Space Weather News for May 11, 2002<br />http://www.spaceweather.com<br /><br />An unexpected interplanetary shock wave swept past Earth at 1000 UT on May<br />11th and triggered a moderate geomagnetic storm. High-latitude sky<br />watchers -- i.e., those in northern Europe, Canada and across the northern<br />tier of US states -- should be alert for auroras after local nightfall on<br />Saturday. Although the shock wave was not a particularly strong one, it<br />stimulated a geomagnetic storm because the interplanetary magnetic field<br />near Earth is pointing south -- a condition that weakens our planet's<br />magnetic defenses against solar wind disturbances. Visit spaceweather.com<br />for updates.