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 to higher latitudes) may occur under elevated background solar wind conditions when the interplanetary magnetic field (IMF) orientation is southward, toward the Earth (which also leads to much stronger storming conditions from CME-related sources).[1][2][3][4][5]
In the Solar System, the Sun can produce intense geomagnetic and energetic particle storms capable of causing severe damage to technology. It can result in large scale power outages, disruption or blackouts of radio communications (including GPS), damage or destruction of submarine communications cables,[6] and temporary to permanent disabling of satellites and other electronics. Intense solar storms may also be hazardous to high-latitude, high-altitude aviation[7] and to human spaceflight.[8] Geomagnetic storms are the cause of aurora.[9] The most significant known solar storm, across the most parameters, occurred in September 1859 and is known as the "Carrington event".[10] The damage from the most potent solar storms is capable of existentially threatening the stability of modern human civilization,[11][8] although proper preparedness and mitigation can substantially reduce the hazards.[12][13]
Proxy data from Earth, as well as analysis of stars similar to the Sun, suggest that the Sun may be also capable of producing so-called "superflares", which are as much as 1,000 times stronger than any flares in the historical record.[14][15][16] Other research, like models of solar flares[17] and statistics of extreme solar events reconstructed using cosmogenic isotope data in terrestrial archives, indicate otherwise.[18] The discrepancy is not yet resolved and may be related to a biased statistic of the stellar population of solar analogs.[19]
This section contains a list of possible events that are indicated by indirect, or proxy data. The scientific value of such data remains unresolved.[20][21]
12400–12399 BCE Probable Miyake event, which would be the largest known and twice the 774–775 event.[22]
7176 BCE Found in beryllium-10 (and other isotopes) spike in ice cores and corroborated by tree rings.[23] It unexpectedly appears to have occurred near a Solar minimum[23] and was as strong as, or probably even slightly stronger than the famous 774–775 CE event.
The most extreme storm ever documented by most measures; telegraph machines reportedly shocked operators and caused small fires; aurorae visible in tropical areas; first solidly established connection of flares to geomagnetic disturbances. Extreme storming directly preceded this event in late August.
An extreme storm, estimated at Dst −531 nT arose from a fast CME (mean ≈1500 km/s), occurred during the ascending phase of the minimum of the relatively weak solar cycle 14, which is the most significant storm on record in a solar minimum period. Aurora was conservatively observed to ≈44.1° ILAT, and widespread disruptions and overcharging of telegraph systems occurred.[47][48]
Sep 1909
Geomagnetic storm of September 1909
Dst calculated to have reached −595 nT, comparable to the March 1989 event[49]
Among most extreme known geomagnetic storms; farthest equatorward (lowest latitude) aurora ever documented;[50] burned out fuses, electrical apparatus, and telephone station; caused fires at signal tower and telegraph station; total communications blackouts lasting several hours.[51] A paper in 2019 estimates a peak Dst of −907±132 nT.[52]
Fastest CME transit time recorded; most extreme solar particle event (SPE) by some measures and the most hazardous to human spaceflight during the Space Age; severe technological disruptions, caused accidental detonation of numerous magnetic-influence sea mines[67]
Most extreme storm of the Space Age by several measures. Outed power grid of province of Quebec.[68] Caused interference to United States power grid.[69]
Caused by an X8-class solar flare aimed directly at Earth
Apr 2001
A solar flare from a sunspot region associated with this activity and preceding this period produced the then largest flare detected during the Space Age at about X20 (the first event to saturate spaceborne monitoring instruments, this was exceeded in 2003) but was directed away from Earth.[73][74]
Nov 2001
Geomagnetic storm of November 2001
A fast-moving CME triggered vivid aurorae as far south as Texas, California, and Florida[75]
Among top few most intense storms of the Space Age; aurora visible as far south as Texas and the Mediterranean countries of Europe. A solar flare with x-ray flux estimated to be around X45 occurred from an associated active region on 4 November but was directed away from Earth.[76][77][78][79][80]
A mild solar particle and geomagnetic storm of otherwise little consequence[91] led to the premature reentry and destruction of 40 SpaceXStarlink satellites launched February 3, 2022 due to increased atmospheric drag.[92]
X1.2(X1.3)-class flares[93] and X4.5-class flare.[94] The flares with a magnitude of 6–7 occurred between 30 April and 4 May 2024. On 5 May the strength of the solar storm reached 5 points, which is considered strong according to the K-index. The rapidly growing sunspot AR3663 became the most active spot of the 25th solar cycle. On 5 May alone, it emitted two X-class (strongest) flares and six M-class (medium) flares. Each of these flares resulted in a short-term but profound disconnection of the Earth's radio signal, resulting in signal loss at frequencies below 30 MHz.[95]
An extreme (G5) geomagnetic storm alert was issued by the National Oceanic and Atmospheric Administration (NOAA) – the first in almost 20 years.[96][97] The final storms reaching the highest level of NOAA's G-scale before Solar Cycle 25 occurred in 2005 in May,[98][99][100] August,[101] and September, respectively.
With a NOAA rating of G5, a peak Dst of −412 nT, and aurorae seen at far lower latitudes than usual in both hemispheres, this geomagnetic storm was the most powerful to affect Earth since November of 2003.
Oct 2024
October 2024 solar storm
Triggered by an X1.8 solar flare that produced a relatively fast CME.[102][103] The storm reached a peak Dst of −341 nT.[104]
Events not affecting Earth
The above events affected Earth (and its vicinity, known as the magnetosphere), whereas the following events were directed elsewhere in the Solar System and were detected by monitoring spacecraft or other means.
^T. Y. Lui, Anthony; Consolini, Giuseppe; Kamide, Yosuke, eds. (2005). "What Determines the Intensity of Magnetospheric Substorms?". Multiscale Coupling of Sun-Earth Processes (1st ed.). Elsevier. pp. 175–194. doi:10.1016/B978-044451881-1/50014-9. ISBN978-0444518811.
^Bell, Trudy E.; T. Phillips (6 May 2008). "A Super Solar Flare". NASA Science News. National Aeronautics and Space Administration. Retrieved 2014-05-07.
^Hisashi Hayakawa; Yusuke Ebiharaa; José M. Vaquero; Kentaro Hattori; Víctor M. S. Carrasco; María de la Cruz Gallego; Satoshi Hayakawa; Yoshikazu Watanabe; Kiyomi Iwahashi; Harufumi Tamazawa; Akito D. Kawamura; Hiroaki Isobe (2018). "A Great Space Weather Event in February 1730". Astronomy & Astrophysics. 616: A177. arXiv:1807.06496. Bibcode:2018A&A...616A.177H. doi:10.1051/0004-6361/201832735. S2CID119201108.
^Meyer, P.; Parker, E. N.; Simpson, J. A (1956). "Solar Cosmic Rays of February, 1956 and Their Propagation through Interplanetary Space". Phys. Rev. 104 (3): 768–83. Bibcode:1956PhRv..104..768M. doi:10.1103/PhysRev.104.768.
^Mitthumsiri, W.; A. Seripienlert; U. Tortermpun; P.-S. Mangeard; A. Sáiz; D. Ruffolo; R. Macatanga (2017). "Modeling polar region atmospheric ionization induced by the giant solar storm on 20 January 2005". J. Geophys. Res. Space Phys. 122 (8): 7946. Bibcode:2017JGRA..122.7946M. doi:10.1002/2017JA024125. S2CID134815719.
^Ngwira, Chigomezyo M.; A. Pulkkinen; M. Leila Mays; M. M. Kuznetsova; A. B. Galvin; K. Simunac; D. N. Baker; X. Li; Y. Zheng; A. Glocer (2013). "Simulation of the 23 July 2012 extreme space weather event: What if this extremely rare CME was Earth directed?". Space Weather. 11 (12): 671–9. Bibcode:2013SpWea..11..671N. doi:10.1002/2013SW000990. hdl:2060/20150010106. S2CID4708607.
^Ying D. Liu; J. G. Luhmann; P. Kajdič; E. K.J. Kilpua; N. Lugaz; N. V. Nitta; C. Möstl; B. Lavraud; S. D. Bale; C. J. Farrugia; A. B. Galvin (2014). "Observations of an extreme storm in interplanetary space caused by successive coronal mass ejections". Nature Communications. 5 (3481): 3481. arXiv:1405.6088. Bibcode:2014NatCo...5.3481L. doi:10.1038/ncomms4481. PMID24642508. S2CID11999567.