Andrew Yee[_1_]
November 9th 07, 11:17 PM
ESA News
http://www.esa.int
9 November 2007
Lifting the Venusian veil, two years since launch
Venus Express, launched two years ago today, has been adding much to our
knowledge of Earth's twin. The satellite has recently peeked through the
planet's thick veil of clouds and sent new images of its surface.
Venus' surface is a scorching 735 K, or 462 C, and emits a lot of infrared
radiation. All of this radiation is scattered numerous times by its thick 25
km-layer of clouds before it escapes into space. This gives Venus a weak
glow, but also makes it hard for an orbiting satellite to get a true picture
of the planet's countenance.
Despite the thick haze, infrared light, invisible to the naked eye, can
escape at certain wavelengths through spectral windows. ESA's Venus Express
carries the Venus Monitoring Camera (VMC), which has used one of the
spectral windows to see through the haze and map the surface of our
neighbour on its night side.
Unveiling Venus
The areas mapped with the VMC cover the Beta and Phoebe Regios in the mid-
to equatorial latitudes visited in the 1970s by several Soviet Venera and US
Pioneer Venus landers. The pictures reveal highlands and mountains of
elevation up to 5 km above the Venusian 'sea level'. Even when looking
through the infrared window, observing Venus' surface from orbit is similar
to looking though a frosted window, when one can only see the silhouette of
an object.
The mapped area includes some of the most typical geological units on Venus.
Beta Regio and Phoebe Regio represent tesserae -- some of the oldest terrain
on the planet. In 1990, the radar on board the US spacecraft Magellan
detected anomalously high reflectivity of the tops of Rhea Mons and Theia
Mons. This indicates the presence of still unknown conductive,
semiconductive, ferroelectric or ferromagnetic materials.
The images are being used to study the variation of mineralogical
composition on Venus and are being correlated with the topography and radar
reflectivity of the surface. They are also being used to search for ongoing
volcanic activity.
Happy birthday Venus Express!
For more information:
Hakan Svedhem, ESA Venus Express Project Scientist
Email: Hakan.Svedhem @ esa.int
[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/esaSC/SEM57353R8F_index_1.html ]
http://www.esa.int
9 November 2007
Lifting the Venusian veil, two years since launch
Venus Express, launched two years ago today, has been adding much to our
knowledge of Earth's twin. The satellite has recently peeked through the
planet's thick veil of clouds and sent new images of its surface.
Venus' surface is a scorching 735 K, or 462 C, and emits a lot of infrared
radiation. All of this radiation is scattered numerous times by its thick 25
km-layer of clouds before it escapes into space. This gives Venus a weak
glow, but also makes it hard for an orbiting satellite to get a true picture
of the planet's countenance.
Despite the thick haze, infrared light, invisible to the naked eye, can
escape at certain wavelengths through spectral windows. ESA's Venus Express
carries the Venus Monitoring Camera (VMC), which has used one of the
spectral windows to see through the haze and map the surface of our
neighbour on its night side.
Unveiling Venus
The areas mapped with the VMC cover the Beta and Phoebe Regios in the mid-
to equatorial latitudes visited in the 1970s by several Soviet Venera and US
Pioneer Venus landers. The pictures reveal highlands and mountains of
elevation up to 5 km above the Venusian 'sea level'. Even when looking
through the infrared window, observing Venus' surface from orbit is similar
to looking though a frosted window, when one can only see the silhouette of
an object.
The mapped area includes some of the most typical geological units on Venus.
Beta Regio and Phoebe Regio represent tesserae -- some of the oldest terrain
on the planet. In 1990, the radar on board the US spacecraft Magellan
detected anomalously high reflectivity of the tops of Rhea Mons and Theia
Mons. This indicates the presence of still unknown conductive,
semiconductive, ferroelectric or ferromagnetic materials.
The images are being used to study the variation of mineralogical
composition on Venus and are being correlated with the topography and radar
reflectivity of the surface. They are also being used to search for ongoing
volcanic activity.
Happy birthday Venus Express!
For more information:
Hakan Svedhem, ESA Venus Express Project Scientist
Email: Hakan.Svedhem @ esa.int
[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/esaSC/SEM57353R8F_index_1.html ]