Astronomy -Indianapolis

The sun is the center of our solar system. It is a yellow star, considered to be a class G2V, based on spectral classification.

The moon is a natural satellite of Earth. It has no atmosphere, and completes its orbit around Earth approximately every month. Although it has weak gravity, its proximity to Earth affects the ocean tides.

Asteroids mainly orbit in the asteroid belt, which lies between Mars and Jupiter. It is unknown if they are pieces of a planet that never formed or if they are the result of a space collision. They come in a variety of sizes, and asteroids that come within a close proximity to Earth are considered as "Near-Earth Objects".

Meteors and meteorites are bits of space rock resulting from the collision and breaking apart of asteroids, comets, and other celestial bodies. During meteor showers, meteors pass close enough to Earth to be pulled into the atmosphere, resulting in an illuminating display as the rock disintegrates while it plummets to the surface.

Mercury, named after the Roman messenger god, is the first planet in the solar system. It is the smallest planet, with an 88 Earth-day orbit around the sun. It has no atmosphere and a cratered surface.

Venus, named after the Roman goddess of love, is the second planet in the solar system. Although it is similar to Earth in size, this planet has a thick, sulfuric atmosphere and rocky, desert-like landscape. Venus is easily viewed from Earth, and has been nicknamed the morning and evening star.

The third planet from the sun, Earth has a varied landscape, oceans, an atmosphere, and is currently the only planet known to sustain life. Although we have only occupied the planet for a short time in cosmic years, there is still much to learn.

Mars, named after the Roman god of war, is the fourth planet in the solar system. It is slightly smaller than Earth and has red, rocky terrain, most likely due to rich iron deposits in the soil. The only known inhabitants are the robots sent by NASA to study the planet.

Jupiter is the fifth planet in the solar system, and it is the largest. It is a gas giant, and is known for its red spot, which is an enormous storm that was discovered in the 17th century, and is still active today. Jupiter has 63 known moons, and also has a planetary ring.

Saturn is the sixth planet in the solar system. Known for its rings, it is the second largest gas giant and has approximately 62 moons. It takes approximately 29 Earth years for it to complete an orbit around the sun.

Uranus is the seventh planet in the solar system. Considered as an ice/gas giant, Uranus has rings, rotates in retrograde, and it is believed to have 27 moons.

Neptune, named for the Roman god of the sea, is the eighth planet in the solar system. It has a blue appearance due to the presence of methane in its atmosphere. It also has rings, and is considered a gas/ice giant like Uranus.

There are five known dwarf planets in the solar system. Pluto is probably the best known, considering its change in status from planet to dwarf planet after scientists redefined planetary traits. Other dwarf planets include: Ceres, Eris, Haumea, and Makemake.