Except for a single episode in ToS and the traveller, I don't remember of any occurrences of intergalactic travel or communication in even in Star Trek, and in Star Trek you've got magic like subspace and warp drive. If we were to use means that fall within the physical limits as we currently know them, is it possible to communicate with another galaxy, even if the technology is stretched to its limits?
Save for the few small galaxies that orbit the Milky Way, the closest galaxy to us is Andromeda, and it's 2.5 million light-years away. Now, waiting 5 million years for a reply doesn't concern me that much, nobody is talking about two-way communication, but what about the signal strength?
Is it possible to construct a combo of a precise and powerful laser and a huge radio telescope so that two civilisations that know about each other's existence can send messages that will be received at such distance? Now, that's easy, what if they don't know about each other? The sending party doesn't know where to send it, and the laser encompasses the whole galaxy (can we get lasers that precise?), and the receiving party listens for everything that comes from every nearby galaxy. How powerful would the laser have to be so it can be distinguished from the other radio noise coming from the sender, and without the ability on the part of the receiver to isolate any specific part of the sending galaxy? Can it be done with an acceptable amount of power?
For some reason I'm feeling concerned that we could be the only advanced civilization in our galaxy (only 500 million estimated planets in the habitable zone...), plus some people are warning against active SETI, and active SETI towards another galaxy would be more or less completely harmless, because you would get no reply let alone visitors.
(Though it would be wrong to call it “active SETI”, but at least we could get famous somewhere.)
Save for the few small galaxies that orbit the Milky Way, the closest galaxy to us is Andromeda, and it's 2.5 million light-years away. Now, waiting 5 million years for a reply doesn't concern me that much, nobody is talking about two-way communication, but what about the signal strength?
Is it possible to construct a combo of a precise and powerful laser and a huge radio telescope so that two civilisations that know about each other's existence can send messages that will be received at such distance? Now, that's easy, what if they don't know about each other? The sending party doesn't know where to send it, and the laser encompasses the whole galaxy (can we get lasers that precise?), and the receiving party listens for everything that comes from every nearby galaxy. How powerful would the laser have to be so it can be distinguished from the other radio noise coming from the sender, and without the ability on the part of the receiver to isolate any specific part of the sending galaxy? Can it be done with an acceptable amount of power?
For some reason I'm feeling concerned that we could be the only advanced civilization in our galaxy (only 500 million estimated planets in the habitable zone...), plus some people are warning against active SETI, and active SETI towards another galaxy would be more or less completely harmless, because you would get no reply let alone visitors.
(Though it would be wrong to call it “active SETI”, but at least we could get famous somewhere.)
