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Hale's Law
In solar physics, Hale's law, also known as Hale's polarity law or the Hale–Nicholson law, describes the tendency for bipolar active regions within the same northern or southern hemisphere to have the same leading magnetic polarity with respect to the solar rotation, and for those in the opposite hemisphere to have the opposite leading polarity. It further describes how this pattern reverses from one sunspot cycle to the next. It is named after George Ellery Hale and Seth Barnes Nicholson. Hale's law, along with Joy's law (astronomy), Joy's law, provides observational evidence for the solar dynamo. History The solar magnetic field was first detected in 1909 by George Ellery Hale when he showed observationally that sunspots had strong, bipolar magnetic fields. With these observations, Hale also noted how the majority of sunspot groups within the same northern or southern hemisphere shared the same leading polarity and that this pattern reversed across the equator. As solar cycl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hale's Law Diagram
Hale's or Hale Bros., was a department store based in Sacramento with branches throughout the San Francisco Bay Area. In 1880 Prentis Cobb Hale and his two brothers opened the Criterion store in Downtown Sacramento, and in 1881 they renamed it Hale Brothers & Company. The company opened large branches in San Francisco (1892) and San Jose, California, San Jose (1896), Salinas, Stockton and Petaluma, and via an acquisition of Whitthorne & Swann in 1906, Oakland. The Sacramento store was last located at 825-831 K Street (Sacramento), K Street, with a storefront measuring some 123 feet on K and 160 feet on Ninth. The San Jose store was at the corner of 1st and San Carlos. The San Francisco store was first located at 989 Market Street, then moved to 901 Market at Fifth in a building designed by Reid & Reid. In 1949, Hale's bought their Sacramento rival, Weinstock's, Weinstock, Lubin & Co. In the same year, Hale's merged with Los Angeles-based Broadway Stores, Broadway Department Store ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Cycle 15
Solar cycle 15 was the fifteenth solar cycle since 1755, when extensive recording of solar sunspot activity began. The solar cycle lasted 10.1 years, beginning in July 1913 and ending in August 1923. The maximum smoothed sunspot number observed during the solar cycle was 175.7 (August 1917), and the starting minimum was 2.5.SIDC Monthly Smoothed Sunspot Number. During the minimum transit from solar cycle 15 to 16, there were a total of 534 days with no sunspots.Spotless Days.Solaemon's Spotless Days Page. History Geomagnetic storms in March 1918, August 1919, October 1919, and March 1920 affected telegraph lines, while a solar flare on 13 May 1921 also affected rail signal and switching equipment, in what was known as the "New York Railroad Storm." 1921 A May 1921 geomagnetic storm, major geomagnetic storm during 13–15 May 1921 caused damage in communication systems and aurora displays in much of the eastern United States. In Sweden, the event caused major disruptions to the te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Solar Cycles
Solar cycles are nearly periodic 11-year changes in the Sun's activity that are based on the number of sunspots present on the Sun's surface. The first solar cycle conventionally is said to start in 1755 when Rudolf Wolf began extensive reporting of sunspot activity. The source data are the revised International Sunspot Numbers (ISN v2.0), as available at SILSO. Sunspot counts exist since 1610 but the cycle numbering is not well defined during the Maunder minimum. It was proposed that one cycle might have been lost in the late 18th century, but this remains not fully confirmed. Solar cycles can be reconstructed indirectly, using the radiocarbon Carbon-14, C-14, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and coll ... 14C proxy, for the last millennium. The smoothing is done using the traditional SIDC smo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sunspot
Sunspots are phenomena on the Sun's photosphere that appear as temporary spots that are darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. 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 activity, sunspots accompany other active region phenomena such as coronal loops, prominences, and reconnection events. Most solar flares and coronal mas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnevyshev–Ohl Rule
The Gnevyshev–Ohl rule (GO) is an empirical rule according to which the sum of Wolf’s sunspot numbers over an odd cycle exceeds that of the preceding even cycle—see the Figure. The rule breaks down under certain conditions. In particular, it invertes the sign across the Dalton minimum The Dalton Minimum was a period of low sunspot count, representing low solar activity, named after the English meteorologist John Dalton, lasting from about 1790 to 1830 or 1796 to 1820, corresponding to the period solar cycle 4 to solar cycle ..., but can be restored with the "lost cycle" in the end of the 18th century. The nature of the GO rule is still unclear. References Solar phenomena {{sun-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spörer's Law
Spörer's law predicts the variation of sunspot latitudes during a solar cycle. It was discovered by the English astronomer Richard Christopher Carrington around 1861. Carrington's work was refined by the German astronomer Gustav Spörer. At the start of a sunspot cycle, sunspots tend to appear around 30° to 45° latitude on the Sun's surface. As the cycle progresses, sunspots appear at lower and lower latitudes, until they average 15° at solar maximum. The average latitude of sunspots then continues to drift lower, down to about 7° and then while the old sunspot cycle fades, sunspots of the new cycle start appearing at high latitudes. See also * Solar variation * Wolf number * Joy's law (astronomy) In astronomy, Joy's law describes the distribution of sunspots in active region An active region is a temporary region in the Sun's atmosphere characterized by a strong and complex magnetic field. They are often associated with sunspots and are ... References Solar pheno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Monopole
In particle physics, a magnetic monopole is a hypothetical elementary particle that is an isolated magnet with only one magnetic pole (a north pole without a south pole or vice versa). A magnetic monopole would have a net north or south "magnetic charge". Modern interest in the concept stems from particle theories, notably the grand unified and superstring theories, which predict their existence. The known elementary particles that have electric charge are electric monopoles. Magnetism in bar magnets and electromagnets is not caused by magnetic monopoles, and indeed, there is no known experimental or observational evidence that magnetic monopoles exist. Some condensed matter systems contain effective (non-isolated) magnetic monopole quasi-particles, or contain phenomena that are mathematically analogous to magnetic monopoles. Historical background Early science and classical physics Many early scientists attributed the magnetism of lodestones to two different "magnetic fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Magnetogram
In solar observation, a magnetogram is a pictorial representation of the spatial variations in strength of the solar magnetic field. Solar magnetograms are produced by solar magnetographs. Some magnetographs only measure the absolute value of the magnetic field strength while others are capable of measuring the 3-dimensional magnetic field. The latter are referred to as ''vector magnetographs''. The measurements are usually done based on the Zeeman effect. The first magnetograph was constructed by George Ellery Hale George Ellery Hale (June 29, 1868 – February 21, 1938) was an American solar astronomer, best known for his discovery of magnetic fields in sunspots, and as the leader or key figure in the planning or construction of several world-lea ... in 1908. References Magnetic devices {{Sun-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photospheric
The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will escape without being scattered. A photosphere is the deepest region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. Stars, except neutron stars, have no solid or liquid surface. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Composition of the Sun The Sun is composed primarily of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Cycle 25
Solar cycle 25 is the current solar cycle, the 25th since 1755, when extensive recording of solar sunspot activity began. It began in December 2019 with a minimum smoothed sunspot number of 1.8. It is expected to continue until about 2030. Predictions Widely varying predictions regarding the strength of cycle 25 ranged from very weak with suggestions of slow slide in to a Maunder minimum like state to a weak cycle similar to previous cycle 24 and even a strong cycle. Upton and Hathaway predicted that the weakness of cycle 25 would make it part of the Modern Gleissberg Minimum. The Solar Cycle 25 Prediction Panel predicted in December 2019 that solar cycle 25 will be similar to , with the preceding solar cycle minimum in April 2020 (± 6 months), and the number of sunspots reaching a (smoothed) maximum of 115 in July 2025 (± 8 months). This prediction is in line with the current general agreement in the scientific literature, which holds that solar cycle 25 will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Cycle 24
Solar cycle 24 is the most recently completed solar cycle, the 24th since 1755, when extensive recording of solar sunspot activity began.Kane, R.P. (2002).Some Implications Using the Group Sunspot Number Reconstruction. ''Solar Physics'' 205(2), 383-401. It began in December 2008 with a minimum smoothed sunspot number of 2.2, and ended in December 2019. Activity was minimal until early 2010. It reached its maximum in April 2014 with a 23 months smoothed sunspot number of 81.8. This maximum value was substantially lower than other recent solar cycles, down to a level which had not been seen since cycles Solar cycle 12, 12 to Solar cycle 15, 15 (1878-1923). Predictions Prior to the minimum between the end of Solar Cycle 23 and the beginning of Solar Cycle 24, two theories predicted how strong Solar Cycle 24 would be. One camp postulated that the Sun retained a long memory (Solar Cycle 24 would be active) while the other asserted that it had a short memory (quiet). Prior to 2006, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Cycle 14
Solar cycle 14 was the fourteenth solar cycle since 1755, when extensive recording of solar sunspot activity began. The solar cycle lasted 11.5 years, beginning in January 1902 and ending in July 1913. The maximum smoothed sunspot number observed during the solar cycle was 107.1, in February 1906 (the lowest since the Dalton Minimum), and the starting minimum was 4.5.SIDC Monthly Smoothed Sunspot Number. During the minimum transit from solar cycle 14 to 15, there were a total of 1023 days with no sunspots (the second highest recorded of any cycle to date).Spotless Days.Solaemon's Spotless Days Page. Geomagnetic storms in November 1903, March 1905, and September 1909 affected telegraph lines. See also *List of solar cycles Solar cycles are nearly periodic 11-year changes in the Sun's activity that are based on the number of sunspots present on the Sun's surface. The first solar cycle conventionally is said to start in 1755 when Rudolf Wolf began extensive reporting o ... Refere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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