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“Will you have an echo on the moon?”—
The moon is an echoless wasteland, sadly. Echoes happen when a sound wave bounces off of something and reflects back towards you. This is pretty noticeable in canyons, or other places where there’s a big, relatively flat wall at some distance away from you. If you shout, you’ll hear a faint response, and the delay depends on how far away you are from the wall that’s reflecting the sound.
But echoes are all caused by sound waves, and sound always needs a medium to travel through. Fundamentally, sound is a compression wave; if there’s nothing to compress, there’s no way for the wave to move. On earth, we hear echoes as the sound we create moves through the air. But the moon doesn’t have an atmosphere, so there’s no air for the sound to travel through, so any noise would die instantly. And if you can’t have sound, you can’t have echoes.
That said, if you were on the moon, it’d be quite unwise to remove the helmet from your space suit, so you’d simply get an echo off the front of your helmet instead. Unfortunately, the sound would come back to you so quickly that you wouldn’t be able to hear it as a separate sound.
Have you got a question of your own? Something making you curious? Feel free to ask!