Featured Research

from universities, journals, and other organizations

Happy Birthday, Venus Express!

Date:
November 12, 2006
Source:
European Space Agency
Summary:
One year after its launch on November 9, 2005, and a few months into its science phase, ESA's Venus Express keeps working well and continues to gather lots of data about the hot and noxious atmosphere of the planet. Newly released images show additional details of the thick cloud deck that surrounds Venus.

This night-side, false-colour image was taken by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board Venus Express on 23 September 2006, when the spacecraft was flying at about 60 000 kilometres over the planet around the point of furthest distance from the surface (apocentre).
Credit: s: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA

One year after its launch on 9 November 2005 and a few months into its science phase, ESA's Venus Express keeps working well and continues to gather lots of data about the hot and noxious atmosphere of the planet. Newly released images show additional details of the thick cloud deck that surrounds Venus.

It was 11 April 2006 when, after a delicate manoeuvre, Venus Express entered into orbit around Venus, and started a series of gradually smaller loops around the planet to reach its 24-hour science orbit (spanning between 66 000 over the South pole and 250 kilometres over the North pole) on 7 May 2006.

"From that time onwards this unique spacecraft, equipped with the most advanced instruments ever used for atmospheric investigations at Venus, has started gathering views and information on the thick atmosphere, its cloud system and its dynamics – during experiment tests in the beginning, and on a nominal basis after 4 June 2006," said Hεkan Svedhem, Venus Express Project Scientist.

From the very first images of the approaching planet and from the South Pole views obtained on 12 April - the first of this area taken in the infrared in the history of Venus’ exploration - scientists immediately obtained novel glimpses about an extraordinarily complex weather system.

This is ruled by huge and still largely unexplained forces at work in the atmosphere, causing hurricane-force winds and generating the amazing double-eyed vortices over both poles.

It was indeed this European spacecraft to entirely reveal for the first time the double vortex over the planet's South pole, with its 3D structure so much differentiated over different altitudes and similarly shaped (but mirrored) to that present over the North pole.

Newly released images, obtained in July and September 2006 by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board Venus Express, show new details of the cloud structure. This thick layer of clouds, located around 60 kilometres altitude over the surface, blocks part of the thermal radiation coming from below.

However, VIRTIS is designed to catch the only radiation that can pass through the lower atmopshere and the cloud deck, making use of the so called 'infrared windows'. Through these 'windows', thermal (infrared) radiation at specific wavelengths can cross the lower atmosphere and escape towards space. By doing so, it carries information about the lower atmospheric layers and the surface that VIRTIS can collect from orbit.

The first, false-colour night-side image, was taken at a 1.7-micrometre wavelength on 23 September 2006, when the spacecraft was flying at about 60 000 kilometres over the planet around the point of furthest distance from the surface (apocentre). It shows an area close to the South pole.

"The bright big spot on the left of the image corresponds to an area where the cloud deck is thinner," said Giuseppe Piccioni, VIRTIS co-Principal Investigator. "Such regions, similar to large holes, allow the thermal radiation from below the clouds layer to increase significantly with respect to the surrounding areas, and make it possible to probe very deep in the atmosphere with a limited attenuation from the clouds."

The atmospheric layers below the cloud deck, and the fact that they are blocking almost all thermal radiation coming from the surface, are the main responsible for the tremendous green-house effect at work on the planet – the most powerful found in the Solar System. It maintains the surface temperature as high as 450°C!

The second, night-side image of the southern hemisphere was taken by VIRTIS on 29 July 2006 from a distance of about 64 000 kilometres over the surface (around the orbit apocentre) at a wavelength of 1.7 micrometres. The South pole is visible on the top left of the image.

This image provides a remarkable example of a wave structure, running from the bottom to the top-right, each 'wave' extending about 150 kilometres. This peculiar cloud feature is often seen at a latitude of about 55Ί South.

"Despite the fact that the cloud structure is very variable and dynamic at Venus, recurrent patterns and structures tend to appear in the same locations," said Pierre Drossart, VIRTIS co-Principal Investigator. "They are mostly visible in the infrared, sometimes very easily, some other times less. When they are very faint and hidden, we need to play with the intensity of the images."

The picture also shows a part of the polar vortex (top left). Regions of thinner clouds are present also in this image. They are visible as bright spots (top left corner), as they allow more thermal radiation to escape towards deep space from the hotter regions below.

The region between the black stripe around the pole and the wave structure contains the so called 'cold collar', a region in which the temperature of the clouds is lower than that of the surrounding area. Similar cold-collar structures are present at both poles. The cold collar over the South pole cannot be clearly seen in this image (1.7 micrometre wavelenght), but it was was imaged by VIRTIS at 5 micrometres in April 2006.

In the meantime, VIRTIS and the other instruments on board Venus Express keep observing the mysterious atmosphere of Venus. Well done so far and…happy anniversary, Venus Express!


Story Source:

The above story is based on materials provided by European Space Agency. Note: Materials may be edited for content and length.


Cite This Page:

European Space Agency. "Happy Birthday, Venus Express!." ScienceDaily. ScienceDaily, 12 November 2006. <www.sciencedaily.com/releases/2006/11/061109130702.htm>.
European Space Agency. (2006, November 12). Happy Birthday, Venus Express!. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2006/11/061109130702.htm
European Space Agency. "Happy Birthday, Venus Express!." ScienceDaily. www.sciencedaily.com/releases/2006/11/061109130702.htm (accessed July 25, 2014).

Share This




More Space & Time News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: ISS Cargo Ship Launches in Kazakhstan

Raw: ISS Cargo Ship Launches in Kazakhstan

AP (July 23, 2014) — The Progress 56 cargo ship launched from the Baikonur Cosmodrome in Kazakhstan Wednesday. NASA says it will deliver cargo and crew supplies to the International Space Station. (July 23) Video provided by AP
Powered by NewsLook.com
Raw: Cargo Craft Undocks from Space Station

Raw: Cargo Craft Undocks from Space Station

AP (July 22, 2014) — A Russian Soyuz cargo-carrying spacecraft undocked from the International Space Station on Monday. The craft is due to undergo about ten days of engineering tests before it burns up in the Earth's atmosphere. (July 22) Video provided by AP
Powered by NewsLook.com
NASA Ceremony Honors Moon Walker Neil Armstrong

NASA Ceremony Honors Moon Walker Neil Armstrong

AP (July 21, 2014) — NASA honored one of its most famous astronauts Monday by renaming a historic building at the Kennedy Space Center in Florida. It now bears the name of Neil Armstrong, the first man to walk on the moon. (July 21) Video provided by AP
Powered by NewsLook.com
Neil Armstrong's Post-Apollo 11 Life

Neil Armstrong's Post-Apollo 11 Life

Newsy (July 19, 2014) — Neil Armstrong gained international fame after becoming the first man to walk on the moon in 1969. But what was his life like after the historic trip? Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:  

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile iPhone Android Web
          Follow Facebook Twitter Google+
          Subscribe RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins