Space Weather, Auroras, Solar Flares and CMEs

[Parsons]

I find this is very interesting. The Carrington Event of 1859 is something I was aware of since I first gained interest in solar flares / CME's, and is in fact what increased my interest in their potential effects. When I first got into the phenomenon, it was just before I 'awoke' and was searching the internet for potential "end of the world" scenarios, with the front runner being a Carrington Event-level solar storm.

Based on what I have read about the event, if it were to happen in our modern day world of gadgetry and electricity, it would have devastating effects. Damage could range from destroying a few power transformers/grids and communication satellites, to destroying virtually all electrical grids and most satellites (if it were much worse than the Carrington Event). Considering nearly everything relies on electricity, I don't feel I need to go into detail about what it would do to the population of the world.

Over the years, I have come to a neutral point where I no longer welcome such an event, but I also accept whatever comes. I would actually have a slight bias towards not seeing such an event occur.

However, I know statistically, it is only a matter of time until the Earth is hit by a CME equally as powerful. It could be any day, or it may be in hundreds, or even thousands of years. Historically, it must have happened before there was any kind of science to measure solar flares and geomagnetic storms.

Finally, to the point of this post. It looks like we had another roughly equally powerful CME only 155 years after the Carrington Event which did not hit us:

SOLAR 'SUPERSTORM' NARROWLY MISSES EARTH: The heliophysics community is buzzing today in response to an article in Nature Communications, which describes an intense solar storm that narrowly missed Earth almost two years ago. On July 23, 2012, a CME rocketed away from the sun at 2000 km/s, almost four times faster than a typical eruption. The storm tore through Earth orbit, but fortunately Earth wasn't there. Instead it hit the STEREO-A spacecraft, which experienced the most intense solar proton storm since 1976. Researchers have been analyzing the data ever since, and they have concluded that the storm was akin to the Carrington Event of 1859. Scroll past this movie of the CME to learn more:



"Had it hit Earth, it probably would have been like the big one in 1859," says Janet Luhmann of UC Berkeley, a co-author of the paper. "The effect today [on] our modern technologies would have been tremendous."

The Carrington Event was a series of powerful CMEs that hit Earth head-on, sparking Northern Lights as far south as Tahiti. Intense geomagnetic storms caused global telegraph lines to spark, setting fire to some telegraph offices and disabling the 'Victorian Internet." A similar storm today would have a catastrophic effect on modern power grids and telecommunication networks. According to a study by the National Academy of Sciences, the total economic impact could exceed $2 trillion or 20 times greater than the costs of a Hurricane Katrina. Multi-ton transformers fried by such a storm could take years to repair.

The paper in Nature Communications describes what gave the July 2012 storm Carrington-like potency. For one thing, the CME was actually two CMEs separated by only 10 to 15 minutes. Plus the CMEs traveled through a region of space that had been cleared out by another CME four days earlier. As a result, they were not decelerated as much as usual by their transit through the interplanetary medium.

The storm clouds crossed Earth's orbit in a place where Earth itself would be about 1 week later, so it was a relatively narrow escape. The whole episode highlights the perils of space weather. Many observers have noted that the current solar cycle is weak, perhaps the weakest in 100 years. Now we see that even a weak solar cycle can produce a very strong storm. Earth is not safe from these kind of events, so it's time to be prepared.

The original research reported here may be found in Nature Communications: "Observations of an extreme storm in interplanetary space caused by successive coronal mass ejections" by Ying D. Liu et al., published on March, 18, 2014.