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Eclipse
An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three celestial objects is known as a syzygy. Apart from syzygy, the term eclipse is also used when a spacecraft reaches a position where it can observe two celestial bodies so aligned. An eclipse is the result of either an occultation (completely hidden) or a transit (partially hidden). The term eclipse is most often used to describe either a solar eclipse, when the Moon's shadow crosses the Earth's surface, or a lunar eclipse, when the Moon moves into the Earth's shadow. However, it can also refer to such events beyond the Earth–Moon system: for example, a planet moving into the shadow cast by one of its moons, a moon passing into the shadow cast by its host planet, or a moon passing into the shadow of another moon. A binary star system can ... [...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] |
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] |
Eclipse Vs New Or Full Moons, Annotated
An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three celestial objects is known as a syzygy. Apart from syzygy, the term eclipse is also used when a spacecraft reaches a position where it can observe two celestial bodies so aligned. An eclipse is the result of either an occultation (completely hidden) or a transit (partially hidden). The term eclipse is most often used to describe either a solar eclipse, when the Moon's shadow crosses the Earth's surface, or a lunar eclipse, when the Moon moves into the Earth's shadow. However, it can also refer to such events beyond the Earth–Moon system: for example, a planet moving into the shadow cast by one of its moons, a moon passing into the shadow cast by its host planet, or a moon passing into the shadow of another moon. A binary star system can a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Eclipse
A lunar eclipse occurs when the Moon moves into the Earth's shadow. Such alignment occurs during an eclipse season, approximately every six months, during the full moon phase, when the Moon's orbital plane is closest to the plane of the Earth's orbit. This can occur only when the Sun, Earth, and Moon are exactly or very closely aligned (in syzygy) with Earth between the other two, which can happen only on the night of a full moon when the Moon is near either lunar node. The type and length of a lunar eclipse depend on the Moon's proximity to the lunar node. When the moon is totally eclipsed by the Earth, it takes on a reddish color that is caused by the planet when it completely blocks direct sunlight from reaching the Moon surface, as only the light reflected from the lunar surface has been refracted by Earth's atmosphere. This light appears reddish due to the Rayleigh scattering of blue light, the same reason sunrise and sunsets are more orange than during the day. Un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eclipse Cycle
Eclipses may occur repeatedly, separated by certain intervals of time: these intervals are called eclipse cycles. The series of eclipses separated by a repeat of one of these intervals is called an eclipse series. Eclipse conditions Eclipses may occur when Earth and the Moon are aligned with the Sun, and the shadow of one body projected by the Sun falls on the other. So at new moon, when the Moon is in conjunction with the Sun, the Moon may pass in front of the Sun as viewed from a narrow region on the surface of Earth and cause a solar eclipse. At full moon, when the Moon is in opposition to the Sun, the Moon may pass through the shadow of Earth, and a lunar eclipse is visible from the night half of Earth. The conjunction and opposition of the Moon together have a special name: syzygy (Greek for "junction"), because of the importance of these lunar phases. An eclipse does not occur at every new or full moon, because the plane of the Moon's orbit around Earth is tilted with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eclipse Season
An eclipse season is the period, roughly every six months, when eclipses occur. Eclipse seasons are the result of the axial parallelism of the Moon's tilted orbital plane ( tilted five degrees to the Earth's orbital plane), just as Earth's weather seasons are the result of the axial parallelism of Earth's tilted axis as it orbits around the Sun. During the season, the "lunar nodes" – the line where the Moon's orbital plane intersects with the Earth's orbital plane – aligns with the Sun and Earth, such that a solar eclipse is formed during the new moon phase and a lunar eclipse is formed during the full moon phase. Only two (or occasionally three) eclipse seasons occur during each year, and each season lasts about 35 days and repeats just short of six months later, thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. During the eclipse season, the Moon is at a low ecliptic latitude (less than around 1.5° north or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saros (astronomy)
The saros () is a period of exactly 223 synodic months, approximately 6585.3211 days, or 18 years, 10, 11, or 12 days (depending on the number of leap years), and 8 hours, that can be used to predict eclipses of the Sun and Moon. One saros period after an eclipse, the Sun, Earth, and Moon return to approximately the same relative geometry, a near straight line, and a nearly identical eclipse will occur, in what is referred to as an eclipse cycle. A sar is one half of a saros. A series of eclipses that are separated by one saros is called a ''saros series''. It corresponds to: *6,585.321347 solar days *18.029 years *223 synodic months *241.999 draconic months *18.999 eclipse years (38 eclipse seasons) *238.992 anomalistic months The 19 eclipse years means that if there is a solar eclipse (or lunar eclipse), then after one saros a new moon will take place at the same node of the orbit of the Moon, and under these circumstances another eclipse can occur. History The earliest disco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umbra01
The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object. Assuming no diffraction, for a collimated beam (such as a point source) of light, only the umbra is cast. These names are most often used for the shadows cast by celestial bodies, though they are sometimes used to describe levels, such as in sunspots. Umbra The umbra (Latin for "shadow") is the innermost and darkest part of a shadow, where the light source is completely blocked by the occluding body. An observer within the umbra experiences a total eclipse. The umbra of a round body occluding a round light source forms a right circular cone. When viewed from the cone's apex, the two bodies appear the same size. The distance from the Moon to the apex of its umbra is roughly equal to that between the Moon and Earth: . Since Earth's diameter is 3.7 times the Moon's, its umbra extends correspondingly farther: roughly . Penumbra The penum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecliptic
The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic against the background of stars. The ecliptic is an important reference plane and is the basis of the ecliptic coordinate system. Sun's apparent motion The ecliptic is the apparent path of the Sun throughout the course of a year. Because Earth takes one year to orbit the Sun, the apparent position of the Sun takes one year to make a complete circuit of the ecliptic. With slightly more than 365 days in one year, the Sun moves a little less than 1° eastward every day. This small difference in the Sun's position against the stars causes any particular spot on Earth's surface to catch up with (and stand directly north or south of) the Sun about four minutes later each day than it would if Earth did not orbit; a day on Earth is therefore 24 hours ... [...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] |
Node (astronomy)
An orbital node is either of the two points where an orbit intersects a plane of reference to which it is inclined. A non-inclined orbit, which is contained in the reference plane, has no nodes. Planes of reference Common planes of reference include the following: * For a geocentric orbit, Earth's equatorial plane. In this case, non-inclined orbits are called ''equatorial''. * For a heliocentric orbit, the ecliptic or invariable plane. In this case, non-inclined orbits are called ''ecliptic''. * For an orbit outside the Solar System, the plane through the primary perpendicular to a line through the observer and the primary (called the ''plane of the sky''). Node distinction If a reference direction from one side of the plane of reference to the other is defined, the two nodes can be distinguished. For geocentric and heliocentric orbits, the ascending node (or north node) is where the orbiting object moves north through the plane of reference, and the descending node (or s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transit (astronomy)
In astronomy, a transit (or astronomical transit) is a phenomenon when a celestial body passes directly between a larger body and the observer. As viewed from a particular vantage point, the transiting body appears to move across the face of the larger body, covering a small portion of it. The word "transit" refers to cases where the nearer object appears smaller than the more distant object. Cases where the nearer object appears larger and completely hides the more distant object are known as ''occultations''. However, the probability of seeing a transiting planet is low because it is dependent on the alignment of the three objects in a nearly perfectly straight line. Many parameters of a planet and its parent star can be determined based on the transit. In the Solar System One example of a transit involves the motion of a planet between a terrestrial observer and the Sun. This can happen only with inferior planets, namely Mercury and Venus (see transit of Mercury and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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