Order within the Solar System

The bodies of the Solar System are ordered and arranged due to the way the Solar System formed (according to the Solar Nebula Theory, condensation, and accretion).

Arrangement of Planets in the Solar System

• Denser, rocky materials settled near the Sun at the center of the Solar System. Thus, the inner "terrestrial" planets are solid and rocky

• Less dense materials (liquid, ice, and gas) were pushed outwards, away from the young Sun. Thus, the outer "jovian" planets are like "gas giants".

Inner/Terrestrial Planets

• Closer to the Sun ("inner" Solar System)

• Smaller, rocky and solid

• 0 to 2 moons per planet (3 total)

• No rings

• Warmed by solar radiation

• Mercury, Venus, Earth, and Mars

Outer/Jovian Planets

• Farther from Sun ("outer" Solar System)

• Larger and mostly gas and ice

• Many moons

• All have rings

• Cooler due to distance from the Sun

• Jupiter, Saturn, Uranus, and Neptune

• Note Earth in picture for scale!

Asteroid/Comets

​Asteroids

• ​Millions of small, rocky objects called asteroids orbit the Sun in the asteroid belt between the orbits of Mars and Jupiter.

• Asteroids are not spherical​

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Comets ​

• A comet is made of gas, dust, and ice and moves around the Sun in an oval-shaped orbit​.

• Comets come from outer parts of the solar system​

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Astronomical Unit (AU)

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• Objects in the solar system are so far apart that astronomers use a larger distance unit.

• AU is the average distance from Earth to the sun – about 150 million km (93 million miles)