منابع مشابه
Fractionation of hydrogen and deuterium on Venus due to collisional ejection.
The fractionation factor f is important for interpreting the current escape fluxes of H and D on Venus and how the D/H ratio has evolved. The escape flux is currently governed by the two processes of charge exchange and collisional ejection by fast oxygen atoms. Using a best-fit parameterized equation for the O-H scattering angle phase function, more accurate branching ratios for the oxygen i...
متن کاملVenus was wet: a measurement of the ratio of deuterium to hydrogen.
The deuterium-hydrogen abundance ratio in the Venus atmosphere was measured while the inlets to the Pioneer Venus large probe mass spectrometer were coated with sulfuric acid from Venus' clouds. The ratio is (1.6 +/- 0.2) x 10(-2). The hundredfold enrichment of deuterium means that at least 0.3 percent of a terrestrial ocean was outgassed on Venus, but is consistent with a much greater production.
متن کاملDoublet craters on Venus
Of the impact craters on Earth larger than 20 km in diameter, 10–15% (3 out of 28) are doublets, having been formed by the simultaneous impact of two well-separated projectiles. The most likely scenario for their formation is the impact of well-separated binary asteroids. If a population of binary asteroids is capable of striking the Earth, it should also be able to hit the other terrestrial pl...
متن کاملPlains Tkctonics on Venus
Tectonic deformation in the ploins of Venus is pervasive, with virtually every area of the planet showing evidence for faulting or fracturing. l’his dcfonna[ion can bc classified into three general categories, deiined by the intensity and arcal extent of the surface deformation: distribolcd deformation, conccntramJ defon]lation, and local fracture ptittcrns. Each of these styles offers informfl...
متن کاملVenus Surface Thermal Emission Observed by VIRTIS on Venus Express
The imaging spectrometer VIRTIS is the flight spare of the instrument of the same name on the Rosetta mission. It was refitted to be part of the Venus Express mission orbiting Venus since 2006. VIRTIS can observe nightside thermal emissions at the wavelengths of several atmospheric windows. In three of these windows atmospheric transparency is sufficient to allow a measurable amount of radiatio...
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ژورنال
عنوان ژورنال: Nature
سال: 1989
ISSN: 0028-0836,1476-4687
DOI: 10.1038/340514a0