The Origin and Evolution of the Earth

Big Bang Theory

The leading explanation about how the universe began from a single extremely hot and dense point that exploded and expanded about 13.7 billion years ago.

Nebular Hypothesis

Proposed by Immanuel Kant and revised by Laplace, this theory suggests that the planets were formed from a spinning cloud of gas and dust called a nebula.

Planetesimal Hypothesis

A theory stating that a passing rogue star grazed the sun, causing material to be pulled out, which later condensed into smaller chunks called planetesimals and eventually formed planets.

Evolution of Lithosphere

The process through which the molten early Earth cooled, allowing heavier materials like iron to sink to the core and lighter materials to rise and form the crust.

Degassing

The process by which gases and water vapor trapped deep within the Earth were released through volcanic eruptions, forming the early primitive atmosphere.