I see no reason why extraterrestrial life should not exist given the large amount of stars and also considering the discovered planets within other star systems.
We may have already been contacted by Extraterrestials. The problem is how to prove it!
The benefits of contact are the possible receipt of very advanced technology from a benevolent visitor. The danger is a takeover by a not so friendly visitor.
Humans are already transmitting a beacon in a sense so I see no reason to attempt to hide by not transmitting a more scientifically planned beacon. I would think that a transmission of regularly spaced pulses would be sufficient to attrack extraterrestrial attention; however, I would attempt to encode certain mathematical numbers into the pulses such that the amplitude of these pulses when decoded would form numbers such as pi which aliens would recognize as being of non-natural origin. It would be simple enough to transmit 31415 as a set of continuously repeating and evenly spaced pulses at a specific narrow frequency. In other words, 30%, 10%, 40%, 10%, 50% of full power from the transmitter and then repeat this sequence continuously. What is nice about this is that they would observe some 50% power triplets with this pattern. This should cause them to investigate further and they should then discover the real pattern!!!
31415314153141531415. This approach also conserves power even further since the average power of the pulses is only 28% of the total power (if 100% bursts were used) during a 5 burst sequence.
I run SETI@home because it's great to be a part of real Physics and such a large group doing the same thing and who knows, maybe I will find the signal that is really E.T.!!!
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