Cosmic Blast

July 14, 2000 — Just after dawn on the U.S. East Coast, the Sun unleashed one of the most powerful solar storms ever recorded.

A massive solar flare, followed by a colossal coronal mass ejection (CME), blasted billions of tons of charged particles into space at nearly 3 million miles per hour. The first high-energy particles reached Earth within 15 minutes, while the bulk of the CME struck a day later, triggering geomagnetic storms around the world.

Power grids, navigation systems, and satellites experienced disruptions, and scientists estimated the energy released at about 40 billion times that of the Hiroshima bomb.

Fortunately, Earth’s magnetic field shielded us from most of the radiation. Still, passengers on high-altitude polar flights received doses of radiation comparable to a medical chest x-ray — a reminder of our planet’s thin defense against the Sun’s fury.