SATURN Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn has an average radius about 9 times larger than the Earth's. While only 1/8 the average density of Earth, due to its larger volume, Saturn's mass is just over 95 times greater than Earth's. Sixty-two known moons orbit the planet; fifty-three are officially named
Saturn has nine rings, consisting mostly of ice particles with a smaller amount of rocky debris and dust. The average distance between Saturn and the Sun is over 1 400 000 000 km (9 AU). With an average orbital speed of 9.69 km/s, it takes Saturn 10,759 Earth days (or about 29½ years), to finish one revolution around the Sun.
URANUS Uranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. Uranus's mass is roughly 14.5 times that of the Earth, making it the least massive of the giant planets. Its diameter is slightly larger than Neptune's at roughly four times Earth's.
Uranus has 27 known natural satellites. Uranus has thirteen distinct rings. Although there is no well-defined solid surface within Uranus's interior, the outermost part of Uranus's gaseous envelope that is accessible to remote sensing is called its atmosphere.
NEPTUNE Neptune is the eighth and farthest planet from the Sun in the Solar System. Neptune is an intermediate body between Earth and the larger gas giants: its mass is seventeen times that of the Earth but just 1/19th that of Jupiter. Neptune has 13 known moons.
The average distance between Neptune and the Sun is 4.50 billion km (about 30.1 AU), and it completes an orbit every 164.79 years. Neptune and Uranus are often considered a sub-class of gas giant termed "ice giants", due to their smaller size and higher concentrations of volatiles relative to Jupiter and Saturn.
ASTEROIDS Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones. the term asteroid has come increasingly to refer specifically to the small rocky–icy and metallic bodies of the inner Solar System.
Asteroids are commonly classified according to two criteria: the characteristics of their orbits, and features of their reflectance spectrum. A large majority of known asteroids orbit in the main asteroid belt between the orbits of Mars and Jupiter or co-orbital with Jupiter . The mass of all the objects of the Main asteroid belt, lying between the orbits of Mars and Jupiter, is estimated to be about 3.0-3.6×1021 kg, or about 4 percent of the mass of the Moon.
METEOROID A meteoroid is a sand- to boulder-sized particle of debris in the Solar System. The visible path of a meteoroid that enters Earth's atmosphereis called a meteor, or colloquially a shooting star or falling star. If a meteoroid reaches the ground and survives impact, then it is called a meteorite. Many meteors appearing seconds or minutes apart are called a meteor shower.
The visible light produced by a meteor may take on various hues, depending on the chemical composition of the meteoroid, and its speed through the atmosphere. Some of the possible colors and the compounds responsible for them are: orange/yellow (sodium); yellow (iron); blue/green (copper); purple (potassium); and red (silicate). Any sound generated by a meteor in the upper atmosphere, such as a sonic boom, should not be heard until many seconds after the meteor disappeared.
COMET A comet is an icy, small Solar System body that, when close enough to the Sun, displays a visible coma, and sometimes also a tail. Comets are distinguished from asteroids by the presence of a coma or a tail.
Comet nuclei are known to range from about 100 meters to more than 40 kilometres across. They are composed of rock, dust, water ice, and frozen gases such as carbon monoxide, carbon dioxide, methane and ammonia. The streams of dust and gas thus released form a huge, extremely tenuous atmosphere around the comet called the coma, and the force exerted on the coma by the Sun's radiation pressure and solar wind cause an enormous tail to form, which points away from the sun.
WHY IS PLUTO A DWARF PLANET? The new rules for planethood contain the following: The object must orbit the Sun. The object must have enough mass and gravity to pull itself into a sphere The object must have cleared its orbit This is where Pluto falls down. The mass of Pluto accounts for only a fraction of the mass of the objects in its orbit, while Earth has more than a million times the mass of its orbital companions.