A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Select the first letter of the word from the list above to jump to appropriate section of the glossary. If the term you are looking for starts with a digit or symbol, choose the '#' link. - M - magnitude A measure of the brightness of celestial objects. Absolute magnitude refers to the intrinsic brightness of an object, while the relative magnitude factors in distance from Earth, and refers to its brightness as seen from this planet's vantage point. Magnitude is measured on an inverse scale: a -3 magnitude object is brighter than a +3 magnitude object. +6 magnitude or less is required to view celestial objects with the naked eye, given clear viewing conditions. Maheo Cheyenne creator god, who occupies the highest point in the sky, the "blue sky lodge", home of the Sun, moon and stars. main sequence Definition Mars Fourth planet from the Sun, and the first of the superior planets. Viewable by the naked eye, it often exhibits a reddish tinge. Named after the Roman god of war, it orbits the Sun in 687 days. medicine wheel A wheel-shaped arrangement of stones used by several Native American tribes, aligned to the directions, at which ritual or meditations are performed. megaliths Large stones moved around into purposeful places by Neolithic peoples. Mercury First planet from the Sun, and sometimes viewable by the naked eye just before sunrise or just after sunset. Named after the Roman messenger of the gods, Mercury orbits the Sun in 88 days. meteor The luminous trail left behind by a meteoroid as it travels through the Earth' atmosphere. meteorite A solid extraterrestrial object that survives its journey through Earth's atmosphere, and lands on the ground. meteoroid A small solid body in extraterrestrial space, which may or may not enter Earth's atmosphere. Milky Way The spiral-shaped galaxy our solar system is a part of. We see it as a band of white and stars when the sky is sufficiently dark. moon Moons are solid satellites which revolve around planets. Back to Top