via HACKADAY: The Hunt For Alien Radio Signals Began Sooner Than You Think

Every 26 months, Earth and Mars come tantalizingly close by virtue of their relative orbits. The closest they’ve been in recent memory was a mere 55.7 million kilometers, a proximity not seen in 60,000 years when it happened in 2003.

However, we’ve been playing close attention to Mars for longer than that. All the way back in 1924, astronomers and scientists were contemplating another close fly by from the red planet. With radio then being the hot new technology on the block, the question was raised—should we be listening for transmissions from fellows over on Mars?

Flashback to 1924, a time when the cosmos was less understood but no less marveled at. Earth and Mars were drawing near, and with that, an ambitious, albeit quaint by today’s standards, attempt to probe the Red Planet for signs of life was set into motion. It wasn’t with the sophisticated rovers or orbiters of the modern era. Instead, the plan was to keep out a listening ear for potential Martian radio broadcasts.