The new images by the Curiosity rover on Mars show "dramatic evidence" of ancient groundwater in crisscrossing low ridges, NASA said.

Mars' opposition occurs about every two years and coincides with the planet's retrograde motion, which began on Dec. 7 and will end Feb. 23. Retrograde occurs when a planet appears to be moving ...

Mars orbits at an average distance of 142 million miles (228 million km) from the sun. Its orbit is about 1.5 times the size of Earth's. Sunlight takes about 13 minutes to get to Mars, while it ...

So in a way, the ancient connection between the planet Mars and blood wasn’t completely wrong. Rust, which is a common form of iron oxide found here on Earth, also often has a reddish color.

Mars may once have held enough water to fill oceans and form coastlines. The planet’s red dust contains water and likely formed in cold conditions.