Despite being one of the three terrestrial spheres blessed with a global magnetic field (with the other two being Earth and Jupiter’s moon Ganymede), Mercury’s invisible shield will not protect future explorers from the wrath of the Sun.
Earth and Mercury are the only two magnetized planets in the solar system, and as such, they can somewhat deflect the solar wind around them. The solar wind is a squall of hot plasma, or charged particles, continuously emanating from the sun. Earth, which has a relatively strong magnetosphere, can shield itself from most of the solar wind. Mercury, which has a comparatively weak magnetosphere and is 2/3 closer to the sun, is a different story.
“Our results tell us is that Mercury’s weak magnetosphere provides very little protection of the planet from the solar wind,” [said Thomas] Zurbuchen [a professor in the Department of Atmospheric, Oceanic and Space Sciences and Aerospace Engineering at the U-M College of Engineering.] (Space Daily)
Although Mercury could prove its worth in the future, for now it looks like residents living upon the first “rock” from the Sun, will have to avoid contact with the fiery rays during the Mercurian day, and venture above ground at night.
Unless humanity uses Mercury as a penal colony, the planet will probably be home to mining corporations seeking to strip the world of precious metal and minerals which are needed upon other worlds (such as Earth, Luna and Mars).
(Image Credit: NASA)