Kalam Cosmological Argument

Everything that begins to exist has a cause of its existence. The universe began to exist Therefore the universe has a cause of its existence. For comparison to modern cosmology, the second premise is the key one, and the key reference for that discussion is William Lane Craig's book. The cosmological evidence for a beginning of the universe comes from the expansion of the universe and the increase of entropy.

The Expansion of the Universe Implies a Beginning

The clearly observed expansion of the universe as evidenced by red shifts leads to the Hubble's law. The results from the WMAP probe give a good value for the Hubble constant, and it would appear that we could extrapolate backward to the beginning of the universe, a process which yields 13.7 billion years for the projected age of the universe. But the approach to zero spatial extent, the "singularity", is not something that current physics and astronomy can handle. Although it has been projected from general relativity and gravitational time dilation that one would reach an event horizon in the process and therefore have a "beginning of time", we certainly don't know that. There are lots of things we don't fully understand about the early universe, such as inflation and the effects of quantum gravity. It appears that there is a complete breakdown of our laws of physics before the Planck time, so we have to approach the process with humility.

The Inevitable Increase in Entropy Implies a Beginning

Beginning of the Universe

When one looks at the question of how the universe began from the framework of physics, astronomy and cosmology, the picture is congruent with the picture one gets from Genesis. In particular, the standard model of physics points to a beginning of the universe in the finite past, and the modeling of processes in the universe finds a scenario which is exceptionally fine-tuned to a framework in which intelligent life is possible.

Some of the focal points for the modeling of the universe:

• The expanding universe projects back to a beginning
• The expansion rate is just right to make atoms and galaxies possible.
• The balance of the fundamental forces is on a razor's edge.
• Carbon hanging by a thread (The Hoyle resonance)

Hoyle: "I do not believe than any scientist who examined the evidence would fail to draw the inference that the laws of nuclear physics have been deliberately designed with regard to the consequences they produce inside the stars."

Hawking & Mlodinow: "Such calculations show that a change of as little as 0.5% in the strength of the strong nuclear force, or 4 percent in the electric force, would destroy either nearly all carbon or all oxygen in every star, and hence the possibility of life as we know it. "

Expanding Universe

The galaxies we see in all directions are moving away from the Earth, as evidenced by their red shifts. Hubble's law describes this expansion.

The fact that we see all other galaxies moving away from us does not imply that we are the center of the universe! All galaxies will see all other stars moving away from them in an expanding universe. A rising loaf of raisin bread is a good visual model: each raisin will see all other raisins moving away from it as the loaf expands.

The fact that the universe is expanding then raises the question "Will it always expand?" Since the action of gravity works against the expansion, then if the density were large enough, the expansion would stop and the universe would collapse in a "big crunch". This is called a closed universe. If the density were small enough, the expansion would continue forever (an open universe). At a certain precise critical density, the universe would asymtotically approach zero expansion rate, but never collapse. Remarkably, all evidence indicates that the universe is very close to that critical density. Discussions about the expansion of the universe often refer to a density parameter Ω which is the density divided by the critical density, such that Ω = 1 represents the critical density condition.

Setting for Quantum Gravity

The picture of the expanding universe appears to follow the standard model back to the point where quantum gravity must be considered.