Fierce solar magnetic storm barely missed Earth in 2012

"Perfect storm" could have knocked out the electrical grid and disabled satellites and GPS, costing trillions worldwide
March 21, 2014

This image captured on July 23, 2012 at 12:24 a.m. EDT shows a coronal mass ejection that left the sun at the unusually fast speeds of over 1,800 miles per second (credit: NASA/STEREO)

According to University of California, Berkeley, and Chinese researchers, a rapid succession of coronal mass ejections — the most intense eruptions on the sun — sent a pulse of magnetized plasma barreling into space and through Earth’s orbit.

Had the eruption come nine days earlier, when the ignition spot on the solar surface was aimed at Earth, it would have hit the planet, potentially wreaking havoc with the electrical grid, disabling satellites, and GPS, and disrupting our increasingly electronic lives.

The solar bursts would have enveloped Earth in magnetic fireworks matching the largest magnetic storm ever reported on Earth, the Carrington event of 1859.

The dominant mode of communication at that time, the telegraph system, was knocked out across the United States, even electrically shocking telegraph operators. Meanwhile, the Northern Lights lit up the night sky as far south as Hawaii.

In a paper appearing Tuesday, March 18 in the journal Nature Communications, former UC Berkeley postdoctoral fellow and research physicist Ying D. Liu, now a professor at China’s State Key Laboratory of Space Weather, UC Berkeley research physicist Janet G. Luhmann and their colleagues report their analysis of the magnetic storm, which was detected by NASA’s STEREO A spacecraft.

“Had it hit Earth, it probably would have been like the big one in 1859, but the effect today, with our modern technologies, would have been tremendous,” said Luhmann, who is part of the STEREO (Solar Terrestrial Relations Observatory) team and based at UC Berkeley’s Space Sciences Laboratory.

Economic costs in the trillions 

Magnetogram Sept. 1, 1859 (credit: British Geological Survey)

According to a study conducted for FEMA and cited in a 2008 National Research Council study (Severe Space Weather Events—Understanding Societal and Economic Impacts: A Workshop Report — downloadable free), “impacts [of a severe geomagnetic storm] would be felt on interdependent infrastructures, with, for example, potable water distribution affected within several hours; perishable foods and medications lost in about 12–24 hours; and immediate or eventual loss of heating/air conditioning, sewage disposal, phone service, transportation, fuel resupply, and so on.

“The effects on these interdependent infrastructures could persist for multiple years, with a potential for significant societal impacts and with economic costs that could be measurable in the several-trillion dollars-per-year range.”

A considerably smaller event on March 13, 1989, led to the collapse of Canada’s Hydro-Quebec power grid and a resulting loss of electricity to six million people for up to nine hours.

“An extreme space weather storm — a solar superstorm — is a low-probability, high-consequence event that poses severe threats to critical infrastructures of the modern society,” warned Liu, who is with the National Space Science Center of the Chinese Academy of Sciences in Beijing.

“The cost of an extreme space weather event, if it hits Earth, could reach trillions of dollars with a potential recovery time of 4–10 years. Therefore, it is paramount to the security and economic interest of the modern society to understand solar superstorms.”

A fast-moving magnetic storm

Based on their analysis of the 2012 event, Liu, Luhmann and their STEREO colleagues concluded that a huge outburst on the sun on July 22 propelled a magnetic cloud through the solar wind at a peak speed of more than 2,000 kilometers per second, four times the typical speed of a magnetic storm. It tore through Earth’s orbit but, luckily, Earth and the other planets were on the other side of the sun at the time. Any planets in the line of sight would have suffered severe magnetic storms as the magnetic field of the outburst tangled with the planets’ own magnetic fields.

The researchers determined that the huge outburst resulted from at least two nearly simultaneous coronal mass ejections (CMEs), which typically release energies equivalent to that of about a billion hydrogen bombs, separated by only 10 to 15 minutes.

The speed with which the magnetic cloud plowed through the solar wind was so high, they concluded, because another mass ejection four days earlier had cleared the path of material that would have slowed it down.

One reason the event was potentially so dangerous, aside from its high speed, is that it produced a very long-duration, southward-oriented magnetic field. This orientation drives the largest magnetic storms when they hit Earth because the southward field merges violently with Earth’s northward field in a process called reconnection. Storms that normally might dump their energy only at the poles instead dump it into the radiation belts, ionosphere and upper atmosphere and create auroras down to the tropics.

“These gnarly, twisty ropes of magnetic field from coronal mass ejections come blasting from the sun through the ambient solar system, piling up material in front of them, and when this double whammy hits Earth, it skews the Earth’s magnetic field to odd directions, dumping energy all around the planet,” Luhmann said.

Detecting solar blasts

“People keep saying that these are rare natural hazards, but they are happening in the solar system even though we don’t always see them,” she added. “It’s like with earthquakes — it is hard to impress upon people the importance of preparing unless you suffer a magnitude 9 earthquake.”

All this activity would have been missed if STEREO A — the STEREO spacecraft ahead of us in Earth’s orbit and the twin to STEREO B, which trails in our orbit — had not been there to record the blast.

The goal of STEREO and other satellites probing the magnetic fields of the sun and Earth is to understand how and why the sun sends out these large solar storms and to be able to predict them during the sun’s 11-year solar cycle. This event was particularly unusual because it happened during a very calm solar period.

The work was supported by NASA and also involved UC Berkeley’s Space Sciences Laboratory, the Université de Toulouse, the University of Helsinki; the University of New Hampshire, Lockheed-Martin Solar and Astrophysics Laboratory,  the University of Graz, and the Austria Space Research Institute of the Austrian Academy of Sciences.

Abstract of Nature Communications paper

Space weather refers to dynamic conditions on the Sun and in the space environment of the Earth, which are often driven by solar eruptions and their subsequent interplanetary disturbances. It has been unclear how an extreme space weather storm forms and how severe it can be. Here we report and investigate an extreme event with multi-point remote-sensing and in situ observations. The formation of the extreme storm showed striking novel features. We suggest that the in-transit interaction between two closely launched coronal mass ejections resulted in the extreme enhancement of the ejecta magnetic field observed near 1 AU at STEREO A. The fast transit to STEREO A (in only 18.6 h), or the unusually weak deceleration of the event, was caused by the preconditioning of the upstream solar wind by an earlier solar eruption. These results provide a new view crucial to solar physics and space weather as to how an extreme space weather event can arise from a combination of solar eruptions.