Robert’s Out of This World Space Odyssey: The Asteroid Belt, Where They Teach You to Hate Dinosaurs

It’s time to say goodbye to the “Earth-like” rocky planets of the inner galaxy and move on to explore the gas giants. If you really were traveling from Mars to Jupiter, you would run into another major component of our galaxy: the asteroid belt.

The asteroid belt (the main belt) is an area of the solar system between the orbits of Mars and Jupiter that contains over 4,000 named asteroids that are just orbiting the sun (there are millions of asteroids total). The vast majority of the asteroids in our solar system can be found in the belt. That’s great and all, but if you don’t know what an asteroid is, then you probably do not care.

An asteroid is basically leftover material from the formation of our solar system about 4.6 billion years ago. Sometimes referred to as minor planets, asteroids are nothing more than pieces of space rock. These rocks are leftover because when Jupiter finished forming, it had such an affect that the material between it and Mars stopped forming as well, leaving us with the asteroid belt.

Asteroids are irregularly shaped and covered in collision marks. They all orbit the sun and even rotate – although it looks more like they are just tumbling along. They vary greatly in size. Ceres is the largest and is roughly 952 kilometers (592 miles) in diameter. This monster asteroid is said to contain 1/3 of the total mass of all asteroids. Others are not even a mile in diameter. The smallest asteroid ever discovered is barely 20 feet across. Some of the larger asteroids have small moons orbiting them. Several pair off (sometimes in groups of three) and orbit each other as they orbit the sun.

Getting through the asteroid belt isn’t a big deal. It is such a large space and the asteroids are typically rather small (in comparison to other things in space). If you took every asteroid in our solar system and put them together, you wouldn’t even be able to make something the size of our moon.

The asteroids within the belt are all unique and are classified into three main categories based on their composition. S-Types (stony) are made up of iron, nickel and silicates, M-Types (metallic) are made of metallic metals (i.e. nickel and iron) and C-Types are made of silicates and clay (these are the most common).

Jupiter is a big boy and has a ginormous gravitational field. As it orbits it is able to alter the belt and send some asteroids flying out of the belt in random directions throughout the galaxy. When an asteroid is sent our direction it is referred to as a near-Earth asteroid. Scientists are always tracking these crazy rocks. A near-Earth asteroid that collided with the Earth is believed to be what killed the dinosaurs.