Several billion years ago, Earth was hospitable. Now, the Sun is becoming a red giant, Earth is too hot to survive on. However, Titan, one of Saturn's moons, has defrosted, and an atmosphere.
The earth is getting much too hot to live on, the Sun is turning into a red giant, swelling to fifty times its size. The seas on Earth are drying up. The planet is becoming a desert, and Mercury is getting sucked into the Sun. Meanwhile, one of Saturn's moons, Titan, has defrosted from a ice planet. It also has an atmosphere, which makes it hospitable for humans. From there, a new planet Earth will be formed.