Assuming ETI is still using radio (or lasers, or some other form of electromagnetic radiation) for communications, it would be energy-wasteful to broadcast in all directions when you could simply beam the data directly to the intended recipient. Of course, there may be some cases when you WANT to broadcast (police radios, cell phones, TV/Radio, etc), but these signals quickly attenuate by inverse square law. When the signal strength gets below the natural background hum of the galaxy itself, it gets lost.
It has been suggested that some civilizations may protect their planets from meteor strikes by searching the surrounding space with huge radars, and it might be possible to pick up some of that radiation here. This is not that different from our missile defence radars putting out a signal that might be picked up by alien listeners. Beams can be heard a lot further away than broadcasts, but they are also very unlikely to be picked up by anyone unless the transmitter and receiver are pointing in the right direction (at each other). This is unlikely to happen by accident.
Space/Science » in reply to re: Nothing personal, it's strictly business. Good points, Hank.
Radio Silence
The whole thread (36 posts)
- Bets on future planetary detections
- # 3..Meet The Neighbours:
- "My view on the extra-terrestrial situation is very much a positive, albiet still highly secretive one."
- re: # 3..Meet The Neighbours: Valid question.
- re: # 3..Meet The Neighbours: Valid question.
- It doesn't matter if the Neighbor are nice or not
- re: Bets on future planetary detections
- Deal me in
- # 3..Meet The Neighbours: