[LINK] "When the Sun Went Medieval on Our Planet"

[rfmcdonald]

The Dragon's Tales linked to Phil Plait's Bad Astronomy post suggesting, on the basis of two events in 774 and 993 CE, that the sun is much more violently active and much more frequently so than we thought. This has implications for us, obviously, in our high-tech world.

The Sun generates ridiculously strong magnetic fields in its interior, and these can store vast amounts of energy. They can release this energy explosively on the surface, creating intense solar flares. Sometimes the loops of magnetism do this far above the Sun’s surface, creating what are called coronal mass ejections. These are less intense (that is, less concentrated bursts of energy) than flares, but far larger and more powerful; think of flares versus CMEs like solar tornadoes versus hurricanes.

[. . .]

When I wrote about the 774 event on this blog before, I mentioned that a flare or coronal mass ejection was unlikely to be the source due to the amount of energy needed to create these radioactive elements. However, that new research indicates that the Sun is the most likely culprit for this interplanetary assault, and that, in turn, means the Sun can produce more powerful events than we previously thought.

Yikes.

We’ve known for a long time that the Sun is capable of producing huge magnetic explosions. In 2003 it let rip a series of solar storms so powerful that one of them set the record for the biggest flare seen in modern times. And the strongest known was also the very first solar explosion ever seen—called the Carrington Event, after an astronomer who studied it—and happened in 1859. It created aurora as far south as Mexico and Hawaii! Events like that can also create what are called geomagnetically induced currents, or GICs: The Earth’s magnetic field shakes so violently that it induces currents in conductors on the ground. Telegraph operators reported being able to send messages even though the power was disconnected; enough electricity was flowing through the lines to work the devices.

There's more. In 2012 the Sun blew out another blockbuster that was in many ways the equal of the one in 1859, but happily for us it was sent off in another direction, and missed the Earth. Had it hit us, the huge flux of charged particles would have overloaded satellites. Worse, the GIC would’ve caused widespread power failures and blackouts. A much smaller solar storm in 1989 did just that in Quebec.

The first of the events may have been five times bigger.