Key molecule discovered in Venus's atmosphereMay 16, 2008Venus 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. Hydroxyl, an important but difficult-to-detect molecule, is made up of a hydrogen and oxygen atom each. It has been found in the upper reaches of the Venusian atmosphere, some 100 km above the surface, by Venus Express's Visible and Infrared Thermal Imaging Spectrometer, VIRTIS. The elusive molecule was detected by turning the spacecraft away from the planet and looking along the faintly visible layer of atmosphere surrounding the planet's disc. The instrument detected the hydroxyl molecules by measuring the amount of infrared light that they give off. The band of atmosphere in which the glowing hydroxyl molecules are located is very narrow; it is only about 10 km wide. By looking at the limb of the planet, Venus Express looked along this faint atmospheric layer, increasing the signal strength by about 50.
Hydroxyl is thought to be important for any planet's atmosphere because it is highly reactive. On Earth it has a key role in purging pollutants from the atmosphere and is thought to help stabilise the carbon dioxide in the martian atmosphere, preventing it from converting to carbon monoxide. On Mars it is also thought to play a vital role in sterilising the soil, making the top layers hostile to microbial life. The reactive molecule has been seen around comets, but the method of production there is thought to be completely different from the way it forms in planetary atmospheres. "Because the venusian atmosphere had not been studied extensively before Venus Express arrived on the scene, we have not been able to confirm much of what our models tell us by observing what is actually happening. This detection will help us refine our models and learn much more," says one of the Principal Investigators of the VIRTIS experiment, Giuseppe Piccioni, from the Istituto di Astrofisica Spaziale e Fisica Cosmica in Rome, Italy. On Earth, the glow of hydroxyl in the atmosphere has been shown to be closely linked to the abundance of ozone. From this study, the same is thought to be true at Venus. Now, scientists can set about estimating the amount of ozone in the planet's atmosphere. Venus Express has shown that the amount of hydroxyl at Venus is highly variable. It can change by 50% from one orbit to the next and this may be caused by differing amounts of ozone in the atmosphere. "Ozone is an important molecule for any atmosphere, because it is a strong absorber of ultraviolet radiation from the Sun," says Piccioni. The amount of the radiation absorbed is a key parameter driving the heating and dynamics of a planet's atmosphere. On Earth, it heats the stratosphere (layer of the atmosphere) making it stable and protecting the biosphere from harmful ultraviolet rays. Computer models will now be able to tell how this jump and drop in ozone levels over short intervals affects the restless atmosphere of that world. "Venus Express has already shown us that Venus is much more Earth-like than once thought. The detection of hydroxyl brings it a step closer," says Piccioni. He and his colleagues are only reporting the initial detection from a few orbits in their latest paper. They are working on the analysis of data from about 50 other orbits and more observations will follow. European Space Agency | |||||||||||||||||||||
|
Related Venus Current Events and Venus News Articles Worlds in collision Two terrestrial planets orbiting a mature sun-like star some 300 light-years from Earth recently suffered a violent collision, astronomers at UCLA, Tennessee State University and the California Institute of Technology will report in a December issue of the Astrophysical Journal, the premier journal of astronomy and astrophysics. Volcanic Activity Shaped Mercury After All Scientists have long anguished over how little is known about Mercury, the innermost of the four terrestrial planetary bodies in our solar system. Active submarine volcanoes found near Fiji Several huge active submarine volcanoes, spreading ridges and rift zones have been discovered northeast of Fiji by a team of Australian and American scientists aboard the Marine National Facility Research Vessel, Southern Surveyor. Astonomers find tiny planet orbiting tiny star An international team of astronomers led by David Bennett of the University of Notre Dame has discovered an extra-solar planet of about three Earth masses orbiting a star with a mass so low that its core may not be large enough to maintain nuclear reactions. The result was presented Monday (June 2) at the American Astronomical Society annual meeting in St. Louis. Hot climate could shut down plate tectonics A new study of possible links between climate and geophysics on Earth and similar planets finds that prolonged heating of the atmosphere can shut down plate tectonics and cause a planet's crust to become locked in place. NASA Calls on APL to Send a Probe to the Sun The Johns Hopkins University Applied Physics Laboratory is sending a spacecraft closer to the sun than any probe has ever gone - and what it finds could revolutionize what we know about our star and the solar wind that influences everything in our solar system. It's a unisex brain with specific signals that trigger 'male' behavior Research by Yale scientists shows that males and females have essentially unisex brains - at least in flies - according to a recent report in Cell designed to identify factors that are responsible for sex differences in behavior. Northern lights glimmer with unexpected trait An international team of scientists has detected that some of the glow of Earth's aurora is polarized, an unexpected state for such emissions. 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. More Venus Current Events and Venus News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||