EVER WISH E.T. WOULD PHONE YOUR HOME? THE scientists at the SETI (Search for Extraterrestrial Intelligence) Institute do. They seek unnatural variations in light and radio waves that may indicate alien civilizations. Some scientists even hope to send signals of our own out to the black, but it's not easy to be seen and heard over all the stars, asteroids, and interstellar dust. We don't have beacons powerful enough to reach the whole universe, nor receivers capable of monitoring the entire expanse. Other civilizations might, but there's no way to tell until they finally hail us. All we know is how far our strongest signals could travel. Here's where we're searching-and where we fall short.
展开▼
