Watch this updated full res 1080p version of our classic show. Why did Earth thrive and our sister planet, Venus, died? From the fires of a sun's birth... twin planets emerged. Then their paths diverged. Nature draped one world in the greens and blues of life. While enveloping the other in acid clouds... high heat... and volcanic flows. Why did Venus take such a disastrous turn?
For as long as we have gazed upon the stars, they have offered few signs... that somewhere out there... are worlds as rich and diverse as our own. Recently, though, astronomers have found ways to see into the bright lights of nearby stars.
They've been discovering planets at a rapid clip... using observatories like NASA's Kepler space telescope... A French observatory known as Corot ... .And an array of ground-based instruments. The count is approaching 500... and rising. These alien worlds run the gamut... from great gas giants many times the size of our Jupiter... to rocky, charred remnants that burned when their parent star exploded.
Some have wild elliptical orbits... swinging far out into space... then diving into scorching stellar winds. Still others orbit so close to their parent stars that their surfaces are likely bathed in molten rock. Amid these hostile realms, a few bear tantalizing hints of water or ice... ingredients needed to nurture life as we know it. The race to find other Earths has raised anew the ancient question... whether, out in the folds of our galaxy, planets like our own are abundant... and life commonplace? Or whether Earth is a rare Garden of Eden in a barren universe?
With so little direct evidence of these other worlds to go on, we have only the stories of planets within our own solar system to gauge the chances of finding another Earth. Consider, for example, a world that has long had the look and feel of a life-bearing planet. Except for the moon, there's no brighter light in our night skies than the planet Venus... known as both the morning and the