New details on venusian clouds revealed

May 30, 2008
New details on venusian clouds revealed
This beautiful, false-colour ultraviolet image of the Southern hemisphere of Venus was obtained by the Venus Monitoring Camera (VMC) on board ESA’s Venus Express on 27 July 2007. It was taken from a distance of 30 000 km from the planet’s surface at a wavelength of 365 nanometres. The planet is seen from the southern hemisphere: the south pole is at the bottom, while equator is at the top. Credits: ESA/MPS/DLR/IDA

As ESA's Venus Express orbits our sister planet, new images of the cloud structure of one of the most enigmatic atmospheres of the Solar System reveal brand-new details.

Venus is covered by a thick layer of clouds that extends between 45 and 70 km above the surface. These rapidly-moving clouds are mainly composed of micron-sized droplets of sulphuric acid and other aerosols (fine solid or liquid droplets suspended in a gas), the origin of which is unknown.

Earlier missions have shown that the clouds resemble Earth's light fogs, but their thickness creates an impenetrable veil.

The Venus Monitoring Camera (VMC) on board Venus Express has been observing the top of the cloud layer in visible, near-infrared and ultraviolet wavelengths. Ultraviolet observations have shown a wealth of new details including a variety of markings created by variable concentrations of different aerosols located at the top of the cloud layer.

The image presented here (top of the article) is a global view of the southern hemisphere of Venus, obtained from a distance of 30 000 km. The south pole is at the bottom, while equator is at the top.

The appearance of the cloud veil changes dramatically from the equator to the pole. At low latitudes, the shapes are spotty and fragmented. This is indicative of vigorous, convective movement – like that of boiling water in a pot – powered by the radiation of the sun heating the clouds and the atmosphere itself. The bright lace visible on top of the darker cloud deck is made of freshly formed droplets of sulphuric acid.

At mid latitudes, the scene changes – convective patterns give way to more streaky clouds indicating that convection is weaker here, as the amount of sunlight absorbed by the atmosphere decreases.

At high latitudes, the cloud structure changes again. Here it appears as a dense, almost featureless haze forming a kind of polar cap or 'hood' on Venus. The dark, circular feature visible at the lower edge of the image is one of the dark streaks usually present in the polar region, indicating atmospheric parcels spiralling around and towards the pole.

Additional images provide close-up views of the structures described above and show details never seen before. This is possible thanks to the elongated orbit of Venus Express, which allows imaging of the same phenomena from decreasing distances.

Source: ESA

Explore further: Computer simulation suggests early Earth bombarded by asteroids and comets

add to favorites email to friend print save as pdf

Related Stories

Misinformation diffusing online

1 hour ago

The spread of misinformation through online social networks is becoming an increasingly worrying problem. Researchers in India have now modeled how such fictions and diffuse through those networks. They described details ...

Brother of Hibiscus is found alive and well on Maui

1 hour ago

Most people are familiar with Hibiscus flowers- they are an iconic symbol of tropical resorts worldwide where they are commonly planted in the landscape. Some, like Hawaii's State Flower- Hibiscus brackenridgei- are en ...

Congressional rift over environment influences public

1 hour ago

American citizens are increasingly divided over the issue of environmental protection and seem to be taking their cue primarily from Congress, finds new research led by a Michigan State University scholar.

Recommended for you

Lifetime of gravity measurements heralds new beginning

5 hours ago

Although ESA's GOCE satellite is no more, all of the measurements it gathered during its life skirting the fringes our atmosphere, including the very last as it drifted slowly back to Earth, have been drawn ...

NASA's IceCube no longer on ice

8 hours ago

NASA's Science Mission Directorate (SMD) has chosen a team at NASA's Goddard Space Flight Center in Greenbelt, Maryland, to build its first Earth science-related CubeSat mission.

Tidal forces gave moon its shape, according to new analysis

23 hours ago

The shape of the moon deviates from a simple sphere in ways that scientists have struggled to explain. A new study by researchers at UC Santa Cruz shows that most of the moon's overall shape can be explained by taking into ...

User comments : 0