By Allison Poskey
First Off.. The Planets!
There are eight planets in our Solar system, and they all orbit the sun. The Sun is the center of our Solar System. The order of the planets from the middle out is
The planets orbit the Sun because of gravity, the Sun's gravitational pull keeps the planets in orbit. The further away from the Sun the less gravity a planet would have, and vice versa. The mass of a planet can also effect the gravitational pull from the Sun. The greater mass of a planet will have a stronger gravitational pull, and vice versa. So for example, if we were to go to Neptune, since it has a larger mass than Earth we would have a very hard time to move at all.
Rotation and Revolution
Mercury- 24 Earth years
Venus- .62 Earth Years
Earth- 365 days 5 hours (One Earth day)
Mars- 1.9 Earth years
Jupiter- 12 Earth years
Saturn- 29 Earth years
Uranus- 84 Earth years
Neptune- 165 Earth years
Mercury- 59 days
Venus- 243 Earth Days
Earth- 24 hours (One Earth day)
Mars- 1.03 Earth days
Jupiter- .41 Earth days
Saturn- .43 Earth days
Uranus- 3/4 of an Earth day
Neptune- .67 Earth days
The Inner Planets
The first four planets are known as "The Inner Planets" they are the planets that are closest to the Sun. The inner planets are
These planets are sometimes called the terrestrial planets because of their closeness to Earth, and they have rocky, solid bodies. These Inner Planets have thin atmospheres, and they have very few moons.
The Outer Planets
The four "Outer Planets" are the planets that are the farthest away from the Sun. The Outer planets are
These Outer Planets are very large, much larger than Earth. These planets have strong gravities, and many moons and rings. Unlike Earth these planets are mostly made up of gases, and so the nickname Gas Giants was given.
Galilean Moons were discovered by Galileo in 1610. Galilean Moons are the four largest moons orbiting Jupiter. They are named after the lovers of Zues. Their names are
Galilean Moons helped to disprove the theory that Earth was the center of the solar system. Galilean Moons also helped to show the importance of telescopes as a tool for astronomers.
Asteroids, Comets, and Meteors!
Most asteroids are very small, but a handful of them can get to be quite large. One called Ceres is considered to be a dwarf planet, which is what Pluto is! A ring of asteroids lies beyond the orbit of Mars.
Comets are made up of bits of rock, and dust mixed with frozen compounds. Comets are frequently found in deep space, on their way toward, or from the Sun in lengthy elliptical orbits. Their orbits can take dozens or even thousands of years to complete only one orbit. The Sun's energy blows comet material away, so that the "tail" faces the Sun.
The difference between meteors and asteroids is size, a meteoroid compared to an asteroid is like sand to a boulder. Meteors are constantly shooting in outer space, and are pulled in by the gravity of other planets and moons. They streak through the object's atmosphere becoming a meteor, and if it doesn't burn up entirely, and ends up striking the surface, then it would be called a meteorite.
In this picture you can see the asteroid belt that lies beyond Mars' orbit.
In this picture you see the different parts of a comet.
In this picture you can see a meteor in the sky... Make a wish!