Humans have been predicting eclipses for thousands of years, but it's harder than you might think
Retrieved on:
Monday, April 17, 2023
But it turns out calculating exactly when and where we can watch an eclipse in its full glory can be surprisingly hard.
Key Points:
- But it turns out calculating exactly when and where we can watch an eclipse in its full glory can be surprisingly hard.
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Since the late 19th century, adventurous female 'eclipse chasers' have contributed to science in Australia
Watching the Sun and the Moon
- Being so dominant in the sky, the Sun and the Moon were the most captivating celestial bodies for ancient cultures to observe.
- While the Sun’s movement is quite simple, the Moon moves across the sky with much more complexity.
- During a lunar eclipse, where Earth blocks sunlight that would otherwise illuminate a full moon, the dimmed Moon takes on a bloody hue.
The not-so-mythical Saros cycle
- This 18-year cycle, which can persist as a sequence for over a thousand years, is now known as a Saros cycle.
- The Saros cycle represents how long it takes for the Sun-Earth-Moon system to return to almost exactly the same triangular configuration.
- This is much more frequent than an 18-year Saros cycle, and is possible because multiple repeating Saros sequences overlap at once (roughly a dozen), each offset by at least six months.
- After about a thousand years, when one long-term Saros sequence ends, another will begin with slightly different timing.
From antiquity to modern day
- Yes, if we are talking about lunar eclipses, and perhaps even partial solar eclipses.
- That is, they wouldn’t have predicted that 18 years later (567 BCE) a total solar eclipse was visible in what is now the United States.
- But significantly, it could not predict total solar eclipses at a precise place on Earth – just their timing.
- Entering the modern era of science, the first true prediction of a total solar eclipse (both in time and location) occurred in 1715.