Satellite detects large mass of water in Mars canyon
<i>The FREND instrument searches for neutrons to map hydrogen content in the Martian soil.</i><p><i>FREND revealed an area with an unusually large amount of hydrogen in the colossal Valles Marineris canyon system: assuming the hydrogen we see is bound into water molecules, as much as 40% of the near-surface material in this region appears to be water.</i><p>How confident are we that hydrogen detected really is water?