Venus Express' infrared camera goes filmingMay 08, 2007An exciting new series of videos from ESA's Venus Express has been capturing atmospheric details of day and night areas simultaneously, at different altitudes. The south pole of the planet and its gigantic double vortex has been pictured as never before. The south pole of Venus and the double-eyed storm permanently rule atmospheric phenomena in that area of the planet. They are key to understanding the global atmospheric dynamics on Venus and will contribute to a better comprehension of the global meteorology of the planet. In the search for all possible clues on how to solve the global atmospheric 'puzzle', the team of scientists behind the Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) on board Venus Express, have tried something new - starting from the south pole. They started by focusing on this target from the advantageous position of the orbit apocentre (the furthest distance of the spacecraft from the planet). This allows the instrument to keep the target in the field of view for longer than in other portions of the orbit, where the spacecraft travels faster. In this favourable position, scientists made efficient use of the multi-wavelength capability of VIRTIS. By using wavelengths longer than 3 microns in the thermal infrared range, VIRTIS can obtain a combined view of the day and night sides simultaneously. This is more convenient since at shorter wavelengths, the difference between the thermal radiation emitted on the day and night sides is too high to observe both regions simultaneously without 'blinding' some channels of the camera. "It is comparable to looking at bright, sun-illuminated snow and at a dark sky without having to change your glasses," said Giuseppe Piccioni, VIRTIS co-Principal Investigator. "In addition, within this observation process, not only can we look at the dark and lit sides of the south pole at the same time, but we can also look into the atmosphere at different depths. What we are building is the most complete 3D data set of the Venusian atmosphere to date." The VIRTIS videos of the south polar vortex presented here are the result of combined observations at two different wavelengths (3.8 and 1.7 microns, respectively) used at the same time. The various images were taken over five orbits, during a time-span of about 8 hours per orbit. The 3.8-micron channel was chosen because of its compatibility (in exposure time) with the 1.7-micron observations, as well as for its capability to provide information about the cloud deck at about 65 kilometres altitude over the planet. The 1.7-micron wavelength was chosen to probe the atmosphere below the clouds when looking at the night side. It is clearly possible to see that the morphology of the vortex changes a lot during the 8-hour observation session and from one orbit to the next (one Venus Express orbit is 24 hours long). It is interesting to note that due to 'bad weather conditions', by the time of the observations, the videos do not show the maximum achievable image contrast. In fact, the visibility of the polar structure was somewhat reduced by the local increase of the upper atmospheric haze. "If the weather permits, by extending the time span of our future observations, we may have the chance to obtain even clearer and more detailed views of the polar vortex," added Piccioni. "With video sequences of this kind, combining all the pieces of information together, we can study the dynamics and the evolution of the vortex both in the short and the long term," said Pierre Drossart, the other co-Principal Investigator on VIRTIS. "What we want to understand is the overall 3D thermal structure of the vortex, especially the vertical variation of the horizontal winds." The next step will be the correlation of this data and data collected in the next sessions, with fluid dynamics computer models. This will eventually help the scientists create the best possible atmospheric model of Venus to date. European Space Agency |
|||||||||||||||||||||
| Related Venus Express Current Events and Venus Express News Articles 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. Where did Venus's water go? Venus Express has made the first detection of an atmospheric loss process on Venus's day-side. Last year, the spacecraft revealed that most of the lost atmosphere escapes from the night-side. Venus comes to life at wavelengths invisible to human eyes A pale yellow-green dot to the human eye, Earth's twin planet comes to life in the ultraviolet and the infrared. New images taken by instruments on board ESA's Venus Express provide insight into the turbulent atmosphere of our neighbouring planet. Key molecule discovered in Venus's atmosphere Venus Express has detected the molecule hydroxyl on another planet for the first time. This detection gives scientists an important new tool to unlock the workings of Venus's dense atmosphere. Plan to identify watery Earth-like planets develops Astronomers are looking to identify Earth-like watery worlds circling distant stars from a glint of light seen through an optical space telescope and a mathematical method developed by researchers at Penn State and the University of Hawaii. Venus Express reboots the search for active volcanoes on Venus ESA's Venus Express has measured a highly variable quantity of the volcanic gas sulphur dioxide in the atmosphere of Venus. Scientists must now decide whether this is evidence for active volcanoes on Venus, or linked to a hitherto unknown mechanism affecting the upper atmosphere. Mars and Venus are surprisingly similar Using two ESA spacecraft, planetary scientists are watching the atmospheres of Mars and Venus being stripped away into space. The simultaneous observations by Mars Express and Venus Express give scientists the data they need to investigate the evolution of the two planets' atmospheres. The light and dark of Venus Venus Express has revealed a planet of extraordinarily changeable and extremely large-scale weather. Bright hazes appear in a matter of days, reaching from the south pole to the low southern latitudes and disappearing just as quickly. Basque Country University researchers publish two articles in Nature on latest discoveries on Venus 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. Setting stars reveal planetary secrets Watching the stars set from the surface of the Earth may be a romantic pastime but when a spacecraft does it from orbit, it can reveal hidden details about a planet's atmosphere. More Venus Express Current Events and Venus Express News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||