Curiosity has been on Mars for 118 days now, but she's still just getting warmed up. Since October, the rover has sampled and analyzed its first five scoops of Martian soil, and NASA announced the results (which aren't these results) at a press conference this morning.
Curiosity's tummy contains several sophisticated instruments designed to figure out what things are made of, including SAM and CheMin. SAM stands for Sample Analysis at Mars (like, duh), and is really three instruments, a quadrupole mass spectrometer, a gas chromatograph, and a tunable laser spectrometer, all of which team up to look for organic molecules. CheMin is an X-ray diffraction spectrometer that can identify minerals based on how X-rays are deflected off of them.
These first few scoops of Mars dirt were intended to be a bit of a test run, to make sure that SAM and CheMin were working properly, and also to clean any lingering contaminants from Earth out of the rover's sample chambers: a fine sand was deliberately chosen to help scrub things out. This doesn't render the results of the analysis any less interesting, of course, although if you were hoping for evidence of Martians, prepare for disappointment.
Curiosity found mostly evidence of volcanic origins for the soil, with common igneous minerals as well as small bits of volcanic glass. A few water molecules were spotted as well; not anything you'd be able to go swimming in, but more than were expected. The sample also contained oxygen and chlorine, probably in the form of perchlorate, which formed chlorinated methane compounds when heated. Now, methane (CH4) is a simple organic compound, meaning that it contains carbon, but NASA scientists are cautioning that it's possible (or even likely) that the carbon is of Earth-origin, left over in the sample chamber.
Really, the most important piece of news here is that everything on Curiosity works, and works well with everything else, meaning that the rover is ready to start heading for the top of Mt. Sharp, doing all kinds of exciting science along the way.