A lava planet is a planet made mostly of lava which is a type of hot, melted rock. It is very hot on a lava planet and the environment is very harsh. The temperature on a lava planet is usually over 1000 degrees Celsius (about 1832 degrees Fahrenheit)! The ground on a lava planet is much like wet sand and the sky is a dark, orange color. It is very difficult for life to survive on a lava planet.