Space is silent.
for grown-ups
What we actually know
Yes, for any sound a person could hear. Sound is a shake that passes from one bit of stuff to the next: through air, water, or something solid. Space is very nearly empty, so there's almost nothing to carry it. An astronaut on a spacewalk couldn't hear a friend shout from right beside them. Their suits have microphones, and they talk by radio, which needs no air.
The round's record is one of the oldest experiments on it. In 1660 Robert Boyle reported pumping the air out of a glass jar with a bell inside, and the bell's sound faded as the air went. (Early pumps couldn't empty a jar completely, so the round says only "fainter and fainter".) Many school science rooms still do this with a buzzer or a phone in a jar.
Two honest wrinkles, so the round doesn't over-claim. Space isn't a perfect vacuum. In 2022 NASA released a "black hole sound" from the Perseus galaxy cluster, and it's real: the cluster is full of thin hot gas, and the black hole sends pressure waves through it. But those waves are about 57 octaves below middle C, far too deep for any ear. Scientists raised them by 57 and 58 octaves so we could hear them. And sound can reach an astronaut through something they're touching: on the Moon, the astronauts' microphones picked up their tools through their suits.
This is a hard-to-check claim: nobody playing can go to space to listen. The move is to check how people found out.
Sources: Museo Galileo, Florence, "Sound in the vacuum" (Boyle's bell-jar, reported in New Experiments Physico-Mechanicall, 1660); NASA Chandra X-ray Center, "A Universe of Sound: Perseus" (chandra.si.edu/sound/perseus.html); HowStuffWorks, "Can humans hear in space?" (spacesuit radios). You may read that Boyle used a ticking watch. That version is common, but we couldn't trace it to Boyle's own text, so the round uses the bell.
What kids usually bring
- "There's no air in space." Exactly the right idea. The round asks where they got it, and the bell-jar shows why it matters.
- "Someone told me space is silent." A fine where-from. The round asks whether the record says the same.
- "Astronauts talk by radio." A good clue to work from: why would they need radios if they could just shout?
- "In films, spaceships go boom." Seeing it is real seeing. The round asks who made the film, and whether they were in space at the time.
- "Rockets are really loud." True, down here in the air. A launch is one of the loudest things people make. The round asks what happens to the roar where the air runs out.
- "I've heard a black hole sound." Real, and a great find. It's waves in thin gas, far too deep for ears, made higher so we could hear them.
At dinner
Ask: "How could anyone find out what space sounds like, without going there?" Then try the round's take-home: watch a space scene in a film together and ask who made the bangs.
Then the one rule: say their reason back before you give yours.
The round never tells your child what to think. This card tells you what we know, so you're never caught out. If your child wants to argue with it, that is the point.
