Transcription: Why did this water disappear? This is one of the great questions scientists face as they study the planet Mars. The most widely accepted hypothesis is that this water disappeared along with Mars's atmosphere. Mars has an atmosphere, but one that's very thin and which undoubtedly does not reflect the planet's original atmosphere. When the planet was formed, it must have had an atmosphere, one that was much warmer, much denser and more humid. This atmosphere was composed of the gases released by the rocks making up the planet when they were still hot. So this atmosphere must have survived for tw ...
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