21/11/2012 03:50 GMT | Updated 20/01/2013 05:12 GMT

Nasa Mystery: Mars 'Find For The History Books' Kept Secret... For Now

Nasa may have discovered signs of life on Mars - but it's not telling. Yet.

The space agency has reportedly found something of huge importance on the Red Planet, thanks to the latest samples gathered by the $2.5bn Curiosity rover, according to media reports which emerged on Tuesday.

The find is described as "one for the history books" - but Nasa is keeping its cards close to its chest.

It's checking and rechecking the data to make sure it's found... whatever it is that it's found, before making an announcement in December.

It is speculated that the Sample Analysis at Mars instrument may have found organic compounds, or evidence of the same, in a dirt sample. It is also possible the rover may have found proof of Methane in the Martian air - a sign that life once existed in some form on the planet.

"This data is gonna be one for the history books," Curiosity chief scientist John Grotzinger, of Caltech in Pasadena, told NPR. "It's looking really good."

Mars Photos From NASA Curiosity said that the announcement would be made at Autumn meeting of the American Geophysical Union, which takes place on 3 to 7 December in San Francisco.

The rover began driving again on 16 November after six weeks at rest, taking soil samples and testing its instruments.

It has not yet used its rock-boring drill, which is expected to turn up even more interesting data.