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Sulpicius Gallus crater on the moon (at left)

Solar eclipses may have had the greater impact on human history, but eclipses of the moon have also played a part.

Although they don’t have the same dramatic effect of darkness, the red color of an eclipsed moon, caused by the reflection of sunrises and sunsets around half the world, has often been viewed as an omen of bloodshed.

In the 4th century B.C., a Roman army preparing to fight the Macedonians at Pydna, in Greece, were warned not to worry when they saw an eclipse of the moon on the eve of the battle.

According to the historian Livy and other Roman writers, the military tribune Gaius Sulpicius Gallus correctly predicted the lunar eclipse and persuaded the Roman troops that it was nothing to fear.

“He then explained that on the following night the moon would lose her light from the second hour to the fourth, and no one must regard this as a portent, because this happened in the natural order of things at stated intervals, and could be known beforehand and predicted,” Livy wrote.

Source: Christopher Columbus to Thailand’s Kings: 11 Curious Eclipse Stories

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Solar eclipses also feature in one of the earliest science fiction stories, the “Somnium,” (or “The Dream”) written by the German astronomer and mathematician Johannes Kepler and published in 1634.

In the story, Kepler’s hero hears a description of space travel by “daemons” that live in the shadow of moon.

When a solar eclipse occurs, Kepler’s daemons are able to travel between the moon and the Earth on a “bridge of shadow” — and they sometimes even take human passengers with them.

“We confer with other daemons of the same region and plan an alliance so when the sunlight first begins to leave a region of space, we move in massed ranks into the shadow,” said Kepler’s lunar daemon.

“For if the sharp point of the moon’s shadow touches the earth, which often happens, our allied squadrons fall upon the earth.

 

Source: Christopher Columbus to Thailand’s Kings: 11 Curious Eclipse Stories

Explaining Science

As discussed in my previous post, Kepler’s improvement of Copernicus’s heliocentric system led to its more general acceptance, and his three laws describing the way planets move are fundamental laws of astronomy. However, this wasn’t his only contribution to science. He was one of the greatest thinkers of the seventeenth century scientific revolution and in this post I’ll outline some of his other major achievements.

Statue of Kepler in Linz, Austria – image from Wikimedia Commons

The Keplerian telescope

The Italian astronomer Galileo Galilei (1564-1642) was the first person to take observations of celestial objects with a telescope . However, Galileo’s telescope could only magnify objects 30 times before the image became distorted. It also had a narrow field of view

In 1610 Kepler began theoretical and experimental investigations of the way that different combinations of lenses could work together to produce a magnified image. He published his finding in…

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