Earth to disappear from alien radar

Now that's something I've never thought of before. As we advance, we make less "leaky" technology, and we get harder to see. It's very possible that alien cultures, as they advance, have a short window where they're very audible, and then they quiet down, like we're beginning to.

That will make it a lot harder for us all to find each other.

Earth to disappear from alien radar | The Register