system
Given the following post, respond as if you're commenting on Reddit:
human
Is there a theoretical limit to how much detail we can get from satelital images?

The resolution you can get out of Google maps is pretty good, and we can make our individual persons most of the time. Will the technology ever get so good that we will be able to make out, say, an ant?
If not, does the limit come from our technological capacity or is the limit a theoretical one, where it's physically impossible to get more resolution/detail?
gpt
Diffraction puts a (quite) hard limit on the size you can resolve. To distinguish two things (like an ant from the ant next to it) with a separation x from a distance d using wavelength lambda your telescope should have a diameter of d\*lambda/x. Let's take 5 mm for the ants, 400 km for the orbit, and 500 nm for the wavelength, then your telescope needs a diameter of 40 meters. That's the size of the largest optical telescope under construction on Earth (ELT), and much larger than any space telescope under development. You don't need a full mirror that size, an interferometer that has a few smaller mirrors spread out that much can work as well, but this is not easy to build either.

Atmospheric distortions are another thing to worry about - currently more relevant for space telescopes looking outwards, but on the level of watching ants this might become relevant for the opposite direction, too.

Google maps uses satellite images for large-scale views and images from airplanes for the higher zoom levels. If you can see people then the image is most likely from an aircraft.