Frickle atmosphere

Sep 4, 2007 10:56 GMT  ·  By

Surprises keep coming from Venus, exposed by Venus Express, which by now has completed 500 tours around the planet in 500 Earth days.

The spacecraft maintains excellent conditions, it even receives four times more sun radiation than Mars Express, as the spacecraft design seems to be the right one.

With each new orbiting, the board instruments are switched on and off, shifting modes and targets and the spacecraft monitors its subsystems continuously, that's why the very few problems were rapidly solved by the ship's controllers.

By now, the operation has gathered about 1 Terabit, or one million million bits, a quantity of data which has been sent to Earth.

"The scientists analyzing the data have a challenging but exciting task ahead." said H?kan Svedhem, Venus Express Project Scientist.

The researchers will have to categorize the information and to choose the most important data from this huge amount of images, spectra and temperature profiles, pressure and chemical composition.

Soon, the first detailed analyses will be presented to the public.

One of the greatest surprises was Venus' extremely unstable atmosphere. Recent data delivered by the Visible and Near-Infrared Mapping Spectrometer (VIRTIS) revealed rapid shifts in the planet's atmospheric, from one day to another. The images above were taken in 8 orbits within 10 consecutive Earth days in February 2007, with a wavelength of about 2.3 micrometres, in the evening sector of the night side.

The quarter is during late evening (pre-midnight hours). You must know that Venus rotates very slowly, that's why a day on Venus means 243 Earth days. The observed zone, near south pole, was located 50,000 to 65,000 km away from Venus Express.

The contrast is determined by the deeper cloud layers, located at an altitude of about 50 km. The mid latitudes represent a type of transition zone with mostly laminar flow. Towards the equator, the atmosphere flow is more convective, while the polar zones are dominated by vortexes.

The bottom row and the leftmost images in the middle row represent laminar flow; the rest is turbulent flow. Bright hues represent less cloudy areas, while darker areas are cloudy zones, appearing this way because radiation reflected by hotter regions below the clouds is trapped by the clouds.