Were the Scorching Conditions on Venus Once Earth-Like?

Evidence suggests that the so called "habitable zone" changes as the Sun ages. Many years ago, Venus may have resembled Earth and been home to life. But as the sun aged and grew brighter, a runaway greenhouse effect turned Venus into the hottest planet in the solar system. SPACE S DEEPEST SECRETS Tuesdays 9/8c on Science http://www.sciencechannel.com/spaces-deepest-secrets/ Subscribe to Science Channel: http://bit.ly/SubscribeScience SPACE S DEEPEST SECRETS shares the stories of the men and women who pushed their ingenuity and curiosity beyond the limits to uncover some of the most groundbreaking findings in the history of space exploration. Facebook: https://www.facebook.com/ScienceChannel Twitter: https://twitter.com/ScienceChannel