Imagine this

On a very hot planet, aliens might have very thick skin to protect them from the heat, and be very low to the ground allowing them to easily crawl under rocks to find shade. They might have long tongues so they can dig in the dry sand for food. Perhaps they would look like a cross between a lizard and a spider!

Imagine a planet which is very cold and very dark. Aliens living there might be big, with a thick layer of fat to protect them from the cold. Unlike us, they wouldn't rely on sight to find there way around. Maybe, like some snakes, they would use touch to feel their way around. What would they look like? Maybe like a polar bear crossed with a giant worm!

What about a planet similar to ours but with only one type of animal on it. They wouldn't be able to eat other animals or plants like we do, so maybe they would get their energy from gases in the atmosphere, or from minerals in rocks. Would they have enormous lungs, or huge teeth? Or would they be so different from anything on Earth that we can't even imagine what they might look like?

You can see that because other planets in the universe might be completely unlike Earth, aliens could look very different to anything we've ever seen. It's fun to think about though, so try to work out what other planets could be like, and then use your imagination to create your very own alien. If you need some help, try our 'Alien Creator' section.