This sequence of images was taken by the Ultraviolet/Visible/Near-Infrared spectrometer (VIRTIS) on board ESA’s Venus Express spacecraft between 12 and 19 April 2006, during the first orbit (capture orbit) around the planet.
The images were obtained at six different time slots and different distances from the planet (top left: 12 April, from 210 000 kilometres; top centre: 13 April, from 280 000 kilometres; top right: 14 April, from 315 000 kilometres; bottom left:16 April, from 315 000 kilometres; bottom centre: 17 April, from 270 000 kilometres; bottom right: 19 April, from 190 000 kilometres), while the spacecraft moved along a long ellipse around Venus. The separate images can be downloaded here [ VOI_1_12_04_2006_b, VOI_2_13_04_2006_b, VOI_3_14_04_2006_b, VOI_4_16_04_2006_b, VOI_5_17_04_2006_b, VOI_6_19_04_2006].
Each image is the composite of the day side of Venus (left, in blue, taken in visible light at 380 nanometres) and the night side (right, in a red colour scheme, taken in infrared light at 1.7 microns).
The visible part shows solar radiation reflected by the atmosphere. The infrared part shows complex cloud structures, revealed by the thermal radiation coming up from different atmospheric depths. Venus Express can resolve these structures by use (for the first time from orbit) of the so so-called ‘infrared windows’ present in the atmosphere of Venus. In fact, if observed at certain wavelengths, it is possible to detect thermal radiation leaking from the deepest atmospheric layers, revealing what lies beneath the dense cloud curtain situated at about 60 kilometres altitude.
In the colour scheme of the presented infrared images, the brighter the colour, the more radiation comes up from the lower layers.
Before launch – Venus Express undergoing thermal vacuum testing with simulated Sun exposure, by INTESPACE, Toulouse.
The Venus Express container is moved from the Yubileiny airport to the MIK 112 hangar, where a series of tests on the spacecraft are performed before launching from the Baikonur Cosmodrome, Kazakhstan.
The Soyuz FG-Fregat vehicle carrying Venus Express, ESA's first probe to Venus, lifts off from the Baikonur Cosmodrome, Kazakhstan, at 04:33 CET on 9 November 2005.
This image, of the ‘eye of the hurricane’ on Venus was taken by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board Venus Express.
This picture shows a region in the venusian atmosphere about 60 km from the surface, at a wavelength of about 5 micrometres. In this figure, the dipole assumes an eye-like shape and from here until the last image, it is possible to see how its shape evolves rapidly in a span of only 24 hours.
The yellow dot in the image indicates the location of the south pole.
This global view of the southern hemisphere of Venus is a mosaic of images obtained by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board ESA’s Venus Express on 16 May 2006.
The night-side hemisphere (in red at the top) is made of infrared images taken at 1.74 micrometres, showing the lower layers of the cloud deck surrounding the planet at about 45-km altitude.
The day-side hemisphere (in blue at the bottom) is made of ultraviolet images taken at 480 nanometres. It shows the cloud top layer at about 65-km altitude.
The red part of the central panel was taken at 3.8 micrometres, and shows the double vortex at the south pole, at an altitude of about 60 km, surrounded by a collar of ‘cold’ air.
This image is a composite of four different views of the Venusian cloud system. The images were acquired on 24 September 2006 by the Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) on board ESA’s Venus Express, from distances of about 65 000 kilometres (top left), 60 000 kilometres (top right), 53 000 kilometres (bottom left), 37 000 kilometres (bottom right) from the planet’s surface.
The images, showing a complex cloud system, were taken on the night-side of Venus (04:00 local time), at a wavelength of 1.7 micron that allows viewing the deep atmospheric layers.
The grey-scale of the images is such that white signifies more transparency, therefore less clouds, while darker or blacker regions represent opacity, or thicker clouds.
This figure shows the volcanic peak Idunn Mons (at 46°S, 214.5°E) in the Imdr Regio area of Venus. The topography derives from data obtained by NASA’s Magellan spacecraft, with a vertical exageration of 30 times. Radar data (in brown) from Magellan has been draped on top of the topographic data. Bright areas are rough or have steep slopes. Dark areas are smooth.
The coloured overlay shows the heat patterns derived from surface brightness data collected by the visible and infrared thermal imaging spectrometer (VIRTIS) aboard ESA’s Venus Express spacecraft. Temperature variations due to topography were removed. The brightness signals the composition of the minerals that have been changed due to lava flow. Red-orange is the warmest area and purple is the coolest. The warmest area is situated on the summit, which stands about 2.5 km above the plains, and on the bright flows that originate there. Idunn Mons has a diameter of about 200 km.
The VIRTIS data was collected from May 2006 to the end of 2007.
Read more: Venus is alive – geologically speaking
The rise and fall of sulphur dioxide in the upper atmosphere of Venus over the last 40 years, expressed in units of parts per billion by volume (ppbv). The dataset on the left is mostly from NASA’s Pioneer Venus, which was in orbit around Venus from 1978 to 1992. The dataset on the right is from ESA’s Venus Express, which has been studying Venus since 2006. A clear rise in the concentration of sulphur dioxide (SO2) concentration was observed at the start of the mission, with a subsequent decrease. The increase in sulphur dioxide can be interpreted either as evidence for volcanic activity or for decadal-scale variations in the circulation of Venus’ vast atmosphere.
The data are superimposed on an artist impression of Venus, depicting a volcanic terrain surrounded by a thick, noxious atmosphere.
Artist’s impression of an active volcano on Venus. Results from a long-term study of Venus find evidence of a clear injection of sulphur dioxide into its upper atmosphere. One possible interpretation is that volcanic activity increased the sulphur dioxide component of the upper atmosphere, although an alternative is that a change in atmospheric circulation dredged up the gas.
Long-term studies of the atmosphere of Venus by ESA’s Venus Express find that the average wind speeds at low latitudes (between the equator and 50º north or south) have increased from roughly 300 km/h to 400 km/h over the first six years of the mission.
In this graph, the white line shows the data derived from manual cloud tracking, and the black line is from digital tracking methods.
Read more: The fast winds of Venus are getting faster
The change in ionosphere of Venus during normal solar wind conditions (left) and reduced solar wind activity (right), as observed by ESA’s Venus Express spacecraft in August 2010. The yellow lines show a projection of the solar magnetic field lines as they interact with the ionosphere.
Venus Express follows an elliptical orbit around the planet once every 24 hours, passing within 250 km of the north pole and 66 000 km over the south pole. The observations were made on the nightside of the planet, when Venus Express was within 15 000 km of the centre of the planet. Although the spacecraft only took measurements within two Venus radii, the findings suggest that the ionosphere likely extends to even greater distances during periods of reduced solar wind intensity.
Read more: When a planet behaves like a comet
False colour composite of a ‘glory’ seen on Venus on 24 July 2011. The image is composed of three images at ultraviolet, visible, and near-infrared wavelengths from the Venus Monitoring Camera. The images were taken 10 seconds apart and, due to the motion of the spacecraft, do not overlap perfectly. The glory is 1200 km across, as seen from the spacecraft, 6000 km away.
Read more: Venus glory