Brine on Mars?
Bagels writes "A new article on MSNBC (coming originally from Space.com) reports that the both Rovers may have struck water in the form of brine. The Opportunity rover found hints of salty water in the trench that it dug, and scientists note that the Spirit rover is currently digging a trench of its own to investigate the soil that clings to its treads, suggesting the possibility of moisture. The brine would only be small amounts of water mixed with salt, which can exist in liquid form at very low temperatures. More images are available over at NASA's rover site." Reader
frovingslosh would like to add: "I'm just hoping that when you get around to posting one of the many stories that the rover has found mud on Mars that you might include a link to the slashdot article where I predicted this but got moderated as 'funny'." Done!
Not this old argument again
The permanent Martian ice caps are just that, water ice. They expand and shrink seasonally, with much of the winter increase being CO2 ("dry") ice. In the Martian summers the poles are too warm for CO2 ice, in the Martian winters, too cold for some of the atmospheric CO2 not to freeze out. (So yes, at any given time, one pole is mostly water ice, the other mostly (covered with) dry ice -- except in spring and fall when the CO2 is changing poles -- which is also when you tend to get planetary dust storms. Imagine that.)
This has been more or less known since some astronomer first pointed a spectrometer at Mars, and largely confirmed by subsequent observation and exploration.
The only real discussion is the percentages of same, and how much (if any) water or water ice is in the soil further from the poles.
It's called science. I suggest you familiarize yourself with how it works.