 |
|
The light and dark of Venus
February 22, 2008Venus 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. Such 'global weather', unlike anything on Earth, has given scientists a new mystery to solve.
The cloud-covered world of Venus is all but a featureless, unchangeable globe at visible wavelengths of light. Switch to the ultraviolet and it reveals a truly dynamic nature. Transient dark and bright markings stripe the planet, indicating regions where solar ultraviolet radiation is absorbed or reflected, respectively.
Venus Express watches the behaviour of the planet's atmosphere with its Venus Monitoring Camera (VMC). It has seen some amazing things. In July 2007, VMC captured a series of images showing the development of the bright southern haze. Within days, the high-altitude veil continually brightened and dimmed, moving towards equatorial latitudes and back towards the pole again.
Such global weather suggests that fast dynamical, chemical and microphysical processes are at work on the planet. During these episodes, the brightness of the southern polar latitudes increased by about a third and faded just as quickly, as sulphuric acid particles coagulate.
"This bright haze layer is made of sulphuric acid," says Dmitri Titov, VMC Co-Investigator and Venus Express Science Coordinator, Max Planck Institute for Solar System Research, Germany. That composition suggests the existence of a formation process to the VMC team.
At an altitude of about 70 km and below, Venus's carbon dioxide-rich atmosphere contains small amounts of water vapour and gaseous sulphur dioxide. These are usually buried in the cloud layer that blocks our view of the surface at visible wavelengths.
However, if some atmospheric process lifts these molecules high up above the cloud tops, they are exposed to solar ultraviolet radiation. This breaks the molecules, making them highly reactive. The fragments find each other and combine quickly to form sulphuric acid particles, creating the haze.
"The process is a bit similar to what happens with urban smog over cities," says Titov. With over 600 orbits completed, the VMC team now plan to look for repeating patterns of behaviour in the build-up and decrease of the haze layer.
What causes the water vapour and sulphur dioxide to well up in the first place? The team does not know yet. Titov says that it is probably an internal dynamical process in the planet's atmosphere. Also, the influence of solar activity on haze formation has not been completely ruled out.
When the team have worked out what causes the hazes and their vigorous dynamics, there is still another problem waiting to be solved. The dark markings on these images are one of the biggest remaining mysteries of Venus's atmosphere. They are caused by some chemical species, absorbing solar ultraviolet radiation. However, as yet, planetary scientists do not know the identity of the chemical. Now that they can spot these dark patches quickly with VMC, the team hopes to use another Venus Express instrument, VIRTIS, to pinpoint the exact chemical composition of these regions.
European Space Agency
"This bright haze layer is made of sulphuric acid," says Dmitri Titov, VMC Co-Investigator and Venus Express Science Coordinator, Max Planck Institute for Solar System Research, Germany. That composition suggests the existence of a formation process to the VMC team.
At an altitude of about 70 km and below, Venus's carbon dioxide-rich atmosphere contains small amounts of water vapour and gaseous sulphur dioxide. These are usually buried in the cloud layer that blocks our view of the surface at visible wavelengths.
However, if some atmospheric process lifts these molecules high up above the cloud tops, they are exposed to solar ultraviolet radiation. This breaks the molecules, making them highly reactive. The fragments find each other and combine quickly to form sulphuric acid particles, creating the haze.
"The process is a bit similar to what happens with urban smog over cities," says Titov. With over 600 orbits completed, the VMC team now plan to look for repeating patterns of behaviour in the build-up and decrease of the haze layer.
What causes the water vapour and sulphur dioxide to well up in the first place? The team does not know yet. Titov says that it is probably an internal dynamical process in the planet's atmosphere. Also, the influence of solar activity on haze formation has not been completely ruled out.
When the team have worked out what causes the hazes and their vigorous dynamics, there is still another problem waiting to be solved. The dark markings on these images are one of the biggest remaining mysteries of Venus's atmosphere. They are caused by some chemical species, absorbing solar ultraviolet radiation. However, as yet, planetary scientists do not know the identity of the chemical. Now that they can spot these dark patches quickly with VMC, the team hopes to use another Venus Express instrument, VIRTIS, to pinpoint the exact chemical composition of these regions.
European Space Agency
Venus Current Events and Venus News RSSNAE 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
 |
The Birth of Venus: A Novel by Sarah Dunant (Author) Alessandra Cecchi is not quite fifteen when her father, a prosperous cloth merchant, brings a young painter back from northern Europe to decorate the chapel walls in the family’s Florentine palazzo. A child of the Renaissance, with a precocious mind and a talent for drawing, Alessandra is intoxicated by the painter’s abilities. But their burgeoning relationship is interrupted when Alessandra’s parents arrange her marriage to a wealthy, much older man. Meanwhile, Florence is changing, increasingly subject to the growing suppression imposed by the fundamentalist monk Savonarola, who is seizing religious and political control. Alessandra and her native city are caught between the Medici state, with its love of luxury, learning, and dazzling art, and the hellfire preaching and... |
 |
Gillette Venus Shaving Cartridges for Women, 8-Count Package by Gillette Venus Shaving Cartridges for Women feature three blades surrounded by soft cushions, resulting in fewer missed hairs and a more comfortable shave. The pivoting rounded head hugs your curves and fits easily into hard-to-shave areas. The indicator strip contains skin-soothing aloe and Vitamin E, and the blue stripe fades away when it's time to change blades. Each cartridge is individually sealed in waterproof packaging, making it easy to store in the shower. |
 |
Venus Starring: Peter O'Toole, Leslie Phillips, Beatrice Savoretti, Philip Fox, Lolita Chakrabarti Directed By: Roger Michell Academy Award® nominee Peter O’Toole (2006 Best Actor) leads a powerful cast to deliver a charming and poignant portrayal of Maurice, an aging veteran actor who becomes absolutely taken with Jessie – the grandniece of his closest friend. When Maurice tries to soften the petulant and provincial young girl with the benefit of his wisdom and London culture, their give-and-take surprises both Maurice and Jessie as they discover what they don’t know about themselves. Featuring brilliant performances from a superb supporting cast, VENUS is a witty and wise celebration of how the greatest lessons in life can come from the most unlikely places. |
 |
Venus by Suzan-Lori Parks (Author) |
 |
Gillette Venus Breeze 2 in 1 Cartridges Plus Shave Gel Bars for Women, 8 Cartridges by Gillette Triple Blades self adjust to level of Skin Conditioning Solid. All Intuition cartridges are interchangeable, but enhanced pivoting works only when Intuition Plus handle is used with Plus cartridge. |
 |
One Touch of Venus Starring: Ava Gardner, Robert Walker, Mary Benoit, Ralph Brooks, Russ Conway Also With: Franz Planer (Cinematographer), Kurt Weill (Composer) A fantasy comedy about a young window dresser (Robert Walker) who kisses a statue of Venus, which then comes to life in the form of Ava Gardner. The problems begin, however, when Venus falls in love with him... |
 |
Gillette Venus Embrace Cartridge, 8-Count Package by Gillette Venus Embrace Cartridge 8 count. Venus Embrace hugs your curves to get virtually every hair; for a whole new level of smoothness. |
 |
The Forgery of Venus: A Novel by Michael Gruber (Author) An artist born outside his time, Chaz Wilmot can paint like Leonardo, Goya, Gainsborough—and he refuses to shape his talent to fit the fashion of the day. His unique abilities attract the attention of Werner Krebs, an art dealer with a dark past and shadier present, and soon Wilmot is working with a fervor he hasn't felt in years. But his creative burst is accompanied by strange interludes—memories that are not memories . . . and he begins to wonder if he is really the person he believes he is. When a previously unknown masterpiece by the Spanish painter Velázquez is discovered, the artist suddenly finds himself lost in a mirrored house of illusions—and propelled into a secret world of greed, lies . . . and murder. |
 |
Gillette for Women Venus Divine Cartridges, 8-Count Boxes by Gillette Intensive Moisture. The closest shave for divinely smooth skin - even in sensitive spots. Three Intensive Moisture strips enriched with Natural Aloe and Botanical Oils. Three Comfort-Coated Blades for a close and comfortable shave. Pivoting Rounded Head h |
 |
Venus by Bananarama |
| © 2009 BrightSurf.com |