General Science

Top 5 Most Famous Eclipses in History

posted: 08/10/17
by: Chris Mahon

The First Prediction of a Solar Eclipse: May 28, 585 BC

This one is contentious territory for astronomers and historians alike, but it's still one of the most famous eclipses on record. According to Herodotus, the Greek philosopher Thales was able to predict a solar eclipse that dawned over a battlefield where the armies of Aylattes, the king of Lydia, were fighting Cyaxares, the king of Media. The battle was only the latest struggle in a war going back fifteen years, but upon seeing the sky darken and the sun disappear, both armies took it as a sign from the gods that it was time to broker peace.

What scholars disagree on is whether Thales could actually have predicted the eclipse; there is no written documentation on how he did it, and it wasn't until Anaxagoras (about two centuries later) that the Greeks realized that eclipses were caused by the moon passing in front of the sun, and could therefore be predicted at all. Still, the battlefield at the River Halys, where the two armies of Medes and Lydians met during the eclipse, went on to become the border between the two kingdoms for years after.

Anaxagoras Discovers the Truth of Solar Eclipse: February 17, 478 BC

The story of Anaxagoras has strong historical and scientific footing, but it's still pretty incredible: After witnessing a solar eclipse in Athens, Anaxagoras of Clazomenae collected reports from various people on what they saw during the eclipse. Since an eclipse's shadow is often narrow and only viewable from certain vantage points, Anaxagoras noticed that there were discrepancies in the accounts, which he used to put forth a groundbreaking hypothesis: that the eclipse was caused by an object passing in front of the sun, and that object (based on his calculations) was probably the moon.

This wouldn't be the last time a Greek philosopher used basic knowledge of mathematics and shadows to make scientific breakthroughs -- in 240 BC, Eratosthenes was able to use the angles of shadows in two separate cities to calculate a rough estimate of the circumference of the Earth.

An Eclipse Saves Christopher Columbus: Thursday, February 29, 1504

You'd think that after scoring the title of "Discoverer of the New World" after his famous voyage in 1492, Christopher Columbus would drop the mic and walk off-stage, but for ten years afterwards he continued making journeys across the Atlantic to "discover" new territories. What most people don't know is that Columbus' story almost ended on Jamaica in 1502, where he was stranded for months with the native Arawak. Both groups became increasingly hostile toward one another, until Columbus' crew mutinied and murdered some of the Arawaks for not supplying them with food.

Now dealing with a tribe of angry natives, Columbus used an almanac to figure out that a lunar eclipse was imminent, which he leveraged using an elaborate lie: according to Columbus, the Arawaks' refusal to give him and his crew food was displeasing his god, who would show his displeasure by turning the moon blood-red. When moonrise on the date came, Columbus' prediction was confirmed, and he and his crew were able to survive until they were rescued.

An Eclipse Triggers the Discovery of Helium: August 16, 1868

The Earth has an abundance of three things: hydrogen, helium, and Star Wars merch. It may come as a surprise, then, to learn that the first time helium was identified, it was by observing the sun. On August 16, 1868, two scientists, a French astronomer named Jules Janssen and an English scientist named Joseph Norman Lockyer, were watching the sun closely to try and figure out what the giant red flames coming off the sun were made of. While watching for these "solar prominences," both saw something else: a yellowish color in the spectrum.

The yellow light they were seeing didn't match the signature of any known element, leading both scientists to claim that they'd discovered something entirely new. Both were roundly criticized by the scientific community for their claims until 1895, when they were vindicated by William Ramsay. The element they discovered now bears the name "helium," after "helios," the Greek word for "sun."

The Eclipse That Changed Physics Forever: May 29, 1919

It seems like the story of most groundbreaking scientific discoveries begins with a scientist being mercilessly discredited by their peers for upsetting the current model of things, only to be proven correct years later (after they've either died in ignominy or gone insane). Einstein was one of the lucky few whose history-changing hypotheses were proven within his lifetime, thanks to the help of Sir Arthur Eddington, who used a solar eclipse to get a good look at gravitational deflection (or lensing), which occurs when light is bent by an object's gravitational field.

After Eddington's accurate measurements of light during the eclipse (which finally put to rest the rivalry between Newtonian physics and Einstein's hypotheses), Einstein's theory of general relativity became accepted almost overnight, ushering in a new era of scientific discovery.

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