Earth

Overview
Earth, also known as planet Earth, Terra, the Blue Planet, Earth Prime, Midgard, Gaia and the Blue Pearl, is a life-housing planet located in the Solar System estimated to have been formed over 4.5 billion years ago. Before the age of space travel, Earth was assumed the only planet in the galaxy to house life.

History
Earth was formed around 9 billion years after the events of the Big Bang, which started the age of the universe. Planet Earth thus formed over 4.5 billion years ago, while life has scientifically been accepted to have started some 3.7 billion years ago, with evidence supporting even earlier life.