JohnnyUtah_QB1 t1_j9tmiux wrote on February 24, 2023 at 1:59 PM

I’ve seen it suggested that our most powerful telescopes would struggle with separating Earth-like signals from cosmic background noise from sources around 100 light years out. The distance could be increased if someone was intentionally focusing high powered communications directly at us wanting to be seen, but as far as detecting incidental signals it’s not very far out with respect to the the vastness of the galaxy.

In terms of searching we’ve barely looked around the galaxy. That being said, there’s about 60,000 stars within that radius. So the sample set isn’t zero.

Italiancrazybread1 t1_j9txjdp wrote on February 24, 2023 at 3:18 PM

You technically can pick out very low signals from the background noise if the signal is repeated continuously, or for at least a long enough time that the receiver gets all the information from the signal.

This is how we are able to receive signals from the voyager probes from so far away. The probes repeat their signal many times because here on Earth we likely won't get the full message the first time. Every time the message gets sent, we decipher more and more of the message.

JohnnyUtah_QB1 t1_j9tzhvt wrote on February 24, 2023 at 3:30 PM

I presume that estimation was accounting for that. The fact that signal power exponentially diminishes over distance is really challenging for us.

In the context of these distances Voyager has barely walked out the front door. It's just 0.002 Light Years away. At 100 Light Years away its signal would be 5 million times fainter than it is now, many order of magnitude below the detection threshold of any equipment that exists. No amount of listening with current technology would ever detect that energy level