About the Asteroid Belt

Misconceptions

• A misconception about the asteroid belt is that it is like a superhighway in space, where one asteroid after another flies in close proximity to each other. However, there is a great distance between asteroids in the belt. Hundreds of thousands of miles often separate asteroids from one another. The asteroids are also not round. Many are oblong and some even assume stranger and more bizarre shapes such as one would find in a bag of potatoes.

History

• The first asteroid to be spotted with a telescope was Ceres. It was discovered by the Italian astronomer Giuseppe Piazzi on Jan. 1, 1801. Piazzi named the rocky body for the Roman goddess of the harvest. Ceres remains the largest asteroid ever found, with a diameter of 568 miles. Other large asteroids since located in the asteroid belt are Vesta and Pallas.

Theories/Speculation

• Most researchers say the asteroids came into existence when a planet in that region of the solar system failed to form. Rather than the material combining as it did for the other planets around the sun, this one was unable to do so and the remains of this material are the asteroids that occupy the belt. Other schools of thought point to a collision in space, perhaps between a small planet and a comet, which caused the rubble that now circles the sun in this part of space.

Considerations

• Estimates of the total mass of all the combined asteroids in the belt come up with a number that suggests it is less than a thousandth of the total mass possessed by planet Earth. If the largest asteroids were somehow situated side by side, they would only stretch for a distance of about 930 miles. The gravitational forces of Jupiter and the solar winds from the sun have more than likely pulled many asteroids out of the belt where they were flung into deep space or captured as "moons" by larger planets.

Expert Insight

• There is evidence that asteroids do collide with each other. When this occurs, the resulting smaller asteroids normally will stay in a similar orbit to the originals. Asteroids that escape the belt and then make their way to Earth can enter the atmosphere and burn up from the friction as meteors. Those that can withstand this heat and have some small piece reach the ground are called meteorites. Studies of these meteorites shows that more than 92 per cent of asteroids are made of stony materials and almost 6 per cent are a combination of nickel and iron.