We know that Mars once had a landscape with oceans and rivers, but what happened to it?
- Although Mars is a freezing dry world today, it is thought the planet was once like Earth.
- If liquid water once existed on Mars, ancient life could be suspended in ice.
- In 2001, the Mars Odyssey spacecraft used cosmic rays and gamma rays to detect hydrogen beneath the surface of Mars.
- The discovery of hydrogen on Mars suggests a vast frozen ocean, which might once have been partially liquid.