What size Moon structure could we see from Earth? © Getty Images

What size Moon structure could we see from Earth?

The Moon itself has a radius of around 1,700km & is 380,000km away, so how big would a structure on the Moon have to be for us to see it with the naked eye?

Asked by: David McLellan, Glasgow

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The average human eye has a resolving power of around 1/60th of a degree, meaning that under good conditions it can see objects at distances up to roughly 3500 times the size of the object. The Moon being around 380,000km away, means that under ideal conditions we should be able to see objects around 100km across.


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