles 10^-16 m away from our universe without any interaction between the particles (remember, the string length is 10^-33 cm, so a distance of 10^-16 m between strings is equivalent to something being 10¹⁶ km away from an object 1 metre in length, which is a collosal distance considering the sun is only 150 million km away from the earth). In fact many parallel universes could exist but for now we'll just assume one additional universe. There is no interaction or movement of particles between universes, except for the graviton which is the particle that imparts gravitational attraction. The theory is that the graviton does move between the two universes, but spends 80% of its time in the other universe (probabilistic theory comes in here). Because the graviton spends so little time in this universe its affect is weaker, which could account for the observed phenomena.

Esoteric significance

I find this theory particularly interesting. It proposes a parallel universe, probably one composed of energy only (no mass), extremely close to our universe, and the possibility of particles moving between universes. What if consciousness was linked to a particle that has yet to be detected by science? Here we have a model for heaven and earth. Birth is the entry of consciousness particles from the other dimension to a physical body in this universe, and death is its return. The birthing process effectively locks it in, and death releases it. This is not too different from what the ancient Sages have been telling us for thousands of years. The LHC may start unlocking some of these mysteries and providing some evidence for this model.