system
Given the following post, respond as if you're commenting on Reddit:
human
Would it be possible to link a telescope on Earth with one on Mars to see farther and more clearly the same way that telescopes in different locations on Earth can be linked?
gpt
Yes, but there's a lot of things that make it tricky.

Firstly, you need to know the distance between telescopes down to a precision that scales with wavelength. So if you're doing radio frequencies, you need to know the distance down to like 10s of cm or tighter. That's doable even even across the entire diameter of Earth if you're careful, but from Earth to Mars it gets tricky, especially as the distance is changing over time (this makes combining the signals a lot more complicated as well!) For visible light we're talking like 100s of nanometres, which is doable on-site for telescopes physically next to each other, but is tricky to do across the Earth, let alone from Earth to Mars.

Secondly, you need to combine the signals somehow. For low frequencies, you get data slow enough you can save it to disk and combine the signals digitally. But even with all our modern infrastructure, this can be too much data to send through the internet. For the Event Horizon Telescope, they literally shipped the hard drives around the world to combine the data, because at that scale it's the most efficient and least error-prone way to do it ("Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway"). So getting that much data from Mars to Earth is a genuine problem. It's even worse in optical and infrared wavelengths, because the frequency is so high that it's just not practical to save that much data, so instead we physically combine the actual beams of light, which isn't really doable beyond telescopes on a single site.

Finally, resolution isn't everything. We actually have ground-based infrared interferometers with much higher resolution than the James Webb Space Telescope. Having a big collecting area is also really important, as that gives you high sensitivity. Also, interferometers only give you resolution in the direction between the telescopes. You'd get very high resolution along the Earth-Mars axis, but low resolution at right-angles to that. Basically, each "pixel" would be extremely long and thin - basically you're getting a high-resolution 1D image of some object (although as Mars and Earth move relative to each other, you could build up a proper 2D image over time).