The great German astronomer Johannes Kepler wrote what might be the first science fiction novel, Somnium, which was published in 1634 (a few years after his death). As a serious scientist, he described the Moon and the sort of creatures that might live on it as accurately as the knowledge of the time allowed. The Moon was an incredibly alien world, he told his readers. Nights were 15 Earth days long “and dreadful with uninterrupted shadow”. The cold at night was more intense than anything experienced on Earth, while the heat of day was terrific. Animals that lived on the Moon adapted to these harsh conditions. Some went into hibernation, while others evolved hard shells and other protection.