EuroVenus : a pan-European Venus research initiative is launched.
Extrait du Observatoire de Paris centre de recherche et enseignement en astronomie et
astrophysique relevant du Ministère de l'Enseignement supérieur et de la Recherche.
https://www.obspm.fr/new-research-into-our-sister-planet-a-pan.html
EuroVenus : a pan-European
Venus research initiative is
launched.
Date de mise en ligne : lundi 21 octobre 2013
Observatoire de Paris centre de recherche et enseignement en astronomie et
astrophysique relevant du Ministère de l'Enseignement supérieur et de la
Recherche.
Copyright © Observatoire de Paris centre de recherche et enseignement en astronomie et astrophysique relevant du Ministère de l'Enseignement
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EuroVenus : a pan-European Venus research initiative is launched.
Venus is Earth's twin sister and nearest neighbour. It was created at the same time as Earth
and Mars, out of the same materials, and is almost exactly the same size as the Earth. Venus
today is an inhospitable place ; it has lost almost all of its water, and it is left with a massive
atmosphere dominated by carbon dioxide, whose greenhouse warming heats the planet's
surface up to some 450°C. How and why did this once Earthlike planet end up with such a
different fate ? Failing to understand what caused this change in destiny means we will never
fully account for the Earth's origin and evolution. An international team of planetary
scientists has been awarded funding by the European Union for three years (Oct. 2013-Sep.
2016) to continue to study Venus using the European Space Agency's Venus Express mission
and coordinated observations using large ground-based telescopes aimed at Venus (CFHT,
ALMA, IRTF). The project will focus on winds, chemistry, clouds/hazes and temperature
structure of Venus. Like climate studies on Earth, we rely on long series of inter-calibrated
measurements.
Venus also has much to teach us about how Earthlike planets work. Venus has an enormous greenhouse warming,
caused mainly by carbon dioxide - its atmosphere has over 100,000 times more CO2 than does is found on the Earth
- but as on Earth, a very important role is played by the cloud layer. The upper atmospheres of Venus and Earth are
remarkably similar not only in basic meteorological variables of pressure temperature, but also in their chemical
cycles, involving sulphate aerosols, water, and halogen species. Finally, Venus winds are also intriguing ; although
the planet spins around only once every 243 days, the atmosphere spins over 50 times faster, taking only around 4-5
days to complete a full circumnavigation of the planet. This is called atmospheric super-rotation, and is thought to be
inevitable for all Earthlike planets with slow rotation rates - but its underlying mechanisms remain unclear.
Mars may be the planet dominating the headlines these days, with NASA's rovers and orbiters and the European
Space Agency's capable "Mars Express" satellite - but Venus gets far less attention. There is only one spacecraft
currently at Venus, and that is the European Space Agency's Venus Express satellite. Venus Express has been
orbiting Venus since 2006, using a range of cameras and other scientific instruments to look at the atmosphere at all
levels from the ground up to the edge of space. Venus Express has far outlived its original mission duration of 500
days, so it has done exceptionally well, but it cannot keep going forever, because it uses fuel on a daily basis to help
control its height above the planet and the direction in which it is pointing ; at some point within the next couple of
years its fuel reserves will be exhausted and it will eventually burn up in Venus's atmosphere. The scientific
examination of the datasets will continue for many years later, though, as new generations of scientists can examine
and re-examine the data safely stored on Earth.
European researchers are currently leading the world when it comes to Venus research, not only using Venus
Express but also using telescopes. Venus is the closest planet to Earth, so is a spatially extended target for
telescope observation. Telescopes may be far from Venus, but they are very sensitive because of their enormous
mirrors and sophisticated instrumentation. European researchers have developed techniques which allow them to
directly measure wind speeds on Venus, using the phenomenon of Doppler shift as used in speed cameras on Earth,
using telescope observations from Earth. Faint traces gases such as sulphur dioxide SO2 can be measured from
earth, giving clues about other processes such as volcanic eruptions, lightning and cloud processes. These
telescopic observations from Earth ensure that our knowledge of Venus will continue to grow even when there is no
spacecraft at the planet.
The EuroVenus project is funded by the European Commission's Seventh Framework Program (FP7/2007-2013)
under Grant 606798 for a duration of three years (oct. 2013-sep. 2016) to study various aspects of Venus in a
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EuroVenus : a pan-European Venus research initiative is launched.
co-ordinated way using both space-based observations (in particular from Venus Express) and ground-based
observations (from telescopes). The project brings together researchers from France (Observatoire de
Paris-Meudon/LESIA), Belgium (Belgium Institute for Space Aeronomy), Germany (Rhenish Institute for
Environmental Research at the University of Cologne), Portugal (Faculty of Sciences and Center for Astronomy and
Astrophysics of the University of Lisbon, and the UK (University of Oxford).
La mission Venus Express de l'Agence spatiale européenne, lancée en 2006, a permis l'exploration détaillée
de l'atmosphère depuis le sol jusqu'à l'espace, grâce à un ensemble d'instruments et de caméras à son bord.
Venus Express, qui a été la première mission vers Vénus en près de deux décennies - la précédente mission
vers Vénus fut lancée en 1989 - a donné aux chercheurs européens un leadership mondial pour l'étude de
cette atmosphère, un cas unique parmi les planètes du Système solaire. (ESA)
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EuroVenus : a pan-European Venus research initiative is launched.
Les constituants chimiques minoritaires de l'atmosphère de Vénus, tout comme les vents dans la haute
atmosphère, peuvent être cartographiés à l'aide d'instruments au sol dans les domaines de longueur d'onde
millimétrique, sub-millimétrique, visible jusqu'à l'infrarouge thermique. Ces méthodes ont l'avantage d'établir
des cartes instantanées sur l'ensemble du disque de la planète, au contraire des observations de Vénus
Express depuis l'orbite de Vénus. De nombreux grands instruments au sol seront mis à contribution dans le
projet EuroVénus, en particulier le grand télescope Atacama Large Millimeter Array (ALMA) . (ESO)
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