Introduction to Asteroids

 

Asteroids are a group of small rocky objects that orbit around our sun. Our entire solar system formed from a giant molecular cloud. These molecular clouds contain gas clouds and dust materials, which weigh about 106 to 108 solar masses.  Due to some sort of shockwave, these molecular clouds begin to collapse, and the gravity makes the clouds fall inwards, and due to angular momentum, they start to spin and form a flattened protoplanetary disk. At the centre, the materials start to accumulate more and form our sun. Accretion of these molecular clouds in the protoplanetary disk forms planetesimals such as planets, asteroids, comets, dwarf planets and other solar bodies. In the Tauri phase, the star creates strong solar storms, which clean up the molecular clouds which didn't form as planetesimals. From these, we can infer that most of the asteroids we see now were created along with our sun and other planetesimals.   

 During the formation of the solar system, most of the asteroids were trapped between Mars and Jupiter, these asteroids are called main belt asteroids. Trojan asteroids are found at the Lagrange points of the planets, and some asteroids orbit within our inner solar system. Generally, the asteroids range between a few meters and several kilometres in diameter. Asteroids are sometimes also called Minor planets. The first discovered asteroid was Ceres, and it is also the largest known asteroid so far, which is also classified as a dwarf planet. Ceres was discovered by Giuseppe Piazzi on January 1st, 1801, at the Palermo Observatory. In the early days, some planetesimals like Pluto and Ceres were classified as planets in the same category. However, as astronomers learn more about space, they theorise some criteria only if an object follows those criteria, it will be considered a planet, but Pluto and Ceres failed the criteria and became dwarf planets and asteroids. This is also applied to all other objects in our solar system, and they are classified accordingly. An object to be classified as an asteroid should follow some criteria, like it should orbit around the Sun, should not be a planet or dwarf planet, have no atmosphere, be primarily rocky or metallic, not display cometary activity and so on.