SPECULATION is mounting that Mars rover Curiosity may have found evidence of life on the red planet after Nasa promised an announcement that is "one for the history books".

Scientists have refused to give much away and are busy double checking the results from the rover's on-board laboratory known as Sam (Sample Analysis at Mars), which breaks down soil and air samples.

One of the mission's chief scientists, John Grotzinger, got the ball rolling when he talked to a journalist from radio network NPR last week. "This data is gonna be one for the history books," he said. "It's looking really good.

I wonder if Mars ever had any air for primitive life to work for a while? Or was there life that didn't need air?

I think they've already found evidence of water having been there once.