Back in 2012, the Sun erupted with a powerful solar storm that just missed the Earth but was big enough to “knock modern civilisation back to the 18th century,” Nasa said.
The extreme space weather that tore through Earth's orbit on July 23, 2012, was the most powerful in 150 years, according to a statement posted on the US space agency website Wednesday.
However, few Earthlings had any idea what was going on.
“If the eruption had occurred only one week earlier, Earth would have been in the line of fire,” said Daniel Baker, professor of atmospheric and space physics at the University of Colorado.
Instead the storm cloud hit the STEREO-A spacecraft, a solar observatory that is “almost ideally equipped to measure the parameters of such an event,” Nasa said.
Scientists have analysed the treasure trove of data it collected and concluded that it would have been comparable to the largest known space storm in 1859, known as the Carrington event.
The National Academy of Sciences has said the economic impact of a storm like the one in 1859 could cost the modern economy more than two trillion dollars and cause damage that might take years to repair.
How do solar storms cause damage?
Solar storms can cause widespread power blackouts, disabling everything from radio to GPS communications to water supplies -- most of which rely on electric pumps.
Step 1: They begin with an explosion on the Sun's surface, known as a solar flare, sending X-rays and extreme UV radiation toward Earth at light speed.
Step 2: Hours later, energetic particles follow and these electrons and protons can electrify satellites and damage their electronics.
Step 3: Next are the coronal mass ejections, billion-ton clouds of magnetised plasma that take a day or more to cross the Sun-Earth divide. These are often deflected by Earth's magnetic shield, but a direct hit could be devastating.
