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Space Weather
Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the varying conditions within the Solar System and its heliosphere. This includes the effects of the solar wind, especially on the Earth's magnetosphere, ionosphere, thermosphere, and exosphere. Though physically distinct, space weather is analogous to the terrestrial weather of Earth's atmosphere of Earth, atmosphere (troposphere and stratosphere). The term "space weather" was first used in the 1950s and popularized in the 1990s. Later, it prompted research into "space climate", the large-scale and long-term patterns of space weather. History For many centuries, the effects of space weather were noticed, but not understood. Displays of aurora (astronomy), auroral light have long been observed at high latitudes. Beginnings In 1724, George Graham (clockmaker), George Graham reported that the needle of a magnetic compass was regularly deflected from magnetic north over the course of each day. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Weather Effects
Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as ''spacetime''. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework. In the 19th and 20th centuries mathematicians began to examine geometries that are non-Euclidean, in which space is conceived as '' curved'', rather than '' flat'', as in the Euclidean space. According to Albert Einstein's theory of general relativity, space around gravitational fields deviates from Euclidean space. Experimental tests of general relativity have confirmed that non-Euclidean geometries provide a better model f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Compass
A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with magnetic north. Other methods may be used, including gyroscopes, magnetometers, and GPS receivers. Compasses often show angles in degrees: north corresponds to 0°, and the angles increase clockwise, so east is 90°, south is 180°, and west is 270°. These numbers allow the compass to show azimuths or bearings which are commonly stated in degrees. If local variation between magnetic north and true north is known, then direction of magnetic north also gives direction of true north. Among the Four Great Inventions, the magnetic compass was first invented as a device for divination as early as the history of science and technology in China, Chinese Han dynasty (since c. 206 BC),#Li, Li Shu-hua, p. 176 and later adopted for navigation by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellites
A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. Many communications satellites are in geostationary orbit above the equator, so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form satellite constellations in low Earth orbit, where antennas on the ground have to follow the position of the satellites and switch between satellites frequently. The radio waves used for telecommunications links travel by line of sight and so are obstructed by the curve of the Earth. The purpose of communications satellites is to re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Jamming
Radar jamming and deception is a form of electronic countermeasures (ECMs) that intentionally sends out radio frequency signals to interfere with the operation of radar by saturating its receiver with noise or false information. Concepts that blanket the radar with signals so its display cannot be read are normally known as jamming, while systems that produce confusing or contradictory signals are known as deception, but it is also common for all such systems to be referred to as jamming. There are two general classes of radar jamming, mechanical and electronic. Mechanical jamming entails reflecting enemy radio signals in various ways to provide false or misleading target signals to the radar operator. Electronic jamming works by transmitting additional radio signals towards enemy receivers, making it difficult to detect real target signals, or take advantage of known behaviors of automated systems like radar lock-on to confuse the system. Various Electronic counter-countermeasur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kristian Birkeland
Kristian Olaf Bernhard Birkeland (born 13 December 1867 – 15 June 1917) was a Norway, Norwegian space physics, space physicist, inventor, and professor of physics at the University of Oslo, Royal Fredriks University in Oslo. He is best remembered for his theories of atmospheric electric currents that elucidated the nature of the aurora borealis. In order to fund his research on the aurorae, he invented the Coilgun, electromagnetic cannon and the Birkeland–Eyde process of nitrogen fixation process, fixing nitrogen from the air. Birkeland was nominated for the Nobel Prize seven times. Life and death Birkeland was born in Christiania (Oslo today) to Reinart Birkeland and Ingeborg (née Ege) and wrote his first scientific paper at the age of 18. Birkeland married Ida Charlotte Hammer in May 1905. They had no children and, due to Birkeland's preoccupation with his work, they divorced in 1911. Suffering from severe paranoia due to his use of barbital as a sleeping aid, he died und ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Flare
A solar flare is a relatively intense, localized emission of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and other eruptive solar phenomena. The occurrence of solar flares varies with the 11-year solar cycle. Solar flares are thought to occur when stored magnetic energy in the Sun's atmosphere accelerates charged particles in the surrounding plasma. This results in the emission of electromagnetic radiation across the electromagnetic spectrum. The typical time profile of these emissions features three identifiable phases: a ''precursor phase'', an ''impulsive phase'' when particle acceleration dominates, and a ''gradual phase'' in which hot plasma injected into the corona by the flare cools by a combination of radiation and conduction of energy back down to the lower atmosphere. The extreme ultraviolet and X-ray radiation from solar flares is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Christopher Carrington
Richard Christopher Carrington (26 May 1826 – 27 November 1875) was an English astronomer whose 1859 astronomical observations demonstrated the existence of solar flares as well as suggesting their electrical influence upon the Earth and its aurorae; and whose 1863 records of sunspot observations revealed the differential rotation of the Sun. Life Carrington was born at Chelsea, the second son of Richard Carrington, the proprietor of a large brewery at Brentford, and his wife Esther Clarke Aplin. He entered Trinity College, Cambridge, in 1844; but, though destined for the church, rather by his father's than by his own desire, his scientific tendencies gradually prevailed, and received a final impulse towards practical astronomy from Professor Challis's lectures on the subject. This change in the purpose of his life was unopposed, and he had the prospect of ample means; so that it was purely with the object of gaining experience that he applied, shortly after taking his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telegraph
Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas pigeon post is not. Ancient signalling systems, although sometimes quite extensive and sophisticated as in China, were generally not capable of transmitting arbitrary text messages. Possible messages were fixed and predetermined, so such systems are thus not true telegraphs. The earliest true telegraph put into widespread use was the Chappe telegraph, an optical telegraph invented by Claude Chappe in the late 18th century. The system was used extensively in France, and European nations occupied by France, during the Napoleonic era. The electric telegraph started to replace the optical telegraph in the mid-19th century. It was first taken up in Britain in the form of the Cooke and Wheatstone telegraph, initially used mostly as an aid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Storm Of 1859
The Carrington Event was the most intense geomagnetic storm in recorded history, peaking on 1–2 September 1859 during solar cycle 10. It created strong auroral displays that were reported globally and caused sparking and even fires in telegraph stations. The geomagnetic storm was most likely the result of a coronal mass ejection (CME) from the Sun colliding with Earth's magnetosphere. The geomagnetic storm was associated with a very bright solar flare on 1 September 1859. It was observed and recorded independently by British astronomers Richard Carrington and Richard Hodgson—the first records of a solar flare. A geomagnetic storm of this magnitude occurring today has the potential to cause widespread electrical disruptions, blackouts, and damage to the electrical power grid. History Geomagnetic storm On 1 and 2 September 1859, one of the largest geomagnetic storms (as recorded by ground-based magnetometers) occurred. Estimates of the storm strength ( Dst) range f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sunspots
Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are one of the most recognizable Solar phenomena and despite the fact that they are mostly visible in the solar photosphere they usually affect the entire solar atmosphere. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. Sunspots appear within active regions, usually in pairs of opposite magnetic polarity. Their number varies according to the approximately 11-year solar cycle. Individual sunspots or groups of sunspots may last anywhere from a few days to a few months, but eventually decay. Sunspots expand and contract as they move across the surface of the Sun, with diameters ranging from to . Larger sunspots can be visible from Earth without the aid of a telescope. They may travel at relative speeds, or proper motions, of a few hundred meters per second when they first emerge. Indicating intense magnetic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geomagnetic Storm
A geomagnetic storm, also known as a magnetic storm, is a temporary disturbance of the Earth's magnetosphere that is driven by interactions between the magnetosphere and large-scale transient Plasma (physics), plasma and magnetic field structures that originate on or near the Sun. The structures that produce geomagnetic storms include interplanetary coronal mass ejections (CME) and corotating interaction regions (CIR). The former often originate from solar active regions, while the latter originate at the boundary between high- and low-speed streams of solar wind. The frequency of geomagnetic storms increases and decreases with the sunspot cycle. During solar maximum, solar maxima, geomagnetic storms occur more often, with the majority driven by CMEs. When these structures reach Earth, 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 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward Sabine
Sir Edward Sabine (; 14 October 1788 – 26 June 1883) was an Irish physicist, geodesist,astronomer, geophysicist, ornithologist, polar explorer, soldier, and the 30th president of the Royal Society. He led the effort to establish a system of magnetic observatories in various parts of British territory all over the globe. Much of his life was devoted to their direction and to analysing their observations. Other research focused on the birds of Greenland, ocean temperatures, the Gulf Stream, barometric measurement of heights, arc of the meridian, glacial transport of rocks, the volcanoes of the Hawaiian Islands and various points of meteorology. Early life Edward Sabine was born 14 October 1788 in Great Britain St. (Parnell St.), Dublin. His Father, Joseph Sabine, was a member of a prominent Anglo-Irish family who was visiting his Irish relatives at the time of his son's birth. The family connections with Ireland can be traced back to the 17th century. His mother, Sara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
