A solar eclipse occurs when the Moon passes between the Sun and the Earth so that the Sun is wholly or partially obscured. The Sun (Sol is the Star at the center of the Solar System. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 This can only happen during a new moon, when the Sun and Moon are in conjunction as seen from the Earth. This article is about the lunar phase for other uses see New Moon (disambiguation. Conjunction is a term used in Positional astronomy and Astrology. Up to four solar eclipses occur each year, but total solar eclipses are nevertheless rare at any location because during each eclipse totality exists only in the relatively tiny area of the Moon's umbra. For other uses of the word "umbra" see Umbra (disambiguation.

A total solar eclipse is a spectacular natural phenomenon and many people travel to remote locations to observe one. A natural phenomenon is a non-artificial event in the physical sense and therefore not produced by Humans although it may affect humans (e The 1999 total eclipse in Europe helped to increase public awareness of the phenomenon, as illustrated by the number of journeys made specifically to witness the 2005 annular eclipse and the 2006 total eclipse. On August 11, 1999, a total eclipse of the Sun, with an eclipse magnitude of 1 The solar eclipse that took place on October 3, 2005 was an Annular eclipse of the Sun with a magnitude of 0 The solar eclipse that took place on March 29, 2006 was a total eclipse of the Sun that was visible from a narrow corridor which traversed half the The next solar eclipse will occur on August 1, 2008, and will be a total eclipse. The Solar eclipse of August 1, 2008 was a total eclipse of the Sun with a magnitude of 1

In ancient times, and in some cultures today, solar eclipses have been attributed to supernatural causes. Total solar eclipses can be frightening for people who are unaware of their astronomical explanation, as the Sun seems to disappear in the middle of the day and the sky darkens in a matter of minutes. Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study

Geometry of a Total Solar Eclipse (not to scale).

Photo of 1999 total eclipse. On August 11, 1999, a total eclipse of the Sun, with an eclipse magnitude of 1

Types

Annular eclipse.

There are four types of solar eclipses:

• A total eclipse occurs when the Sun is completely obscured by the Moon. The intensely bright disk of the Sun is replaced by the dark silhouette of the Moon, and the much fainter corona is visible. A corona is a type of plasma " atmosphere " of the Sun or other celestial body extending millions of Kilometres into space most easily During any one eclipse, totality is visible only from at most a narrow track on the surface of the Earth.
• An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or annulus, surrounding the outline of the Moon.
• A hybrid eclipse is intermediate between a total and annular eclipse. At some points on the surface of the Earth it is visible as a total eclipse, whereas at others it is annular. Hybrid eclipses are rather rare.
• A partial eclipse occurs when the Sun and Moon are not exactly in line, and the Moon only partially obscures the Sun. This phenomenon can usually be seen from a large part of the Earth outside of the track of an annular or total eclipse. However, some eclipses can only be seen as a partial eclipse, because the umbra never intersects the Earth's surface.

The match between the apparent sizes of the Sun and Moon during a total eclipse is a coincidence. Coincidence is the noteworthy alignment of two or more events or circumstances without obvious causal connection The Sun's distance from the Earth is about 400 times the Moon's distance, and the Sun's diameter is about 400 times the Moon's diameter. Geometry, a diameter of a Circle is any straight Line segment that passes through the center of the circle and whose Endpoints are on the Because these ratios are approximately the same, the sizes of the Sun and the Moon as seen from Earth appear to be approximately the same: about 0. 5 degree of arc in angular measure. This article describes the unit of angle For other meanings see Degree.

Because the Moon's orbit around the Earth is an ellipse, as is the Earth's orbit around the Sun, the apparent sizes of the Sun and Moon vary. In Mathematics, an ellipse (from the Greek ἔλλειψις literally absence) is a Conic section, the locus of points in a ^[1][2] The magnitude of an eclipse is the ratio of the apparent size of the Moon to the apparent size of the Sun during an eclipse. In a Solar eclipse, the magnitude of the eclipse is the ratio between the apparent Angular diameters of the Moon and that of the Sun during the An eclipse when the Moon is near its closest distance from the Earth (i. e. , near its perigee) can be a total eclipse because the Moon will appear to be large enough to cover completely the Sun's bright disk, or photosphere; a total eclipse has a magnitude greater than 1. Conversely, an eclipse when the Moon is near its farthest distance from the Earth (i. e. , near its apogee) can only be an annular eclipse because the Moon will appear to be slightly smaller than the Sun; the magnitude of an annular eclipse is less than 1. In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from Slightly more solar eclipses are annular than total because, on average, the Moon lies too far from Earth to cover the Sun completely. A hybrid eclipse occurs when the magnitude of an eclipse is very close to 1: the eclipse will appear to be total at some locations on Earth and annular at other locations. ^[3]

The Earth's orbit around the Sun is also elliptical, so the Earth's distance from the Sun varies throughout the year. This also affects the apparent sizes of the Sun and Moon, but not so much as the Moon's varying distance from the Earth. When the Earth approaches its farthest distance from the Sun (the aphelion) in July, this tends to favor a total eclipse. In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from As the Earth approaches its closest distance from the Sun (the perihelion) in January, this tends to favor an annular eclipse. In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from

Terminology

The Moon transiting in front of the Sun as seen from STEREO-B on February, 25 2007 at 4. STEREO (Solar TErrestrial RElations Observatory is a solar observation mission which was launched on 26 October 2006 at 0052 GMT. 4 times the distance between the Earth and the Moon. ^[4]

Central eclipse is often used as a generic term for a total, annular, or hybrid eclipse. This is, however, not completely correct: the definition of a central eclipse is an eclipse during which the central line of the umbra touches the Earth's surface. It is possible, though extremely rare, that part of the umbra intersects with Earth (thus creating an annular or total eclipse), but not its central line. This is then called a non-central total or annular eclipse. ^[5]

The term solar eclipse itself is strictly speaking a misnomer. The phenomenon of the Moon passing in front of the Sun is not an eclipse, but an occultation. In Shia Islam The Occultation is a term used to designate the hidden state of the Imam of the Time. Properly speaking, an eclipse occurs when one object passes into the shadow cast by another object. For example, when the Moon disappears at full moon by passing into Earth's shadow, the event is properly called a lunar eclipse. Full moon is a Lunar phase that occurs when the Moon is on the opposite side of the Earth from the Sun. A lunar eclipse occurs whenever the Moon passes through some portion of the Earth's shadow Therefore, technically, a solar eclipse actually amounts to an eclipse of the Earth.

Predictions

Geometry

Diagram of solar eclipse (not to scale).

The diagram to the right shows the alignment of the Sun, Moon and Earth during a solar eclipse. The dark gray region below the Moon is the umbra, where the Sun is completely obscured by the Moon. For other uses of the word "umbra" see Umbra (disambiguation. The small area where the umbra touches the Earth's surface is where a total eclipse can be seen. The larger light gray area is the penumbra, in which only a partial eclipse can be seen. For other uses of the word "umbra" see Umbra (disambiguation.

The Moon's orbit around the Earth is inclined at an angle of just over 5 degrees to the plane of the Earth's orbit around the Sun (the ecliptic). The orbit of the Moon around the Earth is completed in approximately 27 The ecliptic is the apparent path that the Sun traces out in the sky during the year Because of this, at the time of a new moon, the Moon will usually pass above or below the Sun. A solar eclipse can occur only when the new moon occurs close to one of the points (known as nodes) where the Moon's orbit crosses the ecliptic. An orbital node is one of the two points where an Orbit crosses a Plane of reference which it is inclined to

As noted above, the Moon's orbit is also elliptical. In Mathematics, an ellipse (from the Greek ἔλλειψις literally absence) is a Conic section, the locus of points in a The Moon's distance from the Earth can vary by about 6% from its average value. Therefore, the Moon's apparent size varies with its distance from the Earth, and it is this effect that leads to the difference between total and annular eclipses. The distance of the Earth from the Sun also varies during the year, but this is a smaller effect. On average, the Moon appears to be slightly smaller than the Sun, so the majority (about 60%) of central eclipses are annular. It is only when the Moon is closer to the Earth than average (near its perigee) that a total eclipse occurs. ^[6][7]

The Moon orbits the Earth in approximately 27. 3 days, relative to a fixed frame of reference. This is known as the sidereal month. The month is a unit of Time, used with Calendars which is approximately as long as some natural period related to the motion of the Moon; However, during one sidereal month, the Earth has revolved part way around the Sun, making the average time between one new moon and the next longer than the sidereal month: it is approximately 29. 5 days. This is known as the synodic month, and corresponds to what is commonly called the lunar month. The month is a unit of Time, used with Calendars which is approximately as long as some natural period related to the motion of the Moon; In Lunar calendars a lunar month is the time between two identical syzygies ( New moons or Full moons.

A Total eclipse in the umbra.
B Annular eclipse in the antumbra.
C Partial eclipse in the penumbra

The Moon crosses from south to north of the ecliptic at its ascending node, and vice versa at its descending node. An orbital node is one of the two points where an Orbit crosses a Plane of reference which it is inclined to However, the nodes of the Moon's orbit are gradually moving in a retrograde motion, due to the action of the Sun's gravity on the Moon's motion, and they make a complete circuit every 18. Direct motion is the motion of a Planetary body in a direction similar to that of other bodies within its system and is sometimes called prograde motion. 6 years. This means that the time between each passage of the Moon through the ascending node is slightly shorter than the sidereal month. This period is called the draconic month. The month is a unit of Time, used with Calendars which is approximately as long as some natural period related to the motion of the Moon;

Finally, the Moon's perigee is moving forwards in its orbit, and makes a complete circuit in about 9 years. The time between one perigee and the next is known as the anomalistic month. The month is a unit of Time, used with Calendars which is approximately as long as some natural period related to the motion of the Moon;

The Moon's orbit intersects with the ecliptic at the two nodes that are 180 degrees apart. Therefore, the new moon occurs close to the nodes at two periods of the year approximately six months apart, and there will always be at least one solar eclipse during these periods. Sometimes the new moon occurs close enough to a node during two consecutive months. This means that in any given year, there will always be at least two solar eclipses, and there can be as many as five. However, some are visible only as partial eclipses, because the umbra passes above Earth's north or south pole, and others are central only in remote regions of the Arctic or Antarctic. The Arctic is the Region around the Earth 's North Pole, opposite the Antarctic region around the South Pole. ^[8][9]

Path

During a central eclipse, the Moon's umbra (or antumbra, in the case of an annular eclipse) moves rapidly from west to east across the Earth. For other uses of the word "umbra" see Umbra (disambiguation. The Earth is also rotating from west to east, but the umbra always moves faster than any given point on the Earth's surface, so it almost always appears to move in a roughly west-east direction across a map of the Earth (there are some rare exceptions to this which can occur during an eclipse of the midnight sun in Arctic or Antarctic regions). The midnight sun is a phenomenon occurring in Latitudes north and nearby to the south of the Arctic Circle and south and nearby to the north of the

The width of the track of a central eclipse varies according to the relative apparent diameters of the Sun and Moon. In the most favourable circumstances, when a total eclipse occurs very close to perigee, the track can be over 250 km wide and the duration of totality may be over 7 minutes. Outside of the central track, a partial eclipse can usually be seen over a much larger area of the Earth. ^[10]

Occurrence and cycles

Total Solar Eclipse Paths: 1001–2000. This image was merged from 50 separate images from NASA. ^[11]

Total solar eclipses are rare events. Although they occur somewhere on Earth every 18 months on average^[12], it has been estimated that they recur at any given place only once every 370 years, on average. The total eclipse only lasts for a few minutes at that location, as the Moon's umbra moves eastward at over 1700 km/h. Totality can never last more than 7 min 40 s, and is usually much shorter: during each millennium there are typically fewer than 10 total solar eclipses exceeding 7 minutes. A millennium (pl millennia) is a period of Time equal to one thousand Years (from Latin la mille, thousand and la annum The last time this happened was June 30, 1973. Events 350 - Roman usurper Nepotianus, of the Constantinian dynasty, is defeated and killed by troops of the Usurper Year 1973 ( MCMLXXIII) was a Common year starting on Monday (link will display full calendar of the 1973 Gregorian calendar. Observers aboard a Concorde aircraft were able to stretch totality to about 74 minutes by flying along the path of the Moon's umbra. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout The next eclipse of comparable duration will not occur until June 25, 2150. Events 524 - Battle of Vézeronce, the Franks defeat the Burgundians 2150 is the title of a work of Fiction written by Don and Thea Plym in 1970. The longest total solar eclipse during the 8,000-year period from 3000 BC to 5000 AD will occur on July 16, 2186, when totality will last 7 min 29 s. Events 622 - The beginning of the Islamic calendar. 1054 - Three Roman legates fractured relations between the Western and The 22nd century of the Common Era will span the years 2101&ndash2200 of the Gregorian calendar. ^[13]

If the date and time of any solar eclipse are known, it is possible to predict other eclipses using eclipse cycles. may occur repeatedly separated by certain intervals of time these intervals are called eclipse cycles. Two such cycles are the Saros and the Inex. Saros or Sáros may refer to Saros cycle, a method for predicting solar eclipses SS Saros, a shipwreck off the southeast coast The inex is an Eclipse cycle of about 29 years The cycle was first described by Crommelin in 1901 but was named by George van den Bergh who studied it The Saros cycle is probably the best known, and one of the most accurate, eclipse cycles. The Inex cycle is itself a poor cycle, but it is very convenient in the classification of eclipse cycles. After a Saros cycle finishes, a new Saros cycle begins one Inex later, hence its name: in-ex. A Saros cycle lasts 6,585. 3 days (a little over 18 years), which means that after this period a practically identical eclipse will occur. The most notable difference will be a shift of 120° in longitude (due to the 0. 3 days) and a little in latitude. A Saros series always starts with a partial eclipse near one of Earth's polar regions, then shifts over the globe through a series of annular or total eclipses, and ends at the opposite polar region. A Saros lasts 1226 to 1550 years and 69 to 87 eclipses, with about 40 to 60 central. ^[14]

Final totality

Spectacular solar eclipses are an extreme rarity within the universe at large. They are seen on Earth because of a fortuitous combination of circumstances that are statistically very improbable. Even on Earth, spectacular eclipses of the type familiar to people today are a temporary (on a geological time scale) phenomenon. Many millions of years in the past, the Moon was too close to the Earth to precisely occult the Sun as it does during eclipses today; and many millions of years in the future, it will be too far away to do so.

Due to tidal acceleration, the orbit of the Moon around the Earth becomes approximately 3. Tidal acceleration is an effect of the Tidal forces between an orbiting Natural satellite ( i 8 cm more distant each year. It is estimated that in 600 million years, the distance from the Earth to the Moon will have increased by 23,500 km, meaning that it will no longer be able to completely cover the Sun's disk. This will be true even when the Moon is at perigee, and the Earth at aphelion. In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from

A complicating factor is that the Sun will increase in size over this timescale. This makes it even more unlikely that the Moon will be able to cause a total eclipse. We can therefore say that the last total solar eclipse on Earth will occur in slightly less than 600 million years. ^[15]

Activities during solar eclipse

Meteorological measurements

A special weather station used for meteorological measurements during solar eclipses. ^[16]

A marked drop of the intensity of the solar radiation occurs during solar eclipse. It influences the actions in the atmosphere. An atmosphere (from Greek ατμός - atmos, " Vapor " + σφαίρα - sphaira, " Sphere " The variations of the atmospheric actions display in changes of standard meteorological and physical quantities. Quantity is a kind of property which exists as magnitude or multitude We can notice it by a measurement of the air temperature and other meteorological quantities (e. g. : air humidity, soil temperature, colour of the solar radiation). Humidity is the amount of water vapor in the air In daily language the term "humidity" is normally taken to mean Relative humidity.

The progressions of the quantities are usually detected by special weather stations because of a short duration of a total (annular) solar eclipse. A weather station is a facility with instruments and equipment to make observations of atmospheric conditions in order to provide information to make weather forecasts The properties of the devices usually are: high speed of measurement, high resolution and sensitivity. Acquired results show very interesting variations in progressions of meteorological and physical quantities (e. g. : colour of the light). ^[16]

Photography of the phenomenon

Photographing an eclipse is possible with fairly common film camera equipment. In order for the disk of the sun/moon to be easily visible, a fairly high magnification telephoto lens is needed (70-200mm for a 35mm camera), and for the disk to fill most of the frame, a longer lens is needed (over 500mm). As with viewing the sun directly, looking at it through the viewfinder of a camera can produce damage to the retina, so care is advised. ^[17]

Measuring of the light Einstein's inflexion

Observing of surrounded fauna and flora

Historical eclipses

Astronomers Studying an Eclipse by Antoine Caron

Historical eclipses are a valuable resource for historians, in that they allow a few historical events to be precisely dated, from which other dates and a society's calendar can be deduced. Antoine Caron (1521 in Beauvais - 1599 in Paris) was a French master Glassmaker illustrator Mannerist painter A solar eclipse of June 15, 763 BC mentioned in an Assyrian text is important for the Chronology of the Ancient Orient. Events 763 BC - Assyrians record a Solar eclipse that will be used to fix the Chronology of Mesopotamian history Events and trends 763 BC — June 15 — A Solar eclipse at this date (in month Sivan) is used to fix the Chronology of the The Assyrians are an Ethnic group whose origins lie in what is today Iraq, Iran, Turkey and Syria. See Short chronology for a timeline in absolute dates The Chronology of the Ancient Near East is a framework of dates for Also known as the eclipse of Bur Sagale, it is the earliest solar eclipse mentioned in historical sources that has been successfully identified. The Assyrian eclipse is also known as Bur-Sagale (Bur-Saggile Pur-Sagale or Par-Sagale eclipse Perhaps the earliest still-unproven claim is that of archaeologist Bruce Masse; on the basis of several ancient flood myths that mention a total solar eclipse, he links an eclipse that occurred May 10, 2807 BC with a possible meteor impact in the Indian Ocean. The story of a Great Flood (also known as the Deluge) sent by a Deity or deities to destroy Civilization as an act of Divine retribution is a Events 1291 - Scottish Nobles recognize the authority of Edward I of England. The 29th century BC is a Century which lasted from the year 2900 BC to 2801 BC See also Impact crater An impact event is the Collision of a large Meteoroid, Asteroid or Comet (generically The Indian Ocean is the third largest of the world's Oceanic divisions covering about 20% of the water on the Earth 's surface ^[18] There have been other claims to date earlier eclipses, notably that of Mursili II (likely 1312 BC), in Babylonia, and also in China, during the 5th year (2084 BC) of the regime of king Zhong Kang of Xia dynasty, but these are highly disputed and rely on much supposition. Mursili II (also spelled Mursilis II) was a king of the Hittite Empire (New kingdom ca Babylonia was an Amorite state in lower Mesopotamia (modern southern Iraq) with Babylon as its capital Zhong Kang ( was the fourth sovereign of the legendary Xia Dynasty. ^[19][20]

Herodotus wrote that Thales of Miletus predicted an eclipse which occurred during a war between the Medians and the Lydians. Herodotus of Halicarnassus ( Greek: Hēródotos Halikarnāsseús) was a Greek Historian who lived in the 5th century BC ( 484 BC&ndash Thales of Miletus According to Bertrand Russell, "Philosophy begins with Thales The Medes were an ancient Iranian people who lived in the northwestern portions of present-day Iran. Defining Lydia Aside from a legend related by Herodotus, who states that the name Lydia came from king Lydus at the time of the fall of Troy Soldiers on both sides put down their weapons and declared peace as a result of the eclipse. Exactly which eclipse was involved has remained uncertain, although the issue has been studied by hundreds of ancient and modern authorities. One likely candidate took place on May 28, 585 BC, probably near the Halys river in the middle of modern Turkey. Events 585 BC - A Solar eclipse occurs as predicted by Greek philosopher and scientist Thales, while Alyattes is battling Events and trends 589 BC — Apries succeeds Psammetichus II as king of Egypt. Turkey (Türkiye known officially as the Republic of Turkey ( is a Eurasian Country that stretches ^[21]

An annular eclipse of the Sun occurred at Sardis on February 17, 478 BC, while Xerxes was departing for his expedition against Greece, as Herodotus recorded. Sardis, also Sardes ( Lydian: Sfard, Greek: Σάρδεις, Persian: Sparda) modern Sart in Events 1500 - Battle of Hemmingstedt. 1600 - Philosopher Giordano Bruno is burned alive at Campo de' Fiori Events By place Greece Despite Spartan opposition Athens is refortified as well as rebuilt after the Xerxes I of Persia was a King of Persia (reigned 485–465 BC of the Achaemenid dynasty. The term ancient Greece refers to the period of Greek history lasting from the Greek Dark Ages ca ^[22] Hind and Chambers considered this absolute date more than a century ago. ^[23] Herodotus also reports that another solar eclipse was observed in Sparta during the next year, on August 1, 477 BC. The city of Sparta ( Doric Σπάρτα Attic Σπάρτη Events 30 BC - Octavian (later known as Augustus enters Alexandria, Egypt, bringing it under the control of the Roman Events By place Greece The Spartan co-ruler Leotychides and the Athenian leader Themistocles ^[24][25][26] The sky suddenly darkened in the middle of the day, well after the battles of Thermopylae and Salamis, after the departure of Mardonius to Thessaly at the beginning of the spring of (477 BC) and his second attack on Athens, after the return of Cleombrotus to Sparta. In the Battle of Thermopylae, which occurred in August 480 BC (and was detailed almost entirely by Herodotus) an alliance of Greek City-states fought The Battle of Salamis ( Ancient Greek:) was a decisive naval battle between the Greek City-states and Persia in September 480 BC in the This page is about the historical figure for the Millipede Genus, see Mardonius (genus Mardonius (d Thessalia redirects here For the Butterfly Genus, see Thessalia (butterfly. Athens (ˈæθənz Αθήνα Athina,) the Capital and largest city of Greece, dominates the Attica periphery as one of the world's The city of Sparta ( Doric Σπάρτα Attic Σπάρτη Note that the modern conventional dates are different by a year or two, and that these two eclipse records have been ignored so far. ^[27] The Chronicle of Ireland recorded a solar eclipse on June 29, 512 AD, and a solar eclipse was reported to have taken place during the Battle of Stiklestad in the summer of 1030. The Chronicle of Ireland is the modern name for a hypothesized collection of Ecclesiastical Annals recording events in Ireland from 432 Events 512 - A Solar eclipse is recorded by a monastic chronicler in Ireland. Events By Place Byzantine Empire Emperor Anastasius I ends a period of moderate eclectic policy and starts strongly favoring his own The Battle of Stiklestad ( Old Norse Stiklarstaðir) in 1030 is one of the most famous battles in the history of Norway.

It has also been attempted to establish the exact date of Good Friday by means of solar eclipses, but this research has not yielded conclusive results. Good Friday, also called Holy Friday or Great Friday, is the Friday preceding Easter Sunday ("Pascha" ^[28] Research has manifested the inability of total solar eclipses to serve as explanations for the recorded Good Friday features of the crucifixion eclipse. Good Friday, also called Holy Friday or Great Friday, is the Friday preceding Easter Sunday ("Pascha" The phrase " Crucifixion eclipse " refers to a three-hour period of daytime darkness that was reported by the Synoptic gospels of the Christian Bible to have ^[29] (Good Friday is recorded as being at Passover, which is also recorded as being at or near the time of a full moon. Passover ( Hebrew, Yiddish: פֶּסַח Pesach, Tiberian: pɛsaħ Israeli: Pesah, Pesakh, Yiddish )

The ancient Chinese astronomer Shi Shen (fl. Middle Chinese ( or Ancient Chinese as used by linguist Bernhard Karlgren, refers to the Chinese language spoken during Southern and Northern Shi Shen ( fl 4th century BC) was a Chinese Astronomer and contemporary of Gan De born in the State of Wei, also known as the 4th century BC) was aware of the relation of the moon in a solar eclipse, as he provided instructions in his writing to predict them by using the relative positions of the moon and sun. ^[30] The 'radiating influence' theory for a solar eclipse (i. e. , the moon's light was merely light reflected from the sun) was existent in Chinese thought from about the 6th century BC (in the Zhi Ran of Zhi Ni Zi),^[31] and opposed by the Chinese philosopher Wang Chong (27–97 AD), who made clear in his writing that this theory was nothing new. Chinese philosophy is Philosophy written in the Chinese tradition of thought Wang Chong ( 27&ndashc 100 AD Wang also accurately described the process of the Water cycle. Year 27 was a Common year starting on Wednesday (link will display the full calendar of the Julian calendar. Year 97 was a Common year starting on Sunday (link will display the full calendar of the Julian calendar. ^[32] This can be said of Jing Fang's writing in the 1st century BC, which stated:

The moon and the planets are Yin; they have shape but no light. In Chinese philosophy, the concept of yin and yang ( is used to describe how seemingly opposing forces are bound together intertwined and interdependent in the This they receive only when the sun illuminates them. The former masters regarded the sun as round like a crossbow bullet, and they thought the moon had the nature of a mirror. A crossbow is a Weapon consisting of a bow mounted on a stock that shoots projectiles often called bolts Some of them recognized the moon as a ball too. Those parts of the moon which the sun illuminates look bright, those parts which it does not, remain dark. ^[31]

The ancient Greeks had known this as well, since it was Parmenides of Elea around 475 BC who supported the theory of the moon shining because of reflected light, and was accepted in the time of Aristotle as well. Parmenides of Elea ( Greek:, early 5th century BC was an Ancient Greek Philosopher born in Elea, a Greek city on the southern coast of Elea may refer to Velia (town, Italy Elea Kyrenia, Cyprus Elea Nicosia, Cyprus Aristotle (Greek Aristotélēs) (384 BC – 322 BC was a Greek philosopher a student of Plato and teacher of Alexander the Great. ^[31] The Chinese astronomer and inventor Zhang Heng (78–139 AD) wrote of both solar and lunar eclipses in the publication of Ling Xian in 120 AD, supporting the radiating influence theory that Wang Chong had opposed (Wade-Giles):

The sun is like fire and the moon like water. Zhang Heng ( (CE 78–139 was an astronomer, mathematician, inventor, geographer, cartographer, artist, poet Year 78 was a Common year starting on Thursday (link will display the full calendar of the Julian calendar. Wade-Giles (ˌweɪdˈʤaɪlz) sometimes abbreviated Wade, is a Romanization system (phonetic notation and Transcription) for the Mandarin The fire gives out light and the water reflects it. Thus the moon's brightness is produced from the radiance of the sun, and the moon's darkness (pho) is due to (the light of) the sun being obstructed (pi). The side which faces the sun is fully lit, and the side which is away from it is dark. The planets (as well as the moon) have the nature of water and reflect light. The light pouring forth from the sun (tang jih chih chhung kuang) does not always reach the moon owing to the obstruction (pi) of the earth itself—this is called 'an-hsü', a lunar eclipse. When (a similar effect) happens with a planet (we call it) an occulation (hsing wei); when the moon passes across (kuo)(the sun's path) then there is a solar eclipse (shih). ^[33]

The later Chinese scientist and statesman Shen Kuo (1031–1035 AD) also wrote of eclipses, and his reasoning for why the celestial bodies were round and spherical instead of flat (Wade-Giles spelling):

The Director [of the Astronomical Observatory] asked me about the shapes of the sun and moon; whether they were like balls or (flat) fans. Shen Kuo or Shen Kua ( (1031&ndash1095 style name Cunzhong and pseudonym Mengqi Weng, was a Polymathic Chinese Wade-Giles (ˌweɪdˈʤaɪlz) sometimes abbreviated Wade, is a Romanization system (phonetic notation and Transcription) for the Mandarin If they were like balls they would surely obstruct (ai) each other when they met. I replied that these celestial bodies were certainly like balls. How do we know this? By the waxing and waning (ying khuei) of the moon. The moon itself gives forth no light, but is like a ball of silver; the light is the light of the sun (reflected). When the brightness is first seen, the sun(-light passes almost) alongside, so the side only is illuminated and looks like a crescent. When the sun gradually gets further away, the light shines slanting, and the moon is full, round like a bullet. If half of a sphere is covered with (white) powder and looked at from the side, the covered part will look like a crescent; if looked at from the front, it will appear round. Thus we know that the celestial bodies are spherical. . . Since the sun and moon are in conjunction (ho) and in opposition (tui) once a day, why then do they have eclipses only occasionally?' I answered that the ecliptic and the moon's path are like two rings, lying one over the other (hsiang tieh), but distant by a small amount. (If this obliquity did not exist), the sun would be eclipsed whenever the two bodies were in conjunction, and the moon would be eclipsed whenever they were exactly in position. But (in fact) though they may occupy the same degree, the two paths are not (always) near (each other), and so naturally the bodies do not (intrude) upon one another. ^[34]

Viewing

Photo taken in Valladolid, Spain, during the October 3, 2005, annular eclipse. ||-||} is an industrial city and it is a Municipality in north-central Spain, upon the Pisuerga River and within the Ribera del Duero wine-making region Spain () or the Kingdom of Spain (Reino de España is a country located mostly in southwestern Europe on the Iberian Peninsula. The solar eclipse that took place on October 3, 2005 was an Annular eclipse of the Sun with a magnitude of 0

Looking directly at the photosphere of the Sun (the bright disk of the Sun itself), even for just a few seconds, can cause permanent damage to the retina of the eye, because of the intense visible and invisible radiation that the photosphere emits. The vertebrate retina is a light sensitive part inside the inner layer of the Eye. This damage can result in permanent impairment of vision, up to and including blindness. Blindness is the condition of lacking Visual perception due to Physiological or Neurological factors The retina has no sensitivity to pain, and the effects of retinal damage may not appear for hours, so there is no warning that injury is occurring. ^[35]

Under normal conditions, the Sun is so bright that it is difficult to stare at it directly, so there is no tendency to look at it in a way that might damage the eye. However, during an eclipse, with so much of the Sun covered, it is easier and more tempting to stare at it. Unfortunately, looking at the Sun during an eclipse is just as dangerous as looking at it outside an eclipse, except during the brief period of totality, when the Sun's disk is completely covered (totality occurs only during a total eclipse and only very briefly; it does not occur during a partial or annular eclipse). Viewing the Sun's disk through any kind of optical aid (binoculars, a telescope, or even an optical camera viewfinder) is even more hazardous. ^[36]

Glancing at the Sun with all or most of its disk visible is unlikely to result in permanent harm, as the pupil will close down and reduce the brightness of the whole scene. If the eclipse is near total, the low average amount of light causes the pupil to open. Unfortunately the remaining parts of the Sun are still just as bright, so they are now brighter on the retina than when looking at a full Sun. As the eye has a small fovea, for detailed viewing, the tendency will be to track the image on to this best part of the retina, causing damage. The fovea, also known as the fovea centralis, is a part of the Eye, located in the center of the Macula region of the Retina.

Partial and annular eclipses

Eclipse glasses.

Viewing the Sun during partial and annular eclipses (and during total eclipses outside the brief period of totality) requires special eye protection, or indirect viewing methods. The Sun's disk can be viewed using appropriate filtration to block the harmful part of the Sun's radiation. Sunglasses are not safe, since they do not block the harmful and invisible infrared radiation which causes retinal damage. Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of Only properly designed and certified solar filters should ever be used for direct viewing of the Sun's disk. ^[37]

The safest way to view the Sun's disk is by indirect projection. This can be done by projecting an image of the disk onto a white piece of paper or card using a pair of binoculars (with one of the lenses covered), a telescope, or another piece of cardboard with a small hole in it (about 1 mm diameter), often called a pinhole camera. A' pinhole camera' is a very simple Camera with no lens and a single very small Aperture. The projected image of the Sun can then be safely viewed; this technique can be used to observe sunspots, as well as eclipses. A sunspot is a region on the Sun 's surface ( Photosphere) that is marked by intense magnetic activity which inhibits Convection, forming However, care must be taken to ensure that no one looks through the projector (telescope, pinhole, etc. ) directly. Viewing the Sun's disk on a video display screen (provided by a video camera or digital camera) is safe, although the camera itself may be damaged by direct exposure to the Sun. A video camera is a Camera used for electronic Motion picture acquisition initially developed by the Television industry but now common in other applications Many compact digital still cameras can record Sound and moving Video as well as still Photograph. The optical viewfinders provided with some video and digital cameras are not safe.

In the partial eclipse path one will not be able to see the spectacular corona or nearly complete darkening of the sky, yet, depending on how much of the sun's disk is obscured, some darkening may be noticeable. If two-thirds or more of the sun is obscured, then an effect can be observed by which the daylight appears to be dim, as if the sky were overcast, yet objects still cast sharp shadows.

Totality

Diamond ring

It is safe to observe the total phase of a solar eclipse directly with the unaided eye, binoculars or a telescope, when the Sun's photosphere is completely covered by the Moon; indeed, this is a very spectacular and beautiful sight, and it is too dim to be seen through filters. The Sun's faint corona will be visible, and even the chromosphere, solar prominences, and possibly even a solar flare may be seen. A corona is a type of plasma " atmosphere " of the Sun or other celestial body extending millions of Kilometres into space most easily The chromosphere (literally "colour sphere" is a thin layer of the Sun 's atmosphere just above the Photosphere, roughly 10000 kilometres deep A prominence is a large bright feature extending outward from the Sun's surface often in a loop configuration A solar flare is a violent explosion in a star's (like the Sun 's atmosphere releasing as much Energy as 6 × 1025 Joules Solar flares However, it is important to stop directly viewing the Sun promptly at the end of totality. The exact time and duration of totality for the location from which the eclipse is being observed should be determined from a reliable source.

Baily's beads.

Also very beautiful are the effects just before (and just after) totality. When the shrinking visible part of the photosphere becomes very small, Baily's beads will occur. As the Moon "grazes" by the Sun during a Solar eclipse, the rugged lunar limb topography allows beads of sunlight to shine through in some places These are caused by the sunlight still being able to reach Earth through lunar valleys, but no longer where mountains are present. Totality then begins with the diamond ring effect, the last bright flash of sunlight. The diamond ring effect is a feature of total Solar eclipses Just before the Sun disappears or just after it emerges from behind the Moon, the rugged lunar ^[38] Note that it is not entirely safe to view Baily beads or the diamond ring without proper eye protection (because in both cases the photosphere is still visible).

Other observations

For astronomers, a total solar eclipse forms a rare opportunity to observe the corona (the outer layer of the Sun's atmosphere). Historically Astronomy was more concerned with the classification and description of phenomena in the sky while Astrophysics attempted to explain these phenomena A corona is a type of plasma " atmosphere " of the Sun or other celestial body extending millions of Kilometres into space most easily Normally this is not visible because the photosphere is much brighter than the corona. According to the point reached in the solar cycle, the corona can appear rather small and symmetric, or large and fuzzy. The solar cycle, or the solar magnetic activity cycle, is the main source of periodic variation of all solar phenomena driving variations in Space weather. It is very hard to predict this prior to totality. ^[39]

During a solar eclipse, special (indirect) observations can also be done with the unaided eye only. Normally the spots of light which fall through the small openings between the leaves of a tree, have a circular shape. These are images of the Sun. During a partial eclipse, the light spots will show the partial shape of the Sun, as seen on the picture. Another famous phenomenon is shadow bands (also known as flying shadows), which are similar to shadows on the bottom of a swimming pool. They only occur just prior to and after totality, and are very difficult to observe. Many professional eclipse chasers have never seen them. ^[40]

During a partial eclipse, a related effect that can be seen is anisotropy in the shadows of objects. Particularly if the partial eclipse is nearly total, the unobscured part of the sun acts as an approximate line source of light. This means that objects cast shadows which have a very narrow penumbra in one direction, but a broad penumbra in the perpendicular direction.

1919 observations

The original photograph of the 1919 eclipse which was claimed to confirm Einstein's theory of general relativity. Albert Einstein ( German: ˈalbɐt ˈaɪ̯nʃtaɪ̯n; English: ˈælbɝt ˈaɪnstaɪn (14 March 1879 – 18 April 1955 was a German -born theoretical General relativity or the general theory of relativity is the geometric theory of Gravitation published by Albert Einstein in 1916

In 1919, the observation of a total solar eclipse helped to confirm Einstein's theory of general relativity. Year 1919 ( MCMXIX) was a Common year starting on Wednesday (link will display the full calendar of the Gregorian calendar (or a Common Albert Einstein ( German: ˈalbɐt ˈaɪ̯nʃtaɪ̯n; English: ˈælbɝt ˈaɪnstaɪn (14 March 1879 – 18 April 1955 was a German -born theoretical General relativity or the general theory of relativity is the geometric theory of Gravitation published by Albert Einstein in 1916 By comparing the apparent distance between two stars, with and without the Sun between them, Arthur Eddington stated that the theoretical predictions about gravitational lenses were confirmed, though it now appears the data were ambiguous at the time. Sir Arthur Stanley Eddington, OM (28 December 1882 – 22 November 1944 was an English Astrophysicist of the early 20th century The predictive power of a Scientific theory refers to its ability to generate testable predictions A gravitational lens is formed when the light from a very distant bright source (such as a Quasar) is "bent" around a massive object (such as a cluster of The observation with the Sun between the stars was only possible during totality, since the stars are then visible. ^[41]

Before sunrise, after sunset

The phenomenon of atmospheric refraction makes it possible to observe the Sun (and hence a solar eclipse) even when it is slightly below the horizon. Atmospheric Refraction is the deviation of Light or other Electromagnetic wave from a straight line as it passes through the atmosphere due to the It is however possible for a solar eclipse to attain totality (or in the event of a partial eclipse, near-totality) before (visual and actual) sunrise or after sunset from a particular location. When this occurs shortly before the former or after the latter, the sky will appear much darker than it would otherwise be immediately before sunrise or after sunset. On these occasions, an object (especially a planet, often Mercury) may be visible near the sunrise or sunset point of the horizon when it could not have been seen without the eclipse. A planet, as defined by the International Astronomical Union (IAU is a celestial body Orbiting a Star or stellar remnant that is ^[42]

Eclipses and transits

In principle, the simultaneous occurrence of a Solar eclipse and a transit of a planet is possible. But these events are extremely rare because of their short durations. The next anticipated simultaneous occurrence of a Solar eclipse and a transit of Mercury will be on July 5, 6757, and a Solar eclipse and a transit of Venus is expected on April 5, 15232. Transit of Mercury Closeup - Nov 8 2006jpg|right|thumb|300px|Close-up of Mercury during the Nov Events 1295 - Scotland and France form an alliance the beginnings of the Auld Alliance, against England. The 7th millennium is a period of time that will begin on January 1, 6001 and will end on December 31, 7000 A transit of Venus across the Sun takes place when the Planet Venus passes directly between the Sun and Earth, obscuring a small portion of the Events 456 - St Patrick returns to Ireland as a missionary bishop ^[43]

Only 5 hours after the transit of Venus on June 4, 1769, there was a total solar eclipse, which was visible in Northern America, Europe and Northern Asia as partial solar eclipse. Events 781 BC - The first historic Solar eclipse is recorded in China. Year 1769 ( MDCCLXIX) was a Common year starting on Sunday (link will display the full calendar of the Gregorian calendar (or a This was the lowest time difference between a transit of a planet and a solar eclipse in the historical past.

More common, but still quite rare, is a conjunction of any planet (not confined exclusively to Mercury or Venus) at the time of a total solar eclipse, in which event the planet will be visible very near the eclipsed Sun, when without the eclipse it would have been lost in the Sun's glare. Conjunction is a term used in Positional astronomy and Astrology. At one time, some scientists hypothesized that there may be a planet (often given the name Vulcan) even closer to the Sun than Mercury; the only way to confirm its existence would have been to observe it during a total solar eclipse. Vulcan was a small Planet proposed to exist in an Orbit between Mercury and the Sun in a 19th-century hypothesis However, it is now known that no such planet exists. While there does remain some possibility for small Vulcanoid asteroids to exist, none have ever been found. Vulcanoids are a hypothetical group of Asteroids that may orbit in a dynamically stable zone between 0

Artificial satellites

Shadow of the moon, seen from the ISS in 2006. The solar eclipse that took place on March 29, 2006 was a total eclipse of the Sun that was visible from a narrow corridor which traversed half the

Artificial satellites can also pass in front of, or transit, the Sun as seen from Earth, but none are large enough to cause an eclipse. At the altitude of the International Space Station, for example, an object would need to be about 3. 35 km across to blot the Sun out entirely. These transits are difficult to watch, because the zone of visibility is very small. The satellite passes over the face of the Sun in about a second, typically. As with a transit of a planet, it will not get dark. ^[44]

Artificial satellites do play an important role in documenting solar eclipses. Images of the umbra on the Earth's surface taken from Mir and the International Space Station are among the most spectacular eclipse images in history. Mir (Мир which can mean both Peace and World, and was the name given to peasant communes in pre-revolutionary Russia was a Soviet (and ^[45] Observations of eclipses from satellites orbiting above the Earth's atmosphere are of course not subject to weather conditions.

The direct observation of a total solar eclipse from space is rather rare. The only documented case is Gemini 12 in 1966. Gemini 12 (officially Gemini XII) was a 1966 Manned spaceflight in NASA 's Gemini program. Year 1966 ( MCMLXVI) was a Common year starting on Saturday (link will display full calendar of the 1966 Gregorian calendar. The partial phase of the 2006 total eclipse was visible from the International Space Station. The solar eclipse that took place on March 29, 2006 was a total eclipse of the Sun that was visible from a narrow corridor which traversed half the At first, it looked as though an orbit correction in the middle of March would bring the ISS in the path of totality, but this correction was postponed. ^[46]

See also

Eclipses elsewhere

• Solar eclipses on Jupiter
• Solar eclipses on Pluto
• Transit of Phobos from Mars
• Transit of Deimos from Mars

Eclipse lists

• Articles on individual solar eclipses
• List of solar eclipses
• List of solar eclipses seen from China
• List of solar eclipses visible from the United Kingdom 1000 - 2090 AD

Miscellaneous

• Allais effect
• Crucifixion eclipse
• Solar eclipses in fiction

Notes

References

• Needham, Joseph (1986). Science and Civilization in China: Volume 3. Taipei: Caves Books, Ltd.

External links

General

• Solar eclipse time sequence
• NASA's Eclipse Home Page, Fred Espenak
• Mark's eclipse chasing website
• Solar Eclipse Resources
• Solar Eclipse Meteorological Measurement, The Observatory and Planetarium in Plzen (The Czech Republic)
• Detailed eclipse explanations and predictions, Hermit Eclipse
• Prof. Druckmüller's eclipse photography site
• World Atlas of Solar Eclipse Paths, F. Fred Espenak (1953—) is an American Astrophysicist. He works at the Goddard Space Flight Center. Espenak
• Animated maps of present and past eclipses all over the world (ShadowandSubstance. com)
• NightSkyInfo.com: All About Solar Eclipses
• Wendy Carlos' Total Eclipse Page Musician Wendy Carlos has been an avid solar eclipse photographer since the 1960s. Wendy Carlos (born Walter Carlos, November 14 1939 is an American Composer and electronic Musician.

Eye safety

• Eye Safety During Solar Eclipses, F. Espenak (NASA Goddard Space Flight Center)
• How to Watch a Partial Solar Eclipse Safely, A. M. MacRobert (Sky & Telescope magazine)
• UK hospitals assess eye damage after solar eclipse, British Medical Journal, August 21, 1999, p. Events 1192 - Minamoto Yoritomo becomes Seii Tai Shōgun and the De facto ruler of Japan. Year 1999 ( MCMXCIX) was a Common year starting on Friday (link will display full 1999 Gregorian calendar) 319–469