Well, nobody really realized that is was, it was simply "said," if you will.
We are called Earth. "Blue Planet" is a nickname for Earth, since our planet comprises primarily of water.
Mars is The Earth's brother planet
planet earth is known for being the only planet to support life
destroy planet earth
Earth is a rocky planet because the gas giants are in the outer planets and earth is in the inner planet.
There is not fifth planet on Earth, since Earth is a planet...
Earth.
The earth is the only planet on earth.
The planet after the Earth is Mars.
the planet after earth is mars
Earth is the third planet from the sun.
Planet Earth - about 80%.
Earth does not have planets, it is a planet.
the planet we live on is earth
The 'Blue Planet' is one of the nicknames of planet Neptune.
Planet earth is the only planet that we know of that has life on it.
It should be --- Earth Day, Planet Earth.