The solar storm of 2012 was an unusually large and strong
coronal mass ejection
A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accepted ...
(CME) event that occurred on July 23 that year. It missed Earth with a margin of approximately nine days, as the equator of the Sun rotates around its own axis with a period of about 25 days.
The region that produced the outburst was thus not pointed directly towards Earth at that time. The strength of the eruption was comparable to the 1859
Carrington Event
The Carrington Event was the most intense geomagnetic storm in recorded history, peaking from 1 to 2 September 1859 during solar cycle 10. It created strong auroral displays that were reported globally and caused sparking and even fires in mult ...
that caused damage to electrical equipment worldwide, which at that time consisted mostly of
telegraph
Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas p ...
systems.
Overview
![Solar cycle 24 sunspot number progression and prediction](https://upload.wikimedia.org/wikipedia/commons/0/01/Solar_cycle_24_sunspot_number_progression_and_prediction.gif)
The eruption tore through Earth's orbit, hitting the
STEREO
Stereophonic sound, or more commonly stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configuration ...
-A spacecraft. The spacecraft is a solar observatory equipped to measure such activity, and because it was far away from the Earth and thus not exposed to the strong electrical currents that can be induced when a CME hits the Earth's
magnetosphere
In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior dynam ...
,
[ it survived the encounter and provided researchers with valuable data.
Based on the collected data, the eruption consisted of two separate ejections which were able to reach exceptionally high strength as the ]interplanetary medium
The interplanetary medium (IPM) or interplanetary space consists of the mass and energy which fills the Solar System, and through which all the larger Solar System bodies, such as planets, dwarf planets, asteroids, and comets, move. The IPM sto ...
around the Sun had been cleared by a smaller CME four days earlier.[
The event occurred at a time of high ]sunspot
Sunspots are phenomena on the Sun's photosphere that appear as temporary spots that are darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. Sun ...
activity during solar cycle 24
Solar cycle 24 is the most recently completed solar cycle, the 24th since 1755, when extensive recording of solar sunspot activity began.Kane, R.P. (2002).Some Implications Using the Group Sunspot Number Reconstruction. ''Solar Physics'' 205(2), 3 ...
.
Predicted effects
Had the CME hit the Earth, it is likely that it would have inflicted serious damage to electronic systems on a global scale.[ A 2013 study estimated that the economic cost to the United States would have been between US$600 billion and $2.6 trillion.][''Solar Storm Risk to the North American Electric Grid'' Lloyd's 2013](_blank)
/ref> Ying D. Liu, professor at China's State Key Laboratory of Space Weather, estimated that the recovery time from such a disaster would have been about four to ten years.
Historical comparisons
The record fastest CME associated with the August 1972 solar storm
The solar storms of August 1972 were a historically powerful series of solar storms with intense to extreme solar flare, solar particle event, and geomagnetic storm components in early August 1972, during solar cycle 20. The storm caused widespre ...
is thought to have occurred in a similar process of earlier CMEs clearing particles in the path to Earth. This storm arrived in 14.6 hours, an even shorter duration after the parent flare erupted than for the great solar storm of 1859.
See also
* List of solar storms
Solar storms of different types are caused by disturbances on the Sun, most often from coronal mass ejections (CMEs) and solar flares from active regions, or, less often, from coronal holes. Minor to active solar storms (i.e. storming restricted ...
References
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External links
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2012 in science
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