NASA Tests EM Drive

[AFTT47]

We haven't been broadcasting powerful radio signals for even 100 years and already, our RF footprint is rapidly decreasing. We are using satellite transmitters to better focus our emissions where we want them to go. More efficient. We are also turning towards fiber optic transmission of data. Again, more efficient.

Alien civilizations don't need RF leakage to detect us. They could detect us by analyzing the spectra of sunlight filtered by our atmosphere. Our activities have already left an unmistakable footprint there. If they are interested, they know we're here.

It would take radio telescopes enormously larger than what we have to detect RF leakage even from Alpha Centauri. We might detect deliberate transmissions aimed in our direction but why would an alien civilization do that? They know we would detect life once we had space-borne telescopes large enough to look at their atmosphere. We might even detect artificial habitats optically in the same way. There is no need to broadcast one's existence aside from a deliberate effort to communicate. But the closest alien civilization within even a ten thousand year technological window of us is probably thousands of light years away. Catching their message at the right time might be very unlikely.