|
E. W. Maunder
Edward Walter Maunder (12 April 1851 – 21 March 1928) was a British astronomer. His study of sunspots and the solar magnetic cycle led to his identification of the period from 1645 to 1715 that is now known as the Maunder Minimum. Early and personal life Maunder was born in 1851, in London, the youngest child of a minister of the Wesleyan Society. He attended King's College London but never graduated. He took a job in a London bank to finance his studies. In 1873 Maunder returned to the Royal Observatory, taking a position as a spectroscopic assistant. Shortly after, in 1875, he married Edith Hannah Bustin, who gave birth to six children: four sons (one of whom died in infancy) and two daughters. Following the death of Edith in 1888, in 1890 he met Annie Scott Dill Russell (later Annie Russell Maunder), a mathematician and astronomer educated at Girton College in Cambridge, with whom he collaborated for the remainder of his life. She worked as a " lady computer" at the Obse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Astronomy
The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies. It is by far the most important source of energy for life on Earth. The Sun has been an object of veneration in many cultures. It has been a central subject for astronomical research since antiquity. The Sun orbits the Galactic Center at a distance of 24,000 to 28,000 light-years. Its distance from Earth defines the astronomical unit, which is about or about 8 light-minutes. Its diameter is about (), 109 times that of Earth. The Sun's mass is about 330,000 times that of Earth, making up about 99.86% of the total mass of the Solar System. The mass of outer layer of the Sun's atmosphere, its ''photosphere'', consists mostly of hydrogen (~73%) and helium (~25%), with much smaller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliographic Latitude
In solar observation and imaging, coordinate systems are used to identify and communicate locations on and around the Sun. The Sun is made of plasma, so there are no permanent demarcated points that can be referenced. Background The Sun is a rotating sphere of plasma at the center of the Solar System. It lacks a solid or liquid surface, so the interface separating its interior and its exterior is usually defined as the boundary where plasma becomes opaque to visible light, the photosphere. Since plasma is gaseous in nature, this surface has no permanent demarcated points that can be used for reference. Furthermore, its rate of rotation varies with latitude, rotating faster at the equator than at the poles. Cardinal directions In observations of the solar disk, cardinal directions are typically defined so that the Sun's northern and southern hemispheres point toward Earth's northern and southern celestial poles, respectively, and the Sun's eastern and western hemispheres point ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
English Heritage
English Heritage (officially the English Heritage Trust) is a charity that manages over 400 historic monuments, buildings and places. These include prehistoric sites, a battlefield, medieval castles, Roman forts, historic industrial sites, Listed building, listed ruins, and architecturally notable English country houses. The charity states that it uses these properties to "bring the story of England to life for over 10 million people each year". Within its portfolio are Stonehenge, Dover Castle, Tintagel Castle, and the "best-preserved" parts of Hadrian's Wall. English Heritage also manages the London blue plaque scheme, which links influential historical figures to particular buildings. When originally formed in 1983, English Heritage was the operating name of an executive non-departmental public body of the Her Majesty's Government, British Government, officially titled the Historic Buildings and Monuments Commission for England, that ran the national system of heritage prot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Astronomical Association
The British Astronomical Association (BAA) was formed in 1890 as a national body to support the UK's amateur astronomers. Throughout its history, the BAA has encouraged observers to make scientifically valuable observations, often in collaboration with professional colleagues. Among the BAA's first presidents was Walter Maunder, discoverer of the seventeenth century dearth in sunspots now known as the Maunder Minimum which he achieved by analysing historical observations. Later, this spirit of observing the night sky scientifically was championed by George Alcock, who discovered five comets and five novae using nothing more than a pair of binoculars. The BAA continues to contribute to the science of astronomy, even despite modern competition from space-based telescopes and highly automated professional observatories. Modern digital sensors, coupled with techniques such as lucky imaging, mean that even modest amateur equipment can rival what professional observatories could h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maunder (lunar Crater)
Maunder is a lunar impact crater that is located on the far side of the Moon, just beyond the western limb. This region is sometimes brought into view during favorable librations, but not much detail can be seen. The crater lies at the northern end of the Mare Orientale, within the ring of mountains named Montes Rook, and it is the largest crater on this lunar mare. To the southeast is the crater Kopff, and due south is the small Hohmann. The rim of Maunder is roughly circular, with a sharp edge that has not been significantly eroded. The inner walls are somewhat terraced, and slump down to a rough but level interior floor. At the midpoint of the crater is a double central peak, with the northeastern peak being the larger of the two. Surrounding the crater is a rough outer rampart that mixes with the rugged terrain along the northern half of the rim. Secondary impacts are visible in the surface to the south. Maunder is a crater of Eratosthenian age. Name origin The crater was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact Crater
An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters are typically circular, though they can be elliptical in shape or even irregular due to events such as landslides. Impact craters range in size from microscopic craters seen on lunar rocks returned by the Apollo Program to simple bowl-shaped depressions and vast, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth. Impact craters are the dominant geographic features on many solid Solar System objects including the Moon, Mercury (planet), Mercury, Callisto (moon), Callisto, Ganymede (moon), Ganymede, and most small moons and asteroids. On other planet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Illusion
In visual perception, an optical illusion (also called a visual illusion) is an illusion caused by the visual system and characterized by a visual perception, percept that arguably appears to differ from reality. Illusions come in a wide variety; their categorization is difficult because the underlying cause is often not clear but a classification proposed by Richard Gregory is useful as an orientation. According to that, there are three main classes: physical, physiological, and cognitive illusions, and in each class there are four kinds: Ambiguities, distortions, paradoxes, and fictions. A classical example for a physical distortion would be the apparent bending of a stick half immersed in water; an example for a physiological paradox is the motion aftereffect (where, despite movement, position remains unchanged). An example for a physiological fiction is an afterimage. Three typical cognitive distortions are the Ponzo illusion, Ponzo, Poggendorff illusion, Poggendorff, and MÃ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martian Canals
During the late 19th and early 20th centuries, it was erroneously believed that there were "canals" on the planet Mars. These were a network of long straight lines in the equatorial regions from 60° north to 60° south latitude on Mars, observed by astronomers using early telescopes without photography. They were first described by the Italian astronomer Giovanni Schiaparelli during the opposition of 1877, and attested to by later observers. Schiaparelli called these ''canali'' (" channels"), which was mis-translated into English as "canals". The Irish astronomer Charles E. Burton made some of the earliest drawings of straight-line features on Mars, although his drawings did not match Schiaparelli's. Around the turn of the century there was even speculation that they were engineering works, irrigation canals constructed by a civilization of intelligent aliens indigenous to Mars. By the early 20th century, improved astronomical observations revealed that, with the possible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmospheric pressure is a few thousandths of Earth's, atmospheric temperature ranges from and cosmic radiation is high. Mars retains some water, in the ground as well as thinly in the atmosphere, forming cirrus clouds, frost, larger polar regions of permafrost and ice caps (with seasonal snow), but no liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. It is half as wide as Earth or twice the Moon, with a diameter of , and has a surface area the size of all the dry land of Earth. Fine dust is prevalent across the surface and the atmosphere, being picked up and spread at the low Martian gravity even by the weak wind of the tenuous atmosphere. The terrain of Mars roughly follows a north-south ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Tangent Arc
Tangent arcs are a type of Halo (optical phenomenon), halo, an atmospheric optical phenomenon, which appears above and below the observed Sun or Moon, tangent to the 22° halo. To produce these arcs, rod-shaped hexagonal ice crystals need to have their long axis aligned horizontally. Description Upper arc The shape of an upper tangent arc varies with the elevation of the Sun; while the Sun is low (less than 29–32°) it appears as an arc over the observed Sun forming a sharp angle. As the Sun is seen to rise above the Earth's horizon, the curved wings of the arc lower towards the 22° halo while gradually becoming longer. As the Sun rises over 29–32°, the upper tangent arc unites with the lower tangent arc to form the circumscribed halo. Lower arc The lower tangent arc is rarely observable, appearing under and tangent to a 22° halo centred on the Sun. Just like upper tangent arcs, the shape of a lower arc is dependent on the altitude of the Sun. As the Sun is o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noctilucent Cloud
Noctilucent clouds (NLCs), or night shining clouds, are tenuous cloud-like phenomena in the upper atmosphere of Earth. When viewed from space, they are called polar mesospheric clouds (PMCs), detectable as a diffuse scattering layer of water ice crystals near the summer polar mesopause. They consist of ice crystals and from the ground are only visible during astronomical twilight. ''Noctilucent'' roughly means "night shining" in Latin. They are most often observed during the summer months from latitudes between ±50° and ±70°. Too faint to be seen in daylight, they are visible only when the observer and the lower layers of the atmosphere are in Earth's shadow, but while these very high clouds are still in sunlight. Recent studies suggest that increased atmospheric methane emissions produce additional water vapor through chemical reactions once the methane molecules reach the mesosphere – creating, or reinforcing existing, noctilucent clouds. General No confirmed recor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
