Moon rising over Earths horizon, composite image. The blue haze of Earths atmosphere can be seen above the horizon. Earth is thought to be the only planet in the solar system that can support life. The Moon (at upper left) has a diameter just over a quarter of the Earths. It orbits at a distance of around 385,000 kilometres, taking nearly 30 days for one orbit. It does not have an atmosphere and is a heavily cratered and barren piece of rock.