Why we might be alone in the Universe

[BrianSoddingBoru4]

And just from the perspective of power usage, it is reasonable to limit the spread of any emission you make.

of course, there is also the question of whether EM radiation is the preferred method of communication.

Based on our understanding of physics, there are certain things, such as probing quantum world at extremely tiny scale, that in principle can only be done with expenditure of ever more enormous amount of energy.  The law of thermodynamics says there is in principle a limit to how efficient such expenditure of energy can be.   So there is an argument that as civilization become more advanced then ours, it will inevitably leak ever more in principle unavoidable waste energy, most likely in the form of EM.

And yet we don't seem to be able to detect this leakage, at least in any form that would indicate it comes from technology.  I happily grant your point that we haven't explored much of the universe, but it seems telling that everywhere we have looked, we've found nothing.

Boru