NASA will reveal 'major' Mars discovery at 11AM ET

NASA will reveal a "major science finding" about Mars at 11:00 AM (ET) today, but don't expect alien fossils. Rather, the space agency will likely explain how channels called "recursive slope lineae" form on the sides of Martian slopes over time. While that may sound dull, such "dark slope streaks" are one of the red planet's most mysterious features. Most scientists think they're caused by flowing saltwater, since they only happen on sun-facing hills that have surface temperatures above freezing. Flowing water on Mars would be a big deal, of course, since it could support primitive forms of life.

There are competing theories as to where the salty water that carves the channels comes from in the first place. Some think it originates deep underground and percolates up via geothermal heating, or comes from ice deposits situated on top of the slopes. Another theory is that it comes from the atmosphere, and condenses onto special salts during the cool evenings. As it happens, a paper is due to be presented on the latter theory, and an author of that paper, Lujendra Ojha, is also scheduled to speak today. That makes it a good bet as today's major finding, but tune in to NASA TV or come back here at 11:00 AM ET to find out for sure.