The search has begun for a planet just like earth-from lush green fields to mountains to cold deep rivers and waterfalls.
Of course, other earths would have to be made up of elements similar to our own, and orbit at a special distance required for liquid water to exist on its surface, called the habitable zone.
Astronomers are using new technology to scan other star systems for clues to unexplored earths. They are now capable of viewing faint wobbles in a star’s motion, that are caused by the gravitational pull of an orbiting planet.
In the winter of 2009 NASA will launch its Kepler mission, designed to seek out planets orbiting massive stars, like how our earth orbits the sun. Kepler will keep an eye out for starlight dimming in 100,000 stars.