NASA has scheduled a press conference for 2 pm EST today (Tuesday) to reveal what the space agency will only call “significant findings“ from Opportunity, one of the twin Mars rovers currently exploring the planet. NASA won’t reveal yet what those discoveries are, but rumors swirl around the possibility that the rover has found some kind of conclusive evidence that the planet once had significant amounts of water on its surface. SPACE.com said there was, in its words, a “palpable buzz” among project scientists over the weekend about the discovery, going so far as to suggest that the discovery might have some kind of biological implications. The press conference will be broadcast on NASA TV, which can be viewed over the web.