Most of us are familiar with the Asteroid Belt as a grouping of very large rocks that orbit the Sun. There’s so much more left to know, so let’s launch this investigation into space.
1: The Asteroid Belt resides within a region of space between the orbits of Mars and Jupiter. This area of the solar system, which lies between 2.2 and 3.2 astronomical units (AU) away from the Sun, is where most of the known asteroids orbit. The belt itself is about 1 AU (150 million kilometers) thick.
2: The belt was discovered by Johann Titius, an 18th-century astronomer, who analyzed a mathematical pattern of planetary layouts in the solar system. Scientists failed to locate the planet that should have existed where the belt resides. Finally, Italian astronomer Giuseppe Piazzi discovered the first known asteroid, Ceres. A second body, Pallas, was found shortly thereafter.
3: Astronomers believed that both Ceres and Pallas were new planets. After several decades, more than 100 new “planets” had been discovered. Astronomers realized these objects were far too tiny to be planets, hence the term “asteroid.” Ceres is also currently classified as a “dwarf planet.”
4: The Asteroid Belt is made up of billions of bodies. Most of them are as small as pebbles. The four largest of the bunch (over 250 miles in diameter) are Ceres, Pallas, Vesta, and Hygiea. Together, these four asteroids contain 50% of the belt’s entire mass.
5. Most asteroids are named by number. Only 7000 asteroids have received numerical or official name designations.
6: Empty space is what makes up most of the Asteroid Belt. The average distance between asteroids is a whopping 600,000 miles, which is larger than 24 times the Earth’s circumference.
7: Objects in the Asteroid Belt are made of rock, stone, and other materials. Some asteroids are solid matter, and others are simply piles of loosely-combined rubble.
8: Scientists once theorized that the asteroids could be combined to form a fifth terrestrial planet (in addition to Mercury, Venus, Earth, and Mars). This theory was overruled because the combined mass of the Asteroid Belt is less than that of the Earth’s moon.
9: Jupiter’s insanely large mass is what caused a true planet not to form in the Asteroid Belt’s location. Jupiter’s gravity scattered multiple protoplanets apart and caused them to crash, which is what created the Asteroid Belt.
10: The Asteroid Belt isn’t the only place where asteroids can be found in the solar system: Others orbit near the Earth, while some asteroids are flung out to the edge of the solar system (and beyond) by various gravitational influences.
11: Scientists generally refer to the Asteroid Belt as the “Main Belt.” This label sets it apart from two other groupings of asteroids, the Lagranians and Centaurs.
12: Asteroids collide within the belt very infrequently. The objects with a larger diameter than 5 miles will collide (on average) once per 10 million years. The resulting dust lingers, however, and is one of the causes of the zodiacal light (as observed from Earth).
13: Most asteroids aren’t large enough to achieve a spherical shape. Many of them are potato shaped, although one (216 Kleopatra) formed in the shape of a doggie bone.
14: The Main Belt is located more than 2.5 times away from the Sun as the Earth. Every so often, an asteroid breaks away from the belt and heads towards the earth. These asteroids are usually only a few hundred feet in diameter and burn up in the Earth’s atmosphere.
15: Asteroids are known to contain resources that are highly valued on earth. These include precious metals such titanium, nickel, and iron. Asteroids also contain water, which could potentially be used to provide for future space colonies.
16: NASA launched a 2007 mission to investigate Ceres and Vesta. This spacecraft, Dawn, reached Vesta and stayed with the asteroid for a year. Dawn is forecasted to reach Ceres in 2015.
17: Asteroid mining remains a very real possibility. NASA concedes that their plans are not financially feasible at this date. The future is wide open, as a number of private companies have expressed interest in funding missions.