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Solar eclipse facts for kids

Kids Encyclopedia Facts
Solar eclips 1999 4
Photo taken during the 1999 eclipse.

When seen from Earth, a solar eclipse (ee klips') happens when the Moon passes between the Earth and the Sun. This makes the Moon fully or partially (partly) cover the sun. Solar eclipses can only happen during a new moon. Every year about two solar eclipses occur. Sometimes there are even five solar eclipses in a year. However, only two of these can be total solar eclipses, and they are quite uncommon.

Eclipses are total only in a narrow track along the Earth, and only for a few minutes. Outside this path, all eclipses are partial, and places far from the track get no eclipse at all. The track can be predicted many years before it happens. Many people who are sometimes called "eclipse chasers" or "umbraphiles" (the moon's shadow is called an umbra) travel to faraway places to see solar eclipses. After the solar eclipse on August 11, 1999, in Europe, people began to show more interest in solar eclipses. On October 3, 2005, there was another solar eclipse, and unusually many people came to see it.

The last total eclipse was the solar eclipse of September 13, 2015. The next will be on August 21, 2017.

A total solar eclipse is a natural phenomenon (event). Long ago, solar eclipses were thought to happen because of something supernatural or as a sign that something bad was going to happen. This is still believed in some cultures today. A total solar eclipse can frighten people who do not know what it means, because the Sun seems to disappear during the day and the sky turns dark in just a few minutes.

Solar eclipses happen somewhere on Earth almost every year, and very similar solar eclipses happen every 18 years, 11.3 days. This period is called the Saros cycle.

Historical eclipses

Antoine Caron Astronomers Studying an Eclipse
Astronomers Studying an Eclipse painted by Antoine Caron in 1571

The oldest recorded solar eclipse was recorded on a clay tablet found at Ugarit, in modern Syria, with two plausible dates usually cited: 3 May 1375 BC or 5 March 1223 BC, the latter being favored by most recent authors on the topic. A solar eclipse of June 15, 763 BC mentioned in an Assyrian text is important for the chronology of the ancient Near East. There have been other claims to date earlier eclipses. The legendary Chinese king Zhong Kang supposedly beheaded two astronomers, Hsi and Ho, who failed to predict an eclipse 4,000 years ago. Perhaps the earliest still-unproven claim is that of archaeologist Bruce Masse, who putatively links an eclipse that occurred on May 10, 2807, BC with a possible meteor impact in the Indian Ocean on the basis of several ancient flood myths that mention a total solar eclipse. The earliest preserved depiction of a partial solar eclipse from 1143 BCE might be the one in tomb KV9 of Ramses V and Ramses VI.

Ibn Yunus eclipses 1004 CE manuscript records Arabic
Records of the solar eclipses of 993 and 1004 as well as the lunar eclipses of 1001 and 1002 by Ibn Yunus of Cairo (c. 1005).

Eclipses have been interpreted as omens, or portents. The ancient Greek historian Herodotus wrote that Thales of Miletus predicted an eclipse that occurred during a battle between the Medes and the Lydians. Both sides put down their weapons and declared peace as a result of the eclipse. The exact eclipse involved remains 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 Asia Minor. An eclipse recorded by Herodotus before Xerxes departed for his expedition against Greece, which is traditionally dated to 480 BC, was matched by John Russell Hind to an annular eclipse of the Sun at Sardis on February 17, 478 BC. Alternatively, a partial eclipse was visible from Persia on October 2, 480 BC. Herodotus also reports a solar eclipse at Sparta during the Second Persian invasion of Greece. The date of the eclipse (August 1, 477 BC) does not match exactly the conventional dates for the invasion accepted by historians.

Chinese records of eclipses begin at around 720 BC. The 4th century BC astronomer Shi Shen described the prediction of eclipses by using the relative positions of the Moon and Sun.

Attempts have been made to establish the exact date of Good Friday by assuming that the darkness described at Jesus's crucifixion was a solar eclipse. This research has not yielded conclusive results, and Good Friday is recorded as being at Passover, which is held at the time of a full moon. Further, the darkness lasted from the sixth hour to the ninth, or three hours, which is much, much longer than the eight-minute upper limit for any solar eclipse's totality. Contemporary chronicles wrote about an eclipse at the beginning of May 664 that coincided with the beginning of the plague of 664 in the British isles. In the Western hemisphere, there are few reliable records of eclipses before AD 800, until the advent of Arab and monastic observations in the early medieval period.

Types

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Hybrid solar eclipse on October 3, 2005

There are four different types of solar eclipses:

  • A total eclipse is when the Sun is completely hidden behind the Moon. The dark shadow of the Moon covers the very bright surface of the Sun. This makes the corona easier to see.
  • An annular eclipse is when the Sun is directly behind the moon, but it looks like the Moon is smaller. This makes the Sun appear as a very bright ring or annulus around the shape of the Moon.
  • A hybrid eclipse (also called annular/total eclipse) is when it looks like a total eclipse in some parts of the Earth, and an annular eclipse in other parts. Hybrid eclipses do not happen as often as other eclipses.
  • A partial eclipse is when the moon is not exactly between the Sun and Earth, so it does not hide the Sun completely. This can usually be seen from a large part of the Earth.

The Sun's distance from the Earth is about 400 times the Moon's distance, and the Sun's diameter is about 400 times as big as the Moon's. This is why the Sun and Moon seem to be about the same size from Earth.

Looking at a solar eclipse

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Looking directly at the bright surface of the Sun itself can hurt the retina of the eye greatly because of the radiation that comes from the Sun. It can even blind people. The retina does not feel pain, so damage may not be felt for hours.

The Sun is usually so bright that it is hard to look at it directly. However, when the Sun is covered in an eclipse, it is easier to look at it. Looking at the Sun during an eclipse is equally dangerous, except in the very short time when the Sun's surface is completely covered. Looking at the Sun's surface through binoculars, a telescope, or even a camera is extremely dangerous and can damage the eye in less than a second.

Looking at the Sun without an eclipse does not usually hurt the eye very greatly, because the pupil of the eye closes down and makes everything darker. If the Sun is almost completely covered, the pupil opens because there is not as much light. However, the parts of the Sun that can be seen are still equally bright, and can hurt the eye very much.

Images for kids

See also

Kids robot.svg In Spanish: Eclipse solar para niños

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