"Life-Line" is a short story by American author Robert A. Heinlein. Published in the August 1939 edition of Astounding, it was Heinlein's first published short story. The protagonist, Professor Hugo Pinero, builds a machine that will predict how long a person will live. It does this by sending a signal along the world line of a person and detecting the echo from the far end. Professor Pinero's invention has a powerful impact on the life insurance industry, as well as on his own life. Pinero is mentioned in passing in the novels Time Enough for Love and Methuselah's Children when the practically immortal Lazarus Long mentions having been examined and being sent away because the machine is "broken". Source: Wikipedia (en)