text: Astronomers are fascinated by Venus because it may well once have been the most Earth-like planet in our solar system. Long ago, Venus was probably covered with oceans and could've possibily supported various forms of life. Today, Venus is still like Earth in some ways, there are valleys, craters, and mountains. There is no way Venus could support life now because of the conditions of the planet. 97 percent of the planet is carbon dioxide and the average temperature of Venus is over 800 degrees Fahrenheit.