We Have Announced Our Presence to the Stars

There are those who predict a dire catastrophe if we broadcast our presence to another star. The extraterrestrials will come and – eat us, or something equally unpleasant. (Actually, if we are especially tasty, they need only sample one of us, determine what sequence of our amino acids makes us appetizing, and then reconstruct the relevant proteins on their own planet. The high freightage makes us economically, if not gastronomically, unappetizing.) The message aboard Pioneer 10 was critici...