Space weather

Space weather

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Space weather is the concept of changing environmental conditions in near-Earth space or the
space from the Sun's atmosphere to the Earth's atmosphere. It is distinct from the concept of
weather
Weather
Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...

 within the Earth's planetary atmosphere
(troposphere
Troposphere
The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 80% of the atmosphere's mass and 99% of its water vapor and aerosols....

 and stratosphere
Stratosphere
The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down. This is in contrast to the troposphere near the Earth's surface, which is cooler...

). Space Weather is the description of changes in the
ambient plasma
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...

, magnetic fields
Earth's magnetic field
Earth's magnetic field is the magnetic field that extends from the Earth's inner core to where it meets the solar wind, a stream of energetic particles emanating from the Sun...

, radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...


and other matter
Matter
Matter is a general term for the substance of which all physical objects consist. Typically, matter includes atoms and other particles which have mass. A common way of defining matter is as anything that has mass and occupies volume...

 in space.
Much of space weather is driven by energy carried through interplanetary
space by the solar wind from regions near the surface of the Sun and the Sun's atmosphere
(chromosphere
Chromosphere
The chromosphere is a thin layer of the Sun's atmosphere just above the photosphere, roughly 2,000 kilometers deep....

 and corona
Corona
A corona is a type of plasma "atmosphere" of the Sun or other celestial body, extending millions of kilometers into space, most easily seen during a total solar eclipse, but also observable in a coronagraph...

).The term space weather is sometimes used to refer
to changes in interplanetary (and occasionally
interstellar
Interstellar medium
In astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space...

) space.

Space weather has two focal points: scientific research and applications. The term
space weather was not used until the 1990s. Prior to that time, activities now known as
space weather were considered to be part of physics or aeronomy
Aeronomy
Aeronomy is the science of the upper region of the atmosphere, where dissociation and ionization are important. The term aeronomy was introduced by Sydney Chapman, and the above definition stems from 1960. Today the term also includes the science of the corresponding regions of the atmospheres of...

 or space exploration.

History of space weather


For centuries, people have noticed the aurora
Aurora (astronomy)
An aurora is a natural light display in the sky particularly in the high latitude regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere...

, which is caused by space weather, but
did not understand it. Navigators in the Medieval Ages
Middle Ages
The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

 in Europe using a lodestone
Lodestone
A lodestone or loadstone is a naturally magnetized piece of the mineral magnetite. They are naturally occurring magnets, that attract pieces of iron. Ancient people first discovered the property of magnetism in lodestone...

 as
a magnetic compass noted
that occasionally the stone's direction was deflected from magnetic north. This was described in
1600 in De Magnete
De Magnete
De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure is a scientific work published in 1600 by the English physician and scientist William Gilbert and his partner Aaron Dowling...

 but was not understood to be caused by space weather until
the 19th century. Space weather affected the first electrical telegraphs in the 1840 in various
areas at various times. The great solar storm of 1859
Solar storm of 1859
The solar storm of 1859, also known as the Solar Superstorm, or the Carrington Event, which occurred during solar cycle 10, was the most powerful solar storm in recorded history, and the largest flare, observed by Richard Christopher Carrington, became known as the Carrington Super...

 disrupted telegraph operations around the
world, causing articles to be published in many major newspapers at that time.
Richard Carrington correctly connected the disruption with a solar flare observed the day
before and a great deflection of the Earth's magnetic field (or
geomagnetic storm
Geomagnetic storm
A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in the interplanetary medium. A geomagnetic storm is a major component of space weather and provides the input for many other components of space weather...

) simultaneous with the telegraph disruption. With this connection, space
weather, as we now know it, became a subject of academic research within the study of solar
physics.
Kristian Birkeland
Kristian Birkeland
Kristian Olaf Birkeland was a Norwegian scientist. He is best remembered as the person who first elucidated the nature of the Aurora borealis. In order to fund his research on the aurorae, he invented the electromagnetic cannon and the Birkeland-Eyde process of fixing nitrogen from the air...

 explained the physics of aurora by creating artificial aurora in his
laboratory and predicted the solar wind
Solar wind
The solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in temperature and speed over time...

. With the introduction of radio for commercial and
military uses, it was noted that periods of extreme static or noise occurred. Severe radar jamming
during a large solar event in 1942 led to the discovery of solar radio bursts (radio waves which
cover a broad frequency range created by a solar flare
Solar flare
A solar flare is a sudden brightening observed over the Sun surface or the solar limb, which is interpreted as a large energy release of up to 6 × 1025 joules of energy . The flare ejects clouds of electrons, ions, and atoms through the corona into space. These clouds typically reach Earth a day...

), another aspect of space weather.

In the 20th century, the interest in space weather has expanded as military and commercial systems
have come to depend on systems affected by space weather.
Communications satellites are a vital part of global commerce. Weather satellite
Weather satellite
The weather satellite is a type of satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be either polar orbiting, seeing the same swath of the Earth every 12 hours, or geostationary, hovering over the same spot on Earth by orbiting over the equator while...

 systems
provide information about terrestrial weather. The signals from satellites of the
Global Positioning System
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

 are used in a wide variety of commercial products and processes.
Space weather phenomena can interfere with or damage these satellites or interfere with the radio
signals to and from these satellites. Space weather phenomena can cause damaging surges in
long electrical transmissions lines and expose passengers and crew of aircraft travel
to radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...

,
especially on polar routes.

The International Geophysical Year
International Geophysical Year
The International Geophysical Year was an international scientific project that lasted from July 1, 1957, to December 31, 1958. It marked the end of a long period during the Cold War when scientific interchange between East and West was seriously interrupted...

 (IGY), created an enormous increase in research into
space weather. Ground-based data obtained during IGY demonstrated that the aurora occurred
in an auroral oval, a permanent region of luminescence 15 to 25 degrees in latitude from the
magnetic poles and 5 to 20 degrees wide. In 1958, the
Explorer I
Explorer I
Explorer 1 was the first Earth satellite of the United States, launched as part of its participation in the International Geophysical Year...

 satellite discovered the Van Allen belts
Van Allen radiation belt
The Van Allen radiation belt is a torus of energetic charged particles around Earth, which is held in place by Earth's magnetic field. It is believed that most of the particles that form the belts come from solar wind, and other particles by cosmic rays. It is named after its discoverer, James...

 or regions of radiation particles trapped by the Earth's magnetic field. In January
1959, the Soviet
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....

 Luna 1
Luna 1
Luna 1 , first known as First Cosmic Ship, then known as Mechta was the first spacecraft to reach the vicinity of the Moon and the first of the Luna program of Soviet automatic interplanetary stations successfully launched in the direction of the Moon.While traveling through the outer Van Allen...

 first directly observed the solar wind and
measured its strength. In 1969, INJUN-5 (a.k.a. Explorer 40) made the first
direct observation of the electric field impressed on the Earth's high latitude ionosphere by the
solar wind. In the early1970's, Triad data demonstrated that permanent electric
currents flowed between the auroral oval and the magnetosphere. From these and other fundamental discoveries, research into space weather
has grown exponentially.

Within our own solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...

, space weather is greatly influenced by the speed and density of
the solar wind
Solar wind
The solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in temperature and speed over time...

 and the interplanetary magnetic field
Interplanetary Magnetic Field
The interplanetary magnetic field is the term for the solar magnetic field carried by the solar wind among the planets of the Solar System....

 (IMF) carried by the solar wind
plasma. A variety of physical phenomena are associated with space weather, including
geomagnetic storm
Geomagnetic storm
A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in the interplanetary medium. A geomagnetic storm is a major component of space weather and provides the input for many other components of space weather...

s and substorms, energization of the Van Allen radiation belt
Van Allen radiation belt
The Van Allen radiation belt is a torus of energetic charged particles around Earth, which is held in place by Earth's magnetic field. It is believed that most of the particles that form the belts come from solar wind, and other particles by cosmic rays. It is named after its discoverer, James...

s,
ionospheric disturbances and scintillation of satellite-to-ground radio signals and long-range radar
signals, aurora
Aurora (astronomy)
An aurora is a natural light display in the sky particularly in the high latitude regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere...

 and geomagnetically induced current
Geomagnetically induced current
Geomagnetically induced currents , 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...

s at Earth's surface.
Coronal mass ejection
Coronal mass ejection
A coronal mass ejection is a massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space....

s and their associated shock wave
Shock wave
A shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium or in some cases in the absence of a material medium, through a field such as the electromagnetic field...

s are also important drivers of
space weather as they can compress the magnetosphere
Magnetosphere
A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...

 and trigger
geomagnetic storm
Geomagnetic storm
A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in the interplanetary medium. A geomagnetic storm is a major component of space weather and provides the input for many other components of space weather...

s. Solar energetic particles
Solar Energetic Particles
Solar Energetic Particles are high-energy particles coming from the Sun which had been first observed in the early 1940s. They consist of protons, electrons and heavy ions with energy ranging from a few tens of keV to GeV...

, accelerated by coronal mass ejections or
solar flare
Solar flare
A solar flare is a sudden brightening observed over the Sun surface or the solar limb, which is interpreted as a large energy release of up to 6 × 1025 joules of energy . The flare ejects clouds of electrons, ions, and atoms through the corona into space. These clouds typically reach Earth a day...

s, are also an important driver of space weather as they can damage electronics
onboard spacecraft (e.g. Galaxy 15
Galaxy 15
Galaxy 15 is an American telecommunications satellite which is owned by Intelsat. It was launched for and originally operated by PanAmSat, and was subsequently transferred to Intelsat when the two companies merged in 2006. It was originally positioned in geostationary orbit at a longitude of 133°...

 failure), and threaten the life of astronauts.

The term space weather came into usage in the 1990s when it became apparent that the impact of
the space environment on human systems demanded a more coordinated research and application
framework. The purpose of the National Space Weather Program in the
USA is to focus research on the needs of the commercial and military communities which are
affected by space weather, to connect the research community to the user community, to create
coordination between operational data centers and to create better definitions of what the user
community needs are. The concept was turned into an action plan in
2000, an implementation plan in 2002, an assessment in 2006 and a revised strategic plan in 2010. A revised action plan will be released
in 2011 and a revised implementation plan
will be release in 2012. One part of the National Space Weather Program is to make users aware that space
weather affects their business.

Spacecraft anomalies


Spacecraft malfunction for a variety of reasons. Some malfunctions are reported
but many are not reported. A few failures can
be directly attributed to space weather; many more failures are suspected to have a space weather
component; and many failures are unrelated to space weather. . One indicator that space weather is
a significant driver of spacecraft failure is that 46 of the 70 failures reported in 2003 occurred
during the October 2003 geomagnetic storm. The two most common adverse space weather
effects on spacecraft are radiation damage and spacecraft charging. Radiation (high energy particles)
passes through the skin of the spacecraft and into the electronic components. In most cases the
radiation causes an erroneous signal or changes one bit in memory of a spacecraft's electronics
(single event upset
Single event upset
A single event upset is a change of state caused by ions or electro-magnetic radiation striking a sensitive node in a micro-electronic device, such as in a microprocessor, semiconductor memory, or power transistors. The state change is a result of the free charge created by ionization in or close...

s). In a few cases, the radiation destroys a section of the electronics
(single event latchup
Latchup
Latchup is a term used in the realm of integrated circuits to describe a particular type of short circuit which can occur in an improperly designed circuit...

). Spacecraft charging is the accumulation of an
electrostatic charge on a non-conducting material on the spacecraft's surface by low energy
particles. If enough charge is built-up, a discharge (spark) occurs. Damage to the spacecraft is
done by causing an erroneous signal to be detected and acted on by the spacecraft computer as if
the signal came from the ground controller or the electronics are damaged by a surge of electrical
current. A recent study indicates that spacecraft charging is the predominant space weather effect on spacecraft in geosynchronous orbit
Geosynchronous orbit
A geosynchronous orbit is an orbit around the Earth with an orbital period that matches the Earth's sidereal rotation period...

.

Spacecraft orbit changes


The orbits of spacecraft in low Earth orbit (LEO) decay to lower and lower altitudes due to the
resistance from the friction between the spacecraft's surface (i.e. , drag) and the outer layer of
the Earth's atmosphere (a.k.a. the thermosphere
Thermosphere
The thermosphere is the biggest of all the layers of the Earth's atmosphere directly above the mesosphere and directly below the exosphere. Within this layer, ultraviolet radiation causes ionization. The International Space Station has a stable orbit within the middle of the thermosphere, between...

 and exosphere
Exosphere
The exosphere is the uppermost layer of Earth's atmosphere. In the exosphere, an upward travelling molecule moving fast enough to attain escape velocity can escape to space with a low chance of collisions; if it is moving below escape velocity it will be prevented from escaping from the celestial...

). Eventually, a spacecraft's
orbit will decay so much that it will fall out of orbit and crash to the Earth's surface. Many
spacecraft launched in the past couple of decades have the ability to fire a small rocket (1) to
increase the altitude to compensate for the decay and extend the lifetime in space, (2) to re-enter
the atmosphere and crash into the ocean, or (3) change the orbit to avoid collision with other
spacecraft. In order to accomplish the goal of firing a small rocket, very precise information
about the orbit is needed. A
geomagnetic storm
Geomagnetic storm
A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in the interplanetary medium. A geomagnetic storm is a major component of space weather and provides the input for many other components of space weather...

 can cause an orbit change over a couple of days that otherwise would
occur over a year or more. The geomagnetic storm
Geomagnetic storm
A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in the interplanetary medium. A geomagnetic storm is a major component of space weather and provides the input for many other components of space weather...

 adds heat to the thermosphere. The
atmosphere rises, the atmospheric density where LEO spacecraft orbit increases and drag increases.
The collision of the
Iridium 33 and Cosmos 2251 in February 2010 has demonstrated the importance of having
precise knowledge of all objects in orbit. If a credible collision prediction had been available,
Iridium 33 had the capability to maneuver out of the path of Cosmos 2251.

Effect of radiation on humans in space


The exposure of a human body to ionizing radiation has the same
harmful effects whether the source of the radiation is a medical X-
ray machine, a nuclear power plant or radiation in space. The degree of the harmful effect
depends on the length of exposure and the energy density of the radiation. The ever-present
radiation belts extend down to the altitude of manned spacecraft such as the
International Space Station (ISS) and the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...


but the amount of exposure is
within the lifetime exposure limit under normal conditions. During a major space weather event
which includes a burst of solar energetic particles
Solar Energetic Particles
Solar Energetic Particles are high-energy particles coming from the Sun which had been first observed in the early 1940s. They consist of protons, electrons and heavy ions with energy ranging from a few tens of keV to GeV...

, the flux can increase by one to several
orders of magnitude. There are areas within ISS where the thickness of the spacecraft surface
and equipment can provide extra shielding and may keep the total dose absorbed within lifetime
safe limits. For the Shuttle,
such an event requires an immediate termination of the mission.

Disruption of GPS and other spacecraft signals


The ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...

 bends radio waves in the same manner that water in a swimming pool bends
visible light. When the medium through which the light or radio waves travel
is disturbed, the light image or radio
information is distorted and can become unrecognizable. The degree of distortion (scintillation) of a radio
wave by the ionosphere depends on the frequency of the radio signal. Radio signals in the
VHF
Very high frequency
Very high frequency is the radio frequency range from 30 MHz to 300 MHz. Frequencies immediately below VHF are denoted High frequency , and the next higher frequencies are known as Ultra high frequency...

 band (30 to 300 MHz) can be distorted beyond recognition by a
disturbed ionosphere. Radio signals in the UHF
Ultra high frequency
Ultra-High Frequency designates the ITU Radio frequency range of electromagnetic waves between 300 MHz and 3 GHz , also known as the decimetre band or decimetre wave as the wavelengths range from one to ten decimetres...

 band (300 MHz to 3
GHz) will propagate through a disturbed ionosphere but a receiver may not be able to keep
locked to the carrier frequency. The Global Positioning System
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

 uses signals at 1575.42 MHz
(L1) and 1227.6 MHz (L2) which can be distorted by a disturbed ionosphere and a receiver computes
an erroneous position or fails to compute any position. Because the GPS
signals are used by wide range of applications, any space weather event which makes GPS signal
unreliable, the impact on society can be significant.
For example the Wide Area Augmentation System
Wide Area Augmentation System
The Wide Area Augmentation System is an air navigation aid developed by the Federal Aviation Administration to augment the Global Positioning System , with the goal of improving its accuracy, integrity, and availability...

 (WAAS) operated by
the Federal Aviation Administration
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...

 is used as a precision navigation tool for commercial
aviation in North America. It is disabled by every major space weather event. In some cases WAAS
is disabled for minutes and in a few cases it has been disabled for a few days. Major space
weather events can push the disturbed polar ionosphere 10o to 30o of latitude toward the
equator and can cause large ionospheric gradients (changes in density over distance of 100's of
km) at mid and low latitude. Both of these factors can distort GPS signals.

Disruption of long-distance radio signals


Radio wave in the HF
High frequency
High frequency radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters . Frequencies immediately below HF are denoted Medium-frequency , and the next higher frequencies are known as Very high frequency...

 band (3 to 30 MHz) (also known as the shortwave
Shortwave
Shortwave radio refers to the upper MF and all of the HF portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m which marked the original upper limit of the medium frequency band first used...


band) are bent so much by the ionosphere that they are reflected back in the same manner as a
mirror reflects light. Since the ground also reflects HF wave, a signal can be transmitted around
the curvature of the Earth to a distant station. During the 20th century, HF communications was
the only method for a ship or aircraft far from land or a base station to communicate. With the
advent of systems such as Iridium
Iridium satellite constellation
The Iridium satellite constellation is a large group of satellites providing voice and data coverage to satellite phones, pagers and integrated transceivers over Earth's entire surface. Iridium Communications Inc...

, there are now other methods
of communications but HF is still considered to be critical because not all vessels carry the newer
equipment and even if the newer equipment is onboard, HF is considered a critical backup
system. Space weather events can create irregularities in the ionosphere that scatter HF signals
instead of reflecting them and make HF communications over long distance poor or
impossible. At auroral and polar latitudes, small space weather events which occur frequently
disrupt HF communications. At mid-latitudes, HF communications are disrupted by solar radio bursts,
by X-rays from solar flares (which enhance and disturb the ionospheric D-layer) and
by TEC
Total electron content
Total electron content is an important descriptive quantity for the ionosphere of the Earth. TEC is the total number of electrons present along a path between two points, with units of electrons per square meter, where 1016 electrons/m² = 1 TEC unit .TEC is significant in determining the...

 enhancements and irregularities during major geomagnetic storms
which are infrequent.

Transpolar route
Polar route
A polar route refers to an aircraft route across the uninhabited polar ice cap region. The American Federal Aviation Administration defines the North Polar area of operations as the area lying north of 78 deg north latitude , which is entirely north of Alaska and most of Siberia...

s flown by airplanes are particularly sensitive to space weather, in part
because of Federal Aviation Regulations
Federal Aviation Regulations
The Federal Aviation Regulations, or FARs, are rules prescribed by the Federal Aviation Administration governing all aviation activities in the United States. The FARs are part of Title 14 of the Code of Federal Regulations...

 requiring reliable communication over the entire flight.
It is estimated to cost about $100,000 each time such a flight is diverted from a polar route.

Effect of radiation on humans at and near ground level


The Earth's magnetic field guides cosmic ray and solar energetic particles
Solar Energetic Particles
Solar Energetic Particles are high-energy particles coming from the Sun which had been first observed in the early 1940s. They consist of protons, electrons and heavy ions with energy ranging from a few tens of keV to GeV...

 to polar latitudes and radiation
particles enter the mesosphere and stratosphere. Cosmic rays at the top of the atmosphere shatter atmospheric atoms
and create lower energy, but still harmful, radiation particles which penetrate deep into the
atmosphere. All aircraft flying above 10 km (33,000 feet) altitude are exposed to a noticeable amount
of radiation. The
exposure is greater in polar regions than at mid-latitude and equatorial regions. Many commercial aircraft
from Europe and North America to East Asia fly over the polar region. When a space weather event causes
radiation exposure to exceed the safe level set by aviation authorities,
the aircraft's flight path is deviated to avoid the polar region.

Ground Induced Current: electrical transmission, pipelines, etc


A well known ground-level consequence of space weather is geomagnetically induced current
Geomagnetically induced current
Geomagnetically induced currents , 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...

, or ground
induced current or GIC. GIC flows through the ground to depths
of 20 km or more during geomagnetic storms. A well-known example of the adverse effect of a
GIC event is the collapse of the Hydro-Québec
Hydro-Québec
Hydro-Québec is a government-owned public utility established in 1944 by the Government of Quebec. Based in Montreal, the company is in charge of the generation, transmission and distribution of electricity across Quebec....


power network on March 13, 1989. This was
started by a failure of an overloaded transformer
Transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...

, which led to a general
blackout
Power outage
A power outage is a short- or long-term loss of the electric power to an area.There are many causes of power failures in an electricity network...

, which lasted more than 9 hours and affected 6 million people. The
geomagnetic storm
Geomagnetic storm
A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in the interplanetary medium. A geomagnetic storm is a major component of space weather and provides the input for many other components of space weather...

 causing this event was itself the result of a Coronal Mass Ejection
Coronal mass ejection
A coronal mass ejection is a massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space....

,
ejected from the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 on March 9, 1989.
A large geomagnetic storm can effect electric power grids at all latitudes,
A storm as large as the 1859 event could disable the entire electric power grid in Eastern Canada and
Eastern United States. GICs enter power grids, pipelines and other conducting networks
through grounding wires. Pipelines and other activities at high latitudes are affected by GIC driven by modest
levels of auroral activity which occur almost daily. GICs associated with space weather can affect other
systems such as geophysical mapping and hydrocarbon production.

Geophysical exploration


Air and ship borne magnetic surveys
Aeromagnetic survey
An aeromagnetic survey is a common type of geophysical survey carried out using a magnetometer aboard or towed behind an aircraft. The principle is similar to a magnetic survey carried out with a hand-held magnetometer, but allows much larger areas of the Earth's surface to be covered quickly for...

 can be affected by rapid magnetic
field variations during geomagnetic storms. Geomagnetic storms cause data interpretation problems because
the space-weather-related magnetic field changes are similar in magnitude to those of the
sub-surface crustal magnetic field in the survey area. Accurate geomagnetic storm warnings,
including an assessment of the magnitude and duration of the storm, allows for an economic use
of survey equipment.

Geophysics and hydrocarbon production


For economic and other reasons, oil and gas production often involves the directional drilling
Directional drilling
Directional drilling is the practice of drilling non-vertical wells. It can be broken down into three main groups: Oilfield Directional Drilling, Utility Installation Directional Drilling Directional drilling (or slant drilling) is the practice of drilling non-vertical wells. It can be broken down...


of well paths many kilometers from a single wellhead in both the horizontal and vertical
directions. Accuracy requirements are strict, due to target size – reservoirs may only be a few
tens to hundreds of meters across – and for safety reasons, because of the proximity of other
boreholes. Surveying by the most accurate gyroscopic method is expensive, since it can involve
the cessation of drilling for a number of hours. An alternative is to use a magnetic survey, which
enables measurement while drilling (MWD). Near real
time magnetic data can be used to correct the drilling direction and nearby magnetic
observatories prove vital. Magnetic data and space
weather forecasts can also be helpful in clarifying unknown sources of drilling error on an on-going basis.

Effect of space weather on terrestrial weather


The amount of energy entering the troposphere and stratosphere from all space weather
phenomena is trivial compared to the solar insolation
Insolation
Insolation is a measure of solar radiation energy received on a given surface area in a given time. It is commonly expressed as average irradiance in watts per square meter or kilowatt-hours per square meter per day...

 in the visible and infra-red portions of
the solar electromagnetic spectrum. However there does seem to be some linkage between the 11
year sunspot cycle and the Earth's climate
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...

. For example, the
Maunder minimum
Maunder Minimum
The Maunder Minimum is the name used for the period roughly spanning 1645 to 1715 when sunspots became exceedingly rare, as noted by solar observers of the time....

, a 70 year period almost devoid of sunspots, correlates to a cooling of the
Earth's climate. One suggestion for the linkage between space and terrestrial weather is that changes in
cosmic ray
Cosmic ray
Cosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...

 flux cause changes in the amount of cloud formation. Another suggestion is that variations in the EUV flux subtlety influence existing drivers of
the climate and tips the balance between states such as the El Niño/La Niña states. However, a linkage
between space weather and the climate has not been demonstrated conclusively.

Observations of space weather


The observation of space weather is done both for scientific research and for applications. The
type of observation done for science has varied over the years as the frontiers of our
understanding has increased and due to competition for resources from other types of
space-related research. The observations related to applications have been more systematic and has
expanded over the years as awareness and applications have increased.

Observing space weather from the ground


Presently, space weather is monitored at ground level by observing changes in the Earth's
magnetic field over periods of seconds to days, by observing the surface of the Sun and by
observing radio noise created in the Sun's atmosphere.

The Sunspot Number
Wolf number
The Wolf number is a quantity that measures the number of sunspots and groups of sunspots present on the surface of the sun....

 (SSN) is the number of sunspot
Sunspot
Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection by an effect comparable to the eddy current brake, forming areas of reduced surface temperature....

s on the Sun's
photosphere in visible light on the side of the Sun visible to an Earth observer. The number and
total area of sunspots are related to the brightness of
the Sun in the extreme ultraviolet
Extreme ultraviolet
Extreme Ultraviolet radiation is high-energy ultraviolet radiation, generally defined to be electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths from 120 nm down to 10 nm, and therefore having photons with energies from 10 eV up to 124 eV...

 (EUV) and X-ray portions of the solar spectrum
Sunlight
Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...


and to solar activity such as solar flare
Solar flare
A solar flare is a sudden brightening observed over the Sun surface or the solar limb, which is interpreted as a large energy release of up to 6 × 1025 joules of energy . The flare ejects clouds of electrons, ions, and atoms through the corona into space. These clouds typically reach Earth a day...

s and coronal mass ejection
Coronal mass ejection
A coronal mass ejection is a massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space....

s (CMEs).

10.7 cm radio flux (F10.7) is a measurement of RF emissions from the Sun and
is approximately correlated with the solar EUV flux. Since this RF emission is easily obtained
from the ground and EUV flux is not, this value has been measured and disseminated
continuously since 1947. The world standard measurements are made by the
Dominion Radio Astrophysical Observatory
Dominion Radio Astrophysical Observatory
The Dominion Radio Astrophysical Observatory is a research facility founded in 1960 and located south-west of Okanagan Falls, British Columbia, Canada. The site houses three instruments – an interferometric radio telescope, a 26-m single-dish antenna, and a solar flux monitor – and...

 at Penticton, B.C., Canada and reported once a
day at local noon in solar flux units (10-22W·m-2·Hz-1). F10.7
is archived by the National Geophysical Data Center.

Dst index is an estimate of the magnetic field change at the Earth's magnetic equator due to a
ring of electrical current at and just earthward of GEO. The index is based on data from four ground-based
magnetic observatories between 21o and 33o magnetic latitude during a
one hour period. Stations closer to the magnetic equator are not used due to ionospheric effects.
The Dst index is compiled and archived by the World Data Center for Geomagnetism, Kyoto

Kp/ap
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...

 Index: 'a' is an index created from the geomagnetic disturbance at one mid-
latitude (40o to 50o latitude) geomagnetic observatory during a 3 hour
period. 'K' is the quasi-logarithmic counter-part of the 'a' index. Kp and ap are the average of K
and a over 13 geomagnetic observatories to represent planetary-wide geomagnetic disturbances.
The Kp/ap index indicates both
geomagnetic storm
Geomagnetic storm
A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in the interplanetary medium. A geomagnetic storm is a major component of space weather and provides the input for many other components of space weather...

s and substorm
Substorm
A substorm, sometimes referred to as a magnetospheric substorm or an auroral substorm, is a brief disturbance in the Earth's magnetosphere that causes energy to be released from the "tail" of the magnetosphere and injected into the high latitude ionosphere. Visually, a substorm is seen as a sudden...

s (auroral disturbance). Kp/ap is available from 1932
onward.

AE index is compiled from geomagnetic disturbances at 12 geomagnetic observatories in and
near the auroral zones and is recorded at 1 minute intervals. The AE index is made public with a delay of two to three days, which severely limits its
utility for space weather applications. The AE index indicates the intensity of geomagnetic
substorm
Substorm
A substorm, sometimes referred to as a magnetospheric substorm or an auroral substorm, is a brief disturbance in the Earth's magnetosphere that causes energy to be released from the "tail" of the magnetosphere and injected into the high latitude ionosphere. Visually, a substorm is seen as a sudden...

s except during a major geomagnetic storm
Geomagnetic storm
A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in the interplanetary medium. A geomagnetic storm is a major component of space weather and provides the input for many other components of space weather...

 when the auroral zones expand
equatorward from the observatories.

Radio noise burst are observed and reported by the Radio Solar Telescope Network to the U.S.
Air Force and to NOAA. The radio bursts are associated with plasma from a solar flare
interacting with the ambient solar atmosphere.

The Sun's photosphere is observed continuously by a series of
observatories
for activity which can be the precursors to solar flares and CMEs. . The Global Oscillation
Network Group (GONG)
project monitors both the surface and the interior of the Sun by using helioseismology, the
study of sound waves propagating through the Sun and observed as ripples on the solar surface.
GONG can detect sunspot groups on the far side of the Sun. This ability has recently been
verified by visual observations from the NASA STEREO spacecraft.

Neutron Monitor
Neutron monitor
A neutron monitor is a ground-based detector designed to measure the number of high-energy charged particles striking the Earth's atmosphere from outer space. For historical reasons the incoming particles are called "cosmic rays", but in fact they are particles, predominantly protons and Helium...

s on the ground indirectly monitor cosmic rays from the Sun and galactic
sources. Cosmic rays do not reach the Earth's surface due to the shielding of the Earth's
magnetic field and atmosphere. When cosmic rays interact with the atmosphere, atomic
interactions occur which cause a shower of lower energy particles to descend deeper into the
atmosphere and to ground level. The presence of cosmic rays in the near-Earth space environment
can be detected by monitoring high energy neutrons at ground level. Small fluxes of cosmic rays
are present continuously. Large fluxes are produced by the Sun during events related to energetic
solar flares.

Total Electron Content
Total electron content
Total electron content is an important descriptive quantity for the ionosphere of the Earth. TEC is the total number of electrons present along a path between two points, with units of electrons per square meter, where 1016 electrons/m² = 1 TEC unit .TEC is significant in determining the...

 (TEC) is a measure of the ionosphere over a given location. TEC is the number
of electrons in a column one meter square from the base of the ionosphere (approximately 90 km altitude)
to the top of the ionosphere (approximately 1000 km altitude). Many of the measurements of TEC are
made by monitoring the two frequencies transmitted by GPS
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

 spacecraft.
Presently GPS TEC is monitored and distributed in real time from more than 360 stations maintained by
numerous agencies in many countries.

Observing space weather with satellites


After Explorer I
Explorer I
Explorer 1 was the first Earth satellite of the United States, launched as part of its participation in the International Geophysical Year...

 discovered that space was not a void, many research spacecraft have been launched to
discover and characterize the space environment. There have been too many spacecraft since then to
list them all here and they have carried a wide variety of instruments. The spacecraft
of the Orbiting Geophysical Observatory
Orbiting Geophysical Observatory
Orbiting Geophysical Observatory refers to the six satellites launched by the United States that were in use from September 1964 to 1972, designed to study the Earth's magnetosphere. The satellites successfully studied the interactions between the Earth and the Sun, despite a number of technical...

 series were among the first spacecraft with the mission of
discovering the space environment. Significant recent spacecraft are the NASA-ESA Solar-Terrestrial Relations
Observatory (STEREO
STEREO
STEREO is a solar observation mission. Two nearly identical spacecraft were launched into orbits that cause them to respectively pull farther ahead of and fall gradually behind the Earth...

) pair of spacecraft launch in 2006 into solar orbit and
Radiation Belt Storm Probes
Radiation Belt Storm Probes
The Radiation Belt Storm Probes is a NASA mission under the Living With a Star program. The goal of the LWS program is to develop the scientific understanding necessary to effectively address those aspects of the connected Sun-Earth system that directly affect life and society...

 (RBSP) to be launch in 2012 into a highly elliptical Earth-orbit. The two
STEREO
STEREO
STEREO is a solar observation mission. Two nearly identical spacecraft were launched into orbits that cause them to respectively pull farther ahead of and fall gradually behind the Earth...

 spacecraft drift away from the earth by about 22o per year, one leading and
the other trailing the earth in its orbit. Together they compile information about the Sun's surface
and atmosphere in three dimensions. RBSP will obtain detailed information about the radiation
belts, geomagnetic storms and the relationship between the two.

The mission of most spacecraft is unrelated to gathering information about the space environment
for research or applications, but some of these other spacecraft have carried auxiliary instrument
or had some part of their primary payload used for space weather. Some of the earliest such
spacecraft were part of the Applications Technology Satellite
(ATS) series at GEO which were precursors to the modern
Geostationary Operational Environmental Satellite
Geostationary Operational Environmental Satellite
The Geostationary Satellite system, operated by the United States National Environmental Satellite, Data, and Information Service , supports weather forecasting, severe storm tracking, and meteorology research. Spacecraft and ground-based elements of the system work together to provide a continuous...

 (GOES) weather satellite and many
communication satellites. The ATS spacecraft carried environmental particle sensors as auxiliary
payloads and had their navigational magnetic field sensor used for sensing the environment.

Many of the earliest instruments used for monitoring the space environment were and are research
spacecraft which were re-purposed or jointly purposed for space weather applications and forecasting.
One of the first of these is the IMP-8 (Interplanetary Monitoring Platform) The IMP-8
orbited the Earth at 35 Earth Radii and observed the solar wind for two-thirds of its 12-day orbit
from 1973 to 2006. Since the solar wind carries disturbances which affect the magnetosphere
and ionosphere, IMP-8 demonstrated the utility of continuously monitoring the solar wind. IMP-
8 was followed by
ISEE-3
International Cometary Explorer
The International Cometary Explorer spacecraft was originally known as International Sun/Earth Explorer 3 satellite, launched August 12, 1978. It was part of the ISEE international cooperative program between NASA and ESRO/ESA to study the interaction between the Earth's magnetic field and the...

 which was placed near the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

-Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...


Lagrangian point
Lagrangian point
The Lagrangian points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects...

, 235 Earth radii above the surface (about 1.5 million km, or 924,000 miles)
and continuously monitored the solar wind from 1978 to 1982. The next spacecraft to monitor
the solar wind at the point was WIND from 1994 to 1998. After
April 1998, the WIND spacecraft orbit was change to circle the Earth and pass by the
point occasionally. The NASA Advanced Composition Explorer
Advanced Composition Explorer
Advanced Composition Explorer is a NASA space exploration mission being conducted as part of the Explorer program to study matter in situ, comprising energetic particles from the solar wind, the interplanetary medium, and other sources. Real-time data from ACE is used by the Space Weather...

 (ACE) has monitored the
solar wind at the point from 1997 to present. It is estimated to cease operating about
2024. Funding for a replacement for ACE is in the 2012
budget request for NOAA with a planned launch in 2015. The replacement's primary mission
will be space weather forecasting and applications.

In addition to monitoring the solar wind, monitoring the Sun is important to space weather.
Because the solar EUV cannot be monitored from the ground, the joint
NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

-ESA Solar and Heliospheric Observatory
Solar and Heliospheric Observatory
The Solar and Heliospheric Observatory is a spacecraft built by a European industrial consortium led by Matra Marconi Space that was launched on a Lockheed Martin Atlas IIAS launch vehicle on December 2, 1995 to study the Sun, and has discovered over 2100 comets. It began normal operations in May...

 (SOHO) spacecraft was launched and has provide EUV
images of the Sun from 1995 to the present. SOHO is a main source of near-real time solar data
for both research and space weather prediction and inspired the STEREO
STEREO
STEREO is a solar observation mission. Two nearly identical spacecraft were launched into orbits that cause them to respectively pull farther ahead of and fall gradually behind the Earth...

 mission. The
Yohkoh
Yohkoh
Yohkoh , known before launch as Solar-A, was a Solar observatory spacecraft of the Institute of Space and Astronautical Science with United States and United Kingdom collaboration...

 spacecraft at LEO observed the Sun from 1991 to 2001 in the X-ray portion of the solar
spectrum and was useful for both research and space weather prediction. Data from
Yohkoh inspired the Solar X-ray Imager
Solar X-ray Imager
-Operation:The Solar X-ray Imager aboard the GOES 12, GOES 13, GOES 14, and GOES 15 United States NOAA weather satellites is used for early detection of solar flares, coronal mass ejections, and space phenomena that impact human spaceflight and military and commercial satellite communications...

 on GOES.

Spacecraft with instruments whose primary purpose is to provide data for space weather
predictions and applications include the
GOES
Geostationary Operational Environmental Satellite
The Geostationary Satellite system, operated by the United States National Environmental Satellite, Data, and Information Service , supports weather forecasting, severe storm tracking, and meteorology research. Spacecraft and ground-based elements of the system work together to provide a continuous...

 series of spacecraft, the
POES
Polar Operational Environmental Satellites
The Polar Operational Environmental Satellite project operates a constellation of weather satellites in polar orbits around the Earth. It is a joint effort between the National Oceanic and Atmospheric Administration and the European Organisation for the Exploitation of Meteorological Satellites...

 series, the
DMSP
Defense Meteorological Satellite Program
The Defense Meteorological Satellite Program monitors meteorological, oceanographic, and solar-terrestrial physics for the United States Department of Defense. The program is now run by the National Oceanic and Atmospheric Administration. The mission of the satellites was revealed in March 1973...

 series, and the Meteosat
Meteosat
The Meteosat series of satellites are geostationary meteorological satellites operated by EUMETSAT under the Meteosat Transition Programme and the Meteosat Second Generation program....

 series. The
GOES spacecraft have carried a X-Ray Sensor (XRS) which measures the flux from the whole
solar disk in two bands - 0.05 to 0.4 nm and 0.1 to 0.8 nm since 1974, a X-ray imager (SXI) since
2004, a magnetometer which measures the distortions of the Earth’s magnetic field due to space
weather, a whole disk EUV
Extreme ultraviolet
Extreme Ultraviolet radiation is high-energy ultraviolet radiation, generally defined to be electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths from 120 nm down to 10 nm, and therefore having photons with energies from 10 eV up to 124 eV...

 sensor since 2004, and particle sensors
(EPS/HEPAD) which measure ions and electrons in the energy range of (50 keV to 500 MeV).
Starting sometime after 2015, the GOES-R generation of GOES
Goes
Goes is a municipality and a city in the southwestern Netherlands in Zuid-Beveland, in the province Zeeland. The city of Goes has approximately 27,000 residents.-History of Goes:...

 spacecraft will replace the SXI
with a solar EUV image (SUVI) similar to the one on SOHO
Soho
Soho is an area of the City of Westminster and part of the West End of London. Long established as an entertainment district, for much of the 20th century Soho had a reputation for sex shops as well as night life and film industry. Since the early 1980s, the area has undergone considerable...

 and STEREO
STEREO
STEREO is a solar observation mission. Two nearly identical spacecraft were launched into orbits that cause them to respectively pull farther ahead of and fall gradually behind the Earth...

 and the
particle sensor will be augmented with a component to extend the energy range down to 30 eV.

Space weather modeling


Space weather models are computer simulations of the space weather environment. Like
computer models for meteorology, space weather models take a limited set of data values and
extrapolate to values which describe the entire space weather environment or a segment of the
space weather environment in the model. Each model makes a prediction or a set of predictions about
how the environment evolves with time. Computer models use the sets of mathematical equations
to describe the physical processes involved. The
early space weather models were heuristic; i.e., they relate one phenomenon with another
without including any physics in the relationship. Some of these simple models are still used
because they take minimal resources and yield results which are good enough for some purposes.
Present research and development efforts concentrate on complex sets of equations which
account for as many elements of physics as possible. Space weather models differ from
meteorological model in that amount of input is vastly smaller and no single space weather model yet
can reliably predict the environment from the surface of the Sun to the bottom
of the Earth's ionosphere.

A significant portion of space weather model research and development in the past two decades
has been done as part of the Geospace Environmental Model (GEM)
program of the National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...

. Two major centers for modeling are the Center
for Space Environment Modeling (CSEM) and the Center for Integrated Space weather Modeling
(CISM).
The Community Coordinated Modeling Center (CCMC) at the NASA Goddard Space Flight Center is a
facility for coordinating the development and testing of research models, for the improvement of
models and for preparing models for transition to space weather prediction and application.

Modeling efforts to simulate the environment from the Sun to the Earth use several method including
(a) magnetohydrodynamics
Magnetohydrodynamics
Magnetohydrodynamics is an academic discipline which studies the dynamics of electrically conducting fluids. Examples of such fluids include plasmas, liquid metals, and salt water or electrolytes...

 in which the environment is treated as a fluid, (b) particle in cell in
which non-fluid interactions are handled within a cell and then a series of cells are connected
together to describe the environment, (c) first principles in which physical processes are in balance
(or equilibrium) with one another, (d) semi-static modeling in which a statistical or empirical
relationship is described, or a combination of several of these methods.

Examples of space weather events


  • September 2, 1859, largest geomagnetic storm of last 200 years with widespread disruption of telegraph service.
  • January 20, 1994, a geomagnetic storm
    Geomagnetic storm
    A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in the interplanetary medium. A geomagnetic storm is a major component of space weather and provides the input for many other components of space weather...

     temporarily disabled two Canadian communication satellites, Anik
    Anik (satellite)
    The Anik satellites are geostationary communications satellites launched by Telesat Canada for television in Canada. In Inuktitut, Anik means "little brother".-The Satellites:-Anik A:...

    s E1 and E2 and the international communication satellite Intelsat
    Intelsat
    Intelsat, Ltd. is a communications satellite services provider.Originally formed as International Telecommunications Satellite Organization , it was—from 1964 to 2001—an intergovernmental consortium owning and managing a constellation of communications satellites providing international broadcast...

     K.
  • January 7, 1997, a Coronal Mass Ejection
    Coronal mass ejection
    A coronal mass ejection is a massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space....

     hit the Earth's magnetosphere
    Magnetosphere
    A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...

     on January 10 and caused the loss of the AT&T
    AT&T
    AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

     Telstar 401
    Telstar 401
    Telstar 401 was a communications satellite owned by AT&T which was launched in 1993 to replace Telstar 301. It was destroyed by a magnetic storm in 1997....

     communication satellite (a $200 million value).
  • May 15-16, 1921, one of the largest geomagnetic storms caused the entire signal and switching system of the New York Central Railroad below 125th street in New York City to be put out of operation. Worldwide disruption of telegraph service.
  • August 7, 1972, a large Solar Energetic Particles
    Solar Energetic Particles
    Solar Energetic Particles are high-energy particles coming from the Sun which had been first observed in the early 1940s. They consist of protons, electrons and heavy ions with energy ranging from a few tens of keV to GeV...

     events occurred. If astronauts had been in space at the time, the dose would have been deadly or at least life-threatening. Fortunately, this large event happened between the Apollo 16
    Apollo 16
    Young and Duke served as the backup crew for Apollo 13; Mattingly was slated to be the Apollo 13 command module pilot until being pulled from the mission due to his exposure to rubella through Duke.-Backup crew:...

     and Apollo 17
    Apollo 17
    Apollo 17 was the eleventh and final manned mission in the American Apollo space program. Launched at 12:33 a.m. EST on December 7, 1972, with a three-member crew consisting of Commander Eugene Cernan, Command Module Pilot Ronald Evans, and Lunar Module Pilot Harrison Schmitt, Apollo 17 remains the...

     lunar missions.
  • April 21, 2002, the Nozomi Mars Probe was hit by a large Solar Energetic Particles
    Solar Energetic Particles
    Solar Energetic Particles are high-energy particles coming from the Sun which had been first observed in the early 1940s. They consist of protons, electrons and heavy ions with energy ranging from a few tens of keV to GeV...

     event which caused large-scale failure. The mission, which was already about 3 years behind schedule, was eventually abandoned in December 2003.

See also


  • Atmospheric physics
    Atmospheric physics
    Atmospheric physics is the application of physics to the study of the atmosphere. Atmospheric physicists attempt to model Earth's atmosphere and the atmospheres of the other planets using fluid flow equations, chemical models, radiation balancing, and energy transfer processes in the atmosphere...

  • Condegram spiral plot
    Condegram spiral plot
    The Condegram spiral plot is an illustrative device developed by , Associate Professor at the University of Alaska, Fairbanks to display space weather data. Space weather effects on Earth are ultimately driven by processes originating with the Sun, many of which are communicated to Earth by the...

  • Geomagnetic storm
    Geomagnetic storm
    A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere caused by a disturbance in the interplanetary medium. A geomagnetic storm is a major component of space weather and provides the input for many other components of space weather...

  • Heliophysics
    Heliophysics
    Heliophysics is a word coined by Dr. George Siscoe of Boston University and subsequently used by the NASA Science Mission Directorate to encompass the study of the system composed of the Sun's heliosphere and the objects that interact with it—most notably, but not limited to, planetary atmospheres...

  • Meteorology
    Meteorology
    Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...

  • Plasma physics
  • Radio propagation
    Radio propagation
    Radio propagation is the behavior of radio waves when they are transmitted, or propagated from one point on the Earth to another, or into various parts of the atmosphere...

  • Receiver Autonomous Integrity Monitoring
  • Space exploration
    Space exploration
    Space exploration is the use of space technology to explore outer space. Physical exploration of space is conducted both by human spaceflights and by robotic spacecraft....

  • Sudden ionospheric disturbance
    Sudden Ionospheric Disturbance
    A sudden ionospheric disturbance is an abnormally high ionization/plasma density in the D region of the ionosphere caused by a solar flare...

  • Solar energetic particles
    Solar Energetic Particles
    Solar Energetic Particles are high-energy particles coming from the Sun which had been first observed in the early 1940s. They consist of protons, electrons and heavy ions with energy ranging from a few tens of keV to GeV...

  • Space radiation

Further reading

  • Clark, T. D. G. and E. Clarke, 2001. Space weather services for the offshore drilling industry. In Space Weather Workshop: Looking Towards a Future European Space Weather Programme. ESTEC, ESA WPP-194.
  • Carlowicz, M. J., and R. E. Lopez, 2002, Storms from the Sun, Joseph Henry Press, Washington DC, ISBN 0309076420.
  • Reay, S. J., W. Allen, O. Baillie, J. Bowe, E. Clarke, V. Lesur, S. Macmillan, 2005. Space weather effects on drilling accuracy in the North Sea. Annales Geophysicae, Vol. 23, pp 3081–3088.
  • Odenwald, S. 2006, The 23rd Cycle;Learning to live with a stormy star, Columbia University Press, ISBN 0231120788.
  • Bothmer, V.; Daglis, I., 2006, Space Weather: Physics and Effects, Springer-Verlag New York, ISBN 364206289X.
  • Gombosi, Tamas I., Houghton, John T., and Dessler, Alexander J., (Editors), 2006, Physics of the Space Environment, Cambridge University Press, ISBN 9780521607681.
  • Daglis, I. A. (Editor), 2001, Space Storms and Space Weather Hazards, Springer-Verlag New York, ISBN 1402000316.
  • Song, P., Singer, H., and Siscoe, G., (Editors), 2001, Space Weather (Geophysical Monograph), Union, Washington, D.C, ISBN 0875909841.
  • Freeman, John W., 2001, Storms in Space, Cambridge University Press, Cambridge, UK, ISBN 0521660386.

Real-time space weather forecast


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