Complex meteorology at VenusOctober 16, 2006In its relentless probing of Venus's atmosphere, ESA's Venus Express keeps revealing new details of the Venusian cloud system. Meteorology at Venus is a complex matter, scientists say. New night-side infrared images gathered by the Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) in July 2006, clearly show new details of a complex cloud system. The first (false colour) view-the composite of three infrared images acquired by VIRTIS, was taken on 22 July when the spacecraft was flying around the apocentre of its orbit (point of maximum distance from the planet surface) at about 65 000 kilometres altitude. Venus was in the night side. Using its capability to observe at 1.7-micrometre wavelenght, VIRTIS could probe at about 15-20 kilometres altitude, below the thick cloud deck situated at about 60 kilometres from the surface. The thermal radiation coming from the oven-hot surface of Venus is represented by the intensity of the colours: the brighter the colour (towards white), the more radiation comes from the surface, so the less cloudy the region in the line of sight between the view and the spacecraft is. The edge of the images, taken at a time interval of about 30 minutes from each other, do not precisely match. This is due to the fact that clouds on Venus move very rapidly and constantly vary their shape. Venus's atmosphere is certainly the most dynamic among the terrestrial planets that have one, taking only four days to completely rotate around the planet. "Clouds at Venus present repetitive patterns and recurrent features, but they are very variable in position both on short and long time scales," said Giuseppe Piccioni who, with Pierre Drossart, is the instrument co-Principal Investigator. "This makes meteorology a very complex matter for this planet." Since the thermal radiation from the surface of Venus is in practice modulated by the presence of the clouds, taking the negative of the image it is possible to see directly the clouds structure on the night side, and so study its morphology and dynamics. This was done for this other night-side image, acquired by VIRTIS on 29 July around apocentre from a distance of about 65 000 kilometres from the surface. The 2.3-micrometre wavelength used for this image brought the 'view' again down below the cloud deck. The large cloud visible in the centre of the image and extending toward the bottom-right part is about 2000 kilometres long and 500 kilometres wide. This cloud presents the familiar and peculiar shape of clouds at Venus. They are usually elongated due to the very high-speed winds - reaching up the formidable velocity of 360 kilometres per hour and being caused by the 'super-rotation' of the atmosphere. The very cloudy region visible at the top-right of the image is situated beyond 60° South latitude, and represents the transition to the region where the atmosphere is dominated by the effects of the powerful South double polar vortex. European Space Agency |
|||||||||||||||||||||
| Related Venus Current Events and Venus News Articles NAE announces award winners John Casani and Sheila Widnall During its 2009 annual meeting, the National Academy of Engineering (NAE) will present two awards for extraordinary impacts on the engineering profession. Superheavy Element 114 Confirmed: A Stepping Stone to the Island of Stability Scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory have been able to confirm the production of the superheavy element 114, ten years after a group in Russia, at the Joint Institute for Nuclear Research in Dubna, first claimed to have made it. First solid evidence for a rocky exoplanet The longest set of HARPS measurements ever made has firmly established the nature of the smallest and fastest-orbiting exoplanet known, CoRoT-7b, revealing its mass as five times that of Earth's. For carnivorous plants, slow but steady wins the race Like the man-eating plant in Little Shop of Horrors, carnivorous plants rely on animal prey for sustenance. Fortunately for humans, carnivorous plants found in nature are not dependent on a diet of human blood but rather are satisfied with the occasional fly or other insect. University of Hawai'i at Manoa team unravels the chemistry of Titan's hazy atmosphere A team of University of Hawai'i at Mānoa researchers led by Ralf Kaiser, physical chemist at UH Mānoa, unraveled the chemical evolution of the orange-brownish colored atmosphere of Saturn's moon Titan, the only solar system body besides Venus and Earth with a solid surface and thick atmosphere. Unveiling the true face of a gigantic star An international team of astronomers, led by Keiichi Ohnaka at the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, has made the most high resolution images of a dying giant star to date. Sharpest views of Betelgeuse reveal how supergiant stars lose mass Using different state-of-the-art techniques on ESO's Very Large Telescope, two independent teams of astronomers have obtained the sharpest ever views of the supergiant star Betelgeuse. New map hints at Venus's wet, volcanic past Venus Express has charted the first map of Venus's southern hemisphere at infrared wavelengths. The new map hints that our neighbouring world may once have been more Earth-like, with both, a plate tectonics system and an ocean of water. Galileo's notebooks may reveal secrets of new planet Galileo knew he had discovered a new planet in 1613, 234 years before its official discovery date, according to a new theory by a University of Melbourne physicist. Magnetic Tornadoes Could Liberate Mercury's Tenuous Atmosphere As the closest planet to the sun, Mercury is scorching hot, with daytime temperatures of more than 800 degrees Fahrenheit (approximately 450 degrees Celsius). More Venus Current Events and Venus News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||