Question

why is the earth know as blue planet

Answer 1

3/4 of the earth's surface is covered by water.....this abundant water appears blue as it takes the sky color..and no where in the galaxy you'll find this much water and blue color due this it is known as blue planet..

Answer 2

About 71% the earth's surface is covered with water. When pictures of earth are taken from satellites from outer space the presence of this vast amount of water gives the earth an overall blue look that is why earth is called the blue planet.