It is true, any broadcast signal we could generate rapidly dissipates due to inverse square law and would not be detectable above the radio noise more than just a few light months away, no matter how sensitive an alien reciever was. To make things worse, microwaves (the best communications frequency to use for SETI for a variety of reasons) tend to "twinkle" due to clouds of ionized plasmas in the interstellar medium, and the signal smears out quite quickly.
OTOH hand, we are capable of picking up with our own equipment beamed infrared lasers which could conceivably be built by ETIs. Of course, they would have to know exactly where we were to aim the signal at us, and we would need to know exactly where to point our telescopes to see them.
Beamed signals have much better range than broadcast signals. the Arecibo Radio telescope could transmit a focussed beam of microwaves
that would be detectable by an Arecibo-sized receiver on the other side of the galaxy. We are already capable of interstellar communications, in fact, we've had the technology for about a half-century.
Space/Science » in reply to re: "depends a lot on our aliens, too."
Signal attenuation.
The whole thread (35 posts)
- Kepler looking at Red Dwarfs
- The supernova hail. an active SETI technique.
- re: Kepler looking at Red Dwarfs URL problem fixed here
- The SETI implications
- What are alien "Keplers" seeing?