system
Given the following post, respond as if you're commenting on Reddit:
human
Why do scientists listen for radio waves when looking for intelligent life?

Wouldn't it stand to reason a species that has invented intergalactic travel would have something more advanced than radio waves?
gpt
Why assume they’ve invented intergalactic travel? We haven’t, but we still exist. If you were looking for us, looking for radio waves would be one way you could do it.

It won’t find every possible alien civilization, and it wouldn’t have found human civilization at every point of our development, but it could find us now, so it might find someone at a similar stage of development as us, and it’s a relatively easy thing for us to look for.