# Ancient Egyptians Knew Algol was a Variable Star

**URL:** <https://boards.straightdope.com/t/ancient-egyptians-knew-algol-was-a-variable-star/741726>\
**Category:** Miscellaneous and Personal Stuff I Must Share\
**Created:** [December 30, 2015, 2:08pm UTC](https://boards.straightdope.com/t/ancient-egyptians-knew-algol-was-a-variable-star/741726 "2015-12-30T14:08:49Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\
**Post date:** [December 30, 2015, 2:08pm UTC](https://boards.straightdope.com/t/ancient-egyptians-knew-algol-was-a-variable-star/741726/1 "2015-12-30T14:08:49Z")

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Article this month by Lauri Jetsu and Sebastian Porceddu in Plos1, where they find observations in a 12th century BCE papyrus.

> **[Shifting Milestones of Natural Sciences: The Ancient Egyptian Discovery of...](https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0144140)**
>
> The Ancient Egyptians wrote Calendars of Lucky and Unlucky Days that assigned astronomically influenced prognoses for each day of the year. The best preserved of these calendars is the Cairo Calendar (hereafter CC) dated to 1244–1163 B.C. We have...

More popular article here:

> **[This Is The Earliest Known Reference To The 'Demon Star'](https://www.huffpost.com/entry/demon-star-ancient-egypt_n_56817de0e4b06fa68880ba3e?utm_hp_ref=science&ir=Science&section=science)**
>
> Ancient Egyptians appear to have tracked the bright-to-dim cycles of the distant star system with the naked eye.

I’ve long maintained that the ancients knew about Algol’s variability. The evidence usually cited – Chinese, Indian, and Babylonian records – are completely ambiguous, as is the statement that the name – “Algol” = “The Ghoul” – indicates knowledge that it’s somehow weird. (The name is Medieval Arabic, as well, so it’s not good evidence of ancient knowledge).

My argument, first published in 1995, has been through the mythology of Perseus and Medusa attached to the star. I presented it in articles and lectures, before devoting two chapters to it in my 2000 book on **Medusa**.  
Good to see I have corroboration.

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**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\
**Post date:** [December 30, 2015, 2:47pm UTC](https://boards.straightdope.com/t/ancient-egyptians-knew-algol-was-a-variable-star/741726/2 "2015-12-30T14:47:54Z")

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I thought everybody in the “field” already kinda knew that people knew this stuff for a long time.

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**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\
**Post date:** [December 30, 2015, 2:55pm UTC](https://boards.straightdope.com/t/ancient-egyptians-knew-algol-was-a-variable-star/741726/3 "2015-12-30T14:55:14Z")

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> [@billfish678](#):
>
> I thought everybody in the “field” already kinda knew that people knew this stuff for a long time.

Not judging from the literature. I’ve been through it, and there certainly is no such consensus. You occasionally find statements in popular books or on websites that the variability was known, but they never link to any studies or sources – the authors are apparently simply taking it for granted.

This stuff on Egyptian observations has only been emerging over the past couple of years. they published an earlier paper three years ago:

[http://news.discovery.com/space/astronomy/ancient-egyptians-tracked-eclipsing-binary-star-called-algol-120502.htm](http://news.discovery.com/space/astronomy/ancient-egyptians-tracked-eclipsing-binary-star-called-algol-120502.htm)