The Asteroid Belt

In 1801, astronomer Giuseppe Piazzi accidentally discovered the first and largest asteroid while making a star map from the Palermo Observatory. The name of the new body was Ceres. The asteroids exist between Mars and Jupiter. The diameter of the asteroid belt’s only dwarf planet Ceres is just 940 kilometers. It is the largest object in the asteroid belt (FYI, the smallest planet, Pluto has a diameter is just over 2300 kilometers). Between 1801 and 1808 astronomers tracked down three more asteroids Pallas, Juno and Vesta, each smaller than Ceres. A fifth asteroid, Astraea, was discovered in 1845. Since that time almost every year new asteroids have been discovered.

What is this asteroid belt and where is it located?

The asteroid belt is a circumstellar disc in the solar system falling roughly between the planets Mars and Jupiter where the greatest concentration of asteroid orbits can be found. That places it between 2.2 and 3.2 astronomical units (AU) from the Sun. The belt is about 1AU thick. According to scientists, asteroids are the leftovers of the early solar system.

An asteroid may be pulled out of its orbit by the gravitational pull of a larger object such as a planet. Once an asteroid is captured by the gravitational pull of a planet, it may send them into the outer solar system or it may become a satellite of that planet.

In 2011, the Dawn spacecraft traveled to the asteroid belt to study the Vesta, the second largest object there. In 2012 Dawn left Vesta and went into orbit around dwarf planet Ceres. Dawn's goal is to characterize the conditions and processes of the solar system.

NASA has announced two missions to explore previously unexplored asteroids. The first mission is called, Lucy and second mission is called Psyche. Lucy is targeted for launch in 2021. Lucy will study asteroids trapped by Jupiter’s gravity known as Trojan asteroids. Psyche mission is targeted for launch in 2023. This mission will explore a very large and rare object in the solar system’s asteroid belt that’s made of metal. Scientist believe that Psyche may expose the core of a planet that was once size of Mars.

Here are some fascinating facts about the asteroid belt:

1. The asteroid belt contains billions and billions of asteroids.

2. Some asteroids in the asteroid belt are quite large. They are made up of metals, rocks and stones and all are irregularly shaped.

3. There are a great distances between them. If you could stand on an asteroid and look around, the next one would be too far away to see very well. However, the collision between asteroids are continuous.

4. The asteroid belt contains many objects, but the distance between them is quite large because of which a spacecraft can move through this region without hitting any object.

5. The asteroid Ceres is a dwarf planet, the largest one in the inner solar system.

6. All planets originated from a combination of asteroids. Because of strong gravitational forces of Jupiter, these asteroids never became planets.

7. An asteroid may be pulled out of its orbit by the gravitational pull of larger objects, such as planets.

8. Most of the meteorites found so far on earth come from the asteroid belt. By studying these meteorites, scientists have found that they may be composed of silicates (stones), metals (Iron, Nickel) and some amount of carbon-rich substances.

Written by:

Kanchan Ramteke