The Planets/Moon:
There are currently eight planets orbiting our star. Interesting fact: There are more planets than stars in our galaxy.
The inner, rocky planets are Mercury, Venus, Earth & Mars.
The outer planets are gas giants Jupiter & Saturn and ice giants Uranus & Neptune.
Facts about Each Planet:
Mercury:
The smallest & fastest planet, it zips around the sun in only 88 Earth days. Mercury is hot, but not too hot for ice, as crazy as that may sound. The closest planet to the Sun does indeed have ice on its surface, but the ice is found in permanently shadowed craters- those that never receive any sunlight. It is thought that perhaps comets delivered this ice to Mercury in the first place.
Venus:
Venus’ thick atmosphere makes it the hottest planet in our solar system. Both Mercury and Venus have no moons, which can be considered a surprise given there are dozens of other ones around the solar system. Research suggests that Venus could have had one in the past.
Earth:
The only planet in our solar system with liquid water on the surface. About 70% of Earth's surface is covered in water. The remaining 30% is made up of the 7 continental landmasses. Underneath the water that fills the oceans, and the dirt and plants that cover the continents, the Earth’s surface layer is made of rock. This outer layer formed a hard, rocky crust as lava cooled about 4.5 billion years ago.
The Moon (Not a planet):
The Moon is in synchronous rotation with Earth meaning the same side is always facing the Earth. The Moon (or Luna) is the Earth’s only natural satellite and was formed 4.6 billion years ago around some 30-50 million years after the formation of our solar system. Only 59% of the Moon’s surface is visible from Earth. The surface area of the Moon is 14,658,000 square miles or 9.4 billion acres. The Moon is not a planet, but a satellite of the Earth. The Moon rotates at 10 miles per hour compared to the Earth’s rotation of 1000 miles per hour.
The Sun (A Star):
Sun: The sun is a star at the center of our solar system. It is an almost perfect sphere of super-hot gases whose gravity holds the solar system together. The energy produced by the Sun is essential for life on Earth and is a driving force behind the weather here on Earth.
Mars:
Mars was a wet and warm planet billions of years ago. Sometimes called the Red Planet, Mars has long been associated with warfare and slaughter. It is named for the Roman god of war. As long as 3,000 years ago, Babylonian astronomer-astrologers called the planet Nergal for their god of death and pestilence. The planet’s two moons, Phobos (Greek: “Fear”) and Deimos (Greek: “Terror”), were named for two of the sons of Ares and Aphrodite (the counterparts of Mars and Venus, respectively, in Greek mythology).
Jupiter:
The largest planet, its dark red spot is a storm larger than Earth. When ancient astronomers named the planet Jupiter for the Roman ruler of the gods and heavens, they had no idea of the planet’s true dimensions, but the name is appropriate, for Jupiter is larger than all the other planets combined. It takes nearly 12 Earth years to orbit the sun, and it rotates once about every 10 hours, more than twice as fast as Earth; its colorful cloud bands can be seen with even a small telescope. It has a narrow system of rings & 79 known moons, one larger than the planet Mercury and 3 larger than Earth’s Moon.
Saturn:
Saturn has the brightest, most massive and most complex ring system of any planet. Saturn's name comes from the Roman god of agriculture, who is equated with the Greet deity Cronus, one of the Titans and the father of Zeus (the Roman god Jupiter). As the farthest of the planets known to ancient observers, Saturn also was noted to be the slowest-moving. At a distance from the Sun that is 9.5 times as far as Earth’s, Saturn takes approximately 29.5 Earth years to make one solar revolution.
Uranus:
Uranus is tipped on its axis by almost 90-degrees. Uranus is named for the personification of heaven and the son and husband of Gaea in Greek mythology. It w
as discovered in 1781 with the aid of a telescope, the first planet to be found that had not been recognized in prehistoric times. Uranus actually had been seen through the telescope several times over the previous century but dismissed as another star. Its mean distance from the sun is nearly 2.9 billion km (1.8 billion miles), more than 19 times as far as is Earth, and it never approaches Earth more closely than about 2.7 million km (1.7 billion miles). Its relatively low density and large size indicate that, like the other giant planets, Uranus is composed primarily of hydrogen, helium, water, and other volatile compounds; also like its kin, Uranus has no solid surface.
Neptune:
Neptune was the first planet discovered through mathematical calculations, rather than observation. Neptune is almost 4 times the size of Earth but slightly smaller than Uranus, which makes it the smallest in diameter of the four giant, or Jovian, planets. It is more massive than Uranus, however, having a density roughly 25% higher. Like the other giant planets, Neptune consists primarily of hydrogen, helium, water, and other volatile compounds, along with rocky material, and has no solid surface. It receives less than half as much sunlight as Uranus, but heat escaping from its interior makes Neptune slightly warmer than Uranus. The heat liberated may also be responsible for the storminess in Neptune's atmosphere, which exhibits the fastest winds seen on any planet in the solar system.
Pluto: (Dwarf planet)
Pluto was first discovered by a young research assistant in 1930. Photographic evidence of the former 9th planet was first sighted by 24 year old research assistant Clyde Tombaugh. An 11 year old gave Pluto its name when Venetia Burney’s grandfather told her the news of the newly discovered planet, she proposed the name Pluto. Pluto is smaller than Earth’s Moon, nut larger than previously thought. Pluto is 1,473 miles in diameter, according to recent measurements obtained from New Horizons.
Charon: (Pluto's Moon)
Charon is the Moon of planet Pluto. Relative to the planet it orbits, it is the largest satellite in the solar system. At 1220 km diameter, Charon is fully half the size of Pluto(2300 km diameter) Charon and Pluto are separated by only 19,500 km. Although Pluto develops an atmosphere near perihelion, the surface of Charon is water ice which remains frozen at the distance from the Sun. Charon was named after the mythological boatman who ferried the souls of the dead across the River Styx to Hades. NASA has on its drawing board the first mission to explore the Pluto-Charon system. This unmanned spacecraft will not be launched for several years, and it will take 7-10 years to travel to Pluto.
Chiron: (Asteroid/Comet)
Discovered in 1977, is an unusual object whose highly-elliptical, 50-year orbit around the sun brings it within the orbit of Saturn and as far out as the orbit of Uranus. It exhibits properties of both a comet (it has a coma) and an asteroid (it is as big as a large asteroid--some 200 km in diameter-- much larger than the biggest known comet), so it has been designated as one of a class of objects known as Centaurs. These half-comet/half-asteroid objects were named after the mythical half-man/half-horse; Chiron is named after the wisest of the Centaurs. Several objects in this class have been discovered; they may be objects that have escaped from the Kuiper belt, the vast disk of cometary bodies beyond the orbit of Neptune. Chiron is designated alternately as a Comet 95P/Chiron or minor planet (2060) Chiron.