Suppose on the moons of Jupiter there is a growing civilization of intelligent life. Assuming their technology timeline is approximately similar to our own, except lagging behind us, then...
What level of technology (e.g. in terms of an era or century on Earth) would a Jupiter-lunar civilization need in order to detect/deduce civilization on Earth as it exists today?
Maybe it's radio waves that gives us away first, or some kind of thermal signature, or chemical signature, or night lighting, or even our deep space probes. I'm not sure. Regardless of which of our own developments gives us away, what does the other civilization need in order to catch onto us?