Stardate 03:08:98

The Solar System

There are nine planets in the solar system.

The following information can help you learn more about each of them.

MERCURY

The planet nearest to the sun, Mercury has a cratered surface and almost no atmosphere. It is the smallest of the inner planets and has no known satellites. It revolves around the sun in about 88 days.

VENUS

This is the second planet from the sun, and its atmosphere is mainly composed of carbon dioxide. It revolves around the sun in 224.7 days. The entire surface of the planet is covered by a dense layer of clouds.

EARTH

Earth, the fifth largest planet in the solar system, is the only one known to support life. It revolves around the sun in about 365 days. Estimated to be 4.5 billion to 5 billion years old, this planet has one natural satellite, the moon.

MARS

The next planet out from Earth, Mars revolves around the sun in about 687 days. It has many volcanoes, including the largest in the solar system, Olympus Mons.

JUPITER

Jupiter is the largest and most massive of the nine planets. It is the fifth planet away from the sun and has 16 known natural satellites.

SATURN

Revolving around the sun in about 29.5 years, Saturn is the second largest planet. Its most remarkable feature is its ring system, which is composed of billions of water-ice particles.

URANUS

This is the seventh planet from the sun, revolving around it about every 84 years. It was the first planet discovered in modern times with the aid of a telescope.

NEPTUNE

Almost 3 billion miles from the sun, Neptune revolves around the sun every 164.8 years. Its mass is 17.2 times that of Earth.

PLUTO

Pluto, with a rather elliptical orbit around the sun, has a diameter of less than half that of Earth. Its surface consists mainly of frozen nitrogen. It has one known satellite, Charon.

Shop for telescopes and accessories at

More About The Solar System: A primer

Back To Starwatch Index

Enter keywords...

This site operated by