What is Galaxy?

A galaxy is a group of billions of stars, dust and gas bound together by gravitational force. A galaxy can either be on its own or in a cluster. Galaxies come in different shapes and sizes. Scientists have divided them into three categories based on their shapes – spiral, elliptical (oval) and irregular (no shape).

The universe is a huge open space made up of billions of galaxies and an even larger number of stars. Our galaxy is called the Milky Way. Our solar system, including the Sun, the planets and their moons, forms just a tiny part of the Milky Way.