Talk:Eratosthenes

Latest comment: 2 months ago by Daianaz12 in topic Measurement made at Local Apparent Noon (LAN)
WikiProject iconAstronomy High‑importance
WikiProject iconThis article is within the scope of WikiProject Astronomy, which collaborates on articles related to Astronomy on Wikipedia.
HighThis article has been rated as High-importance on the project's importance scale.
WikiProject iconGeography High‑importance
WikiProject iconThis article is within the scope of WikiProject Geography, a collaborative effort to improve the coverage of geography on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
HighThis article has been rated as High-importance on the project's importance scale.
WikiProject Geography To-do list:

Here are some tasks awaiting attention:
WikiProject iconPoetry Mid‑importance
WikiProject iconThis article is within the scope of WikiProject Poetry, a collaborative effort to improve the coverage of poetry on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
MidThis article has been rated as Mid-importance on the project's importance scale.
WikiProject iconMathematics High‑priority
WikiProject iconThis article is within the scope of WikiProject Mathematics, a collaborative effort to improve the coverage of mathematics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
HighThis article has been rated as High-priority on the project's priority scale.
WikiProject iconAncient Egypt Low‑importance
WikiProject iconThis article is within the scope of WikiProject Ancient Egypt, a collaborative effort to improve the coverage of Egyptological subjects on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
LowThis article has been rated as Low-importance on the project's importance scale.
WikiProject Ancient Egypt to-do list:
  • Needed articles.

We should have an article on every pyramid and every nome in Ancient Egypt. I'm sure the rest of us can think of other articles we should have.

  • Cleanup.

To start with, most of the general history articles badly need attention. And I'm told that at least some of the dynasty articles need work. Any other candidates?

  • Standardize the Chronology.

A boring task, but the benefit of doing it is that you can set the dates !(e.g., why say Khufu lived 2589-2566? As long as you keep the length of his reign correct, or cite a respected source, you can date it 2590-2567 or 2585-2563)

  • Stub sorting

Anyone? I consider this probably the most unimportant of tasks on Wikipedia, but if you believe it needs to be done . . .

  • Data sorting.

This is a project I'd like to take on some day, & could be applied to more of Wikipedia than just Ancient Egypt. Take one of the standard authorities of history or culture -- Herotodus, the Elder Pliny, the writings of Breasted or Kenneth Kitchen, & see if you can't smoothly merge quotations or information into relevant articles. Probably a good exercise for someone who owns one of those impressive texts, yet can't get access to a research library.

WikiProject iconClassical Greece and Rome Mid‑importance
WikiProject iconThis article is within the scope of WikiProject Classical Greece and Rome, a group of contributors interested in Wikipedia's articles on classics. If you would like to join the WikiProject or learn how to contribute, please see our project page. If you need assistance from a classicist, please see our talk page.
MidThis article has been rated as Mid-importance on the project's importance scale.
WikiProject iconEgypt Low‑importance
WikiProject iconThis article is within the scope of WikiProject Egypt, a collaborative effort to improve the coverage of Egypt on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
LowThis article has been rated as Low-importance on the project's importance scale.
WikiProject iconLibraries Low‑importance
WikiProject iconThis article is within the scope of WikiProject Libraries, a collaborative effort to improve the coverage of Libraries on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
LowThis article has been rated as Low-importance on the project's importance scale.
WikiProject iconGreece Low‑importance
WikiProject iconThis article is within the scope of WikiProject Greece, a collaborative effort to improve the coverage of Greece on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
LowThis article has been rated as Low-importance on the project's importance scale.
WikiProject iconHistory of Science Low‑importance
WikiProject iconThis article is part of the History of Science WikiProject, an attempt to improve and organize the history of science content on Wikipedia. If you would like to participate, you can edit the article attached to this page, or visit the project page, where you can join the project and/or contribute to the discussion. You can also help with the History of Science Collaboration of the Month.
LowThis article has been rated as Low-importance on the project's importance scale.

Eratosthenes' measure of Earth circumference

Original image
New image

In these changes, @PostaDiDonna: replaced the illustration File:Eratosthenes_measure_of_Earth_circumference.svg with File:Eratostene--Calcolo_Raggio_Terrestre.jpg.

Though I agree with the new caption noting that Syene and Alexandria are not on the same meridian, I believe that the original image is more accurate as the angle is to scale and being an SVG, it can be easily translated.

May I get a second opinion on this?

Thanks,
cmɢʟeeτaʟκ 22:26, 26 August 2021 (UTC)

 Done I've updated it as there has been no objection. cmɢʟeeτaʟκ 22:43, 19 April 2022 (UTC)
Better late than never, they say… Well, I have looked at @PostaDiDonna:’s changes on this page as well as on Earth's circumference#Eratosthenes and frankly, this user’s edits look biased to me. Basically the only reference they quote is Lucio Russo’s book The Forgotten Revolution, and they even went so far as to remove most if not all other references when they disagreed with that book.
While it is a very good and informative book, I hardly see how it makes it worth removing other references, such as Ian Ridpath’s book The Illustrated Encyclopedia of the Universe; Albert van Helden’s book Measuring the Universe: Cosmic Dimensions from Aristarchus to Halley; or an article by Raymond Mercier in The History of Cartography.
I consider the removal of these references a loss for the Wikipedia community—not everyone will, like I did, delve deep into the history of the pages to find other references than Russo’s book.
I have left a long message on their user page (although they seem to have stopped visiting Wikipedia in September 2020) asking for their rationale for replacing all those references by a single reference.
Meanwhile, I will try my best to modify the pages Earth's circumference#Eratosthenes and Eratosthenes to mention the above sources once again, giving them a more neutral point of view.
CielProfond (talk) 03:35, 9 April 2023 (UTC)
Come to think of it, I suspect PostaDiDonna to be Dennis Rawlins or someone close to him, as one of his articles is also extensively referenced.
CielProfond (talk) 03:59, 9 April 2023 (UTC)

Wrong value for the estimation of Earth's circumference?

The article currently states [Eratosthenes] estimated that the meridian has a length of 252,000 stadia (39,060-40,320 km), with an error on the real value between −2.4% and +0.8% (assuming a value for the stadion between 155 and 160 metres) but I am fairly certain the upper limit here is incorrect (as stated in this source which claims it is 29,000 miles or around 46,000km). However, I am hesitant to change the article due to a source being referenced for the values currently used. I would refer to the source itself but I am unable to access the source (as it is a book). SailorFox (talk) 09:03, 28 November 2021 (UTC)

@SailorFox: (I moved this new talk page section to the bottom.) This question is mentioned in the last sentence of Stadion_(unit)#Calculations, and the source there ([1]) seems to support the notion that the margin of error on this calculation has a lot more uncertainty than just 2 or 3%. Danstronger (talk) 14:51, 28 November 2021 (UTC)

The estimation of one stade equal to 155-160 meter is misleading. It should be changed to 185 meter.The cited source (Donald Engels (1985). The Length of Eratosthenes' Stade. American Journal of Philology 106 (3): 298–311. doi:10.2307/295030) clearly states that one stade was 185 meter and not 155-160 meter, which gives an estimate of 46,000km to earth's diameter.The estimation of one stade being equal to 185 meter is the one accepted by most scholars (see, e.g., page 20 in Ptolemaais, Klaudios, J. Lennart Berggren, and Alexander Jones. Ptolemy's Geography: an annotated translation of the theoretical chapters. Princeton University Press, 2000.)

Geometric shapes

Hy I want to put some information about geometry 103.150.209.69 (talk) 17:34, 1 June 2022 (UTC)

Fantasy portrait

So we get another one of these fabricated portraits of the 17th/18th century, without explanation and without sourcing (even in the commons file). Good work! 2A02:AA1:1020:A09C:59CD:2C68:3B5E:177A (talk) 16:58, 25 July 2022 (UTC)

Yup, because they're public domain! What would you prefer? Furius (talk) 19:22, 25 July 2022 (UTC)
A note that it's a fantasy portrait (and not based on, say, a contemporary sculpture) would be a good start. Then add source info. 2A02:AA1:1020:A09C:59CD:2C68:3B5E:177A (talk) 09:41, 26 July 2022 (UTC)
Ok, I've chased this down and it turns out that it is based on an ancient object. No idea whether Lippert had any good reason for thinking sad object depicted Eratosthenes. Probably not. Furius (talk) 20:37, 26 July 2022 (UTC)

Measurement made at Local Apparent Noon (LAN)

This section:

The simplified method works by considering two cities along the same meridian and measuring both the distance between them and the difference in angles of the shadows cast by the sun on a vertical rod (a gnomon) in each city at noon on the summer solstice.

I don't think there is any requirement for the two cities to be at the same meridian if each measurement is taken at Local Apparent Noon (LAN). At LAN in Syene at summer solstice there would be no shadow and at Alexandria On the same day LAN could be determined as the time the shadow of a gnomon was at it shortest.CaptCarlsen (talk) 16:31, 17 February 2024 (UTC)

. Daianaz12 (talk) 14:32, 23 April 2024 (UTC)