Some useless planetary trivia:
@ The sun is 500,000 times brighter than the full moon in the Earth's sky.
@ A "day" (sunrise to sunrise) on Mercury is 180 days. A year is only 88 days.
@ Mercury is 600 deg.F at day and -300 deg.F at night.
@ Mercury and Venus have no moons.
@ A pair of Mercury transits occur every 13 years. Two pairs of Venus transits occur every 234 years.
@ Venus takes longer to rotate on its axis than it does to revolve around the sun.
@ Because of Venus' thick atmosphere, the surface temperature and pressure is 3 and 10 times that of Earth, respectively.
@ At conjunction, Venus can be as close as 24 million miles or as far away as 230 million miles from Earth.
@ Aside from the Sun and the Moon, the 2 brightest objects in the sky are Venus and Jupiter, boasting magnitudes of -4 and -2.5 respectively.
@ There is no "Earthrise" on the Moon. The Earth remains stationary in the lunar sky (that is, if you don't travel across the Moon, like Apollo VIII did on Xmas eve 1968).
@ The phase of the Earth seen from the Moon is the exact compliment of the phase of the Moon seen from Earth.
@ The Moon is larger than Pluto.
@ Because of the Moon's librations, 20% of its "dark side" is exposed over time.
@ Every year at least 4 eclipses occur.
@ A solar eclipse can only occur during a new moon (for some reason, a lot of people don't know that).
@ Annular solar eclipses are rarer than total solar eclipses.
@ At opposition, Mars can be as close as 34 million miles or as far away as 63 million miles from Earth. The closest proximity occurs about every 15 years, exactly the same time NASA starts dreaming about a "Man-to-Mars" mission.
@ Mars has about the same tilt and rotational period as the Earth does. Its year, however, is twice as long. (Damned that Kepler! He's always right!)
@ Mars has a pink sky.
@ Mars' two moons, Phobos and Deimos, are only 20 and 10 miles across, respectively.
@ The highest mountain in the solar system is Mt. Olympus, which peaks 15 miles above the Martian surface and is as wide as the state of Arizona or New Mexico.
@ The largest asteroid in the asteroid belt is Ceres at 620 miles in diameter.
@ The largest moon in the solar system is Jupiter's Ganymede. At 3270 miles in diameter, it is larger than the planet Mercury.
@ A day on Jupiter is a little less than 10 hours. A day on Saturn is a little more than 10 hours.
@ Saturn's visible rings span twice the diameter of Jupiter.
@ Saturn's rings appear on edge every 15 years, and usually occur in "triplets".
@ When Galileo first saw Saturn's rings, he thought he was looking at a very large planet with 2 large stationary moons on either side. When the rings later went "on edge" and not visible, he didn't know what the Hell was going on.
@ Saturn's inner-most moon, Pan was discovered 1990. It plows inside the ring system, and leaves a thin void known as "Encke's division", which was discovered in 1837.
@ Saturn has the most number of moons, with 18 confirmed.
@ There is a planetoid between Saturn and Uranus named Chiron. It was named 'Chiron' after the mythological half-man/half-beast creature, because the planetoid itself is classified as BOTH an asteroid and a comet.
@ A person would weigh less on Saturn or Uranus than on Earth.
@ Uranus is visible to the naked eye.
@ Uranus is tilted sideways on its axis.
@ Uranus is larger in volume than Neptune. Neptune is larger in mass than Uranus.
@ 100 million years from now Neptune's largest moon, Triton, will break apart and form another ring around the planet.
@ Jupiter and Neptune generate more energy than they receive from the sun.
@ All 4 giant planets have rings.
@ Pluto is red.
@ In 1999, Pluto will once again become the furthest planet from the sun.
@ Pluto has 3 moons; Charon, Nix and Hydra. Because Charon is about half the diameter of its mother planet, the barycenter (balancing point) lies beyond Pluto's surface.
@ Some scientists label Pluto as a double planet. Others declare it isn't a planet at all.
@As of August 4 2006, Pluto has been downgraded from planet status to "dwarf planet", along with its other cousins among the Kupier belt; the Planet X system (Xena and Gabriel), Sedna and Quaoar.
@ A planet's northern hemisphere is the side that appears to rotate counter-clockwise. Therefore... Venus, Uranus and Pluto are "upside-down", or in retrograde.
@ A 1st magnitude star is exactly 100 times brighter than a 6th magnitude star.
@ 13000 years from now, all winter constellations will only be viewable in the summer night sky, and visa-versa.