The Big Bang Theory: Evolution of Everything in Universe

The Big Bang theory is the most widely accepted theory of development of universe. Around 13.7 billion years ago everything in entire universe was compressed inside a singularity. Singularity is still not completely understood by scientists. Singularity can be imagined as something that is infinitely small and dense. The moment this singularity started expanding is called as the big bang and this expansion is still going on with immense speed. Some of the galaxies are moving away from our planet faster than the speed of light!. This theory seems weird to conceive by our subconscious brain but scientists have some concrete proofs and years of research to claim it. Science is a machine that runs on the fuel of evidence. Lets check out evidences supporting big bang theory.

Existence of time, space, light, matter and stars appears as it has been there always and will be there for eternity. But truth is something different. Even eternity is a misleading term because once time itself didn't existed.

Let us check out evidences supporting big bang theory.

1. Doppler's effect

The light from distant stars and galaxies has spectral features of the atoms in the gases around the stars. These lights are detected to be shifted toward the red end of the spectrum. Redshift means that the source of light is moving away from us. Comparing the results with different galaxies, it becomes evident that the more distant galaxies are moving away from us faster. This can happen only if universe is expanding. Distant galaxies are moving away from us even faster than the speed of light.

2. Microwave Background radiation

According to the big bang theory, the universe was very hot during its early stage.Theories predicted that after the Big Bang, there would have been a tremendous release of radiation.These radiations should have been shifted from visible light to microwave in last 13.6 billion years. Arno Penzias and Robert Woodrow Wilson, American radio astronomers, accidently discovered this cosmic microwave background radiation while experimenting with the Holmdel Horn Antenna. These microwave radiations are same as predicted by the scientists. In 1978, Penzias and Wilson were awarded the Nobel Prize for Physics for their joint discovery. Every cubic centimetre of space is currently being traversed by 300 photons from the big bang.

The white noise on your TV is consist of about 1% of the microwave radiation from the big bang.

3. Ancient galaxies vs Modern galaxies

Constituent and behaviour of ancient galaxies are quite different from modern galaxies. Our Powerful telescope can capture light from galaxies billions of light years away from us.Light from ancient galaxies and stars took billion years to reach us. It means we are capturing light from billion years past. We can observe galaxies as they were billion years before. Our present universe is different from the ancient universe. These changes are compatible with the big bang theory. A steady state universe can't have these changes.

4. Elements of ancient galaxies

After the big bang , universe expanded and cooled down. New elements formed by nuclear reactions. Through our modern telescopes we can look into ancient galaxies. The mixture of elements in those galaxies is same as predicted by the followers of the big bang theory.

5. Common misconceptions

a. Big bang theory doesn't explain origin of the universe.

The Big Bang explains development of universe from a tiny singularity. It doesn't say anything about how that singularity was originated or what was outside of the universe before the Big Bang. It also doesn't explain what initiated singularity to expand into the universe.

b. There was no explosion

The Big Bang was not an explosion. There was no space to explode into! There was no time either! Infact Big Bang was unimaginably intense expansion of space and time itself!

c. Singularity is not a point appearing somewhere in space

The singularity didn't appear in space but space began inside of the singularity. Prior to the singularity, space, time, matter, energy nothing existed. We don't know from where this singularity came. All we know is that it is expanding and we are inside of it.

d. All galaxies are moving away from us but not as we imagine

Yes! this is true that all galaxies are moving away from us but not in the way our mind imagines it to be. Truth is that galaxies are sitting still on their place and space between them is expanding. You can imagine it like the increasing distance between the dots on an expanding balloon.

e. Expansion of universe is not the reason of increasing distance between the Moon and the Earth

The distance between the Earth and the Moon is determined by the inertia and gravitational forces.If the space between them expanded, the gravitational force would pull the moon back to the original distance. Similarly nuclear forces keeps atoms intact.

f. Edge of the universe.

The more space between the objects, the faster they are moving away from each other. The galaxies which are very far from us, are moving away from us faster than the speed of light. Therefore, light from these galaxies will never reach us. We will never be able to see those far galaxies and edge of the universe!

g. All of the elements that make up our universe were not created in the big bang.

Most of the material generated by the big bang were light elements like hydrogen and helium. Heavy elements were created in the fusion reactions in the center of stars. Heavier elements like copper, gold, uranium, platinum, and silver were created during an event called supernova.