Everyone is being struck by cosmic rays all the time—probably about several each second. Ordinarily, the number of cosmic rays that strike you have no negative effect on your health. Even though the energy of these particles is very high, the number of them striking you is relatively low. If you went beyond Earth’s magnetosphere, though, your health might be at risk. On Earth’s surface, the magnetosphere acts as a shield against cosmic rays by redirecting them toward Earth’s magnetic poles. Thousands of miles up, however, the cosmic ray flux on your body would be much higher, and thus cause potentially more damage to your body’s cells and systems.