preferably facts that differentiate it from the other planets. geographical, physical etc
202129
Earth is the only place in the universe where life is absolutely known to exist, and some scientists believe that biospheres might be rare. The planet's lifeforms are sometimes said to form a "biosphere". This biosphere is generally believed to have begun evolving about 3.5 billion (3.5×109) years ago.\n\nThe biosphere is divided into a number of biomes, inhabited by broadly similar flora and fauna. On land, biomes are separated primarily by latitude. Terrestrial biomes lying within the Arctic and Antarctic Circles are relatively barren of plant and animal life, while most of the more populous biomes lie near the Equator.\n\nThe Earth consists of several atmospheric, hydrologic, and many geologic layers. Its components are the atmosphere, the hydrosphere, the crust, the mantle, and its core. The biosphere is a tiny layer in this composition and is usually not considered part of the physical layers of the Earth.
148121
Mercury, Venus, Earth and Mars are the inner planets. Read all about them (and the other planets too) at the web site.
109537
Might be better to be more specific and tell us the question.  It is hard to just give you information on space - seeing as it is infinite for starters.
244110
There are a few things which distinguish the planet from all others, the most obvious is it's blueish appearance.\n\nNeptune is the eighth or, occasionally, the ninth planet from the Sun due to Pluto's eccentric orbit, and the outermost gas giant in our solar system. Although the smallest of the gas giants, Neptune is more massive than Uranus: its stronger gravitational field has compressed it to a higher density. The planet is named after the Roman god of the sea because of its blue methane clouds. Its astronomical symbol is a stylized version of the god's trident (♆).\n\nFaint dark colored rings have been detected around the blue planet, but are much less substantial than those of Saturn. When these rings were discovered, it was thought that they might not be complete, but this was disproved by Voyager 2. Neptune also has 2,500 km/h winds of hydrogen, helium, and methane that gives the planet its blue appearance.[citation needed] At the time of the 1989 Voyager 2 flyby, it had in its southern hemisphere a Great Dark Spot comparable to the Great Red Spot on Jupiter. Neptune possesses nine confirmed moons and four awaiting confirmation. Neptune's largest moon, Triton, is notable for its retrograde orbit, extreme cold (38K), and extremely tenuous (14 microbar) nitrogen/methane atmosphere.\n\nDiscovered on September 23, 1846, Neptune has been visited by only one spacecraft, Voyager 2, which flew by the planet on August 25, 1989. In 2003, there was a proposal to NASA's "Vision Missions Studies" to implement a "Neptune Orbiter with Probes" mission that does Cassini-level science without fission-based electric power or propulsion. The work is being done in conjunction with JPL and the California Institute of Technology.[1]
45360
Go to NASA at http://www.nasa.gov/home/index.html?skipIntro=1 They have a ton of information about anything related to space
330599
mercury, mars, venus, earth, jupiter, saturn, uranus, pluto and neptune.
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If it doesn't move or twinkle, it is the planet Venus.\n\nThis answer brings me to level 3.  Thanks all!
94777
planets, stars, and quasars
621167
There are billions and billions of planets in our universe.  We know little about the vast majority of them, and to think that there is no intellegent life on another planet is arrogance on our part.
14146
http://www.mapkids.org/solar-system-map.html#WIN\n\n&#92;
352001
Try the CIA world fact book.
517697
Here are your answers:\nhttp://199.6.131.12/en/scictr/watch/living_planet/glossary.htm
329055
10 planets have been discovered so far. 9 of them have been registered. The 10th one was discovered in 1930 & has been claimed to be larger than pluto & rocky in nature. It is currently about 97 times farther from the sun than Earth, or 97 Astronomical Units (AU). For comparison, Pluto is 40 AU from the sun. The object was so far away, however, that its motion was not detected until they reanalyzed the data in January of this year. In the last seven months, the scientists have been studying the planet to better estimate its size and its motions.
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With this information contained...no wonder not anyone really has a handle on the exact definition of a planet.  It will be debated for a long time.\n\n# (astronomy) any of the nine large celestial bodies in the solar system that revolve around the sun and shine by reflected light; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto in order of their proximity to the sun; viewed from the constellation Hercules, all the planets rotate around the sun in a counterclockwise direction\n# satellite: a person who follows or serves another\n# any celestial body (other than comets or satellites) that revolves around a star\nwordnet.princeton.edu/perl/webwn\n\n# A planet (from the Greek πλανήτης, planētēs which means "wanderer" or more forcefully "vagrant, tramp") is an object in orbit around a star that is not a star in its own right. Much like "continent," "planet" is a word without a precise definition, with history and culture playing as much of a role as geology and astrophysics (see Definition of planet). ...\nen.wikipedia.org/wiki/Planet\n\n# Overview of the Planets in the Solar System.}\nen.wikipedia.org/wiki/Planet_(Table)\n\n# Planet is a literary magazine based in Wales.\nen.wikipedia.org/wiki/Planet_(magazine)\n\n# An object orbiting a star that is not a brown dwarf but bigger than an asteroid. This is somewhat ambiguous. In our solar system it is really an historical definition which boils down to "a planet is a member of the set {Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto}". All the known planets orbiting other stars are large gas planets so no ambiguity yet arises there. ...\nwww.astro.uio.no/ita/TNP/nineplanets/help.html\n\n# is the term used for a body in orbit around the Sun. The word comes from the Greek planetes, and means "wanderers." Our solar system has nine planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. An easy way to remember their names in the correct order is to keep in mind the following sentence: My Very Educated Mother Just Served Us Nine Pickles. The first letter of each word is the first letter of each planet. ...\nwww.teachervision.fen.com/page/1513.html\n\n# A major object which orbits around a star. In our solar system, there arenine such objects which aretraditionally called "planets'': Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. (There are no "official'' specifications for how big an object must be to be called a planet rather than, for example, an "asteroid.'') While no individual planet has ever been seen orbiting around another star, we wouldn't expect to see them, given the limits of current technology. ...\nwww.astrosociety.org/education/publications/tnl/14/14.html\n\n# A spherical ball of rock and/or gas that orbits a star. The Earth is a planet. Our solar system has nine planets. These planets are, in order of increasing present distance from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Pluto, and Neptune.\naffy50.tripod.com/Glossary.html\n\n# describes any heavenly body which when viewed from Earth appears to move, as distinguished from fixed stars.\nwww.findyourfate.com/faq/p-glossary.htm\n\n# One of nine major bodies that orbit the Sun, visible to us by reflected sunlight.\nastronomy.nju.edu.cn/astron/AT3/GLOSS_P.HTM\n\n# low-mass body that orbits a star.\nschool.discovery.com/curriculumcenter/solarsystem/glossary.html\n\n# there is no set scientific definition for planet (from the Greek planetes “wanderers”), but as a rule of thumb, a planet: 1) must directly orbit a star or an object that has nuclear fusion; 2) must be small enough that it has not undergone internal nuclear fusion (ie, it is not a star or starlike object); and 3) must be large enough that its self-gravity gives it the general shape of a sphere.\nwww.infoplease.com/ipa/A0004425.h
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try reading  "Men are from Mars, Women are from Venus"\nit explains alot
569688
It might be Seti@Home...\nIt's to look for extra terrestrials...\nhttp://setiathome.berkeley.edu/
248369
The link below has great overview info and statistics (including density) for all the planets, asteroids, comets, etc. \n\nCheck it out!