|
Solar Eclipse Of January 26, 1990
An annular solar eclipse occurred on January 26, 1990. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon's apparent diameter The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is ... is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like an annulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide. Related eclipses Eclipses of 1990 * An annular solar eclipse on January 26. * A total lunar eclipse on February 9. * A total solar eclipse on July 22. * A partial lunar eclipse on August 6. Solar eclipses of 1990–1992 Saros 121 Meton ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annulus (mathematics)
In mathematics, an annulus (plural annuli or annuluses) is the region between two concentric circles. Informally, it is shaped like a ring or a hardware washer. The word "annulus" is borrowed from the Latin word ''anulus'' or ''annulus'' meaning 'little ring'. The adjectival form is annular (as in annular eclipse). The open annulus is topologically equivalent to both the open cylinder and the punctured plane. Area The area of an annulus is the difference in the areas of the larger circle of radius and the smaller one of radius : :A = \pi R^2 - \pi r^2 = \pi\left(R^2 - r^2\right). The area of an annulus is determined by the length of the longest line segment within the annulus, which is the chord tangent to the inner circle, in the accompanying diagram. That can be shown using the Pythagorean theorem since this line is tangent to the smaller circle and perpendicular to its radius at that point, so and are sides of a right-angled triangle with hypotenuse , and the ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Eclipse
A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of the Earth, totally or partially. Such an alignment occurs during an eclipse season, approximately every six months, during the new moon phase, when the Moon's orbital plane is closest to the plane of the Earth's orbit. In a total eclipse, the disk of the Sun is fully obscured by the Moon. In partial and annular eclipses, only part of the Sun is obscured. Unlike a lunar eclipse, which may be viewed from anywhere on the night side of Earth, a solar eclipse can only be viewed from a relatively small area of the world. As such, although total solar eclipses occur somewhere on Earth every 18 months on average, they recur at any given place only once every 360 to 410 years. If the Moon were in a perfectly circular orbit and in the same orbital plane as Earth, there would be total solar eclipses once a month, at every new moon. Instead, because the Moon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of Australia). The Moon is a planetary-mass object with a differentiated rocky body, making it a satellite planet under the geophysical definitions of the term and larger than all known dwarf planets of the Solar System. It lacks any significant atmosphere, hydrosphere, or magnetic field. Its surface gravity is about one-sixth of Earth's at , with Jupiter's moon Io being the only satellite in the Solar System known to have a higher surface gravity and density. The Moon orbits Earth at an average distance of , or about 30 times Earth's diameter. Its gravitational influence is the main driver of Earth's tides and very slowly lengthens Earth's day. The Moon's orbit around Earth has a sidereal period of 27.3 days. During each synodic period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More solar e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Diameter
The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is the angular aperture (of a lens). The angular diameter can alternatively be thought of as the angular displacement through which an eye or camera must rotate to look from one side of an apparent circle to the opposite side. Humans can resolve with their naked eyes diameters of up to about 1 arcminute (approximately 0.017° or 0.0003 radians). This corresponds to 0.3 m at a 1 km distance, or to perceiving Venus as a disk under optimal conditions. Formula The angular diameter of a circle whose plane is perpendicular to the displacement vector between the point of view and the center of said circle can be calculated using the formula :\delta = 2\arctan \left(\frac\right), in which \delta is the angular diameter, and d is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
February 1990 Lunar Eclipse
A total lunar eclipse took place on Friday, February 9, 1990, the first of two lunar eclipses in 1990. Visibility It was visible from all of Africa, Europe, Asia and Australia. The eclipse is sighted over the Philippines since the one that happened on February 20, 1989. Related eclipses Eclipses of 1990 * An annular solar eclipse on January 26. * A total lunar eclipse on February 9. * A total solar eclipse on July 22. * A partial lunar eclipse on August 6. Lunar year series Lunar Saros 133 This lunar eclipse is part of series 133 of the Saros cycle, which repeats every 18 years and 11 days. Series 133 runs from the year 1557 until 2819. The previous eclipse of this series occurred on January 30, 1972 and the next will occur on February 21, 2008. It is the 5th of 21 total lunar eclipses in series 133. The first was on December 28, 1917. The last (21st) will be on August 3, 2278. The longest two occurrences of this series (14th and 15th) will last for a total of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Eclipse Of July 22, 1990
A total solar eclipse occurred on July 22, 1990. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon's apparent diameter is larger than the Sun's, blocking all direct sunlight, turning day into darkness. Totality occurs in a narrow path across Earth's surface, with the partial solar eclipse visible over a surrounding region thousands of kilometres wide. Totality was visible in southern Finland, the Soviet Union (including today's northern Estonia and northern Russia), and eastern Andreanof Islands and Amukta of Alaska. In Finland the solar eclipse occurred during sunrise and enabled observation and photography without protective glasses, which was however hampered by strong clouds. The Sun was totally eclipsed in Helsinki Helsinki ( or ; ; sv, Helsingfors, ) is the Capital city, capital, primate city, primate, and List of cities and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
August 1990 Lunar Eclipse
A partial lunar eclipse took place on Monday, August 6, 1990, the second of two lunar eclipses in 1990. Visibility Relations to other lunar eclipses Eclipses of 1990 * An annular solar eclipse on January 26. * A total lunar eclipse on February 9. * A total solar eclipse on July 22. * A partial lunar eclipse on August 6. Lunar year series Saros series Half-Saros cycle A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, ''The half-saros'' This lunar eclipse is related to two total solar eclipses of Solar Saros 145 Saros cycle series 145 for solar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of the Earth, totally or partially. Such an alignment occurs during an .... See also * List of lunar eclipses * List of 20th-century lunar eclipses Notes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annular Solar Eclipses
Annulus (or anulus) or annular indicates a ring- or donut-shaped area or structure. It may refer to: Human anatomy * ''Anulus fibrosus disci intervertebralis'', spinal structure * Annulus of Zinn, a.k.a. annular tendon or ''anulus tendineus communis'', around the optic nerve * Annular ligament (other) * ''Digitus anularis'', a.k.a. ring finger * ''Anulus ciliaris'', a.k.a. ciliary body * ''Anulus femoralis'', a.k.a. femoral ring * ''Anulus inguinalis superficialis'', a.k.a. superficial inguinal ring * ''Anulus inguinalis profundus'', a.k.a. deep inguinal ring * ''Anuli fibrosi cordis'', a.k.a. fibrous rings of heart * ''Anulus umbilicalis '', a.k.a. umbilical ring Other * Annulus (construction), outer gear ring in an epicyclic gearing * Annulus (botany), structure on fern and moss sporangia * Annular lake, a ring-shaped lake caused by meteor impact * Annulus (mathematics), the shape between two concentric circles * Annulus (mycology), structure on mushroom * Annulus ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1990 In Science
The year 1990 in science and technology involved some significant events. Astronomy and space exploration * January 24 – Japan launches the Hiten spacecraft, the first lunar probe launched by a country other than the Soviet Union or the United States. * February 14 – The '' Pale Blue Dot'' photograph of Earth is sent back from the '' Voyager 1'' probe after completing its primary mission, from around 3.5 billion miles away. * April 24 – The Space Shuttle ''Discovery'' places the Hubble Space Telescope into orbit. * August 16 – Steven Balbus makes his first discovery leading to elucidation of magnetorotational instability. * October 13 – Earth-grazing meteoroid of 13 October 1990: A 44 kilogram, 41.5 km/s meteoroid passes above Czechoslovakia and Poland at 97.9 km. It is the first time calculations of the orbit of such a body based on photographic records from two distant places is made. Biology * The term " rewilding" is first used in print. Computer sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
January 1990 Events
January is the first month of the year in the Julian and Gregorian calendars and is also the first of seven months to have a length of 31 days. The first day of the month is known as New Year's Day. It is, on average, the coldest month of the year within most of the Northern Hemisphere (where it is the second month of winter) and the warmest month of the year within most of the Southern Hemisphere (where it is the second month of summer). In the Southern hemisphere, January is the seasonal equivalent of July in the Northern hemisphere and vice versa. Ancient Roman observances during this month include Cervula and Juvenalia, celebrated January 1, as well as one of three Agonalia, celebrated January 9, and Carmentalia, celebrated January 11. These dates do not correspond to the modern Gregorian calendar. History January (in Latin, '' Ianuarius'') is named after Janus, the god of beginnings and transitions in Roman mythology. Traditionally, the original Roman calendar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> Moon")
.svg "Click for more on -> Earth")
