Nasa will announce the truth behind its mysterious 'historic' find on Mars on Monday - but there are fears it might turn out to be less Earth-shattering than many hoped (an/or feared).

It was previously reported that the space agency's latest news from the Curiosity Mars lander would be "one for the history books".

Mission chief scientist John Grotzinger had made the comments to an American radio station, leading to rampant speculation that a spectacular announcement - possibly concerning evidence of life on the Red Planet, was imminent.

But about a week later Grotzinger clarified his comments in another interview, and said that the news would not be as dramatic as some had hoped.

Now as Nasa prepares to hold its press conference on Monday, it too has tried to dampen speculation about what the rover has found.

"Rumors and speculation that there are major new findings from the mission at this early stage are incorrect," said Nasa officials at the Jet Propulsion Laboratory, where the Curiosity mission is handled.

"The news conference will be an update about first use of the rover's full array of analytical instruments to investigate a drift of sandy soil."

The conference will be held at 12pm eastern standard time on Monday, at the American Geophysical Union in San Francisco.

There is still a chance that the news will have far-reaching implications - and that the rover could discover evidence of life having existed on Mars - but it won't come as soon as Monday.

"At this point in the mission, the instruments on the rover have not detected any definitive evidence of Martian organics," the team said.

In fact, even Curiosity itself has tried to quell speculation.


Curiosity Rover
Everybody, chill. After careful analysis, there are no Martian organics in recent samples. Update Dec 3


Curiosity Rover
Turn that frown upside down: We're fewer than four months into a multi-year mission. We've only just begun!