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Space Topics: Venus
Views of Venus' South Pole from Venus Express
Venus
Express entered orbit at Venus on April 11, 2006. Its
first orbit was a highly elliptical one that carried it to a distance of
350,000 kilometers from the planet's south pole, permitting the spacecraft
essentially to "park" over the pole for several days. From that point
of view it observed a
south polar vortex structure similar to the north
polar one that had been studied by Mariner 10 and Pioneer Venus in the
1970s and 1980s.
Venus Express carries a Visible
and Infrared Thermal Imaging Spectrometer that can capture images penetrating to different
levels within Venus' clouds, depending upon the choice of wavelength.
Venus' thick atmosphere has many different cloud layers, and understanding
this vertical structure is one of the goals of the Venus Express mission.
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First images from Venus Express VIRTIS
These false-color views of the south pole of Venus were captured as
part of a single observation by the VIRTIS imaging spectrometer on
April 12, 2006. The left half is a day-side view composed of ultraviolet
and infrared images and shows swirling clouds at an altitude of 70
to 80 kilometers above the surface. The right half shows heat being
emanated from the surface on Venus' night side. Wispy, opaque clouds
at an atltitude of about 50 kilometers block the thermal energy from
escaping Venus, so the image is in effect a backlit view of the 50-kilometer-altitude
clouds. Credit: ESA / INAF-IASF, Rome, Italy, and Obs. de Paris, France |
The images below were captured over a period of a week in three different
wavelengths:
- Ultraviolet/visible (380 nanometers): At this wavelength, only the day
side of Venus is visible where its uppermost clouds at an elevation of
80 kilometers (50 miles) reflect incoming sunlight. Wispy cloud features
are visible.
- Near infrared (1.7 microns): At this wavelength, clouds floating at elevations
of about 20 to 30 kilometers (12 to 18 miles) block thermal radiation
that is emitted from lower in the atmosphere. The clouds are dark; windows
through the clouds are bright.
- Thermal infrared (5 microns): At this wavelength, heat emitted from the
upper part of the atmosphere at elevations of 60-80 kilometers (35 to
50 miles) is visible. A polar "dipole" feature rotates exactly at the
south pole.
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| April 12, 2006
Range: 210,000 kilometers |
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April 13, 2006
Range: 280,000
kilometers |
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April 14, 2006
Range: 315,000
kilometers |
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April 16, 2006
Range: 315,000 kilometers |
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April 17, 2006
Range: 270,000
kilometers |
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April 19, 2006
Range:
190,000
kilometers |
All images credit: ESA / VIRTIS / INAF-IASF / Obs. de Paris-LESIA |
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A week of weather over Venus' south pole
This animation is made of the 5-micron data (orange-tinted images above),
reprojected so that the south pole stays at the center of the image. The
polar vortex shows up as an unusually warm feature at the south pole, surrounded
by a collar of colder air. Credit: ESA / VIRTIS / INAF-IASF / Obs. de Paris-LESIA
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