According to the Wikipedia article for Transit of Venus, the last time a transit of Mercury and a transit of Venus occurred at the same time was 22 September of 373,173 BC. This is a Featured Article and the statement has been on the page since December 2008, implying authenticity. But I cannot find an academic citation anywhere to back this up.

I can find an academic citation for the occurrence of the next one, in 69,163 AD. But I cannot confirm the previous one.

  • $\begingroup$ See this question: astronomy.stackexchange.com/questions/13227/… $\endgroup$ Commented Jan 30, 2021 at 4:03
  • $\begingroup$ @NilayGhosh That question does not give the answer I'm looking for here, even though it is also about simultaneous transits $\endgroup$ Commented Jan 30, 2021 at 4:51
  • $\begingroup$ (1) That's wikipedia for ya. The first reference is unlinked and is from a non-academic site (Sky & Telescope). The second reference does not support the claim. It lists Mercury transits for a span of seven centuries. (2) All numerical integration techniques degrade in accuracy as time progresses forward or regresses backward. Predictions of transits are extremely sensitive to errors. Claims of transits that occurred 373 thousand years ago are beyond udicrous, at least to me. $\endgroup$ Commented Jan 31, 2021 at 9:47
  • $\begingroup$ @DavidHammen I don't know anything about this, but OP's peer-reviewed source searched 300,000 years into the future and 280,000 years into the past and they seem fairly confident in what they found, so extending that by another 33% might be possible. The claim was added by user Savage84, who only made transit-related edits and often cited savage-garden.org, a now-defunct website that cited SOLEX as a source. I bet it was original research by Savage84, but it may be correct. $\endgroup$
    – benrg
    Commented Feb 1, 2021 at 18:32
  • $\begingroup$ @DavidHammen I dug up the issue of S&T and they reference Jean Meeus and Aldo Vitagliano in the June 2004 Journal of the British Astronomical Association electronic ref to S&T no mention of to the BC date $\endgroup$ Commented Feb 2, 2022 at 1:13


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