Kummakivi is a 500-ton rock in Finland that has been balanced on top of another rock for 11,000 years.

It is a space settlement concept proposed by American physicist Gerard K. O'Neill in his 1976 book The High Frontier: Human Colonies in Space. O'Neill proposed the colonization of space for the 21st century, using materials extracted from the Moon...

This infrared color image shows a special reflection of the hydrocarbon lake Kivu Lacus on Saturn's moon Titan. Kivu Lacus is the smallest lake on Titan - about 77.5 km wide, located very close to the north pole of Titan.This...