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SOLAR SYSTEM |
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Astronomers believe that all
the members in the Solar System were born out of a vast, a spinning cloud of gas and dust
called solar nebula. This process began 5 billion years ago with the formation of the Sun.
All the planets and other objects found in the universe formed from unused material. Solar nebula - when the vast cloud spun and cooled, the material was drawn into the center. It will became denser and more hotter, began generating energy with nuclear fusion, so the Sun born. The rest of the solar nebula formed into a disc containing hydrogen, helium gas with some dust, rock, metal and snow. Rock and metal material near the sun will form inner planets. Snow together with rock, metal and gas form the outer planets. Solar System Overview Our solar system consists of
one central star (the Sun) and nine planets, along with numerous moons, comets, asteroids
and meteoroids. All of the planets revolve around the Sun in the same direction, which is
counter-clockwise if you were looking down on the system from some point above it. Their
orbits are almost circular in nature and in nearly the same plane (called the ecliptic).
Pluto is the one exception to this, having a highly inclined and highly elliptical orbit,
which is why it is sometimes closer to the Sun than Neptune. There are many classifications
for the planets in our system. Here are a few common terms that you may encounter: “Terrestrial Planets” - Mercury, Venus, Earth and Mars.
These are solid bodies, relatively close to the Sun. “Jovian
Planets” - Jupiter, Saturn, Uranus, Neptune. These planets are “gas
giants”. They lack solid surfaces and are larger than the Terrestrial Planets. Pluto is not included in the
above two classifications. “Inner
Planets” - These are the four planets closest to the Sun: Mercury, Venus,
Earth and Mars. “Outer
Planets” - The remaining planets in the system: Jupiter, Saturn, Uranus,
Neptune and Pluto.
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