THE BIG BANG

The Big Bang Theory or simply the Big Bang is a cosmological model that attempts to explain the formation and the early stages of our Universe. The theory is the most comprehensive and accurate explanation backed-up by scientific evidence and observations. The theory says that, about 13.7 billion years (13.7 x 10⁹) ago, the Universe sprang into existence in a massive expansion - the Big Bang. Before the Big Bang, the Universe or the entity that created the Universe was in an extremely hot and dense state and then, it expanded rapidly and this expansion has cooled it to the present diluted state.

The obvious question here is, if there was nothing before the Universe was formed, what really expanded on that fateful day that created the Universe? The answer to this question is still beyond our understanding. So scientists called this unknown entity as ‘Singularity’. What is a "singularity" and where on earth does it come from? Well, to be honest, we don't know for sure. Singularities are zones/regions that defy our current understanding of physics. They are thought to exist at the core of ‘Black Holes’. Black holes are areas of extreme gravitational pressure. The pressure is thought to be so extreme that finite matter is actually squished into infinite density (a mathematical concept that truly boggles the mind). These zones of infinite density are called ‘singularities.’ Our universe is began as an infinitesimally small, infinitely hot, infinitely dense, something - a singularity. Where did it come from? We don't know. Why did it appear? We don't know.

Evidence to support the Big Bang Theory:

• The Universe must certainly have had a beginning.
• Galaxies were to be moving away from us at speeds directly proportional to their distance. This is called "Hubble's Law," after the great Astronomer Edwin Hubble who discovered this phenomenon in 1929. This observation clearly supports the expansion of the universe and suggests that the universe was once ‘together’.
• If the universe was initially as hot as the Big Bang suggests, we should be able to find some remnant of this heat. In 1965, two Radio astronomers Arno Penzias and Robert Wilson discovered a 2.725 degree Kelvin (-270.425 degree Celsius) Cosmic Microwave Background radiation (CMB) which is present everywhere in the observable universe. This is considered to be the remnant which scientists were looking for.
• The abundance of the "light elements" Hydrogen and Helium accumulated in the observable universe are thought to support the Big Bang model of origins.

A common Misconception about the Big Bang:

When we hear ‘Big Bang’, we tend to imagine a giant explosion. Astrophysicists however say that there was no explosion; there was (and continues to be) an ‘expansion’. Instead of imagining a balloon popping and releasing its contents, imagine a balloon expanding: an infinitesimally tiny balloon expanding to the size of our current universe.

Questions to Ponder:

• How can you prove that the expansion that started with the Big Bang is accelerating?
• How can the Universe expand faster than the speed of light during expansion?