Sun and Planets

Our nearest star, the Sun is the center of the Solar System. Generating huge amounts of heat and light energy, it is the Solar System's power plant. The Sun is the source, directly or indirectly, of almost all of the energy we use.

Image at right: The Sun (courtesy of NASA).

The smallest planet in the solar system, Mercury is also the closest to the sun. Mercury bakes by day, but it freezes at night! It is the fastest planet in the Solar System. Mercury's year is the shortest, too. It zips around the Sun every 88 Earth-days.

Image at right: Mercury (courtesy of NASA).

Venus is the brightest planet visible from Earth because it reflects so much sunlight due to its reflective cloud cover. Some people consider Venus to be Earth's twin or sister planet. It is our nearest neighbor and is a rocky planet similar in size, mass, and composition to Earth, but Venus is also very different.

(Image Right: A radar image of Venus collected by the Magellan spacecraft in 1990, Courtesy of NASA)

We live on Earth, the third rock from the Sun. Earth is the largest terrestrial planet and the fifth largest planet in the Solar System. An ideal distance from the Sun for liquid water, Earth teems with life from its high mountains to its deep oceans. Earth is an exciting and often unpredictable place.

(Image Right: Earth, Courtesy of NASA, Apollo 17 crew)

Our neighboring planet, Mars, is the planet most like Earth. A day on Mars is just 40 minutes longer than a day on Earth. There are volcanoes, canyons, and polar icecaps that expand and shrink with the seasons. Yet, Mars is a red, rugged world that is cold, dusty, and dry.

(Image Right: Mars, Courtesy of NASA)

First of the giant planets, Jupiter is the largest planet in the Solar System. It is more than twice as massive as the other planets combined. It is a spinning ball of gas with a super-hot liquid center under incredible pressure.

(Image Right: Jupiter, Courtesy of NASA)

Known for its amazing rings, Saturn is the sixth planet from the sun and the second largest planet in our Solar System. Because it spins so quickly, Saturn bulges at its equator and is thinner at its poles.

Image at right: Saturn (courtesy of NASA).

Uranus (YOOR uh nuhs) was the first planet discovered through a telescope, but when he discovered it in 1781, astronomer William Herschel initially believed it was a comet. The seventh planet from the sun, Uranus appears to be tipped on its side! One pole - and then the other - faces the Sun on the planet's long orbit.

(Image Right: Uranus, courtesy of NASA.)

The weather forecast on Neptune calls for storms, storms and more storms. Cold winds will whip through blue methane clouds at more than 1,200 miles (2,000 km) per hour. The eighth planet from the Sun, Neptune is a cold and distant world.

(Image Right: Neptune, courtesy of NASA.)

In 2006, the International Astronomical Union (IAU) approved dwarf planets as a new classification category for "in-between sized" objects in our Solar System. Currently, there are three dwarf planets: Eris, Ceres, and Pluto (which was demoted from its previous status as a planet). In 2008, The IAU decided on the term plutoid as a name for dwarf planets like Pluto.

(Image Right: The Dwarf Planets (Used with permission, Walter Myers.))