Heavenly Bodies

There are various objects suspended throughout the universe. These are often called heavenly bodies. The most popular and common Heavenly Bodies then are Stars, Comets, Galaxies, Constellations.

Stars

Stars are masses of Hydrogen and Helium gases. A star glows because there is a kind of reaction in the core, like those in nuclear bombs, that generates a huge amount of light and heat. The smaller the star the larger its life. The life of a small star is said to be upto 200 billion years whereas a mid-sized star lasts for about 10 billion years. The Sun is a mid-size star.

Comet

A comet is basically a huge mass of dust and ice revolving on its extremely large orbit around the Sun (not all comets revolve around the Sun but mostly do). Their orbits are so big that most of the times they are far away from the Sun. But when they come near the Sun then ice starts melting and disintegrates from the mass. And the moment the light from the Sun falls on it, we see a glowing tail of the comet. The most famous comet known to all of us is the Hailey's comet.

Galaxy

Galaxies are huge groups of billions of stars. They are often found in group called clusters. It is believed that there are trillions of galaxies in the whole universe. Galaxies are found mainly in three shapes: Spiral, Elliptical and Irregular.

Constellations

Constellations are a group of stars that form a pattern or a figure. These figures are formed and agreed upon by the astronomers to identify a group or individual stars. These stars actually don't have any relationship in between and are several thousand miles apart. The brightest star in the constellation is known as Alpha. It is said that astronomers today have already discovered more than 80 constellations.

Nebula

These are bodies formed by clouds of various gases and space dust. Lot of them give off a glowing effect as the hydrogen gas in them gets heated off from the space radiations. Though there are glowing nebulae in space which absorb all light.