Results 151 to 160 of about 2,029 (193)

Isotopic Composition of the Martian Atmosphere

Science, 1976
Results from the neutral mass spectrometer carried on the aeroshell of Viking 1 show evidence for NO in the upper atmosphere of Mars and indicate that the isotopic composition of carbon and oxygen is similar to that of Earth. Mars is enriched in 15 N relative to Earth by about 75 percent, a consequence of escape ...
Nier, Alfred O., McElroy, Michael B., Yung, Yuk Ling   +2 more
openaire   +3 more sources

Helium in the Martian atmosphere

Journal of Geophysical Research: Planets, 1993
A simple two‐reservoir degassing model for the Earth decribes rather well the current degassing rate of 4He which is equal to (3±1)×106 cm −2s−1 according to data for the helium polar wind and the measured 3He/4He ratio. This value of the helium degassing and loss rate provides an important constraint in modeling of noble gases, and some recent models ...
Vladimir A. Krasnopolsky, Supriya Chakrabarti, G. Randall Gladstone   +2 more
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The Martian atmosphere: Some unanswered questions

Journal of Molecular Evolution, 1979
The study of the Martian atmosphere and its significance for the possible origin of life on Mars is still very incomplete. Further investigations are needed to define the total volatile inventory, the early history of the atmosphere, and the relationship of the atmosphere to the question of indigenous life.
Tobias Owen, T Owen
exaly   +3 more sources

Photochemistry of the Martian atmosphere

Icarus, 1977
A critical analysis is carried out for models which may be fine tuned to give agreement with observational constraints for O2, CO, and O3 in the Martian lower atmosphere and which are in accord also with upper atmospheric data for O and CO. The models have a number of features in common: dynamic mixing must be exceedingly rapid at heights above 90 km ...
T.Y. Kong, M.B. McElroy
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Meteoric ion layers in the Martian atmosphere

Faraday Discussions, 2010
Low-lying plasma layers have been observed sporadically in the Martian atmosphere by radio occultation measurements from spacecraft such as the Mars Express Orbiter and the Mars Global Surveyor. These layers are just a few km wide, and tend to occur around 90 km. It has been proposed that the layers consist of metallic ions, for two reasons: they occur
Charlotte L, Whalley, John M C, Plane
openaire   +2 more sources

Martian atmosphere and crust

Icarus, 1966
Abstract The Martian atmosphere in its average condition is inactive and transparent to long-wave radiation. It is activated when moisture is supplied by the evaporation of the polar cap in spring time. As typical examples, the great yellow cloud in 1956, the Neith-Casius cloud, and the Propontis cloud are described.
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Buildup with Bremsstrahlung in the Martian Atmosphere

Nuclear Science and Engineering, 2020
Photon buildup is a function of energy, medium, and geometry and therefore must be specifically calculated for the case of interest.
Praneel P. Gulabrao, Kevin T. Clarno
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Composition of the Martian atmosphere

Space Science Reviews, 1991
Data on the composition of the Martian atmosphere obtained by instruments aboard the Viking spacecraft are not of sufficient accuracy to address important questions regarding the composition and history of Mars. Laboratory analyses of gases trapped in glassy phases of shergottite meteorite EETA 79001 yield precise data, but it remains to be ascertained
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CO2 solubility in Martian basalts and Martian atmospheric evolution

Geochimica et Cosmochimica Acta, 2011
Abstract To understand possible volcanogenic fluxes of CO 2 to the Martian atmosphere, we investigated experimentally carbonate solubility in a synthetic melt based on the Adirondack-class Humphrey basalt at 1–2.5 GPa and 1400–1625 °C. Starting materials included both oxidized and reduced compositions, allowing a test of the effect of iron oxidation
Ben D. Stanley, Marc M. Hirschmann, Anthony C. Withers   +2 more
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Clues to the Martian Atmosphere

Science, 2001
Some 30 years ago, it was discovered that the main constituent of the thin martian atmosphere is carbon dioxide (CO) but that it only contained trace amounts of carbon monoxide and molecular oxygen, the photodissociation products of CO. Chemical reaction cycles involving water and hydrogen species have been developed to explain these observations, but ...
openaire   +1 more source