Big Bang Theory

Origin and Expansion of the Universe

The Big Bang Theory is the prevailing cosmological model for the observable universe. It posits that the universe originated around 13.8 billion years ago from an incredibly hot, dense state known as a singularity. At this point, all space, time, matter, and energy were concentrated into an infinitely small point.

A violent expansion (not an explosion) occurred, and within fractions of a second, the universe expanded rapidly and continues to do so today. The Hubble Constant, which measures the rate of expansion, is estimated to be about 73 km/s per megaparsec, although this value is still subject to debate.

As space expanded, the universe cooled, allowing subatomic particles to form. Eventually, atoms were created, and this cooling process continues today as the universe grows in size.

Evidence Supporting the Big Bang (Cosmic Microwave Background, Redshift)

1.Cosmic Microwave Background (CMB): The CMB is a faint glow of radiation left over from the early stages of the universe, discovered by Arno Penzias and Robert Wilson in 1965. It dates back to about 380,000 years after the Big Bang, when the universe became transparent, and photons could travel freely through space. The CMB is uniform across the sky, with slight temperature variations (anisotropies) that reflect the density fluctuations from which galaxies eventually formed.