Topic 7 and 8: The Universe and Space Exploration

Big bang theory

The prevailing cosmological model stating that the universe began approximately $13.8\text{ billion}$ years ago as an infinitely hot, dense point and has been continuously expanding and cooling ever since.

Cosmic microwave background (CMB) radiation

The faint, low-frequency electromagnetic radiation uniformly filling space, serving as the leftover 'afterglow' from when the early universe transitioned from an opaque plasma to a transparent state.

Kelvin

A thermodynamic temperature scale where zero ($0\,\text{K} = -273.15\,^\circ\text{C}$) represents absolute zero, the coldest possible temperature, and an increment of $1\,\text{K}$ equals $1\,^\circ\text{C}$.

Recombination