Nuclear Economy

[jwl]

Sure but if were talking deception they might pile up useless coal beside a nuclear plant ect... stuff can be done. I only raise deception so much because if it doesn't matter... then you could just ask the planet if it has split the atom or not anyway,

Well, that depends on their communication system. On a hypothetical alien planet, the way they communicate may be incomprehensible or even undetectable.

[Simon_Jester]

Theoretically- but you have so many reasons to want to crack their communication system so you can talk to them, that asking them a question is a reasonable thing to learn to do.

It's hard to imagine circumstances where it is vital to know whether or not a planet-bound civilization has nuclear power, when you have orbiting starships and are therefore technologically superior to them, AND you can't talk to them or interact with them meaningfully.

[chornedsnorkack]

USA knew that USSR had nuclear weapons within weeks in 1949, because they made air samples.

But after USA launched first satellites in 1958 - how long did USA need to find out the locations of nuclear reactors in USSR?

[Simon_Jester]

Probably a few weeks (months at most) after we orbited a satellite with the necessary sensor capability.

An interstellar civilization would already have that capability.