 
        
        	Phoenix investigated soil and ice in the martian polar regions. The results of this mission and a comparison with Mars-like sites on Earth provide a basis for considering the limits of life and the possibility of life on Mars in the recent or distant past. Mars-like sites on Earth include arid deserts and the polar regions. Studies of the dry permafrost in Antarctica suggests that the Phoenix site may have been habitable as recently as 5 Myr ago.
 Getting Under Europa’s Skin
                    
                    Getting Under Europa’s Skin Tracing Formation and Evolution of Outer Solar System Bodies Through Stable Isotopes and Noble Gas Abundances
                    
                    Tracing Formation and Evolution of Outer Solar System Bodies Through Stable Isotopes and Noble Gas Abundances Photosynthesis, a Planetary Revolution
                    
                    Photosynthesis, a Planetary Revolution Xenon: King of the Gases
                    
                    Xenon: King of the Gases