Site Glossary

capable of providing conditions in which life could potentially survive.

region around a star where surface liquid water could exist under suitable atmospheric conditions.

A graphical method of adding vectors sequentially.

a possible extremely distant state with little usable free energy available for physical processes.

The element produced during hydrogen fusion in most stars.

A graph that compares the luminosity and surface temperature of stars.

Horizontal displacement from launch to landing.

The observation that the farther away a galaxy is, the faster it appears to recede.

The process in which hydrogen nuclei combine to form helium inside stars.

The balance between the inward pull of gravity and the outward pressure produced by fusion.