We measure the extremely long distances between things in space by light years. A light year is the distance that light travels in one Earth year. Light travels at about 300,000 kilometres per second.

Mars has lost immense amounts of water over it lifetime, and scientists aren't sure exactly how. New research hints that the ...

A new map shows hidden Martian rivers stretching thousands of miles, offering fresh evidence of a warm, wet ancient Mars.

Compare Mars and Earth in size, atmosphere, gravity, and potential for life. Discover their differences and shared traits. Explore the mysteries of the Red Planet!

Engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, modified the backup Mariner 4 spacecraft to operate closer to the Sun, and on June 14, 1967, NASA launched Mariner 5 on a 127-day ...