Presence Outside Earth
It is generally thought that the presence of carbonates in rock is strong evidence for the presence of liquid water. Recent observations of the Planetary nebula NGC 6302 shows evidence for carbonates in space, where aqueous alteration similar to that on Earth is unlikely. Other minerals have been proposed which would fit the observations.
Significant carbonate deposits have not been found on Mars via remote sensing or in situ missions, even though Martian meteorites contain small amounts. Groundwater may have existed at both Gusev and Meridiani Planum.
Read more about this topic: Carbonate
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