Saturday, May 26, 2007
Bombardment From The Sun
On July 7, 1988, 3000 homing pigeons fluttered from cages in northern France, circled a few times and set off on their annual race for their homes in southern England. But events on the distant Sun were to doom the race.
Two days before, a solar flare - a colossal explosion on the surface of the Sun - had fired clouds of electrically charged protons and other subatomic particles into space, some of which had disrupted the Earth's magnetic field. When bad weather prevents them from steering by the Sun or the stars, homing pigeons use internal magnetic 'compasses' to guide them. Misled by the celestial disturbances, the pigeons flew way off course. Few made it to their homes.
Pigeons are not the only creatures at risk from solar flares. The high-energy particles they fire out pose a serious risk of radiation sickness and even cancer to space travellers. Space shuttle flights are postponed whenever astronomers observe a flare. If astronauts one day build bases on the Moon or Mars they may need to cover them with rocks as protection against the radiation emitted by solar flares. And long-distance manned spacecraft will have to be equipped with 'storm shelters' for the crew to retreat into when flares occur.