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A planet, as defined by the International Astronomical Union (IAU) for the Solar System, is a body that orbits the Sun, is massive enough to be rounded by its own gravity, and has cleared its neighbouring region of planetesimals. No formal... more

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Uranus Uranus from space Topic William Herschel Mar 13, 1781
Uranus ( or ) is the seventh planet from the Sun and the third-largest and fourth-most massive planet in the solar system. It is named after the ancient Greek deity of the sky (Uranus, ), the father of Kronos (Saturn) and grandfather of Zeus (Jupiter). Uranus was the first planet discovered in modern times. Though it is visible to the naked eye like the five classical planet, it was never recognized as a planet by ancient observers due to its dimness. Sir William Herschel announced its...
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Mars mars.jpg Topic    
Mars (pronounced ) is the fourth planet from the Sun in the Solar System. The planet is named after Mars, the Roman god of war. It is also referred to as the "Red Planet" because of its reddish appearance as seen from Earth. Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact crater of the Moon and the volcano, valley, desert and polar ice caps of Earth. It is the site of Olympus Mons, the highest known mountain in the Solar System, and...
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Venus The term Cytherean can be used to refer to things from or related to the planet Venus, pictured here Topic    
Venus (pronounced ) is the second-closest planet to the Sun, orbiting it every 224.7 Earth days. It is the brightest natural object in the night sky, except for the Moon, reaching an apparent magnitude of −4.6. Because Venus is an inferior planet, from Earth it never appears to venture far from the Sun: its elongation reaches a maximum of 47.8°. Venus reaches its maximum brightness shortly before sunrise or shortly after sunset, for which reason it is often called the Morning Star or the...
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Mercury Reprocessed Mariner 10 image of Mercury Topic    
Mercury (pronounced ) is the innermost and smallest planet in the solar system (since Pluto was re-labelled as a dwarf planet), orbit the Sun once every 88 days. Mercury is bright when viewed from Earth, ranging from −2.0 to 5.5 in apparent magnitude, but is not easily seen as its greatest angular separation from the Sun (greatest elongation) is only 28.3°: It can only be seen in morning and evening twilight. Comparatively little is known about it; the first of two spacecraft to approach...
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Jupiter Jupiter, a class I planet Topic    
Jupiter (pronounced ) is the fifth planet from the Sun and the largest planet within the Solar System. It is two and a half times as massive as all of the other planets in our Solar System combined. Jupiter, along with Saturn, Uranus and Neptune, is classified as a gas giant. Together, these four planets are sometimes referred to as the Jovian planet, where Jovian is the adjectival form of Jupiter. The planet was known by astronomer of ancient times and was associated with the mythology and...
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Saturn The planet Saturn Topic    
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Along with the planets Jupiter, Uranus and Neptune it is classified as a gas giant (also known as a Jovian planet, after the planet Jupiter). It was named after the Roman god Saturnus, equated to the Greek Kronos (the Titan father of Zeus) and the Babylonian Ninurta. Saturn's symbol represents the god's sickle (Unicode: ). The planet Saturn is composed of hydrogen, with small proportions...
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Neptune Neptune from Voyager 2 Topic Urbain Le Verrier Sep 23, 1846
Neptune (, AmE: ) is the eighth and farthest planet from the Sun in the Solar System. It is the fourth largest planet by diameter, and the third largest by mass. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 Earth masses and less dense. The planet is named after the Roman god of the sea. Its astronomical symbol is , a stylized version of the god Neptune's trident. Discovered on September 23, 1846, Neptune was the first planet found by...
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Earth The_Earth_seen_from_Apollo_17.jpg Topic    
Earth (pronounced ) is the third planet from the Sun and is the largest of the terrestrial planet in the Solar System in diameter, mass and density. It is also referred to as the Earth, Planet Earth, the World, and Terra. Home to millions of species, including human, Earth is the only place in the universe where life is known to exist.Scientific evidence indicates that the planet formed 4.54 billion years ago, and life appeared on its surface within a billion years. Since then, Earth's...
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