Research suggests Venus was once a habitable planet similar to Earth. A 2019 study from NASA's Goddard Institute for Space Studies found that Venus could have had shallow oceans on the surface for two to three billion years and this would have supported temperatures of between 68 to 122 degrees Fahrenheit. Around 700 million years ago though, a resurfacing event released carbon dioxide into the atmosphere, turning Venus into a dangerous, inhospitable planet where atmospheric temperatures reach 1...