Make an alien that can survive on the planet Mercury

A popular setting for science fiction writers, there are many examples of the planet Mercury in fiction. Recurring themes include the dangers of being exposed to solar radiation and the possibility of escaping excessive radiation by staying within the planet's slow-moving terminator (the boundary between day and night). Another recurring theme is autocratic governments, perhaps because of an association of Mercury with hot-temperedness.

Mercury was originally believed to be tidally locked to the Sun, orbiting with one face continually turned toward it and another face turned away, allowing for extremes of heat and cold on the same planet and possibly a narrow belt of habitable land between the two. This view of Mercury was eliminated in 1965, when radio astronomers discovered that Mercury actually rotated three times for every two revolutions, exposing all of its surface to the Sun.

Fictional works about Mercury can thus be divided into two groups; those using the "Old Mercury", with its light and dark sides -- chiefly pre-1965 works; and those which reflect more recent scientific knowledge of the planet.

Planet Mercury Physical Properties

Mercury is similar in appearance to the Moon: It is heavily cratered, has no natural satellites and no substantial atmosphere. However, unlike the moon, it has a large iron core, which generates a magnetic field about 1% as strong as that of the Earth. It is an exceptionally dense planet due to the large relative size of its core. Surface temperatures range from about 90 to 700 K (-183 °C to 427 °C), with the subsolar point being the hottest and the bottoms of craters near the poles being the coldest.