Lost argon hints at Mars’ past climate
By 
Katrina Krämer2017-03-31T14:00:00
The red planet might once have had an atmosphere as thick as Earth’s, but has since lost most of its gases to space
Over the last four billion years, Mars has lost most of its gases to space, research suggests. The red planet might have once had an atmosphere as thick as Earth’s – mostly consisting of carbon dioxide – but a constant stream of energetic particles from the sun has since eradicated most of it.