The July 22, 2009 Total Solar Eclipse in China is the longest total solar eclipse in our lifetime, and the second longest in recorded history, next only to the June 20, 1955 eclipse in Manila.
Totality will last 5 min 8.6 sec in Shanghai and 5 min 27.8 sec in Wuhan. In 1955 totality was 6 min 1.0 sec in Manila and 7 min 6.3 sec in San Pablo, Laguna. The 2009 eclipse will not be surpassed in duration until June 13, 2132.
The solar eclipse that will take place on Wednesday, July 22, 2009 will be a total eclipse of the Sun with a magnitude of 1.080 that will be visible from a narrow corridor through northern India, eastern Nepal, northern Bangladesh, Bhutan, the northern tip of Myanmar, central China and the Pacific Ocean, including the Ryukyu Islands, Marshall Islands and Kiribati. Totality will be visible in many large cities, including Surat, Vadodara, Bhopal, Varanasi, Patna, Dinajpur, Chengdu, Chongqing, Wuhan, Hefei, Hangzhou and Shanghai, as well as over the Three Gorges Dam. A partial eclipse will be seen from the much broader path of the Moon's penumbra, including most of South East Asia (all of China and India) and north-eastern Oceania. The eclipse is part of series 136 in the Saros cycle, similar to record setting Solar eclipse of July 11, 1991.In India Best Location to Watch the Celestial event will be Aryabhatta Study Place Taregana,Bihar []
This solar eclipse is the longest total solar eclipse that will occur in the twenty-first century, and will not be surpassed in duration until June 13, 2132. Totality will last for up to 6 minutes and 39 seconds, with the maximum eclipse occurring in the ocean at 02:35:21 UTC about 100 km south of the Bonin Islands, southeast of Japan. The North Iwo Jima island is the landmass with totality time closest to maximum.
A solar eclipse occurs when the Moon lies between the Sun and Earth, casting its shadow on our planet. Depending on the location of the observer on the Earth’s surface, the observer may see a total solar eclipse, a partial solar eclipse or none at all. If the observer is lucky enough to be located in a position where the moon’s umbra contacts the Earth they will witness a total solar eclipse of the sun. For those in the penumbra of the moon they will witness only a partial solar eclipse. Those outside the locations where the moon’s shadow reaches will witness no eclipse at all. The location on the Earth the observer is located is very important to exactly what kind of eclipse is observed.
Figure 8: During a solar eclipse the moon wanders between the Earth and Sun. A total eclipse occurs for observers on the Earth that fall in the umbra of the moon (if it reaches the Earth's surface). Observers in the penumbra experience a partial eclipse. Observers outside the moon’s shadow do not witness an eclipse.
What does the phase of the Moon need to be? "NEW MOON"
There are, in fact, a few types of solar eclipse.
Fig. 1. Total Eclipse of 2009 July 22. Path of totality begins in eastern India and ends over 2,000 mi south of Hawaii. Greatest eclipse duration is 6m39s, longest of the 21st Century but is still nearly 6m in eastern China. Curved lines adjacent to path of total eclipse show regions of decreasing partial eclipse with eclipse magnitudes from 80% to 0%. Click diagram to enlarge. (Cred. Diagram adapted from Fred Espenak, NASA's GSFC.)
The total solar eclipse of July 22 2009 will be visible across south-east Asia and the western Pacific. This will be a spectacular total eclipse, lasting over 6½ minutes at maximum and visible to millions of people over a path up to 258 km wide.
The total eclipse begins just off the coast of India at 00:51:17 UT on July 22, and ends in Polynesia at 04:19:26 UT on July 22. The maximum eclipse is at 02:35:21 UT on July 22, when the total phase will last a stunning 6 minutes and 39 seconds. The partial eclipse will be visible over south-east Asia, Malaysia, Indonesia and the Pacific between 23:58:19 UT on July 21 and 05:12:25 UT on July 22.
The Bonin Islands are the next to see the eclipse at around 02:28 UT, just before the maximum eclipse. The path width is 258 km, and the total eclipse lasts 6 minutes and 39 seconds on the centreline.
Tides Slow Earth Rotation
As the Earth rotates beneath the tidal bulges, it attempts to drag the bulges along with it. A large amount of friction is produced which slows down the Earth's spin. The day has been getting longer and longer by about 0.0016 seconds each century.
Over the course of time this friction can have a noticeable effect. Astronomers trying to compare ancient solar eclipse records with their predictions found that they were off by a significant amount. But when they took the slowing down of the Earth's rotation into account, their predictions agreed with the solar eclipse records. Also, growth rings in ancient corals about 400 hundred million years old show that the day was only 22 hours long so that there were over 400 days in a year. In July 1996 a research study reported evidence, from several sedimentary rock records providing an indicator of tidal periods, that the day was only 18 hours long 900 million years ago.
Eventually the Earth's rotation will slow down to where it keeps only one face toward the Moon. Gravity acts both ways so the Earth has been creating tidal bulges on the Moon and has slowed it's rotation down so much that it rotates once every orbital period. The Moon keeps one face always toward the Earth.
Here is a list of references about the evidence for the slowing down of the Earth's rotation:
1. Growth Rhythms and the History of the Earth's rotation, edited by G.D. Rosenberg and S.K. Runcorn (Wiley: New York, 1975). An excellent source on the eclipse records and the biology of coral and their use as chronometers.
2. Tidal Friction and the Earth's Rotation, edited by P. Brosche and J. Sündermann (Springer Verlag, 1978). The second volume put out in 1982 does not talk about eclipse records or the use of coral but, instead, goes into the astrophysics of the Earth-Moon dynamics and geophysics of internal Earth processes effects on the Earth's rotation.
3. Earth's Rotation from Eons to Days, edited by P. Brosche and J. Sündermann (Springer Verlag, 1990). Has several articles about the use of ancient Chinese observations.
4. Richard Monastersky 1994, Ancient tidal fossils unlock lunar secrets in Science News vol. 146, no. 11, p. 165 of the 10 Sept 1994 issue.
5. C. P. Sonett, E. P. Kvale, A. Zakharian, Marjorie A. Chan, T. M. Demko 1996, Late Proterozoic and Paleozoic Tides, Retreat of the Moon, and Rotation of the Earth in Science vol 273, no. 5271, p. 100 of the 05 July 1996 issue.
X. S. Yang†
Faculty of Engineering, University of Wales Swansea, Singleton Park, Swansea SA2 8PP, United Kingdom
~Received 30 July 2002; published 27 January 2003!
Gravitational and other anomalies seen repeatedly in connection with solar eclipses have led to speculation about a possible gravitational shielding effect as the cause. Here we show that an unusual phenomenon that occurs only during solar eclipses, rapid air mass movement for the bulk of the atmosphere above normal cloud levels,appears to be a sufficient explanation for both the magnitude and behavior of the anomaly previously reported in these pages.
A very accurate Foucault-type pendulum slightly increases its period of oscillation and/or changes its plane of swing ~by up to 13.5o) at sites experiencing a partial eclipse of the Sun, as compared with any other time. This effect was first noticed by Allais over 40 years ago @1#, and both it and related phenomena are now named after him. Some such effect has been seen at several eclipses since then, but also not seen at other eclipses. In recent years, an anomalous
eclipse effect on gravimeters has become well-established even under controlled environmental conditions ~especially pressure!
we see that air mass flow during eclipses might have the right qualitative behavior to explain
the observed Allais gravity anomaly because it occurs mainly near the periphery of the eclipse zone and is in the right direction. The following question now arises: Can an excess air mass of order 1.8% during eclipses be enough to produce a gravitational force of the observed agnitude? Simple reasoning suggests that the cooler air inside the eclipse zone will decrease in volume ~increasing in density! in accord with Boyle’s law as its temperature drops, creating
a ‘‘low’’ pressure region with the unusual character that it would extend to great altitudes. This leaves room for warmer air from outside the eclipse zone on all sides of the advancing
shadow of the Moon to flow rapidly into the eclipse zone and fill the volume emptied by the cooler, denser air there.
This is what happens on a smaller scale across meteorological fronts. When ‘‘highs’’ and ‘‘lows’’ collide, winds are created that attempt to equalize those discordant pressures. Note
that for eclipses, the redistribution of air mass would affect broad areas well outside the eclipse zone through this process because those areas are the reservoir from which the
extra air mass would be drawn. If the shadow were static or slowly moving, air would
flow deep into the eclipse zone until pressures equalized again for the higher density of air mass present. The greatest density would be found in the center of the shadow where
the eclipse is total. However, reality is far from a static situation. The speed of sound is 330 m/s at sea level, and normally changes little with altitude. But the speed of the Moon relative to the Earth averages close to 1000 m/s. The shadow moves at the same speed as the Moon when projected perpendicular to the surface, or faster when projected obliquely. The result is that warmer air from outside the eclipse zone is continually trying to rush toward the cooler regions just inside the shadow, increasing the total mass of air over the ground below. But that air never gets a chance to penetrate very deeply before the shadow has rushed onward, carrying the high-altitude ‘‘front’’ with it faster than air can travel. Hence, the ground barometric pressure is seen to rise during the eclipse, but the amount will be a complex function of the eclipse geometry. Of course, the shadow cools a much larger volume of air than can be above the observer’s horizon. So the production of gravity anomalies at the observer will be dependent on what the upper atmosphere is doing locally as the shadow approaches, covers, and recedes.
"Nothing there is beyond hope, nothing that can be sworn impossible, nothing wonderful, since Zeus, father of the Olympians, made night from mid-day, hiding the light of the shining Sun, and sore fear came upon men."
We may know there's a scientific explanation for them, but solar eclipses continue to exert an almost magical power over us. It's not at all clear we've decreased in gullibility since the days when Columbus used his fore-knowledge of an eclipse to hoodwink the Jamaicans. And even though we know better, during each total solar eclipse, there will be people blinded by the too tempting sight of an eclipsed sun.
The Eclipse Dragon
On the other hand, we don't beat drums, fire arrows into the sky, and stand up to our necks in water in an effort to appease the gods as did the ancient Chinese and Indians. Both the Chinese and the Indians thought a snake attacked the sun during an eclipse. Noise making was an effort to scare the creature away. The earliest recorded eclipse was in China on October 22, 2134. Then two court astrologers lost their heads because, since they had failed to predict it, the emperor had been caught unprepared to make the necessary dragon-scaring noise. Almost a millennium later, in the fourteenth century B.C., an eclipse was described by a Chinese seer as three flames eating the sun.
Eclipses have been seen as evil omens whose presence changed the course of battle. In the eclipse of 585 B.C. -- the one Thales is said to have predicted -- five years of fighting ended between the Medes and Lydians as a result of an eclipse. In 413, the frightened Athenians suddenly abandoned their plan to move from Syracuse when a lunar eclipse appeared. The result was a rout by the Syracusans.
Eclipses may not have been universally feared. The people who built Stonehenge may have derived a sense of control from performing calculations of solar eclipses. Oddly, there is nothing in Egyptian literature about eclipses, although there is speculation that some of the symbols may be ecliptically based.
Scientific Understanding of Eclipses
The Babylonians were the first to calculate the regular intervals at which eclipses occur. It was through contact with the East that Thales of Miletus was able to make the prediction that marked the beginning of the Greek scientific/philosophic era. While there is some doubt as to whether Thales accurately predicted the eclipse attributed to him -- because he didn't fully understand all the cycles necessary to calculate the date and because Herodotus' reporting leaves room for doubt -- he is credited with predicting the May 25, 585 B.C. eclipse.
From www.csudh.edu... greekphil/greek01.htm:
History Of Philosophy In The Classical Period (600 B.C.-600 A.D.)
Thales predicted a total solar eclipse which was visible in Asia Minor in the midst of the battle between Media and Lydia. Herodotus mentioned in his Historia, Book 1, 74: "Suddenly a total solar eclipse took place in the midst of the battle between Lydia and Media. Thales of Miletus had predicted that that solar eclipse would occur at that time and at that place."
Today we can calculate the dates of the total solar eclipses which could be seen in Asia Minor where that battle took place: September 30, 610, June 21, 597 and May 28, 585. In his Natural History, Pliny says of Thales: " ...it was the fourth year during the 48th panathenaia." Since the first Olympic Games took place in 776, the 48th Olympic Games took place approximately 588 B.C. -- in other words, the May 29th, 585 date.
The date of an eclipse referred to in the Bible is known for certain: "`And on that day,' says the Lord God, `I will make the Sun go down at noon, and darken the Earth in broad daylight'." (Amos 8:9) "That day" was June 15, 763 B.C. The date of this eclipse is confirmed by an Assyrian historical record known as the Eponym Canon. In Assyria, each year was named after a different ruling official and the year's events were recorded under that name in the Canon. Under the year corresponding to 763 B. C., a scribe at Nineveh recorded this eclipse and emphasized the importance of the event by drawing a line across the tablet. These ancient records have allowed historians to use eclipse data to improve the chronology of early Biblical times.
This has been identified as a description of the total solar eclipse of April 6, 648 B.C. Another eclipse reference (from the Bible) goes like this:
And I behold when he had opened the sixth seal, and lo, there was a great earthquake; and the Sun became black as sackcloth of hair, and the Moon became as blood. -- Revelation 6:12
This compelling passage is only one of a number of literary and historical connections between eclipses and earthquakes. The Greek historian Thucydides, in writing about the Peloponnesian War, remarked about "earthquakes and eclipses of the Sun which came to pass more frequently than had been remembered in former times." On another occasion he noted "... there was an eclipse of the Sun at the time of a new Moon, and in the early part of the same month an earthquake." Another Greek writer, Phlegon, reported the following events:
In the fourth year of the 202nd Olympiad, there was an eclipse of the Sun which was greater than any known before and in the sixth hour of the day it became night; so that stars appeared in the heaven; and a great earthquake that broke out in Bithynia destroyed the greatest part of Nicaea.
This interest in linking the two types of events by coincidence may have been attempts to derive some order out of the unpredictability of earthquakes, possibly a carryover from the celestial omens of the Babylonians. Oddly enough, this type of coincidence seems to persist. The earthquake in Iran on September 16, 1978, the most devastating one of that year and which killed more that 25,000 people, occurred just 3-1/2 hours before a total lunar eclipse was visible there.
Eclipse Myths and Symbolism
The people of many cultures from all parts of the globe have developed various myths and legends about eclipses. Many believe that an eclipse is an omen of some natural disaster or the death or downfall of a ruler.
Another pervasive myth involves an invisible dragon or other demon who devours the Sun during an eclipse. Many cultures have also developed superstitions about how to counteract the effects of an eclipse. The Chinese would produce great noise and commotion (drumming, banging on pans, shooting arrows into the sky, and the like) to frighten away the dragon and restore daylight. In India people may immerse themselves in water up to their necks, believing this act of worship will help the Sun and Moon defend themselves against the dragon. In Japan, the custom is to cover wells during an eclipse to prevent poison from dropping into them from the darkened sky. And as recently as the last century, the Chinese Imperial Navy fired its ceremonial guns during an eclipse to scare off the invisible dragon.
This ominous view of eclipses is not the only one. In Tahiti, for example, eclipses have been interpreted as the lovemaking of the Sun and the Moon. Even to this day, the Eskimos, Aleuts, and Tlingits of Arctic America believe an eclipse shows a divine providence: the Sun and the Moon temporarily leave their places in the sky and check to see that things are going all right on Earth. But regardless of the meaning given to them, eclipses will continue to occur, always obeying the regular timetables of celestial motions.
When the eclipse of the Sun will then be,
The monster will be seen in full day:
Quite otherwise will one interpret it,
High price unguarded: none will have foreseen it.
Lets for the fun of it, look at the folk lore and myths concerning Solar Eclipses...