Cosmology is where physics and astronomy meet religion. Every religion has its creation myths and cosmologists will always look for scientific theories which coincide with the myths of their religion. Christians like Big Bang theories, Buddhists prefer Steady State theories. Then the atheists produced a variation of a Big Bang which did not need God and the Evangelical Christians realised the the Big Bang took more than 6 days between the bang and the apperence of man and got upset. Science fiction writers preferred infinite universes where anything is possible, but then, not to be outdone, physicists came up with the Multiverse theory in which the whole universe splits in two every time someone makes a decision. All of which proves that man has an infinite ability to make up nonsense.
I think cosmology is fine, just so long as we realise that it is speculation, but I want to challenge the two great myths on which cosmology is founded, Newton's law of gravity and Hubble's red-shift.
Newton's law of gravity works perfectly on the scale of the solar system, but does that imply that it works over inter-galactic distances. Newton's law is what we call in "inverse square law". At twice the distance the force is a quarter; at three times the distance, a ninth. It is the same law that applies the brightness of a light, the loudness of sound and the strength of radio waves, but there are circumstances where the law needs to be modified. The most obvious is the effect of mist on light where we need to include another factor in the equation which takes into account the way the mist adsorbs the light. I think Newton's law of gravity needs a factor like that which comes into effect on a scale of the distance between galaxies.
We measure the size of the universe by what is called red-shift. The further away stars are, the more the colour of their light is shifted towards the red end of the spectrum. Hubble attributed this to the Doppler effect and concluded that the universe is expanding. He also used the red-shift as a means of measuring the distance to distant galaxies. I am not convinced that red-shift is solely attributable to expansion. I think the assumption that photons can travel through space for billions of years without loosing energy is unfounded. Any loss of energy would add to the red shift.
I believe it is naive to say ether that the universe is a certain size, or that it is infinite; naive to say that it was created in the big bang, or that it exists in a steady state. At best, we can state a belief that one thing is more probable than another.
Galileo got put on the rack overnight to reconsider his views when he dared to suggest that the earth was not the centre of the universe. Modern observations of the universe have provided evidence to suggest that our galaxy is at the centre of the universe. The Hubble deep space images show a universe full of galaxies in which ever direction we look. Background blackbody radiation has also shown a remarkably symmetric universe. These observations are consistent with an infinite universe, but cosmologists believe in a finite universe.
The way cosmologists rationalise these inconsistencies is to use Einstein's General Theory of Relativity to claim that the universe is closed in on itself because its mass curves space-time. I regard this as naive. Light certainly can be bent by gravity, but only through very small angles when passing close to very massive objects. The idea that radiation produced at the moment of the big bang heading away from the centre of the universe has been bent in such a way that 15 billion years later, we see it comming towards us from every direction is nothing short of laughable.
I wrote that cosmology is where physics and astronomy meet religion. The ability of the religious to concoct wiered and wonderful myths about creation, evil spirits and good fairies is shared by some cosmologists who seem intent on out-wired-ing myth and science fiction with theories of dark matter and mysterious forces accelerating the expansion of the universe.