Asteroids, Comets, and Meteoroides (Important Facts) {Part-22}

ASTEROIDS, COMETS AND METEOROIDS are all debris remaining from the Nebula from which the Solar System formed 4.6 billion years ago. Asteroids are rocky bodies up to about 1,000 kilometres in diameter, although most are much smaller. Most of them orbit the Sun in the asteroid belt, which lies between the orbits of Mars and Jupiter.

Asteroids

Asteroid Belt

Cometary nuclei exist in huge cloud (called the Oort Cloud)

Oort Cloud

that surrounds the planetary part of the Solar System. They are made of frozen water and dust, and are a few kilometres in diameter. Occasionally, a comet is deflected from the Oort Cloud on to a long, elliptical path that brings it much closer to the Sun. As the comet approaches the Sun, the cometary nucleus starts to vaporise in the heat, producing both a brightly shining Coma (a huge sphere of gas and dust around the nucleus), and a gas tail, and a dust tail.

Meteoroid

Meteoroids are small chunks of stone or stone or iron, which are fragments of asteroids or comets. Meteoroids range in size from tiny dust particles to objects tens of metres across. If a meteoroid enters the Earth's atmosphere, it is heated by friction and appears as a glowing streak of light called a Meteor (also known as a shooting star). Meteor showers occur when the Earth passes through the trail of dust particles left by a comet. Most meteoroids burn up in the atmosphere. The remnants of the few that are large enough to reach the Earth's surface are termed as meteoroids.

Structure of Comet