Much of the internet is buzzing over upcoming "big news" from NASA's Curiosity rover, but the space agency's scientists are keeping quiet about the details.

The report comes by way of the rover's principal investigator, geologist John Grotzinger of Caltech, who said that Curiosity has uncovered exciting new results from a sample of Martian soil recently scooped up and placed in the Sample Analysis at Mars (SAM) instrument.

"This data is gonna be one for the history books. It's looking really good," Grotzinger told NPR in an segment published Nov. 20. Curiosity's SAM instrument contains a vast array of tools that can vaporize soil and rocks to analyze them and measure the abundances of certain light elements such as carbon, oxygen, and nitrogen – chemicals typically associated with life.

The mystery will be revealed shortly, though. Grotzinger told Wired through e-mail that NASA would hold a press conference about the results during the 2012 American Geophysical Union meeting in San Francisco from Dec. 3 to 7. Because it's so potentially earth-shaking, Grotzinger said the team remains cautious and is checking and double-checking their results. But while NASA is refusing to discuss the findings with anyone outside the team, especially reporters, other scientists are free to speculate.

"If it’s going in the history books, organic material is what I expect," says planetary scientist Peter Smith from the University of Arizona's Lunar and Planetary Laboratory. Smith is formerly the principal investigator on a previous Mars mission, the Phoenix lander, which touched down at the Martian North Pole in 2008. "It may be just a hint, but even a hint would be exciting."

Smith added that he is not in contact with anyone from the Curiosity team about their results and offered his assessment as an informed outside researcher.

Organic molecules are those that contain carbon and are potential indicators of life. During its mission, Phoenix heated a sample of soil to search for organics but these efforts were stymied by the presence of perchlorates, chemical salts that sit in the Martian soil. Perchlorates react to heat and destroy any complex organic molecules, leaving only carbon dioxide, which is abundant in the Martian atmosphere.

The Viking landers, which explored opposite sides of Mars in the late 1970s, also conducted a search for organic molecules and came up empty. For decades afterward, astronomers considered Mars to be a dead planet, with conditions not very conducive to life. After the results from Phoenix, scientists realized that perchlorates were probably messing with those earlier findings as well, and could account for their negative outcome.

Curiosity's suite of laboratory instruments are able to slowly heat a sample in a way that doesn't trigger the perchlorates. They can also weigh any molecules present, determining how much carbon, oxygen, and hydrogen they are made from. Simple organic compounds wouldn't be completely shocking, said Smith, since these probably come from meteorites originating in the asteroid belt and probably are around on present-day Mars. But they would indicate that the building blocks for life are present on Mars and might only need the addition of water, which Mars had in the past, in order to produce organisms.

"If they found signatures of a very complex organic type, that would be astounding," said Smith, since they would likely be leftovers from complex life forms that once roamed Mars. But the odds of finding such a startling result in a sample of sand scooped from a random dune are "very, very low," Smith said.

Smith cautioned against speculating too much, since rumors have a way of spreading rapidly when it comes to any discussion of potential life on Mars. During his tenure on the Phoenix mission, his team was evaluating the interesting perchlorate results, which they kept secret during analysis. Rumors got out and then became worse when an unsubstantiated report claimed a member of his team meeting was meeting with the White House.

"When you keep things secret, people start thinking all kinds of crazy things," he said.

Image: NASA/JPL-Caltech/Malin Space Science Systems