caption: two phases for the n - isotope diagram note that atmospheric composition and solar composition is approximately on a mass function
exif: {"Image DocumentName": "The Ne 3-isotope diagram", "Image ImageDescription": "Note that atmospheric composition and solar composition lie (approximately) on a mass fractionation line. Any physical or chemical process, thermodynamic or kinetic, fractionates isotopes by mass and will change 20Ne/22Ne twice as much as 21Ne/22Ne. (atm contains a little nucleogenic 21Ne) But if Earth started out with Solar Ne isotope composition, why is atmosphere heavier in isotopic composition? Preferential degassing of light isotopes would make atmosphere lighter than mantle. Best story is hydrodynamic escape: earliest earth atmosphere was dominated by H2, whose escape flux under influence of early solar wind was so big it could carry away other atoms along with it. Light Ne was preferentially lost from the earth, leaving an isotopically heavy atmosphere.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}