It’s Gail’s first How of the series, so here she is, grinning in the way that only people in video freeze-frames can. Anyway: How noisy can you be in space?

Well, being noisy is Gareth’s speciality, and space is too – so being noisy in space is something he should be excellent at.

But it’s Gail’s How, so on we go: a quick recap about how sound travels. Sound waves are compression waves, traveling through the air as pulses along the direction they travel – like the waves in this spring.

But what if there’s no air? There’s no air in space, so what happens to the sound waves? Allow Gail to demonstrate, with this apparatus.

In the jar, a metronome, ticking away regularly. You lose some of the effect by reading this website, but if you saw the show, you heard the sound leave the metronome, travel to the jar, pass through the jar, travel through the air to Gail’s microphone, and then all that clever TV stuff delivered the sound to your TV set.

So what happens if Gail turns on the vacuum pump to suck the air out of the jar?

Well, this is a website, so: not a lot. However, in the show, you’ll have noticed that the ticking metronome became entirely silent. It’s still ticking, of course – but there’s no air in the jar to transmit the sound it makes. So you don’t hear a thing.

When Gail opened the valve to let the air back in, you heard the metronome again, as clearly as before.

Space is rather like the inside of the jar – there’s no air, so sound can’t travel, and you don’t hear a thing. Of course you can’t breathe either, so it’s all a bit moot, but don’t expect to be hearing exploding spaceships and zipping laser sounds if you ever find yourself in a space battle. Sorry.