Shields Up!

One of the limitations to travel around the solar system is the threat of radiation, but scientists believe a thumb-sized magnet could produce a force field big enough to shield an entire spaceship.

The Sun is constantly shooting high-energy particles out, a solar wind that yields radiation over 1000 times more powerful than that of the atomic bomb dropped on Hiroshima. Fortunately, our magnetosphere (produced by the planet's molten iron core) deflects the solar wind and protects from that radiation. It was thought a (prohibitively) huge magnet would be necessary to produce a similar result for a spaceship, but some Brits have determined much less is necessary to generate a magnetic field.

Because the solar wind is a plasma made up of charged particles, it also carries a magnetic field. When the two fields clash, since the solar wind's field is created by free-moving particles, it yields, altering its orientation to minimise conflict with the mini-magnetosphere's field. Positively charged protons have nearly 2000 times the mass of the negatively charged electrons, so the latter are much more easily deflected. The electrons stay at the surface of the magnetic bubble, while the positive charges penetrate further in. This separation of positive and negative charges generates intense electric fields up to a million times stronger than the magnetic fields that created them. Subsequent solar wind particles hit these electric fields and are strongly deflected. The result is a shielding effect far more powerful than the magnetic field alone might be expected to provide.

New Scientist has the details, and while there is concern that the higher-energy particles in space could blast through such a shield, Rutherford Appleton Lab (who made the discovery) is already in talks with NASA to determine the implications of their find.