Is there water on Mars?
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Scientists have identified recurring brown streaks that appear on Mars during the Martian spring and summer months that disappear again in the fall and winter. Leading minds in the field believe that the cycle is the result of flowing water that seasonaly evaporates:
The images show flows lengthen and darken on rocky equator-facing slopes from late spring to early fall. The seasonality, latitude distribution and brightness changes suggest a volatile material is involved, but there is no direct detection of one. The settings are too warm for carbon-dioxide frost and, at some sites, too cold for pure water. This suggests the action of brines, which have lower freezing points. Salt deposits over much of Mars indicate brines were abundant in Mars’ past. These recent observations suggest brines still may form near the surface today in limited times and places.
Full story at NASA.
