Orion Glossary

The study of the movements and relative positions of celestial bodies claimed as having an influence on human affairs and the natural  world. Astrology is not a science.

Astronomy is the scientific study of stars, space, and the physical universe as a whole.

A flow of matter that is largely confined to a plane and that is spiralling in towards a central object.

The angle between two lines drawn from an observer’s eye to opposite sides of the object being observed.

A body made of mainly rocky materials (including metals) in orbit around the Sun, that is typically much less massive than a planet. Most asteroids are found in the asteroid belt between Mars and Jupiter. Asteroids (and comets) are often called minor planets. The largest known asteroid (Ceres) is classified as a dwarf planet.

A region between Mars and Jupiter in which most asteroids reside in stable orbits. Also called main belt.

The building block of chemistry comprising a tiny, dense, positively charged atomic nucleus (which can contain both protons and neutrons) with circulating negatively charged electrons equal in number to the number of protons in the nucleus.