The oldest known skeleton of our species _Homo sapiens_ is about 300,000 years old. But there was a time when humans didn't exist at all and the world was covered in nothing but slime.
A light invisible to humans makes chemicals in our skin very excited. In fact, the chemicals become so excited they change shape and become vitamin D.
It's a lot more than you might think.
Human genes are one of the main reasons we can't grow wings. And even if humans did have wings, they wouldn't necessarily allow us to fly.
If you could go right into the middle of the Sun, everything would be incredibly bright - and perhaps a little bit pink.
Your faithful friend's view of the world is different than yours, but maybe not in the way you imagine.
If gravity was half as strong, you could jump much higher.
Having longer top eyelashes can enhance our ability to express our feelings and communicate with others. But the most significant reason we have them is to protect our eyes.
Physicists can use bright, hot lasers to slow atoms down so much that they measure -459 degrees Fahrenheit.
How do people in a special airplane flight get to float like there is no gravity – just like astronauts? An aerospace engineer explains.
There are two types of time travel: going back in time and going forward in time. And remarkably, people can feel time at different rates - but usually don't notice it.
Imagine being able to detect a smell from more than a kilometre away. Dogs can sniff out things from a greater distance than that.
Australia is home to 20 of the 25 most venomous snakes in the world.
Burping is a normal way for the body to release swallowed air, and often happens after eating or drinking fizzy drinks!
Mmmmmmm. That smells delicious. Wait, how do you know that?
You might have already felt what it would be like inside a cloud made of condensed water vapor.
Epidemiologists focus on diseases among groups of people. They also study the spread of disease among animals.
Squirrels and chipmunks are distant cousins who have grown a little more apart from each other over millions of years.
Wind travels all over the world. Where does it come from, and why?
Research shows that looking at your dog makes you feel happy.