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I have done some research and so much contradict one another or I simply fail to understand.

Can a moon be used as accurate time keeping and is it possible for it to revolve around the planet once an earth day?

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  • $\begingroup$ Phobos revolves around Mars in 7 hours 39 minutes. $\endgroup$
    – AlexP
    May 26 '20 at 19:21
  • $\begingroup$ A moon is a natural satellite. The ISS is technically a satellite and has an orbital period of ~90 minutes. The only 'real' trick is making the "moon" large enough to be readily visible, but still small enough to have the desired orbital period. (BTW, if you can increase the moon's albedo, that will help.) $\endgroup$
    – Matthew
    May 26 '20 at 19:36
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Yes. Yes, technically.

You can accurately keep time with the moon, although 'accurate' here doesn't mean much because you're talking about on a scale of either hours (using the moon's passage across the sky) or months (measuring by moon cycles). Both of these are consistent enough so you don't need to worry about fluctuations.

Having a moon revolve around a planet in a day means that it needs to be faster, and that means it needs to be closer. As it happens, the Moon is too large for the Earth to be able to rotate around it in a day with no consequences, but it's totally possible for a smaller moon.

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There's no reason that a moon revolving around a planet has to take longer than a day. Jupiter's day lasts around 10 hours. Its fastest moon, Metis, revolves around the planet about every 7 hours. Changing the distance and speed of the moon could have other effects on the planet, such as changing tides and possibly altering the orbit (like how Charon pulls Pluto much more than Luna pulls the Earth).

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  • $\begingroup$ Those orbits are longer than a Jovian day. $\endgroup$ May 28 '20 at 1:58

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