[midasuni]

But we wouldn’t be able to detect human level lunar activity in a million years time.

We can barely detect human activity from 50 years ago when we know exactly where it is.

I think we are More likely to spot ancient Geostationary satellites, which will have drifted away from a perfect circle but should still be noticeable. LAGEOS aren’t in anywhere near that high an orbit but should survive 8 million years. They have a plaque on them designed by Sagan should a future civilisation find them.

[ericbarrett]

You’re right about satellites but I think you’re underestimating how long a monolith could last on the Moon. For something big and built to last, it could be many many millions of years https://bigthink.com/starts-with-a-bang/astronaut-footprints...

[midasuni]

But we haven’t put anything built to last on the moon - rovers and landing stages are very small and relatively fragile

A similar civilisation may have gone to the moon, but thanks to irradiation and micrometeorites over millions of years. Footprints and tyre tracks would certainly be gone, and while you could land at an Apollo landing site and detect remains of refined metal, it’s unlikely to be something you could see from orbit with our level of equipment, you’d have to get up close and personal, and we haven’t done that.