The universe is finite; our universe had a beginning, and it started around 13.7 billion years ago according to Big Bang theorists. The Big Bang Theory suggests that our universe came into existence by a singularity. Singularities are the centers of black holes were there is so much gravitational pull that it creates a zone that has infinitely dense and infinitely hot. From the creation of the singularity, it has expanded and cooled and continues to expand and cool; thus creating our universe. Essentially, there was no big bang or explosion. The Big Bang theory is better represented by an expanding balloon. This means that our universe is growing.
Evidence that demonstrates the Big Bang is true includes: Hubble’s law, the homogeneity of our universe, abundance of light elements, and cosmic microwave background radiation.
Hubble’s law explains that all matter is moving away or expanding, and indicates the rate the universe is expanding. This is evidence to the Big Bang Theory because it proves the universe is expanding.
The homogeneity of universe (on super-horizon scale) proves that our universe was once originated from a same origin and expands together.
The abundance of light elements like hydrogen and helium support the model of the Big Bang Theory.
In 1965 Arno Penzias and Robert Wilson discovered a 2.725 degree Kelvin cosmic microwave background radiation that seemed to prove the universe initially was subjected to intense heat. The cosmic microwave background radiation supports that Big Bang Theory because the Big Bang Theory suggests originally the universe was very hot, and there should be some evidence of the intense heat within our universe.
Many people confuse the Big Bang Theory as the origin of the universe; however, the Big Bang Theory merely describes its cosmic evolution or the universe’s development. No one is yet able to explain the origin of the singularities in which the Big Bang originally developed from.
Both atheists and theists claim that the Big Bang Theory supports their beliefs. Theists believe the Big Bang Theory proves that the universe did have a beginning and that some intelligent being had a play in our development. However, atheists believe the universe made itself out of random choice.
http://csep10.phys.utk.edu/astr162/lect/cosmology/hubble_constant.html
