E', I agree with you that advanced civilizations are likely to continue to monitor the spectrum to keep tabs on what's happening in the galaxy. We, for instance, live in what we like to think of as an industrial/technological age, but we still care very much about the weather. We have better ways of monitoring the weather and reacting to it than were available centuries ago, but we still keep a careful eye on it.

But I also must agree with Larry J when he points out that as technology progresses, civilization becomes more efficient in using energy, not less. I know that Sagan and others speculated that civilizations far more advanced than ours would be using far more energy than we do. And that's likely to be the case. But their control will be better.

In the past, continents were stripped of entire forests so people would have building materials and - very important - firewood for heat. These days, though, we have fossil fuels and other options, like nuclear, solar, wind, hydropower, etc. One day maybe there'll even be fusion. There's still waste, but less energy is wasted. Even though our consumption of energy continues to increase, at the same time we seem to be getting better at using the energy we have. Electronics has been a huge boon in that area. Engineers like yourself have done marvelous things for the rest of humanity.

What happens when we move to really tight-beams for our transmissions between satellites and the ground? Eventually, it should shift to lasers. And we've already made the shift from clumsy clunky analog to much more tightly packed digital.

And, finally, there's scintillation. The jumble of messages our world weakly emits into space only gets more jumbled and disorganized as it moves through interstellar space.

I don't think we'll be picking up any ET broadcasts, or that ET will be picking up any of ours.

But I also don't think that means other life - even other civilizations - can't be found out in the big bad universe. I not only think it can, but that it will.