Often astrologers and scientists have wondered about the origin of everything – the stars, the moon, the planets, the universe. When it comes to cosmologists, they simply answer these questions with two words- Bing Bang.
THE BIG BANG
Around 13.7 billion years ago, a massive expansion happened which blew up space and formed out the universe. The Big Bang theory is a model used for explaining the history of the universe as we know it. It traces the evolution of cosmos right from the beginning.
The present universe is extremely different from the way it used to be. The earlier universe was made of helium, hydrogen, dark matter, aardvarks, neutrinos, photons, gristle etc. At different densities, different matter behaves differently. Presently, dark energy makes up for the universe.
According to the Big Bang Theory, the universe was small consisting of tightly packed up matter. The entire galaxies were crammed into one big mass. Then a big expansion happened which allowed the formation of first few atoms. A cosmic microwave background was formed which presently acts as an evidence for the Big Bang theory.
Based on this model, the entire predictions about the universe are based. The early universe is said to consist of extremely low entropy. The cosmic microwave background radiation provides a thermal imprint to the Big Bang theory.
WHAT HAPPENED IN THE BIG BANG
The universe began with a singularity which consisted of infinite temperature and density. Inflation occurred which made the universe expand faster than the light’s speed. Within few fractions of a second, the size expanded to over 100 times of what it used to be before the bang.
The expanded universe was bereft of any matter yet consisted of the enormous amount of dark energy. The acceleration and smoothing out of the universe took place because of the presence of dark energy. Dark energy is the mysterious force behind the universe’s acceleration.
Gravity, electromagnetism, strong nuclear forces and weak nuclear forces separated out with the inflation of the universe. Hot and dense plasma filled up the universe which cooled down in one microsecond to form protons and neutrons. Deuterium (formed after fusion of protons and neutrons) was formed after three minutes of the Big Bang which led to the formation of helium-4.
After 3,80,000 years of Big Bang, recombination happened which made the universe turn transparent. There are no answers to what preceded the Big Bang.