Geography		$$		Celestial Bodies & the Universe
		The Cosmos

Universe

The Cosmos is commonly called the Universe. Encyclopedia Britannica defines the Universe as '... everything that exists, including matter and energy'. The true size of the cosmos is not known and is difficult to even imagine—it is so immense that the most advanced telescopes made by us do not know its limits. The study of the cosmos is known as Cosmology or Astronomy.

The Universe consists of mostly apparently empty space, with matter concentrated into galaxies as stars, planets and interstellar gas. However, even the apparently empty space is permeated with particles and energies.

According to the Big-bang model of the origin of the Universe, the Universe got created from a titanic explosion of an infinitely hot and dense single "primordial atom." Eventually, galaxies and stars came into existence. It is expanding still, and the separation between the galaxies is increasing.

Our planet, the Earth, is the third planet of the Solar System, which is a part of the Milky Way galaxy, one of the billions of galaxies in the Universe.

		The Cosmos
Geography		$$		Celestial Bodies & the Universe