What would they look like?

So, if it is possible for life to exist on other planets, what would it look like? Well, it almost certainly wouldn't look like it does in Hollywood films. Aliens are usually quite human in shape because actors either play the roles in make up or are used as models for computer designed aliens. Because we have never discovered any aliens and don't really know what other planets might be like, what they look like is down to our imaginations.

A good place to start is right here on Earth. The way life on Earth looks is affected by things such as temperature, the way we get our energy (from food, oxygen, the Sun) and the way we use our senses (sight, smell, hearing). The same things are likely to affect the way aliens would look too. Try imagining what an alien's planet might be like. When you have decided if it's hot or cold, light or dark, wet or dry and so on, you can decide what sort of properties an alien would need to get food and find its way around that environment. To make it easier, try thinking of animals on Earth that live in extreme environments like deserts, the North Pole or deep underwater. Maybe aliens would be similar to some of these animals, or maybe they would look like a mixture of more than one Earth animal.