You can come out of your bomb shelter, put away your confetti, and in all respects calm down. The Curiosity Mars rover has not found life on Mars.

It's true that Curiosity did scoop up some dirt containing sulfur, perchlorate, and water, NASA announced on Monday. And it's true that such chemicals are "ingredients for life."

But no one should get excited about that just yet, the agency hastened to add, because, for one thing, Curiosity might have accidentally brought with it the carbon in the perchlorate.

Besides, perchlorate has been found on Mars before.

And the water isn't the kind of water we have on earth -- you know, the wet kind -- but rather stray molecules of H2O that bind to other molecules of stuff you would definitely not want in a peach daquiri.

NASA was careful to play down the announcement because earlier comments from scientists working on the Curiosity project got a lot of people worked up. On Nov. 20, NPR science reporter Joe Palca quoted John Grotzinger, the team's principal investigator, saying that Curiosity had found something really remarkable with its inboard laboratory, Sample Analysis at Mars, or SAM.

Grotzinger says they recently put a soil sample in SAM, and the analysis shows something exciting. "This data is gonna be one for the history books. It's looking really good," he says.

In the past, at least one other exciting NASA announcement -- the discovery of bacteria that ate arsenic instead of phosphorous -- has deflated on closer inspection.

So after Palca's story was published, NASA sent out this tweet from Curiosity's Twitter account:

What did I discover on Mars? That rumors spread fast online. My team considers this whole mission "one for the history books"

— Curiosity Rover (@MarsCuriosity) November 21, 2012

And when that didn't adequately cool the excitement, Curiosity tweeted again:

Everybody, chill. After careful analysis, there are no Martian organics in recent samples. Update Dec 3 go.nasa.gov/114tJs9

— Curiosity Rover (@MarsCuriosity) November 29, 2012

And Monday's press release was low-key.

"We have no definitive detection of Martian organics at this point, but we will keep looking in the diverse environments of Gale Crater," said SAM Principal Investigator Paul Mahaffy of NASA's Goddard Space Flight Center in Greenbelt, Md...

Still the agency expressed pleasure with the way Curiosity's chemistry lab appeared to be working, and were hopeful of more amazing -- although probably not too amazing -- discoveries to come.