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naked eye planet
subject			fact

naked eye planet	has motion relative to stars epicycloidal
	has been observed for many centuries
	has apparent magnitude brighter than 5
	has definition a planet in our solar system visible to the unaided eye
	is a kind of planet
planet	has composition various elements
	is a part of solar system
	has orbit
	has mass greater than Pluto's mass and less massive than ten times Jupiter's mass
celestial body	has spectra
physical object	has location or center of gravity
	has angular momentum
	has velocity
	has momentum
	has temperature
	has volume
	has extent
	has material

Kinds of naked eye planet :

• Earth (31 facts) - Third planet from the Sun. First forms of life appeared about 3.2 to 3.5 × 10⁹ years ago (Homo sapiens appeared as a species about 10⁵ years ago).
• Jupiter (29 facts) - Fifth planet from the Sun. It is more massive than all other planets and satellites combined; if it were about 80 times more massive, it would become self-luminous due to fusion reactions. The heat flux to from the center to the surface is mainly convective. For both Jupiter and Saturn it is necessary to invoke a substantial source of internal heating (presumably gravitational contraction) to account for the surface temperature (Jupiter radiates about 2 1/2 times as much heat as it receives from the Sun). Jupiter's surface shows pronounced horizontal striations: the light layers (zones) are at a slightly higher altitude and about 15° cooler than the dark layers (belts). It is surrounded by a partial torus of atomic H in the orbit of Io. Thirteen satellites, the four outermost of which have retrograde motion, high eccentricity, and high inclination. (Jupiter XIII, discovered in 1974, has a period of 239 days; i = 26°.7, e = 0.147.)
• Mars (25 facts) - Fourth major planet out from the Sun. Its tiny satellites are locked in synchronous rotation with mars.
• Saturn (24 facts) - Sixth major planet out from the Sun. The most spectacular of the Solar System, it is circled by a series of concentric rings. All the satellites of Saturn are locked in synchronous rotation.
• Venus (24 facts) - Second planet from the Sun. Has retrograde rotation. Mariner 10 has established that the cloud tops rotate every 4 hours retrograde. Radar experiments have established that the surface is somewhat smoother than the Moon, but there are mountains and there is extensive cratering. Last transit of Sun was in 1882; next one will be 2004. Venus's rotation period is in synchronism with Earth - that is, at inferior conjunction the same side is always toward the Earth.

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