Present-day loss of hydrogen and helium from atmosphere to outer space

Range hydrogen ≈3: helium 0.05 kg/sec
Organism Biosphere
Reference Catling DC, Zahnle KJ. The planetary air leak. Sci Am. 2009 May300(5):36-43. p.36 middle column bottom paragraphPubMed ID19438047
Comments "A planet can acquire a gaseous cloak in many ways: it can release vapors from its interior, it can capture volatile materials from comets and asteroids when they strike, and its gravity can pull in gases from interplanetary space. But planetary scientists have begun to appreciate that the escape of gases plays as big a role as the supply. Although Earth’s atmosphere may seem as permanent as the rocks, it gradually leaks back into space. The loss rate is currently tiny, only about three kilograms of hydrogen and 50 grams of helium (the two lightest gases) per second, but even that trickle can be significant over geologic time, and the rate was probably once much higher."
Entered by Uri M
ID 111477