Historical story

During a total eclipse or solar eclipse, the moon casts its shadow on the earth

Last updated:2022-07-25

During a total solar eclipse, the moon slides right between the earth and the sun. In a short time, day turns into night and from the sun only the hot atmosphere can be seen. This relatively rare astronomical event is one of the most spectacular you can experience on Earth.

A few times a year the earth, moon and sun are exactly in line. Seen from Earth, the sun's scorching surface is partially or completely covered by the moon, which "fits in" surprisingly well in size. The sun is about four hundred times bigger than the moon, but it also happens to be about four hundred times further away.

During a total solar eclipse, the day becomes almost night in the course of minutes. The brightest stars become visible. Nature reacts:it becomes quieter, the chickens go to the roost. At that time, a spectacular "burning" ring is visible in the dark sky:the sun's millions of degrees hot atmosphere stretching above the surface. It is one of the most impressive astronomical events you can experience on Earth.

While solar eclipses used to be seen as a bad omen, thousands of years ago some astronomers were able to predict the event from the positions of the moon and sun. More than two thousand years ago, the Greek astronomer Hipparcus was able to determine the distance to the moon within a margin of twenty percent of its true value during an eclipse. Much later, in the nineteenth and twentieth centuries, the happening provided an excellent opportunity for research into the sun's atmosphere, and provided resounding evidence for the general theory of relativity (see Science and the Eclipse). at the bottom of this article).

Today, the scientific value of a solar eclipse is not that great. She is above all a spectacle and a crowd pleaser. In an easily accessible area, an eclipse attracts millions of viewers. Not infrequently, however, the path of an eclipse crosses the sea or over remote places. The first total solar eclipse to hit the European mainland will be in 2026.

Fully or partially

There are at least two solar eclipses every year, many of which are partial eclipses. Although the Earth, Moon and Sun rotate approximately in the same plane, seen from Earth, the Moon often passes above or below the Sun. Sometimes the shadow does fall exactly on the earth, this place is usually no larger than about 150 kilometers and can leave a trail of thousands of kilometers in a few hours.

Partial eclipses are less rare than a full eclipse, but also less spectacular. The moon does not completely cover the sun, but takes a 'bite' out of it. Surrounding the narrow area of ​​a total eclipse is always a much larger area of ​​partial eclipse.

There are also annular eclipses where the outer edge of the sun is not obscured by the moon and remains visible. This happens when the moon is further away from the earth (that distance varies between 363,000 and 405,000 kilometers).

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Look here for a complete list of solar eclipses between 2001 and 2050. Please note, this also concerns eclipses that are not complete and cannot be seen in the Netherlands or Belgium.

Science and the Eclipse

As mentioned, a solar eclipse today has little scientific value. That was different with the eclipse of May 29, 1919. It lent itself perfectly to testing predictions of Albert Einstein's then still young general theory of relativity. This theory states that a heavy object such as the sun measurably bends light from stars much more distant.

Normally, this deflection cannot be measured. The effect is only noticeable near the edge of the sun, but there faint stars are practically invisible due to the bright sunlight. During the eclipse of 1919, the British astronomer Sir Arthur Eddington, among others, saw that stars near the edge of the sun were in a slightly different place. The magnitude of that deviation matched Einstein's predictions. It is considered the first test of general relativity and made Einstein a celebrity in a short time.

Today, the solar eclipse can be used to study the corona or objects that are usually close to the sun, such as the planet Mercury, from Earth. But a telescope must then be exactly in the path of an eclipse, or fly. That is why scientists usually use special satellites in space.

The solar eclipse is above all a fantastic spectacle. If you ever get the chance to see one, grab it!