GENERAL KNOWLEDGE

Detailed explanation-1: -A galaxy is a giant, spinning object made of gas, dust, and stars held together by gravity. Galaxies come in different shapes and sizes and can contain billions of stars. Most occur in groups that are also held together by gravity.

Detailed explanation-2: -Spiral galaxies appear as flat, blue-white disks of stars, gas and dust with yellowish bulges in their centers. These galaxies are divided into two groups: normal spirals and barred spirals.

Detailed explanation-3: -The universe’s largest-known galaxies-giant elliptical galaxies-can contain up to a trillion stars and span two million light-years across. Elliptical galaxies may also be small, in which case they are called dwarf elliptical galaxies.

Detailed explanation-4: -Spiral galaxies look like giant pinwheels. The arms of the pinwheel are made up of stars and lots of gas and dust. Gas and dust are some of the main ingredients needed to form new stars. Young stars burn much hotter than older stars, so spiral galaxies are often some of the brightest in the universe.