Magazine names top 10 science discoveries of 2004

The Mars rovers' discovery that the planet was once wet enough to possibly harbour life has been named by the editors of Science magazine as the year's most important scientific achievement.

The mission of the rovers wasn't to look for life but to see if Mars was once a watery, habitable place.

NASA's rovers, Spirit and Opportunity, landed on Mars early in 2004.

"Inanimate, wheeled, one-armed boxes roaming another planet have done something no human has ever managed," the magazine's editors wrote.

"They have discovered another place in the universe where life could once have existed."

• FROM MARCH 2, 2004: Mars once 'drenched' with water: NASA

• FROM MARCH 23, 2004: Opportunity rover on salty Martian beach

Speaking of the magazine's honour, Steve Squyres, the principal investigator for the rover mission, said it was "gratifying to hear others in the science community see significance in what we've found."

The rovers' findings show Mars was once wet enough to have a shallow, salty sea, the magazine said.

The discoveries reflect the importance of robot missions, said Science editor-in-chief Donald Kennedy.

Editors awarded the first runner-up position to "The Littlest Human," the discovery of the Flores man on an Indonesian island. Fossils show the tiny folks once stood less than one metre tall and had brains less than a third the size of ours.

• FROM OCT. 27, 2004: New find raises questions about earliest humans

Flores man lived about 18,000 years ago, a finding that suggests  Homo floresiensis and  Homo sapiens once shared the planet.

Third place went to "Clone Wars," the cloning of human embryos by South Korean researcher Woo San Hwang and his colleagues.

• FROM 2004: Scientists clone human embryo

The team aimed to show cloning techniques could work to make human embryonic stem cells for research purpose, not to copy humans.