Imagine life without electricity or running water, and you'll understand what nearly befell our planet two years ago. Scientists say that on July 23, 2012, the sun belched its biggest solar flare in more than 150 years and barely missed us, CBS News reports. A week earlier and the storm would have struck Earth on its orbit with "catastrophic" effects, NASA says, blacking out radios, damaging satellite communications and GPS, and "disabling everything that plugs into a wall socket." Such a flare wouldn't hurt human life directly, and the Southern and Northern Lights would be gorgeous, but the blast's mix of X-rays, extreme UV radiation, energetic particles, and massive clouds of magnetized plasma would cause an estimated $2 trillion in damage.
It would also leave "large parts of society" crippled for months or years while workers replaced major transformers and substations, ExtremeTech reports. The sun, on an 11-year solar-storm cycle, has nearly done this before: A massive storm called the "Carrington Event" struck Earth in 1859 but couldn't inflict much electrical damage in the age of steam engines (telegraph lines did spark and set fire), and a pretty powerful storm caused blackouts across Quebec in 1989. One physicist says there's a 12% chance of a big solar blast hitting us over the next decade, which he calls a "sobering figure." Another is quoted in the Guardian saying how lucky we are that the blast wasn't in sync with our orbit: "Earth and its inhabitants were incredibly fortunate that the 2012 eruption happened when it did," he says. "We'd still be picking up the pieces." (Read about the sun's newly discovered "long-lost brother.")