How did Mars lose its atmosphere?

The MAVEN probe is set to launch on Monday in order to get answers to this question.  A theory based upon what we know about the Earth can serve as a model.  The Earth has a magnetic field, Mars doesn't really have one ( it is localized in spots, but not over the entire planet).  As a consequence, the solar wind gets diverted around the Earth and spares its atmosphere.  Mars was not so lucky.  When Mars lost its atmosphere, it also lost its oceans, which made it the dry barren place it is today.  So, MAVEN will investigate Mars' upper atmosphere to confirm what is already suspected.



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