From: Universidad del Pais Vasco
Posted: Saturday, December 1, 2007
Nature journal has published a series of articles devoted to the new discoveries by the European Space Agency's (ESA) Venus Express space probe made on our neighbouring planet. Two researchers from the University of the Basque Country (UPV/EHU), Agustin Sanchez Lavega and Ricardo Hueso of the Planetary Sciences Team at the Higher School of Engineering in Bilbao, are the co-authors of the two articles.
The Venus Express space mission was launched in November 2005 and entered in planetary orbit in April 2006. Since then it has been regularly sending data and images from Venus. Thanks to this space mission, researchers are beginning to reveal some of the secrets of this mysterious planet, so similar in size to the Earth while, at the same time, being an inhospitable world with its high temperatures caused by a runaway greenhouse effect and the poisonous composition of its atmosphere and clouds. Researchers Agustin Sanchez Lavega and Ricardo Hueso took part in the observations and analyses carried out by VIRTIS, a spectrum camera that takes pictures simultaneously in visible and infrared light and obtains high-resolution spectra. Nature magazine has published seven research articles, two of which have been co-written by the abovementioned researchers. The aim of the investigation is the detailed study of the planet's atmosphere, its meteorology, its strange, sulphuric acid cloud formations and the evolution of its climate.
In one of the articles Sanchez-Lavega and Hueso present a detailed study of the chemical processes and the movements which affect two gases that are of great interest for our planet Earth (carbon dioxide and oxygen) and which are present at a distance from the planet surface - at a height of between 95 and 115 km. The upper atmosphere of Venus is very tenuous and its behaviour helps to understand the energy mechanisms occurring between outer space and the deepest and densest atmosphere of the planet. The intense ultraviolet light from the Sun decomposes carbon dioxide molecules into carbon monoxide and oxygen and which then move to the nocturnal side of the planet. Here they recombine to form molecules of oxygen and emit infrared light. The researchers have presented in detail the movements of the masses of excited oxygen which move from the diurnal side (illuminated by the Sun) to the nocturnal side, with speeds of up to 250 km/h, as well as the mechanisms operating in the intense infrared emission of the oxygen.
In the other article the discovery of the South Pole double vortex (the dipole) is presented. This is a whirlwind in rapid rotation around the planet's Pole (it's takes 2.5 days) and which extends throughout the cloud layers at an altitude of between 50 and 65 kms. The study of this meteorological structure is of great interest in order to understand the mechanisms involved in the formation of similar vortexes, especially that of the Earth's Antarctic continent, where this is one of the agents responsible for the appearance of the ozone layer gap. We have discovered that the polar vortex on Venus is a double one, in the shape of an eight and which, at times, forms at a height of 65 km where it is detected at high temperatures. At the deepest cloud layers the whirlwind is unique and its clouds are very opaque (at an altitude of 45-50 km).
With these kinds of comparative studies between the atmospheres of Venus and the Earth, researchers hope to obtain a better understanding of the greenhouse effect, the formation and chemistry of the sulphuric acid clouds, the nature of the vortexes (whirlwinds) in the polar atmospheres of the planets as well as the meteorology of the planets that rotate slowly. The research will enable obtaining knowledge of climate change on our planet. In short, the aim is to understand why a planet which has such a similar mass, size and chemical composition to those of the Earth can have such a different climate evolution.
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