In his 1632 book "Dialogue Concerning the Two Chief World Systems," the astronomer Galileo Galilei first described the principle of relativity - the idea that the universe should behave the same way at all times.
The U.S. government wanted a network that would allow computers to communicate automatically and even if some telephone lines were cut off.
Our planet holds a lot of trash. Since the Industrial Revolution, we humans have produced 30 trillion tons of stuff.
This is the famous - and fake - photograph of the Loch Ness monster, taken near Inverness, Scotland, on April 19, 1934. The photograph was later revealed to be a hoax.
How life on Earth started has puzzled scientists for a long time. And it still does.
There's an imaginary line between the North Pole and the South Pole. We call it the rotation axis.
Everyone knows what a bird is - and pretty much everyone knows what a dinosaur is. But not everyone is aware that birds evolved from dinosaurs approximately 160 million years ago.
An expert explains the history of using 'correctional' facilities to punish people.
Both astrology and astronomy are in the business of making predictions.
