The worst solar-storm season in half a century starts this year. These fiery explosions—which unleash as much energy as a billion hydrogen bombs—could, under the right conditions, black out cities and fry satellites. But new solar scopes can give us advance warning.

Last December, a colossal wave swept across the entire solar surface within minutes, bulldozing everything in its path. The rare tsunami -like shockwave formed on the heels of a major flare that erupted from an Earth-size sunspot 15 minutes earlier. Though that storm didn't have a major impact on Earth, we aren't always so lucky.

The Earth's magnetic shield protects us from the worst effects of solar storms (and even astronauts on the International Space Station can take cover in a heavily shielded module), but technology suffers greatly. Atmospheric and magnetic fluctuations that the storms cause can also disable satellites, burn out transformers, and take down power grids. One CME in 1989 left all of Quebec without power for nine hours.

 Source : PopSci.com