It includes, for example, the case of Mariner 1, an unmanned Venus probe launched in July 1962.

ECONOMIST: Mishaps in space: Foolish, not ghoulish | The

He argues that radar astronomy, which is used to probe things like asteroids and the surface of Venus, already gives off signals that could be picked up by aliens.

ECONOMIST: An argument over whether to send messages to aliens

In 1962, the Mariner II space probe began sending back to Earth man's first information from another planet, Venus.

CNN: Monday,