NASA never spent millions developing a space pen; it was invented privately for $1 million and both American and Russian astronauts used…

Venus rotates so slowly that a single day on the planet lasts longer than its entire year. A sidereal day on Venus takes 243 Earth days,…

Australia stretches roughly 2,500 miles from its east coast to its west coast — wider than the Moon's diameter of about 2,160 miles. The…

Neutron stars are the densest objects in the universe besides black holes. A single teaspoon of neutron star material would weigh…

Despite popular myth, the Great Wall is not visible from low Earth orbit. Its width (15-30 feet) is too narrow to discern, and satellite…