These would probably be fairly difficult to detect. The vast majority of the radio messages we have leaked into space over the last 100 years or so weren't focused. By the time they reached a neighbouring star they might be hard to distinguish from background noise. Also let's say someone did manage to detect these signals and they were 80ly's away. They might not have detected them until say 2000, and if they immediately send back a message, we would not receive this until 2080.
I think our best hope is that an Alien civilisation has begun the search for extrasolar planets, like we have. They will be able to analyse the composition of our atmosphere using spectroscopy.
With this information they would either decide that life either exists or is very likely to exist here, and so would begin transmitting a constant and unmissable signal to us in the hope that we would eventually detect it. Providing we manage to monitor the right frequency and look at the right point in the sky..... as life has existed here on earth for Billions of years, perhaps this signal is already been sent to us and we just need to find it....
It's a long shot but perhaps it's the best one we have.
I think our best hope is that an Alien civilisation has begun the search for extrasolar planets, like we have. They will be able to analyse the composition of our atmosphere using spectroscopy.
With this information they would either decide that life either exists or is very likely to exist here, and so would begin transmitting a constant and unmissable signal to us in the hope that we would eventually detect it. Providing we manage to monitor the right frequency and look at the right point in the sky..... as life has existed here on earth for Billions of years, perhaps this signal is already been sent to us and we just need to find it....
It's a long shot but perhaps it's the best one we have.