/sci/ - Science & Math

FIrst, let's start by saying that observable universe itself is massive with a radius of 46.5 billion light-years, or a diameter of 93 billion light-years, and we haven't even explored or mapped 1% of that.
Now, for the main crux of the issue for those who understand the massive nature of it, why why we haven't received any artificial radio signals, other than the Wow! signal, is because of signal attenuation. By the time signals get here, they're too weak to be picked up by our current technology.
As for why they haven't replied to any of the signals we've either consciously or ambiently sent is, again, due to the massive nature of the observable universe.
We have only been broadcasting radio signals into the universe for around 100 years, that is to say, those radio signals will have only travelled 100 light-years, which isn't really any great distance, and may have passed by exoplanets with extraterrial life that wasn't intelligent enough to receive them.
Part of the way we might be able to mitigate these issues by through the creation of equipment like the James Webb Space Telescope, that will allow us to collect and analyze more data from stars and their exoplanets.
Just wait, we're going to find something.