Here is a bit more information on their theory.  Specifically they compare the Mars differences to our own planet:

Earth is able to survive these solar storms with the help of a protective magnetic field that shields it from the harsh effects of solar winds. Mars on the other hand has lost much of this magnetic field, leaving it defenseless against such winds. Mars’ atmosphere has now been nearly stripped clean by these winds and will lose it entirely in a few billions years. According to NASA, once lost the atmosphere cannot be restored, even with terraforming.

Does this theory sound plausible to you.  Feel free to comment with your ideas and we’re looking forward to hearing more from NASA.

thanks to futurism.com for the great info

thanks to NASA for the pics