... biological and geochemical evolution of Earth’s surface environments. He is particularly interested in the early evolution of the nitrogen cycle, the mechanisms of oxygenation of the terrestrial atmosphere and their consequences on the biosphere and...
... 17O is primarily made by the burning of hydrogen into helium during the carbon-nitrogen-oxygen (CNO) cycle. 18O on the other hand is produced when a nitrogen atom captures a helium atom and is therefore more commonly found in the...
...the sampling procedure, the arm will release a burst of nitrogen gas as it makes contact with the surface of Bennu ...can be captured in the sampler head. The spacecraft has enough nitrogen to allow three sampling attempts, to collect between 60 and ...
... of: 95% by volume of carbon dioxide (CO2), 2.6% molecular nitrogen (N2), 1.9% argon (Ar), 0.16% molecular oxygen (O2), and 0.06% carbon ... the other gases to raise the air pressure again. Nitrogen and argon also follow the pressure changes, but with...
... The destruction of the ozone layer would produce nitrogen compounds that would reduce the amount of visible ... hydrogen and helium was enriched with heavier elements (oxygen, carbon, nitrogen) quickly in the center of the Milky Way, while in the...
..., as viewed in false colour by NASA’s Mars Exploration Rover Opportunity The story of how Earth ended up with its nitrogen- and oxygen-rich current atmosphere is still unfolding, with formation of organic material releasing most of the oxygen...