A geomagnetic storm (commonly referred to as a solar storm) is a temporary disturbance of the Earth's magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field that interacts with the Earth's magnetic field.
The disturbance that drives the magnetic storm may be a solar coronal mass ejection (CME) or a co-rotating interaction region (CIR), a high-speed stream of solar wind originating from a coronal hole. The frequency of geomagnetic storms increases and decreases with the sunspot cycle. During solar maximum, geomagnetic storms occur more often, with the majority driven by CMEs. During solar minimum, storms are mainly driven by CIRs (though CIR storms are more frequent at solar maximum than at minimum).
The increase in the solar wind pressure initially compresses the magnetosphere. The solar wind's magnetic field interacts with the Earth's magnetic field and transfers an increased energy into the magnetosphere. Both interactions cause an increase in plasma movement through the magnetosphere (driven by increased electric fields inside the magnetosphere) and an increase in electric current in the magnetosphere and ionosphere. During the main phase of a geomagnetic storm, electric current in the magnetosphere creates a magnetic force that pushes out the boundary between the magnetosphere and the solar wind.
Several space weather phenomena tend to be associated with or are caused by a geomagnetic storm. These include solar energetic particle (SEP) events, geomagnetically induced currents (GIC), ionospheric disturbances that cause radio and radar scintillation, disruption of navigation by magnetic compass and auroral displays at much lower latitudes than normal.
The largest recorded geomagnetic storm, the Carrington Event in September 1859, took down parts of the recently created US telegraph network, starting fires and shocking some telegraph operators. In 1989, a geomagnetic storm energized ground induced currents that disrupted electric power distribution throughout most of Quebec and caused aurorae as far south as Texas.
A geomagnetic storm is defined by changes in the Dst (disturbance – storm time) index. The Dst index estimates the globally averaged change of the horizontal component of the Earth's magnetic field at the magnetic equator based on measurements from a few magnetometer stations. Dst is computed once per hour and reported in near-real-time. During quiet times, Dst is between +20 and −20 nano-Tesla (nT).
A geomagnetic storm has three phases: initial, main and recovery. The initial phase is characterized by Dst (or its one-minute component SYM-H) increasing by 20 to 50 nT in tens of minutes. The initial phase is also referred to as a storm sudden commencement (SSC). However, not all geomagnetic storms have an initial phase and not all sudden increases in Dst or SYM-H are followed by a geomagnetic storm. The main phase of a geomagnetic storm is defined by Dst decreasing to less than −50 nT. The selection of −50 nT to define a storm is somewhat arbitrary. The minimum value during a storm will be between −50 and approximately −600 nT. The duration of the main phase is typically 2–8 hours. The recovery phase is when Dst changes from its minimum value to its quiet time value. The recovery phase may last as short as 8 hours or as long as 7 days.
The size of a geomagnetic storm is classified as moderate (−50 nT > minimum of Dst > −100 nT), intense (−100 nT > minimum Dst > −250 nT) or super-storm (minimum of Dst < −250 nT).
In 1931, Sydney Chapman and Vincenzo C. A. Ferraro wrote an article, A New Theory of Magnetic Storms, that sought to explain the phenomenon. They argued that whenever the Sun emits a solar flare it also emits a plasma cloud, now known as a coronal mass ejection. They postulated that this plasma travels at a velocity such that it reaches Earth within 113 days, though we now know this journey takes 1 to 5 days. They wrote that the cloud then compresses the Earth's magnetic field and thus increases this field at the Earth's surface. Chapman and Ferraro's work drew on that of, among others, Kristian Birkeland, who had used recently discovered cathode ray tubes to show that the rays were deflected towards the poles of a magnetic sphere. He theorised that a similar phenomenon was responsible for auroras, explaining why they are more frequent in polar regions.
The first scientific observation of the effects of a geomagnetic storm occurred early in the 19th century: From May 1806 until June 1807, Alexander von Humboldt recorded the bearing of a magnetic compass in Berlin. On 21 December 1806, he noticed that his compass had become erratic during a bright auroral event.
On September 1–2, 1859, the largest recorded geomagnetic storm occurred. From August 28 until September 2, 1859, numerous sunspots and solar flares were observed on the Sun, with the largest flare on September 1. This is referred to as the Solar storm of 1859 or the Carrington Event. It can be assumed that a massive coronal mass ejection (CME) was launched from the Sun and reached the Earth within eighteen hours—a trip that normally takes three to four days. The horizontal field was reduced by 1600 nT as recorded by the Colaba Observatory. It is estimated that Dst would have been approximately −1760 nT. Telegraph wires in both the United States and Europe experienced induced voltage increases (emf), in some cases even delivering shocks to telegraph operators and igniting fires. Aurorae were seen as far south as Hawaii, Mexico, Cuba and Italy—phenomena that are usually only visible in polar regions. Ice cores show evidence that events of similar intensity recur at an average rate of approximately once per 500 years.
Since 1859, less severe storms have occurred, notably the aurora of November 17, 1882 and the May 1921 geomagnetic storm, both with disruption of telegraph service and initiation of fires, and 1960, when widespread radio disruption was reported.
In early August 1972, a series of flares and solar storms peaks with a flare estimated around X20 producing the fastest CME transit ever recorded and a severe geomagnetic and proton storm that disrupted terrestrial electrical and communications networks, as well as satellites (at least one made permanently inoperative), and unintentionally detonated numerous U.S. Navy magnetic-influence sea mines in North Vietnam.
The March 1989 geomagnetic storm caused the collapse of the Hydro-Québec power grid in seconds as equipment protection relays tripped in a cascading sequence. Six million people were left without power for nine hours. The storm caused auroras as far south as Texas. The storm causing this event was the result of a coronal mass ejected from the Sun on March 9, 1989. The minimum of Dst was −589 nT.
On July 14, 2000, an X5 class flare erupted (known as the Bastille Day event) and a coronal mass was launched directly at the Earth. A geomagnetic super storm occurred on July 15–17; the minimum of the Dst index was −301 nT. Despite the storm's strength, no power distribution failures were reported. The Bastille Day event was observed by Voyager 1 and Voyager 2, thus it is the farthest out in the Solar System that a solar storm has been observed.
Seventeen major flares erupted on the Sun between 19 October and 5 November 2003, including perhaps the most intense flare ever measured on the GOES XRS sensor—a huge X28 flare, resulting in an extreme radio blackout, on 4 November. These flares were associated with CME events that caused three geomagnetic storms between 29 October and 2 November, during which the second and third storms were initiated before the previous storm period had fully recovered. The minimum Dst values were −151, −353 and −383 nT. Another storm in this sequence occurred on 4–5 November with a minimum Dst of −69 nT. The last geomagnetic storm was weaker than the preceding storms, because the active region on the Sun had rotated beyond the meridian where the central portion CME created during the flare event passed to the side of the Earth. The whole sequence became known as the Halloween Solar Storm. The Wide Area Augmentation System (WAAS) operated by the Federal Aviation Administration (FAA) was offline for approximately 30 hours due to the storm. The Japanese ADEOS-2 satellite was severely damaged and the operation of many other satellites were interrupted due to the storm.
The solar wind also carries with it the Sun's magnetic field. This field will have either a North or South orientation. If the solar wind has energetic bursts, contracting and expanding the magnetosphere, or if the solar wind takes a southward polarization, geomagnetic storms can be expected. The southward field causes magnetic reconnection of the dayside magnetopause, rapidly injecting magnetic and particle energy into the Earth's magnetosphere.
Magnetometers monitor the auroral zone as well as the equatorial region. Two types of radar, coherent scatter and incoherent scatter, are used to probe the auroral ionosphere. By bouncing signals off ionospheric irregularities, which move with the field lines, one can trace their motion and infer magnetospheric convection.
Spacecraft instruments include:
Computers have made it possible to bring together decades of isolated magnetic observations and extract average patterns of electrical currents and average responses to interplanetary variations. They also run simulations of the global magnetosphere and its responses, by solving the equations of magnetohydrodynamics (MHD) on a numerical grid. Appropriate extensions must be added to cover the inner magnetosphere, where magnetic drifts and ionospheric conduction need to be taken into account. So far the results are difficult to interpret, and certain assumptions are needed to cover small-scale phenomena.
It has been suggested that a geomagnetic storm on the scale of the solar storm of 1859 today would cause billions or even trillions of dollars of damage to satellites, power grids and radio communications, and could cause electrical blackouts on a massive scale that might not be repaired for weeks, months, or even years. Such sudden electrical blackouts may threaten food production.
When magnetic fields move about in the vicinity of a conductor such as a wire, a geomagnetically induced current is produced in the conductor. This happens on a grand scale during geomagnetic storms (the same mechanism also influenced telephone and telegraph lines before fiber optics, see above) on all long transmission lines. Long transmission lines (many kilometers in length) are thus subject to damage by this effect. Notably, this chiefly includes operators in China, North America, and Australia, especially in modern high-voltage, low-resistance lines. The European grid consists mainly of shorter transmission circuits, which are less vulnerable to damage.
The (nearly direct) currents induced in these lines from geomagnetic storms are harmful to electrical transmission equipment, especially transformers—inducing core saturation, constraining their performance (as well as tripping various safety devices), and causing coils and cores to heat up. In extreme cases, this heat can disable or destroy them, even inducing a chain reaction that can overload transformers. Most generators are connected to the grid via transformers, isolating them from the induced currents on the grid, making them much less susceptible to damage due to geomagnetically induced current. However, a transformer that is subjected to this will act as an unbalanced load to the generator, causing negative sequence current in the stator and consequently rotor heating.
According to a study by Metatech corporation, a storm with a strength comparable to that of 1921 would destroy more than 300 transformers and leave over 130 million people without power in the United States, costing several trillion dollars. The British Daily Mail even claimed that a massive solar flare could knock out electric power for months, but these predictions are contradicted by a North American Electric Reliability Corporation report that concludes that a geomagnetic storm would cause temporary grid instability but no widespread destruction of high-voltage transformers. The report points out that the widely quoted Quebec grid collapse was not caused by overheating transformers but by the near-simultaneous tripping of seven relays.
Besides the transformers being vulnerable to the effects of a geomagnetic storm, electricity companies can also be affected indirectly by the geomagnetic storm. For instance, internet service providers may go down during geomagnetic storms (and/or remain non-operational long after). Electricity companies may have equipment requiring a working internet connection to function, so during the period the internet service provider is down, the electricity too may not be distributed.
By receiving geomagnetic storm alerts and warnings (e.g. by the Space Weather Prediction Center; via Space Weather satellites as SOHO or ACE), power companies can minimize damage to power transmission equipment, by momentarily disconnecting transformers or by inducing temporary blackouts. Preventative measures also exist, including preventing the inflow of GICs into the grid through the neutral-to-ground connection.
High frequency (3–30 MHz) communication systems use the ionosphere to reflect radio signals over long distances. Ionospheric storms can affect radio communication at all latitudes. Some frequencies are absorbed and others are reflected, leading to rapidly fluctuating signals and unexpected propagation paths. TV and commercial radio stations are little affected by solar activity, but ground-to-air, ship-to-shore, shortwave broadcast and amateur radio (mostly the bands below 30 MHz) are frequently disrupted. Radio operators using HF bands rely upon solar and geomagnetic alerts to keep their communication circuits up and running.
Military detection or early warning systems operating in the high frequency range are also affected by solar activity. The over-the-horizon radar bounces signals off the ionosphere to monitor the launch of aircraft and missiles from long distances. During geomagnetic storms, this system can be severely hampered by radio clutter. Also some submarine detection systems use the magnetic signatures of submarines as one input to their locating schemes. Geomagnetic storms can mask and distort these signals.
The Federal Aviation Administration routinely receives alerts of solar radio bursts so that they can recognize communication problems and avoid unnecessary maintenance. When an aircraft and a ground station are aligned with the Sun, high levels of noise can occur on air-control radio frequencies. This can also happen on UHF and SHF satellite communications, when an Earth station, a satellite and the Sun are in alignment. In order to prevent unnecessary maintenance on satellite communications systems aboard aircraft AirSatOne provides a live feed for geophysical events from NOAA's Space Weather Prediction Center. AirSatOne's live feed allows users to view observed and predicted space storms. Geophysical Alerts are important to flight crews and maintenance personnel to determine if any upcoming activity or history has or will have an effect on satellite communications, GPS navigation and HF Communications.
Telegraph lines in the past were affected by geomagnetic storms. Telegraphs used a single long wire for the data line, stretching for many miles, using the ground as the return wire and fed with DC power from a battery; this made them (together with the power lines mentioned below) susceptible to being influenced by the fluctuations caused by the ring current. The voltage/current induced by the geomagnetic storm could have diminished the signal, when subtracted from the battery polarity, or to overly strong and spurious signals when added to it; some operators learned to disconnect the battery and rely on the induced current as their power source. In extreme cases the induced current was so high the coils at the receiving side burst in flames, or the operators received electric shocks. Geomagnetic storms affect also long-haul telephone lines, including undersea cables unless they are fiber optic.
Damage to communications satellites can disrupt non-terrestrial telephone, television, radio and Internet links. The National Academy of Sciences reported in 2008 on possible scenarios of widespread disruption in the 2012–2013 solar peak.
The Global Navigation Satellite System (GNSS), and other navigation systems such as LORAN and the now-defunct OMEGA are adversely affected when solar activity disrupts their signal propagation. The OMEGA system consisted of eight transmitters located throughout the world. Airplanes and ships used the very low frequency signals from these transmitters to determine their positions. During solar events and geomagnetic storms, the system gave navigators information that was inaccurate by as much as several miles. If navigators had been alerted that a proton event or geomagnetic storm was in progress, they could have switched to a backup system.
GNSS signals are affected when solar activity causes sudden variations in the density of the ionosphere, causing the satellite signals to scintillate (like a twinkling star). The scintillation of satellite signals during ionospheric disturbances is studied at HAARP during ionospheric modification experiments. It has also been studied at the Jicamarca Radio Observatory.
One technology used to allow GPS receivers to continue to operate in the presence of some confusing signals is Receiver Autonomous Integrity Monitoring (RAIM). However, RAIM is predicated on the assumption that a majority of the GPS constellation is operating properly, and so it is much less useful when the entire constellation is perturbed by global influences such as geomagnetic storms. Even if RAIM detects a loss of integrity in these cases, it may not be able to provide a useful, reliable signal.
Geomagnetic storms and increased solar ultraviolet emission heat Earth's upper atmosphere, causing it to expand. The heated air rises, and the density at the orbit of satellites up to about 1,000 km (621 mi) increases significantly. This results in increased drag, causing satellites to slow and change orbit slightly. Low Earth Orbit satellites that are not repeatedly boosted to higher orbits slowly fall and eventually burn up.
Skylab's 1979 destruction is an example of a spacecraft reentering Earth's atmosphere prematurely as a result of higher-than-expected solar activity. During the great geomagnetic storm of March 1989, four of the Navy's navigational satellites had to be taken out of service for up to a week, the U.S. Space Command had to post new orbital elements for over 1000 objects affected and the Solar Maximum Mission satellite fell out of orbit in December the same year.
The vulnerability of the satellites depends on their position as well. The South Atlantic Anomaly is a perilous place for a satellite to pass through.
As technology has allowed spacecraft components to become smaller, their miniaturized systems have become increasingly vulnerable to the more energetic solar particles. These particles can physically damage microchips and can change software commands in satellite-borne computers.
Another problem for satellite operators is differential charging. During geomagnetic storms, the number and energy of electrons and ions increase. When a satellite travels through this energized environment, the charged particles striking the spacecraft differentially charge portions of the spacecraft. Discharges can arc across spacecraft components, harming and possibly disabling them.
Bulk charging (also called deep charging) occurs when energetic particles, primarily electrons, penetrate the outer covering of a satellite and deposit their charge in its internal parts. If sufficient charge accumulates in any one component, it may attempt to neutralize by discharging to other components. This discharge is potentially hazardous to the satellite's electronic systems.
Earth's magnetic field is used by geologists to determine subterranean rock structures. For the most part, these geodetic surveyors are searching for oil, gas or mineral deposits. They can accomplish this only when Earth's field is quiet, so that true magnetic signatures can be detected. Other geophysicists prefer to work during geomagnetic storms, when strong variations in the Earth's normal subsurface electric currents allow them to sense subsurface oil or mineral structures. This technique is called magnetotellurics. For these reasons, many surveyors use geomagnetic alerts and predictions to schedule their mapping activities.
Rapidly fluctuating geomagnetic fields can produce geomagnetically induced currents in pipelines. This can cause multiple problems for pipeline engineers. Pipeline flow meters can transmit erroneous flow information and the corrosion rate of the pipeline can be dramatically increased.
Earth's atmosphere and magnetosphere allow adequate protection at ground level, but astronauts are subject to potentially lethal doses of radiation. The penetration of high-energy particles into living cells can cause chromosome damage, cancer and other health problems. Large doses can be immediately fatal.
Solar proton events can also produce elevated radiation aboard aircraft flying at high altitudes. Although these risks are small, monitoring of solar proton events by satellite instrumentation allows the occasional exposure to be monitored and evaluated and eventually flight paths and altitudes adjusted in order to lower the absorbed dose of the flight crews.
Scientists are still studying whether or not animals are affected by this, some suggesting this is why whales beach themselves. Some have stated the possibility that other migrating animals including birds and honey bees, might be affected since they also use magnetoreception to navigate, and geomagnetic storms alter the Earth's magnetic fields temporarily.
Links related to power grids:
The Aurora of November 17, 1882 was a geomagnetic storm and associated aurora event, widely reported in the media of the time. It occurred during an extended period of strong geomagnetic activity in solar cycle 12.
The event is particularly remembered in connection with an unusual phenomenon, an "auroral beam", which was observed from the Royal Observatory, Greenwich by astronomer Edward Walter Maunder and by John Rand Capron from Guildown, Surrey.Bastille Day event
The Bastille Day Flare or Bastille Day Event was a powerful solar flare on July 14, 2000, the national day of France, occurring near the peak of the solar maximum in solar cycle 23. The X5.7-class flare originated from a sunspot known as Active region 9077, which subsequently caused an S3 radiation storm on Earth fifteen minutes later as energetic protons bombarded the ionosphere. It was the biggest solar radiation event since 1989. The proton event was four times more intense than any previously recorded since the launches of SOHO in 1995 and ACE in 1997. The flare was also followed by a full-halo coronal mass ejection and a geomagnetic super storm on July 15–16. The geomagnetic storm peaked at the extreme level, G5, in the late hours of July 15.
Despite their great distance from the Sun, the Bastille Day event was observed by Voyager 1 and Voyager 2.Cosmic storm
Cosmic storm may refer to:
Cosmic ray burst
Geomagnetic storm, the interaction of the Sun's outburst with Earth's magnetic field
Coronal mass ejection
A geostorm is a geomagnetic storm, a type of weather. Geo storm may also refer to:
Geo Storm, an automobile
Geostorm, a 2017 American disaster filmGeomagnetically induced current
Geomagnetically induced currents (GIC), affecting the normal operation of long electrical conductor systems, are a manifestation at ground level of space weather. During space weather events, electric currents in the magnetosphere and ionosphere experience large variations, which manifest also in the Earth's magnetic field. These variations induce currents (GIC) in conductors operated on the surface of Earth. Electric transmission grids and buried pipelines are common examples of such conductor systems. GIC can cause problems, such as increased corrosion of pipeline steel and damaged high-voltage power transformers. GIC are one possible consequence of geomagnetic storms, which may also affect geophysical exploration surveys and oil and gas drilling operations.January 1938 geomagnetic storm
The 25–26 January 1938 geomagnetic storm (also known as the Fátima Storm) was a massive solar storm which occurred 16–26 January with peak activity on 22, 25 and 26 January and was part of the 17th solar cycle. The effects of the storm were extremely limited, the electrification of Europe and North America was still in its infancy.
This storm's great Aurora was witnessed across Europe and had not been seen since 1706. The storm was remarkable primarily because of how far and wide it was observed. Eventually collected reports would show that the Aurora was witnessed in far north of Canada, and spread as far south as southern California and on the Caribbean island Bermuda. In Europe, the Aurora was seen in Northern Scotland, East Austria, in southern Sicily, Gibraltar, Portugal, and news reports in Southern Australia had seen it. All transatlantic radio communication was interrupted and Canada suffered a 12-hour-long short-wave radio blackout. Gathered crowds in the Netherlands were awaiting the imminent birth of Princess Juliana's baby Princess Beatrix who was eventually born on 31 January 1938: the Dutch people cheered the aurora as a lucky omen.
Canada was witness to the most vivid auroral displays in the nights of 24–25 and 25–26 January. The celestial display on 25–26 January was seen from Canada to Bermuda and from Austria to Scotland. In Salzburg, Austria, some residents called on the fire department as they believed something was on fire in their town. So many alarm bells were rung that the fire departments were constantly moving to new alarms while calming the citizens, the deafening sounds of alarm bells further caused panic causing some residents to flee to rural areas. This same alarm was seen in London where many also believed whole streets were on fire, even the guards of Windsor Castle summoned the fire brigade to put out a non-existent fire. Naturally, this event was better documented in the West. In Switzerland, the Swiss Alps peaks covered in white snow were glowing bright and reflecting some of the Auroral rays causing a reflective disco effect. In San Diego, the National Forest Service was called up in the town of Descanso and routed out of bed on 22 January to respond to a 'great fire in the back country', after they checked out the back roads they discovered it was the Crimson Aurora Borealis in the northern sky, which had not been seen in that region since February 1888. In Bermuda, many people believed that a massive freight ship was on fire at sea too far to see with their naked eyes, Steamship captains believed it so much that they checked in with the wireless stations to learn if there were any S.O.S calls and if they could help. In Scotland, many religious people living in the lowlands were afraid and called the Aurora an ill-omen for Scotland.
The electrical side-effects were severely limited only short-wave radio transmissions were shut down for almost 12 hours in Canada. In England where express trains on the Manchester-Sheffield line where the signalling equipment was inoperable due to electrical disturbances. These coal trains who were moving halted and waited at these junctions for safety reasons. Many teletype systems at local Western Union offices were started, spewed out garbage data and suffered electrical shorts.Due to a particularly thick cloud cover at the beginning of January, only London based Royal Observatory Greenwich was able to observe a large sunspot on 15 January due to a short break in the cloud covers on earth. The latitude of the sunspot was on the +19° N declination on the suns hemisphere, the sunspot at its maximum size covered an area of roughly 3,000 Millionths of the Solar Hemisphere, or 3,000(MSH), the spot resembled a similar spot observed in October 1937. Back then this sunspot became the biggest sunspot observed since records began and trumped the sunspot of the May 1921 geomagnetic storm. The magnetic solar storm was detected on 16 January at around 22:30 GMT by the now defunct Abinger Magnetic Observatory in Surrey, England. A rapid succession of solar flares which created much larger geomagnetic disturbance quickly released towards Earth on 22 January between the hours of 05:00, 09:00 and 10:00, with high frequency, however on 25 January, a day after the massive sunspot had disappeared from direct line of sight over the western side of the Sun, a sudden and rapid barrage of high-frequency waves began at around midday and developed to a new record-breaking highs in the evening. A large movement of the recording magnets at Abinger began at around 17:00 and were extremely noteworthy at 20:00 and 21:30, the geomagnetic disturbance only started calming down at around 03:00 in the morning of 26 January.K-index
The K-index quantifies disturbances in the horizontal component of earth's magnetic field with an integer in the range 0–9 with 1 being calm and 5 or more indicating a geomagnetic storm. It is derived from the maximum fluctuations of horizontal components observed on a magnetometer during a three-hour interval. The label K comes from the German word Kennziffer meaning "characteristic digit". The K-index was introduced by Julius Bartels in 1938.Lagrange (spacecraft)
Lagrange is a 2018 concept study for a solar weather mission by the European Space Agency (ESA). This is a British-led concept that envisions two spacecraft to be positioned at Lagrangian points L1 and L5.Monitoring space weather includes events such as solar flares, coronal mass ejections,
geomagnetic storms, solar proton events, etc. Monitoring would help predict arrival times at the Earth and any potential effect on infrastructure. If funded, both Lagrange missions would launch in the 2020s.List of solar storms
Solar storms of different types are caused by disturbances on the Sun, most often coronal clouds associated with coronal mass ejections (CMEs) produced by solar flares emanating from active sunspot regions, or, less often, from coronal holes. Solar filaments (solar prominences) may also trigger CMEs, trigger flares, or occur in conjunction with flares, and the associated CMEs can be intensified.Magnetic storm (disambiguation)
Magnetic storm can refer to:
A geomagnetic storm
Magnetic Storm (book), the title of a book of paintings by Roger Dean
Magnetic Storm (film), the title of an hourlong PBS NOVA documentary about Earth's changing magnetic fields; see List of Nova episodesMarch 1989 geomagnetic storm
The March 1989 geomagnetic storm occurred as part of severe to extreme solar storms during early to mid March 1989, the most notable being a geomagnetic storm that struck Earth on March 13. This geomagnetic storm caused a nine-hour outage of Hydro-Québec's electricity transmission system. The onset time was exceptionally rapid. Other historically significant solar storms occurred later in 1989, during a very active period of solar cycle 22.May 1921 geomagnetic storm
The May 1921 geomagnetic storm was a significant event caused by the impact of an extraordinarily powerful coronal mass ejection on Earth's magnetosphere. It took place on 13 through 15 May, and was part of solar cycle 15. This event occurred before extensive interconnectivity of electrical systems and the general electrical dependency across infrastructures in the developed world, so the effect was restricted to certain sectors, even though resulting ground currents were up to an order of magnitude greater than those of the March 1989 geomagnetic storm that blacked out large parts of northeastern North America. At the time, scientists gave the size of the sunspot that began on May 10th and caused the storm as 94,000 by 21,000 miles (131,000 km by 33,800 km) in size.Northern lights appeared in much of the eastern United States, creating brightly lit night skies. Telegraph service in the United States was slowed and then virtually eliminated around midnight of the 14th due to blown fuses, and damaged equipment. On the other hand, radio waves were strengthened during the storm due to ionosphere activation, allowing for some strong intercontinental reception. Electric lights did not seem to have been noticeably affected. Undersea cables also suffered from the storm. Damage to telegraph systems were also reported in Europe
and the southern hemisphere.Natural hazard
A natural hazard is a natural phenomenon that might have a negative effect on humans or the environment. Natural hazard events can be classified into two broad categories: geophysical and biological. Geophysical hazards encompass geologic
An example of the distinction between a natural hazard and a natural disaster is that the 1906 San Francisco earthquake was a disaster, whereas living on a fault line is a hazard. Some natural hazards can be provoked or affected by anthropogenic processes (e.g. land-use change, drainage and construction).Solar cycle 22
Solar cycle 22 was the 22nd solar cycle since 1755, when extensive recording of solar sunspot activity began. The solar cycle lasted 9.9 years, beginning in September 1986 and ending in August 1996. The maximum smoothed sunspot number (SIDC formula) observed during the solar cycle was 212.5 (November 1989), and the starting minimum was 13.5. During the minimum transit from solar cycle 22 to 23, there were a total of 309 days with no sunspots.Solar cycle 24
Solar Cycle 24 is the 24th solar cycle since 1755, when extensive recording of solar sunspot activity began. It is the current solar cycle, and began in December 2008 with a smoothed minimum of 2.2 (SIDC formula). Activity was minimal until early 2010. It reached its maximum in April 2014 with a 23 months smoothed sunspot number of only 81.8, comparable to those of cycles 12 through 15. Reversed polarity polar active sunspot regions in December 2016, April 2018, November 2018, May 2019, and July 2019 indicate that a transitional phase to solar cycle 25 is in process.Solar phenomena
Solar phenomena are the natural phenomena occurring within the magnetically heated outer atmospheres in the Sun. These phenomena take many forms, including solar wind, radio wave flux, energy bursts such as solar flares, coronal mass ejection or solar eruptions, coronal heating and sunspots.
These phenomena are apparently generated by a helical dynamo near the center of the Sun's mass that generates strong magnetic fields and a chaotic dynamo near the surface that generates smaller magnetic field fluctuations.The total sum of all solar fluctuations is referred to as solar variation. The collective effect of all solar variations within the Sun's gravitational field is referred to as space weather. A major weather component is the solar wind, a stream of plasma released from the Sun's upper atmosphere. It is responsible for the aurora, natural light displays in the sky in the Arctic and Antarctic. Space weather disturbances can cause solar storms on Earth, disrupting communications, as well as geomagnetic storms in Earth's magnetosphere and sudden ionospheric disturbances in the ionosphere. Variations in solar intensity also affect Earth's climate. These variations can explain events such as ice ages and the Great Oxygenation Event, while the Sun's future expansion into a red giant will likely end life on Earth.
Solar activity and related events have been recorded since the 8th century BCE. Babylonians inscribed and possibly predicted solar eclipses, while the earliest extant report of sunspots dates back to the Chinese Book of Changes, c. 800 BCE. The first extant description of the solar corona was in 968, while the earliest sunspot drawing was in 1128 and a solar prominence was described in 1185 in the Russian Chronicle of Novgorod. The invention of the telescope allowed major advances in understanding, allowing the first detailed observations in the 1600s. Solar spectroscopy began in the 1800s, from which properties of the solar atmosphere could be determined, while the creation of daguerreotypy led to the first solar photographs on 2 April 1845. Photography assisted in the study of solar prominences, granulation and spectroscopy. Early in the 20th century, interest in astrophysics surged in America. A number of new observatories were built with solar telescopes around the world. The 1931 invention of the coronagraph allowed the corona to be studied in full daylight.Solar storm of 1859
The solar storm of 1859 (also known as the Carrington Event) was a powerful geomagnetic storm during solar cycle 10 (1855–1867). A solar coronal mass ejection (CME) hit Earth's magnetosphere and induced one of the largest geomagnetic storms on record, September 1–2, 1859. The associated "white light flare" in the solar photosphere was observed and recorded by British astronomers Richard C. Carrington (1826–1875) and Richard Hodgson (1804–1872). The storm caused strong auroral displays and wrought havoc with telegraph systems.
The now-standard unique IAU identifier for this flare is SOL1859-09-01.
A solar storm of this magnitude occurring today would cause widespread electrical disruptions, blackouts and damage due to extended outages of the electrical grid. The solar storm of 2012 was of similar magnitude, but it passed Earth's orbit without striking the planet, missing by nine days.Solar storm of August 1972
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 widespread electric‐ and communication‐grid disturbances through large portions of North America as well as satellite disruptions. On August 4, 1972, the storm caused the accidental detonation of numerous U.S. naval mines near Haiphong, North Vietnam. The coronal cloud's transit time from the Sun to the Earth is the fastest ever recorded.Statite
A statite (a portmanteau of static and satellite) is a hypothetical type of artificial satellite that employs a solar sail to continuously modify its orbit in ways that gravity alone would not allow. Typically, a statite would use the solar sail to "hover" in a location that would not otherwise be available as a stable geosynchronous orbit. Statites have been proposed that would remain in fixed locations high over Earth's poles, using reflected sunlight to counteract the gravity pulling them down. Statites might also employ their sails to change the shape or velocity of more conventional orbits, depending upon the purpose of the particular statite.
The concept of the statite was invented independently (and approximately simultaneously) by Robert L. Forward (who coined the term "statite") and Colin McInnes, who used the term "halo orbit" (not to be confused with the type of halo orbit invented by Robert Farquhar). Subsequently, the terms "non-Keplerian orbit" and "artificial Lagrange point" have been used as a generalization of the above terms.No statites have been deployed to date, as solar sail technology remains in its infancy. NASA's cancelled Sunjammer solar sail mission had the stated objective of flying to an artificial Lagrange point near the Earth/Sun L1 point, to demonstrate the feasibility of the Geostorm geomagnetic storm warning mission concept proposed by NOAA's Patricia Mulligan.