Horrible Science: Realistic space battle

Why can’t someone hear you scream in space?

Sound is a type of energy made by a vibration. When we talk (or scream), our vocal cords vibrate the air particles around us.

These particles bump into each other, transferring energy to the next particle and the next until eventually the energy reaches our eardrum.

Our eardrum also vibrates. Our brain then interprets this vibration as sound.

In space, there are almost no air particles. It is a vacuum.

If there are no air particles, there is nothing for the sound energy to travel through so the energy cannot be transferred. Therefore, your scream will be silent.

Watch: Realistic space battle

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Think movie space battles are exciting? Well, they’d be a lot less exciting if they were this realistic…

What else can’t you do in space?

In space, many everyday activities become impossible to do because there is not much gravity – much less than there is here on Earth. This is known as microgravity.

Gravity is the force which pulls things down towards the centre of the Earth. Without this force, people are unable to:

Walk because their feet are not pulled down. They end up floating.
Shower or cry properly because water is not pulled down. It forms floating blobs.
Use a normal toilet. Human waste doesn’t fall downward. Special suction systems are used to collect and dispose of it.
Sleep like on Earth. There’s no “lying down”. Astronauts strap themselves into sleeping bags attached to walls to avoid floating around.
Bounce balls. The balls just float.

Why can’t you see lasers in space?

Lasers are beams of light.

On Earth, the air around us is full of tiny things such as dust, water drops, and smoke. When a laser shines, these tiny bits reflect the light into our eyes. Therefore, we can see the laser beam glowing across the room.

In space, there is nothing to reflect the light so the laser beam just travels in a straight line. You’d only see it if the laser hits an object such as a spaceship or planet or shines directly into your eyes.

Horrible Science fact

On Earth, gravity helps to separate liquid and gas in your stomach. In space, there is little gravity so the liquid and gas mix. If you burp, you risk a “wet burp”, which means your food will come back up too.