radioactivity

Nuclear radioactivity

The spontaneous emission of particles or energy from an unstable nucleus.

Alpha decay

A type of radioactive decay involving the emission of an alpha particle from a nucleus.

Beta decay

A type of radioactive decay where a high-energy electron is emitted.

Gamma decay

A form of radioactive decay that involves the emission of high-energy electromagnetic radiation.

Half-life

The time it takes for a substance to decay to 50% of its original sample.

Zircon

A mineral that can indicate the time of formation of the planet due to its resistant nature to decay.

P waves

Primary waves or longitudinal waves that travel through solids, liquids, and gases.

S waves

Secondary waves that travel through solids and semi-solids but cannot travel through liquids.

Convection currents

The circulation of molten rock underneath the earth's crust caused by temperature differences.

Dynamo theory

The theory that a planet will have a strong magnetic field if it has a fast rotation and a liquid core.

Diverging boundaries

Boundaries formed when tectonic plates are driven apart by convection currents in the Earth.

Plate tectonics

The theory that explains the movement of the Earth's plates and the interaction at their boundaries.