UNDATED (CNN) -- NASA says its "Curiosity" rover has made another big discovery on Mars: water!
Don't get too excited, we're only talking about molecules of water in the soil. In a report being published Friday, NASA scientists say the water molecules are bound to tiny soil particles.
They say that means water molecules are likely to be found around the entire planet!
There's not very much, though. Researchers estimate the water molecules make up only two percent of the surface soil.
The findings are detailed in the September 27 edition of the journal "Science".