Using The Moon As A Giant Mirror

You can talk to someone on the other side of the planet by bouncing radio signals off the lunar surface. This moon bounce technique treats our natural satellite like a massive, celestial mirror for radio waves.

Because the Moon is so far away, these signals take about 2.5 seconds to travel there and back. Amateurs often use this method to communicate over vast distances that would normally be blocked by the curve of the Earth. It requires high-powered transmitters and large antennas to capture the faint echoes returning from space. The moon acts as a passive relay that requires no power or technology to function.