Earth is a beautiful planet that revolves around a star called Sun, which is located in one of the arms of our Milky Way Galaxy. It is the only planet known to support life in the Solar System. Humans are the most intelligent civilization on this planet. It's blue when seen from space. Recently, Earth 29 spacecraft was able to land on this planet, after 28 unsuccessful landings of Earth series of spacecrafts. We were able to learn many things about humans, most important of these was the most spoken language of them, which they call English. According to experts, humans are not yet ready to know about our existence. It can take about 1 or 2 more centuries, until they are ready to know about us.
The answer is relative dating.
