The two basic principles that lie at the heart of the ‘Big Bang Theory’ are General Relativity and the Cosmological Principle.
Relativity: Before the modern cosmological worldview became to be generally accepted, the commonly accepted Western view was that the earth played a central part in the creation story, and it was even accepted that the earth was the center around which all other heavenly bodies revolved. This Geocentric (earth-centered) view was challenged by Copernicus, who proposed the Heliocentric view that the earth moved around the sun. Today, it is believed that the earth is a relatively insignificant planet, revolving around a relatively insignificant star, the Sun, which in turn circles around an ordinary galaxy, the Milky Way, that in turn circles around a relatively minor cluster of galaxies called the Local Cluster, which in turn is like a speck in the vastness of the universe. This is called the ‘Mediocrity Principle.” The difference between a heliocentric theory and a geo- centric theory is one of relative motion.
A number of experiments have been conducted in order to measure the absolute motion of the earth through space. In 1881 Albert A. Michelson, together with his colleague Edward Morley, designed and built an apparatus called an interferometer to measure this motion.6 Since it was shown that light acted also as a wave, it was assumed that, just like sound waves have to travel through
some form of material, so space must contain some form of mate- rial through which light traveled. Nobody knew what the medium was, so they called it ‘aether’, and their experiment was designed to measure the earth’s speed through this aether. They expected the answer to be the rotation speed of the Earth at the latitude where the experiment was conducted. The two scientists intended to turn their instrument until they found a maximum fringe shift produced by light traveling in two perpendicular directions. The position of maximum shift would show in which direction the earth was moving and the size of the fringe shift would show how fast it was moving. Much to their surprise, the answer turned out to be zero. No matter how the earth moved, the ‘ocean’ (aether) it moved in always moved with it so that the earth was constantly in still water. What was true for the earth must also be true for every other body in the universe and this seemed incredibly improbable.
In 1905, Albert Einstein faced up to the contradictions that apparently followed from the experiment. He reformatted a theory that had been proposed by Dutch Physicist Hendrick Lorentz, and published his version of the ‘Theory of Relativity’ which provided a mathematical solution to the problem, thus divorcing it from the physical observations, and therefore did not require an aether. The equation e = mc2 was also predicted by relativity. Two assumptions are inherent in the theory:
- No matter how an observer is moving (uniformly), he will always come to the same conclusions about the universe. In other words, all frames of reference are absolutely equivalent.
- No matter how an observer is moving (uniformly), he will always measure the speed at which light reaches him as being the same, a constant, ‘c’.
The Cosmological Principle: This principle, in its simplest form, states that the Universe looks the same from every location within it. In an expanding universe, in which the rate of expansion increases
linearly with distance, the universe should always look the same from any location within it. Accepting this principle overcomes the ap- pearance that everything is moving away from the earth as predicted by the red shift. However, there is no way to test the validity of this principle, because given the vastness of space, we cannot move to a sufficiently distant location to check the validity of the assumption. In fact, from all observations that are possible, the opposite seems to be true. Wherever we have been in space, and wherever we have looked, the principle seems to be violated. There is no uniformity, but rather magnificent variety. Wherever we look within the solar system – the galaxies, the super clusters, and the gas clouds – the heavens speak of anything but a boring uniformity. There is an inhomogeneous distribution of matter, which contradicts the very essence of the principle. The fact that there are structures on ever- larger scales than postulated by the Cosmological Principle does not auger well for the triumph of the principle when extrapolated to include the whole universe. If the principle is in trouble, then the Big Bang is in trouble.
The view that the universe must be uniform is central to the Big Bang theory, and Einstein and other scientists who sought to apply the theory of general relativity to the universe assumed this to be the case. This Cosmological Principle is on very shaky ground, especially since modern technology, telescopes, and space explora- tion opens up substantially more of the universe than was known in Einstein’s day. The great chains of galaxies that curl around vast regions of empty space called ‘voids’ tell a different story. The astrophysicists of today are not unaware of the quandary in which this places them. As the professor of Astrophysics at Nottingham University admits regarding the problem of a non uniform universe:
Were lost … The foundations of the big bang models would crumble away. We’d be left with no explanation for the big bang, or galaxy formation, or the distribution of galaxies in the universe. 7,8