Aphelion Perihelion Albedo Sidereal Period
Astronomy Astrophysics Cosmology Astrology
Angstrom Universe Black Hole Light Year
Comets Meterorites Asteroids Constellations
Earth Mercury Mars Neptune
5 million years 225 million years 125 million years 25 million years
Mercalli scale Antoniadi Scale Richter Scale Mohs Scale