The Cosmos is the name given to everything that is above the terrestrial atmoplane.
Main article: Sun
The Sun is a sphere which revolves above the Earth on a path known as the ecliptic. Its path moves North-South over the year between the Tropic of Capricorn to the Tropic of Cancer. It illuminates a portion of the earth at a time and has daily cycle of one revolution per 24 hours.
Main article: Moon
The Moon is a sphere which revolves above the surface of the Earth in a manner similar to the Sun. It moves at a slower rate of revolution, at about 347.81° per 24 hours, rising and setting 50 minutes later each day. The Moon has a monthly phase cycle, ranging from New Moon to Full Moon.
Main article: Planets
The planets are spheres which move above the face of the Earth and across the sky with apparent relationship to the Sun. Known to antequity as 'wandering stars', the planets were once thought to be key to the nature of the Solar System and the Earth's place in it.
Main article: Stars
The stars are luminous elements which move in a layer above the Sun and Moon at a rate slightly slower than the Sun, resulting in the Sun moving along zodiac constellations throughout the year.
Further information: General Physics
A Note On Sphericity
It is sometimes asked that if the visible celestial bodies are spheres, why isn't the Earth a sphere? The logic that the Earth must be a sphere because the celestial bodies that we see are spheres is only one possible interpretation. It could also be logical that all bodies need a plane of existence to exist upon or over, like all other bodies of human experience. Pebbles in a stream have a stream bed. Basketballs have a basketball court. The game Water Polo consists of a court with a flat bottom and balls which float on a medium. It does not follow because those objects are round, that the courts must also be round.