Women in Astronomy: Aglaonice (2nd Century BCE)

 Aglaonice (2nd Century BCE)

Aglaonice (2nd Century BCE)

Remember that mythicalesque astronomical event at the end of January, the Super Blue Blood Moon? (er was it a Bloody Super Blue Moon??) Well as magical as the name sounds it was actually just a neat happenstance of 3 types of lunar events colliding into one epic night. So a blue moon is just when 2 full moons occur in 1 calendar month - so just a little coincidental math. A super moon is when the Moon is at its perigee - the closest point to Earth in it’s orbit. Lastly, a blood moon is just another name for a total lunar eclipse because as the Sun’s white light passes through our atmosphere the bluer wavelengths get scattered away so only the redder light reaches the Moon casting an orange-red hue across the face of the Moon during the eclipse.1

These phenomena have been recorded throughout history. Some of the very first lunar eclipses were recorded by the Zhou Dynasty in China and is believed to have occurred around 1137 BCE. Another early recording was by the Babylonians in 747 BCE. 2,3 In many ancient Greek and Roman texts, lunar eclipses were thought to be the result of a ‘witch’s magic’. It was even claimed they went as far as to steal the moon to avoid the beginning of the next month and thus avoid paying their debts.4

Remember this is ancient Greece we’re talking about, so I’m sure you can guess the gender of these sorcerers. Yup, all women.

Aglaonice was one such ‘witch’, who is now regarded as being the first Grecian woman astronomer.5 While other ‘sorceresses’ played with partial lunar eclipses, Aglaonice was a skilled astronomer who was able to calculate, and thus predict, when total lunar eclipses would occur. Her intelligence and cunning exploitation of others’ ignorance made her famous. She’s written about in numerous ancient Grecian texts by authors such as Plato, Plutarch and Apollonius of Rhodes. Her fame and profit came by gathering audiences to watch her ‘draw down the Moon.’ There is even a Greek proverb that states “Yes, even as the Moon obeys Aglaonice.”6 For a bit of context, it was around this time, through the use of geometry during lunar eclipses that Grecian astronomers argued for the roundness of Earth.7

While Aglaonice was not one of these astronomers (ya know cause of rampant sexism), what she discovered still puzzles astronomers of all genders to this day! Not only did she predict the time of lunar eclipses, she figured out their ‘type’. She knew during which event(s) the Moon would completely disappear. Completely, as in during the eclipse the Moon was not seen in the sky. A similar type of phenomena has occurred in the past but is often attributed to volcanic dust left in the atmosphere due to an eruption. Yet, no where in historical records is there evidence of such a volcanic eruption during Aglaonice’s time.

It wasn’t until 1920 when the degree of brightness of a lunar eclipse was formulated and determined to be effected most by the 11-year solar cycle, with the minimum brightness occurring during a solar minimum.8 In the 1970s, it was theorized (and slightly studied) that there are longer-term solar cycles which are super-imposed upon the more regular 11-year cycle.9 Combining these two theories, it’s plausible to say, according to Peter Bicknell of Monash University, that Aglaonice’s disappearing Moons occurred during critical minima points in the various solar cycles. So did Aglaonice understand patterns about our Earth-Sun-Moon system, that the collective astronomy community still doesn’t fully understand?

Also, what fantastic event would she have dreamed up as a way to present the Super Blue Blood Moon to the public? Is it too far to also consider her the first Grecian woman science communicator? Possibly, since she did use her knowledge to fool the public for her own gain. Though, you can’t really hate a lady for using her intelligence to make the most of her situation!

Sources and Further Reading

Aglaonice. 2018. Brooklyn Museum,

Blood Red Moon: Total Lunar Eclipse. NASA

Historically significant lunar eclipses. Wikipedia.

Lunar Eclipses of Historical Interest. NASA.

Bicknell, P., 1983, Journal of the British Astronomical Association, 93, 160-163

Danjon, A., 1920, Compt. rend. Acad. Sci. Paris, 171, 1127 and 1207. 9. Eddy, J. A., 1977, Scientific Am., 239, 80.

Aglaonice Image Credit


Katy Wimberly

Katy Wimberly is a grad student at the University of California, Irvine in their Physics Department. She is a National Science Foundation Graduate Research Fellow and the first Junior Board Fellow of the Astronomical Society of the Pacific. You can follow her via twitter and instagram.

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