Objects found in the solar system have characteristics based on surface features and atmosphere (if there is one). These objects move via orbit/revolution and/or rotation.
Rotation vs. Revolution
- Planets may have either a terrestrial (rocky) surface or a gaseous surface. Gaseous planets are considerably larger than terrestrial planets.
- Planets may have rings or other unique surface characteristics.
- Movement of planets is based on revolution (orbit) around the Sun and rotation (turning) on the planet’s axis.
- Moons are studied in relation to the planet they orbit. Not all planets have moons.
- Most are rocky bodies covered with craters, but some have unique characteristics.
- Movement of moons is based on revolution around their planets and rotation on their axis.
- The planets of our solar system—and even some asteroids—hold more than 150 moons in their orbits.
- Most asteroids are rocky bodies that orbit in a region in the solar system known as the Asteroid Belt between Mars and Jupiter.
- They vary in size and shape.
- Movement is based on their revolution around the Sun.
- Some asteroids outside the asteroid belt have orbits that cross Earth’s orbit, which require scientists to monitor their positions.
- Comets have a main body or head (ice, methane and ammonia and dust) and a tail that emerges as the comet gets closer to the Sun during its orbit.
- The effects of the solar winds result in the tail always points away from the Sun.
- Comets have long, narrow, elliptical orbits that cause them to cross paths with other objects in the solar system.
- Most comets originate from regions of the solar system that lie beyond the orbit of Neptune.
- Meteors are chunks of rock that burn upon entering a planet’s atmosphere.
- Prior to entering the atmosphere the chunks of rock move about within the solar system and are known as meteoroids.
- When the chunk of rock strikes the surface of a planet or moon it is known as a meteorite.
It is estimated that approximately 18,000 to 84,000 meteorites bigger than 10 grams fall to Earth each year. But most meteorites are too small to actually fall all the way to the surface.
Astronomers estimate that a staggering one 'trillion' comets may be in our Solar System!