Because space is big. The galaxy might be teeming with life, but the gulfs between stars make visiting our neighbors an impossible mission – at least for now. Remember, it would take thousands of years to travel to the closest star outside our solar system using modern spaceship technology.
As previously mentioned, space is big, so there are tons of regions to listen for alien signals. If we’re not listening precisely in the direction from which a signal is originating, we’d never hear it.
Radio technology may be commonplace here on Earth, but on far-flung worlds, alien societies may have graduated to more advanced communication technologies, like neutrino signals. We can’t decipher those just yet.
Picture Credit : Google