Saturday, September 4, 2010


Earth the third planet in the sun and the fifth largest of eight planets in the solar system.  It is the only place in the universe where life is known to exist and it provides resources that are exploitable by humans for useful purposes. Some of these are non-renewable resources such as mineral fuels that are difficult to replenish on a short time scale and the planet formed 4.54 billion years ago, and life appeared on its surface within a billion years.


Post a Comment