Hobbies And Interests
Comets
Comets are icy rocks that have elongated elliptical orbits around a sun. When their orbit passes near the sun, some of their ice vaporizes, leaving a dramatic trail of gas and dust. This creates a long tail called a coma that is blown by solar radiation and always points away from the sun. Halley's Comet is among the most famous, traveling in an orbit that displays its tail every 75 or 76 years, so for most people, viewing Halley's Comet is a once-in-a-lifetime experience.
Asteroids
Asteroids are solid celestial objects that lack the mass to create an atmosphere or form into a spherical shape. Their diameters range from a few feet to a few hundred miles. Most asteroids of our solar system orbit in the large asteroid field between Mars and Jupiter. Ceres was once considered to be the largest asteroid in our solar system until it was reclassified as a dwarf planet due to its mass and spherical shape.
Meteors
Meteors are natural solid objects that enter a planet's atmosphere. On Earth, they generally measure in size from that of a grain of sand to a softball. Upon entering the atmosphere, heat caused by air's friction causes most of them to vaporize before ever hitting the ground. This creates a taillike streak in the sky, which gives them the nickname and appearance of a shooting star. Meteor showers occur when debris from a comet's stream enters the atmosphere, which makes meteor showers regular and predictable.
Moons
Moons are natural solid objects defined simply by their trait of orbiting objects other than a star. Many moons in our solar system orbit planets, and some orbit the dwarf planets Ceres and Pluto. There are well over 160 moons in our solar system. Earth has one, Mars has two, and Jupiter and Saturn have at least 60 each. Though our moon is barren and rocky, other moons have oceans, atmospheres and volcanic activity.