Asteroids. What do we know about them?
They can be found in two main areas: between the orbits of Mars and Jupiter, and beyond the orbit of Neptune. They are small objects, and get their name because the first discovered were bright and star-like.
The word “asteroid” is a word of Greek origin. It comes from Greek “asteroeides” and means “starlike.” The Greek word “aster” means “star.” The word came into the English language in 1802, about a year after the first asteroid, Ceres, was discovered in 1801. Merriam-Webster defines asteroid as “any of the small rocky celestial bodies found especially between the orbits of Mars and Jupiter.” (1)
Asteroids can be found anywhere in our solar system,. A million or more are believed to be in what is usually called the “asteroid belt” between Mars and Jupiter. Many more-possibly millions-exist beyond the orbit of Neptune.
The “naming” system is rather haphazard. As they are discovered, they receive a number, which is a simple record of their order of discovery. Nearly 100,000 have been discovered and numbered. Approximately 12,000 have also received names. The earliest ones discovered received names of mythological gods, goddesses and heroes. As names of mythical characters got used up, it became a convention to allow discoverers to name their discovery.
Asteroid 136 is named “Austria,” after the nation of Austria. Asteroid 978 is named “Petunia” after the flower, and asteroid 1620 is named “Geographos,” in honor of the National Geographic Society. Asteroid 3352 is named “McAuliffe” after the teacher who flew on the Space Shuttle. Asteroid 5535 is named AnneFrank, for the author of “The Diary of Anne Frank” who died in a German concentration camp.
Asteroids with names are referred to by both their number and name at the same time. Example: 136 Austria. 978 Petunia.
The first asteroid discovered was 1 Ceres. It was discovered on 1 January 1801 by an Italian astronomer, Giuseppe Piazzi (7 July 1746-22 July 1826). He was also a priest and a mathematician. 1 Ceres is the largest of the asteroids. It averages about 950 miles across.
Other asteroids include 2 Pallas, 3 Juno, 4 Vesta and 10 Hygeia. With 1 Ceres, they make up the five largest of the asteroids.
The innumerable asteroids fall into three main classifications, based on their make-up. The first type is the C-type (carbonaceous). They are the most common, making up about three-fourths of asteroids. They are found mostly in the outer portion of the asteroid belt, and are “stony” and rock-like. They are the darkest of the asteroids, reflecting the least amount of sunlight.
The second type is the S-type (silicaceous). They are of mixed composition, being made up of iron and rock, and are brighter than C-type. They are less common, making up around 17% of asteroids. They mostly occupy the inner portion (closest to the sun) of the asteroid belt.
The third main type of asteroid is the M-type (metallic). They make up most of the rest of the asteroids. They are the brightest, as they are made up of metals such as iron and nickel.
Check out the following for much more fascinating asteroid information:
http://www.nineplanets.org/asteroids.html
http://nssdc.gsfc.nasa.gov/planetary/planets/asteroidpage.html
http://nssdc.gsfc.nasa.gov/planetary/text/asteroids.txt
http://burro.astr.cwru.edu/stu/asteroid.html
http://www.edinformatics.com/math_science/solar_system/asteroid_belt.htm
http://www.astronomy-for-kids-online.com/giuseppe-piazzi-biography.html
http://science.nationalgeographic.com/science/space/solar-system/asteroids-comets-article.html
(1) Merriam-Webster’s Collegiate Dictionary, 11th edition. Merriam-Webster, Springfield, Massachusetts. 2003.
