Solar eclipses have been observed throughout history. Ancient eclipse records made in China and Babylonia are believed to be over 4,000 years ago. Recent research has demonstrated that solar eclipses had been depicted in the fascinating mythology of ancient Egypt, and produced evidence that the ancient Egyptians observed solar eclipses over 4,500 years ago.

In ancient China, the solar and lunar eclipses were regarded as heavenly signs that foretell the future of the Emperor; predicting eclipses were of high importance for the state. Over four millenniums ago, two Chinese astrologers were murdered as they failed to predict a solar eclipse.

The ancient Chinese believed that solar eclipses occur when a legendary celestial dragon devours the Sun. They also believed that this dragon attacks the Moon during lunar eclipses. In the Chinese language, the term for eclipse was "chih" which also means "to eat". One ancient Chinese solar eclipse record describes a solar eclipse as "the Sun has been eaten".

It was a tradition in ancient China to bang drums and pots and make loud noise during eclipses to frighten that dragon away. Even more recently, in the nineteenth century, the Chinese navy fired its cannons during a lunar eclipse to scare the dragon that was eating the Moon.

Astronomical computations enable astronomers to calculate the dates and paths of future and past eclipses with great accuracy. Some ancient eclipse records have been particularly significant to astronomers and historians as they enabled certain historical eras and events to be dated accurately.

Astronomers can also examine ancient eclipse records to measure the rate of Earth's spin about its axis over the past millenniums.

Astronomers from NASA's Jet Propulsion Laboratory (JPL) used Chinese observations of five solar eclipses that occurred between 1161 BCE and 1226 BCE to study the rate of Earth's axial rotation over the past 3,200 years. These eclipses were scratched on oxen shoulder blades in the Chinese city of Anyang.

By determining exactly when each of these eclipses was seen and where the Moon's shadow fell on Earth in each eclipse, the scientists found that the day in 1200 BCE was 0.047 second shorter than the present day.

By 20 BCE,Chinese astronomers realized the true nature of solar eclipses, and by

CE 206, Chinese astronomers were able to predict solar eclipses by analyzing the motion of the Moon.

Astronomy flourished in Mesopotamia, the plain between the two great rivers Tigris and Euphrates, in the dawn of civilization. Like the Chinese and Egyptian astronomers, the Babylonian astronomers observed the motions of the Sun, Moon and planets carefully and kept records of the celestial events. They are also credited with remarkable contributions to ancient astronomy.

Three famous solar eclipse records were made in Mesopotamia; one was that of the eclipse of 3 May 1375 BCE, which was visible in the city of Ugarit (located in present Syrian Arab Republic), a total eclipse "that turned day into night" was found to be the eclipse of 31 July 1036 BCE, and an Assyrian record of the solar eclipse of 15 June 763 BCE that was observed in the city of Nineva.

The ancient Greek astronomers have made outstanding contributions to astronomy and their works remained influential till the Renaissance. Eratosthenes (276-194 BCE) estimated the circumference of the Earth with a remarkable accuracy by measuring the angles of the shadows cast at noon in Aswan and Alexandria on the day of the summer solstice.

Aristarchus (ca. 320-250 BCE) made a rough estimate of the lunar diameter and proposed the first known heliocentric model of the Universe. In this model, the Sun, not the Earth, is at the center of the Universe. Hipparchus (190-120 BCE) calculated the first measurement of precession and compiled the first star catalog.

The ancient Greek astronomers had also great knowledge of eclipses.

A fragment of a lost poem by Archilochus (ca. 680–645 BCE), who was a Greek poet and soldier, seems to clearly depict a total solar eclipse:

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.

Herodotus, the father of history, who lived in the 5th century BC, cited that Thales (ca. 624-547 BCE), the Greek philosopher, predicted the solar eclipse of 28 May 585 BCE that put an end to the conflict between the Lydians and the Medes.

Herodotus wrote:

… day was all of sudden changed into night. This event had been foretold by Thales, the Milesian, who forewarned the Ionians of it, fixing for it the very year in which it took place. The Medes and the Lydians when they observed the change, ceased fighting, and were alike anxious to have terms of peace agreed on.

Claudius Ptolemy (ca. 87-150 CE) wrote about eclipses in his epic work Almagest. His writings show that he studied the lunar orbit carefully and had a sophisticated scheme for predicting both solar and lunar eclipses.

One of the most important historical solar eclipses is that of the annular solar eclipse of 27 January 632. It was visible in Medina during the lifetime of Prophet Mohammad, Peace Be Upon Him (PBUH), and coincided with the death of his little son Ibrahim. The Prophet stated explicitly and definitely that the eclipses of the Sun and the Moon are not bad omens, but are cosmic spectacles that demonstrate the might and knowledge of Allah the Great.

The Egyptian astronomer Ibn Yunus (950-1009), who was regarded as one of the greatest observational astronomers of his time, made important, precise observations of lunar and solar eclipses in Cairo.

Two solar eclipses were of a particularly significant position in the history of modern science.

The element helium was discovered on 18 August 1868 by the French astronomer Jules Janssen (1824-1907) when he observed the spectrum of the Sun during a total eclipse in India. Helium is the second most abundant chemical element in the Universe. The chemical composition of our Universe is primarily hydrogen (about 74%) and helium (24%) with less than 2% of all the other elements, e.g., oxygen, carbon, iron, etc. Helium is also of high importance for many industrial and scientific technologies.

The total solar eclipse of 29 May 1919 is famous for astronomical observations that were carried out during that eclipse and confirmed some of Einstein's work on general relativity.

The Great British astronomer Sir Arthur Eddington (1882-1944) travelled to the island of Príncipe near Africa to observe that eclipse. He sought to verify Einstein's conclusion that light is deflected in the gravitational fields of celestial objects, i.e., the gravitational field of a star like the Sun acts as if it were a huge, cosmic lens that refracts light.

Eddington photographed the stars near the Sun during the totality of the eclipse. According to the theory of relativity, the stars in the vicinity of the Sun will appear slightly shifted from their original positions because of the deflection of their light due to the gravitational field of the Sun.

This effect can be observed from Earth only during the totality phase of a total solar eclipse, as the stars cannot be seen in broad daylight. Eddington's measurements confirmed Einstein's work and were regarded as a conclusive proof that gravity bends light rays.

From its orbit in space, the Hubble Space Telescope has made incredible images of cosmic "gravitational lenses", in which massive galaxies bend the light of more distant objects; thanks to Einstein and Eddington!

Fig (1)

An extragalactic gravitational lens imaged by the Hubble Space Telescope

Fig (2)

Natural lenses in space

Eclipses of the Sun are awe-inspiring phenomena. It is no wonder that in many early cultures they were believed to be the end of the world or omens. The word eclipse is of Greek origin meaning "abandonment".

In China, India, southeastern Asia and in Peru there were beliefs that dragons or demons attack the Sun during eclipses. The ancient Egyptian myth of the snake Apep that attacks the boat of the Sun god is believed now to refer to solar eclipses.

The Chinese and the Incas tried to frighten these monsters away but the Indians made a different attempt by immersing themselves in water. They performed this religious ritual to help the Sun struggle against the dragon.

Even today, in some countries, it is still traditional to bang pots, chant or shoot into the air when an eclipse happens.

Some superstitions that believe solar eclipses emit harmful radiation, or cause sickness, still persist.

Muslims pray five times daily, but during eclipses they specially perform the "eclipse prayer". This is one of the traditions of Prophet Mohammad (PBUH). The purpose of this prayer is to remember the might and gifts of Allah the Creator.

Further Reading

Ancient Solar Eclipse Records

Ancient Chinese Solar Eclipse Records

Eclipses Throughout History

Fear and Awe: Eclipses Through the Ages

By Wil Milan

History Eclipsed: The Day(s) the Sun Vanished

Hubble Observations of Gravitational Lenses

Natural lenses in space