Life could exist in another solar system in a different part our galaxy. Or in another galaxy far away. We don't have the perfect technology yet to study such far away places but we're still trying.
When it comes to their own "voices", studies show that cats and dogs use different vocal signals to communicate different messages.
Everything you can touch is made of molecules – but feelings, sound and light are something different.
Ants have something similar to blood, but it's called haemolymph. Some insects use it in unusual ways. When threatened by a predator, blister beetles can squirt haemolymph from their knees.
Travel can come with danger, so dogs have mostly evolved to avoid being over-adventurous. That said, dogs may see some kinds of travel as a chance to find things they want -- like food or a mate.
From about age seven, Spartan children learned to fight and practise obeying orders. They also staged pretend battles. Boys and girls were trained separately.
Our eyes don't grow much at all – but when we're very young, we still need to learn how to see.
When I was little, geologists worked out Earth's surface was made of pieces, like a giant puzzle. Those pieces, called “tectonic plates”, move and bump into each other and mountains form.
Hydrogen peroxide is a chemical that can kill germs. It is found in two things many ants love to eat: nectar and honey dew.
At the end of the day, the problem is that no-one on Earth wants nuclear waste stored near them, and it's not safe or cost-effective to blast it into space.
Whatever your age, whatever your favourite topic -- space, animals, nature, physics, how bodies work -- we've got a Curious Kids article for you.
Some colour blind people only have two kinds of cone cell in their eye. Others have three kinds, but the cones do not pick up the same light waves as the cone cells in most people's eyes do.
Twice every day the Bureau of Meteorology sends out the official weather forecasts for towns and cities across Australia. Here's how we work out what to say in them.
What colours we see depends not just on how things are in the world around us, but also on what happens in our eyes and our brains.
The Moon has gravity of its own, which pulls the oceans (and us) towards it.
When we are asleep our brain does not switch off. It keeps working, but not as hard.
The Earth's core is cooling down, and one day it will be completely solid – when that happens, Earth might look a lot like Mars.
Long ago in the distant past, our entire Universe was microscopic – just like an atom – and obeyed completely different rules of cause and effect.
I have worked on this problem for many years, and to be honest it still blows my mind to really think about just how complex it is.
It can actually be very tricky to define a species, but in the 1900s, scientists found a pretty good way.