Talk:Astronomical unit

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Astronomical unit was nominated as a Natural sciences good article, but it did not meet the good article criteria at the time (April 10, 2018). There are suggestions on the review page for improving the article. If you can improve it, please do; it may then be renominated.

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Rounding errors, or contradicting sources

This article in #Development_of_unit_definition:

> 1 astronomical unit [..] ≈ 499.004783836 light-seconds

Same article, in the table at #Examples:

> Light-second [≈] 0.0019 [au]

I would expect that rounded value to be 0.002 or more, not less. 2A10:3781:11DB:1:1993:C326:C2A3:B78 (talk) 14:12, 16 December 2023 (UTC)[reply]

I agree. Light-second expressed in au is 149,597,780,700 / 299,792,458 = 0.002003989. I made the change Jc3s5h (talk) 16:30, 16 December 2023 (UTC)[reply]

improved

The article mentions the improved measurement of the speed of light in 1983. The way I know it, is that the ability to measure time, or frequency, improved, but the ability to accurately measure distance did not. So, defining c increases the ability to measure distance. But also, defining c means that it is now measured infinitely accurately, by definition. Or, the other way to look at it, you can't measure the speed of light anymore. Gah4 (talk) 09:51, 14 April 2025 (UTC)[reply]

Links to IAU publications

The IAU recently restructured its website, and PDF files of some publications are now made available on Google Drive, for example some resolutions referenced in the article. The original links to the files were removed.
Here is the link to the current page listing resolutions:
https://www.iau.org/Iau/Publications/List-of-Resolutions
The direct link to Resolution B2 adopted at IAU General Assembly 2012 is here:
https://drive.google.com/file/d/1FBKjaswlP-rTs6z6V4WygXsbdHKVHYcP/view
The direct link cannot be included in the article because it will receive a tag "citing a blog or free web host" indicating a source that is not reliable. The workaround that can be used for now is to cite a link to an archived version of the publication instead.
See also https://www.iau.org/Iau/Iau/About/Archive.aspx?hkey=8e870620-d676-447e-b436-805189f20a99
Uxh (talk) 10:09, 20 April 2025 (UTC)[reply]