3 ms·
A counter to that might be that these signals aren't strong enough to accurately detect our exact location at interstellar distances. Parallax is hard at those
by headcanon 8y ago
A counter to that might be that these signals aren't strong enough to accurately detect our exact location at interstellar distances. Parallax is hard at those distances - if we were to get a signal from a point in the sky, whats to say its coming from one star, or another one "behind" it? Not possible to determine from the signal strength alone, since you don't know the signal's original strength.
In Carl Sagan's Contact, we were only able to determine the signal came from the star Vega because it was the only star that would have been at the right distance to receive our earliest radio signal and transmit it back to us - also Vega is relatively close by compared to other stars, close enough that our parallax created by our orbit around Sol was sufficient to get a read on signal source.
A deliberate attempt at active signaling would remove all doubt for an extrasolar observer.
Liu Cixin's The Dark Forest explores this scenario in depth. I would explain more but don't want to reveal some important spoilers.
- jandrese 8y agoIt might be hard for us to figure out where the signal is coming from, but an alien race that is capable of traveling between star systems shouldn't have any problem figuring it out. Frankly if such an alien race exists they already know there is life on Earth just from the changes in chemical composition of our atmosphere. They can even figure out when we discovered agriculture. In a few decades they will even know that we discovered radio communication.