Monday, January 21, 2013

Gravity and the quantum forces: exploratory thoughts on unification

Our universe is constantly being explored and analyzed, and the biggest challenge in physics today is a unified theory that can explain everything. From the sub-atomic quantum world to the macrocosmic universe of galaxies, quasars and supernova.

The world as we know it is explained in terms of 4 forces, described in order of scale from large to small: Gravity - a force that mass exerts on all force, as explained by Mr. Newton over 300 years ago ; The electro-magnetic force as first described to some accurate extent by James Clerk Maxwell in the early 20th century, which is the force that stops us from walking through walls and matter from occupying the same space, and is powering your PC as you read this; And then the 2 quantum forces, the weak nuclear force, responsible for radioactive decay and initiates fusion in stars; and the strong nuclear force, responsible for binding neutrons and protons in an atomic nucleus, a force which when harnessed, destroyed Hiroshima;

One problem faced by physicists and cosmologists is providing a single theory that considers all 4 forces together. Gravity (Einstein's theory of General Relativity) works well over large distances with a lot of mass, while the other 3 forces operate at tiny atomic scales. When the theories are combined, they produce unpredictable, wild results. And while in our given world as we know it today, we can safely use seperate theories to explain the big world and the small world in different terms, we can't do so  under extreme conditions, such as the early stages after the creation of the universe, 13.7 billion years ago. Or in black holes, where immense gravitational forces causes matter to collapse to tiny scales, where both sets of theories are required to explain and predict the behaviour (huge mass - GR, tiny scale - quantum). It is from this necessity that a number of theories have developed, the most popular being String theory and the more evolved M-theory.

There is a very interesting characteristic of quatum particles. In traditional physics, when we think of matter, we think of it as built from atoms, tiny particles arranged together. Even modern day scientists used to consider matter as particles. Until an extraordinary quatum discovery. An experiment was developed that can be used to determine whether something is matter or energy: the double slit experiment. If you're not familiar with it, hit play:

Now consider this: at a quantum scale, particles exist as a wave of potential, a state of possiblity. When  observed, the wave function is collapsed and the wave becomes a point. This is how we experience matter: a single position of a particle out of potentially thousands. As we stop observing, the matter returns to a state of potential.

On the other side of the scale, in the macroscopic level, the world as we know it exists primarily in collapsed particle form. Our constant observation of the world around us holds in it a state of position, of matter. Your table and chair. The roof over your head right now. The atmosphere. The earth. The sun. The andromeda galaxy: all particles in very definite positions.

To go off on a quick tangent. There is an overwhelming similarity in structure betwen an atom and a solar system
  • A central nucleus, being orbited by electrons / planets
  • The centron / nucleus is positive, consisting of protons (positive) and neutrons (neutral). It is massive, compared to electrons. The sun is positive, consisting of hyrogen ions (positive) and helium atoms (neutral). It is massive, compared to the planets.
  • The electrons are negatively charged. The planets are negatively charged. For example, the earth carries around 500 000 C of electric charge (think of the free electrons in our atomosphere that cause lightning). 

There is one characteristic that is, quite different. The atom's particles exist as waves of potential. The macroscopic universe, through observation, exists in a state of collapsed matter. Without mathematical formulas to back this concept and based more on concept, could there be some correlation between the structure of atoms and molecules, the structure of solar systems and galaxies, and the weakness of gravity compared to electromagnetism and the nuclear forces? If energy of a system were compared to water, then think of the amount of force required to contain a certain volume of water with potential, for example by containing it with a balloon. The balloon exerts considerable force around the water to hold it together in 3 dimensions. Now consider the same balloon of water, and the amount of force required at only a single point, for example the neck of the balloon. A fraction of force is required at a single point - all you need to do is stick your finger in to stop the water running out.

Given that quantum theories explain a system of wave potential, then surely the force to maintain the system is a wave function too. And given that cosmological models and general relativity are based on particle physics and the forces in these systems are only 1 dimension of the force in a wave potential system, then it could it be possible to expand on GR and thinking of the current cosmological parameters as the set of parameters for a single point of a function?

There are some challenges that cosmology faces today. One of the biggest is providing an explanation of the total mass-energy of various systems (e.g. galaxies). "Baryonic pressure" - visible matter - only accounts for about 4% of the total mass-energy that can be calculated (this is determined by observing rotational velocities of galaxies and orbital movements around large gravity systems). About 25% is attributed to dark matter, and 70% to dark energy - matter and energy that we to date have not been able to observe. Observe? As Dr. Quantum says: "The act of OBSERVING collapses the wave function". Maybe it happens in the bigger picture too (albeit on a completly different time scale).

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