The Origin and Evolution of the Earth

Big Bang Theory

The most accepted theory regarding the origin of the universe, suggesting that all matter formed in a single point and exploded violently about 13.7 billion years ago, leading to continuous expansion.

Nebular Hypothesis

Proposed by Immanuel Kant and revised by Laplace, this theory states that the planets were formed from a rotating cloud of gas and dust called a nebula associated with the sun.

Planetesimal Hypothesis

A theory suggesting that a passing wandering star approached the sun, pulling out cigar-shaped gaseous material that eventually condensed into small solid bodies called planetesimals.

Differentiation

The process during the earth's early molten stage where heavier materials (like iron and nickel) sank to the centre to form the core, while lighter materials rose to the surface to form the crust.

Degassing

The process through which gases trapped in the earth's interior were released through volcanic eruptions, eventually forming the early atmosphere comprising water vapour, nitrogen, carbon dioxide, methane, and ammonia.