Planets and their moons are not the only objects in our Solar System. Billions of small rocky bodies, called asteroids, also orbit the Sun. An asteroid, often called a minor planet, is a small body made up of rock and metal left over from the formation of the Solar System. Asteroids can range in size from almost 1000km (610 miles) in diameter, to the size of a small car.
4.6 billion Years ago, our solar system formed from a collection of gas and dust surrounding our nascent sun. While much of the gas and dust in this protoplanetary disk coalesced to form the planets, some of the debris was left over.
Some of debris was shattered remnants of planetesimals – bodies within the young sun’s solar nebula that never grew large enough to become planets, and scientists theorize that large collisions in the early, chaotic solar system pulverized these planetesimals into smaller pieces. Other debris never came together due to the massive gravitational pull from Jupiter.
These rocky remnants are now the asteroids that travel about our solar system. Since these “leftovers” contain clues about the early days of our solar system, scientists are eager to study them.
Asteroids are rocky, metallic bodies that orbit the sun. They are made from different kinds of rock and metals, with the metals being mostly nickel and iron. They are sometimes called “minor planets” but they are much, much smaller than the planets or moons. They don’t have atmospheres, but about 150 asteroids are known to have small “moons” orbiting them, and some even have two moons. There are also binary (double) asteroids, where two rocky bodies of roughly equal size orbit each other, as well as triple asteroid systems.
At least one asteroid has rings. This surprise discovery was made in 2013 when scientist watched Asteroid Chariklo pass in front of a star. The asteroid made the background star “blink” several times, which led to the discovery that two rings are surrounding the asteroid.
Picture Credit : Google