inanna: Venus, photographed 11 times by Venus Express, 20th March 2008.

Looking up at the south pole. The terminator (line between night and day) appears to move right; this is actually a result of the movement of the spacecraft. However, if you look closely, the clouds around the pole seem to move relative to the terminator. These images cover (precisely) 4 hours, and Venus’s atmosphere is usually said to rotate in 4 or 5 days (much faster than the turning of the planet itself), so we might expect to see the clouds move 12-15° around the pole during this gif.

From mission day 700. Images have been resized and the disc of the planet brightened.

Image credit: ESA. Animation: AgeOfDestruction.


In anticipation of the New Horizons spacecraft’s historic flyby of Pluto on July 14, here are early images of famous Solar System objects compared with the latest our technology can offer.

From top

  1. Mercury (Mariner 10, 1974 & MESSENGER, 2008)
  2. Venus [Ultraviolet and in false colour] (Mariner 10, 1974 & Venus Express, 2008)
  3. Earth (V-2 Missile, 1946 & International Space Station, 2014)
  4. Moon (J.W. Draper, 1840 & Gregory H. Revera, 2010)
  5. Mars (Mariner 10, 1969 & Mars Orbiter Mission, 2014)
  6. Jupiter (Pioneer 10, 1973 & Cassini, 2001)
  7. Saturn (Pioneer 10, 1979 & Cassini, 2009)
  8. Pluto’s rotation (Hubble Space Telescope, 2003 & New Horizons, 2015)

** Uranus and Neptune are not included as they are only visited by one spacecraft, Voyager 2, in 1986 and 1989 respectively.

Venus Express gets ready to take the plunge

After eight years in orbit, ESA’s Venus Express has completed routine science observations and is preparing for a daring plunge into the planet’s hostile atmosphere.

Venus Express was launched on a Soyuz–Fregat from the Russian Baikonur Cosmodrome in Kazakhstan on 9 November 2005, and arrived at Venus on 11 April 2006.

It has been orbiting Venus in an elliptical 24-hour loop that takes it from a distant 66 000 km over the south pole – affording incredible global views – to an altitude of around 250 km above the surface at the north pole, close to the top of the planet’s atmosphere.

With a suite of seven instruments, the spacecraft has provided a comprehensive study of the ionosphere, atmosphere and surface of Venus.

“Venus Express has taught us just how variable the planet is on all timescales and, furthermore, has given us clues as to how it might have changed since its formation 4.6 billion years ago,” says Håkan Svedhem, ESA’s project scientist.

“This information is helping us decipher how Earth and Venus came to lead such dramatically different lives, but we’ve also noticed that there are some fundamental similarities.”

Image credit: ESA–C. Carreau

Venus, photographed in the UV by Venus Express, 18-19 February 2007.  As well as the clouds, there are some camera artefacts which appear to move with the planet’s “rotation” (Venus rotates extremely slowly, and the apparent rotation here must be caused by the changing position of the spacecraft).

For those playing at home, the raw data for Venus Express is in the Atmospheres node of the PDS, which is why it’s taken so long for me to post a decent Venus gif (who knew there were pictures in the Atmospheres node…?), and also from the ESA’s website via FTP.

(Blog note: This is the 300th gif posted to this Tumblr, a postiversary of sorts, not counting a lone text post and a couple of “doubles”, where the same sequence is shown twice with slightly different editing.  When I started this blog, I wasn’t sure I’d make it to 50 posts, and 200 was my most optimistic goal.  And there’s still a bit of life in it yet: Cassini’s archive is enormous and rewards multiple trawls through it; the astronaut photos are often harder to work with gif-wise because of their unsteady hands, but there’s certainly some interesting material in there.  I think there’s enough to keep the daily updates going till sometime in August.

Thanks to those who’ve been following along; and for those late to the party, there’s plenty in the blog’s archives now, organised by tag (e.g., Voyager, Io).  Almost all major solar system bodies are represented, if there’s a decent time-lapse animation of them (though there’s a couple more asteroids still to come!).)


Venus’s South Pole Vortex –Strange Behavior of a Whirlwind the Size of Europe

The astronomers in the UPV/EHU’s Planetary Science Group have completed a study of the atmospheric vortex of the south pole of Venus, a huge whirlwind the size of Europe similar to Jupiter’s 300-year-0ld Great Red Spot and the South Pole Vortex on Saturn. In the atmosphere there are two main cloud layers separated by a distance of 20km. The astronomers have been closely monitoring the movement of the vortex on both levels, and have been able to confirm the erratic nature of this movement.

“We knew it was a long-term vortex; we also knew that it changes shape every day. But we thought that the centres of the vortex at different altitudes formed only a single tube, but that is not so. Each centre goes its own way, yet the global structure of the atmospheric vortex does not disintegrate,“ explains Itziar Garate-Lopez, head researcher and member of the UPV/EHU’s Planetary Science Group.
The centers of rotation of the upper and lower vortex rarely coincide in their position with respect to the vertical, yet they form a constantly evolving permanent structure on the surface of Venus. Long-term vortices are a frequent phenomenon in the atmospheres of fast rotating planets, like Jupiter and Saturn, for example. Venus rotates slowly, yet it has permanent vortices in its atmosphere at both poles. What is more, the rotation speed of the atmosphere is much greater than that of the planet.

“We’ve known for a long time that the atmosphere of Venus rotates 60 times faster than the planet itself, but we didn’t know why,” says Garate-Lopez. “The difference is huge; that is why it’s called super-rotation. And we‘ve no idea how it started or how it keeps going.” The images above show a thin cloud layer near the South Pole.

The permanence of the Venus vortices contrasts with the case of the Earth. “On the Earth there are seasonal effects and temperature differences between the continental zones and the oceans that create suitable conditions for the formation and dispersal of polar vortices. On Venus there are no oceans or seasons, and so the polar atmosphere behaves very differently,” added Garate-Lopez.

The UPV/EHU team has been able to monitor the evolution of the south pole vortex thanks to one of the instruments on board the European Space Agency’s Venus Express spacecraft, which has been orbiting our neighboring planet since April 2006. The orbit of this craft is very elliptical: it gets very close to the North pole and South pole, yet the planet is observed from a greater distance, which allows a more global vision to be obtained. Also needed was a more extended view offering a detailed view of the planet’s south pole, whereas the north pole is observed from much shorter distances, which prevents it from being observed globally,” explains Garate-Lopez.

The UPV/EHU astronomers have been using the VIRTIS-M infrared camera on the Venus Express probe and have been analysing data obtained in the course of 169 earth days, and in particular, they have been studying in great detail the data on the 25 most representative orbits.

“This camera doesn’t take individual photos like an ordinary camera, it divides the light into different wave lengths that enable various vertical layers of the planet’s atmosphere to be observed simultaneously, says Garate-Lopez. Besides, we have compared images separated by one-hour intervals and this has enabled us to monitor the speed at which the clouds move.“

Recent images from Venus Express shown above do not confirm previous sightings of a double storm system there (shown above), but rather found a single unusual swirling cloud vortex. In the above recently released image sequence taken in infrared light and digitally compressed, darker areas correspond to higher temperatures and hence lower regions of Venus’ atmosphere. Also illuminating are recently released movies, which show similarities between Venus’ southern vortex and the vortex that swirls over the South Pole of Saturn. Understanding the peculiar dynamics of why, at times, two eddies appear, while at other times a single peculiar eddy appears, may give insight into how hurricanes evolve on Earth, and remain a topic of research for some time.

goddess: Venus, photographed by Venus Express, 2nd & 3rd October 2007.

From mission day 530. More gifs.

This gif covers about 10 hours of real time. At the start VEX is near apoapsis, showing the south pole, then moves towards periapsis closer to the equatorial plane, and also further toward the night side. Images in this sequence have been rescaled to give Venus a consistent size even as the spacecraft moves toward the planet - the image appears to “iris in” at the end because the planet is overflowing the frame.

Image credit: ESA/MPS/DLR/IDA. Animation: AgeOfDestruction.

Venus Is More Than Just a Cautionary Tale

Venus shines more brightly in Earth’s sky than any of our stars, but it gets surprisingly little attention nowadays (unless it’s being used as an example of a planetary What Not To Do).

Not that long ago, though, humans seemed rather interested in hurling tons of hardware at our sister planet, which is roughly the same size as Earth. From the 1960s through the early 1980s, Venus was the target of 19 Soviet space missions. The Venera program launched 16 probes at the cloudy world and managed to grab several photos from the planet’s parched surface. NASA has sent a half-dozen spacecraft to the planet – the most recent beingMagellan, which orbited Venus between 1989 and 1994, and mapped 98 percent of the planet’s surface.

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The fast winds of Venus are getting faster

The most detailed record of cloud motion in the atmosphere of Venus chronicled by ESA’s Venus Express has revealed that the planet’s winds have steadily been getting faster over the last six years.

Venus is well known for its curious super-rotating atmosphere, which whips around the planet once every four Earth days. This is in stark contrast to the rotation of the planet itself – the length of the day – which takes a comparatively laborious 243 Earth days.

By tracking the movements of distinct cloud features in the cloud tops some 70 km above the planet’s surface over a period of 10 venusian years (6 Earth years), scientists have been able to monitor patterns in the long-term global wind speeds.

When Venus Express arrived at the planet in 2006, average cloud-top wind speeds between latitudes 50º on either side of the equator were clocked at roughly 300 km/h. The results of two separate studies have revealed that these already remarkably rapid winds are becoming even faster, increasing to 400 km/h over the course of the mission.

“This is an enormous increase in the already high wind speeds known in the atmosphere. Such a large variation has never before been observed on Venus, and we do not yet understand why this occurred,” says Igor Khatuntsev from the Space Research Institute in Moscow and lead author of the Russian-led paper to be published in the journal Icarus.

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Credit: Khatuntsev et al; ESA

Venus Express goes gently into the night
External image

ESA Venus Express Mission patch.

16 December 2014

ESA’s Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year.

Since its arrival at Venus in 2006, Venus Express had been on an elliptical 24‑hour orbit, traveling 66 000 km above the south pole at its furthest point and to within 200 km over the north pole on its closest approach, conducting a detailed study of the planet and its atmosphere.

External image
Visualisation of the Venus Express aerobraking manoeuvre
However, after eight years in orbit and with propellant for its propulsion system running low, Venus Express was tasked in mid-2014 with a daring aerobraking campaign, during which it dipped progressively lower into the atmosphere on its closest approaches to the planet.

Normally, the spacecraft would perform routine thruster burns to ensure that it did not come too close to Venus and risk being lost in the atmosphere. But this unique adventure was aimed at achieving the opposite, namely reducing the altitude and allowing an exploration of previously uncharted regions of the atmosphere.

The campaign also provided important experience for future missions – aerobraking can be used to enter orbit around planets with atmospheres without having to carry quite so much propellant.

Between May and June 2014, the lowest point of the orbit was gradually reduced to about 130–135 km, with the core part of the aerobraking campaign lasting from 18 June to 11 July.

After this month of ‘surfing’ in and out of the atmosphere at low altitudes, the lowest point of the orbit was raised again through a series of 15 small thruster burns, such that by 26 July it was back up to about 460 km, yielding an orbital period of just over 22 hours.

The mission then continued in a reduced science phase, as the closest approach of the spacecraft to Venus steadily decreased again naturally under gravity.

External image
Venus Express aerobraking
Under the assumption that there was some propellant still remaining, a decision was taken to correct this natural decay with a new series of raising manoeuvres during 23–30 November, in an attempt to prolong the mission into 2015.

However, full contact with Venus Express was lost on 28 November. Since then the telemetry and telecommand links had been partially re-established, but they were very unstable and only limited information could be retrieved.

“The available information provides evidence of the spacecraft losing attitude control most likely due to thrust problems during the raising manoeuvres,” says Patrick Martin, ESA’s Venus Express mission manager.

“It seems likely, therefore, that Venus Express exhausted its remaining propellant about half way through the planned manoeuvres last month.”

Unlike cars and aircraft, spacecraft are not equipped with fuel gauges, so the time of propellant exhaustion for any satellite – especially after such a long time in space – is difficult to predict. The end could not be predicted but was not completely unexpected either.

External image
Without propellant, however, it is no longer possible to control the attitude and orient Venus Express towards Earth to maintain communications. It is also impossible to raise the altitude further, meaning that the spacecraft will naturally sink deeper into the atmosphere over the coming weeks.

“After over eight years in orbit around Venus, we knew that our spacecraft was running on fumes,” says Adam Williams, ESA’s acting Venus Express spacecraft operations manager.

“It was to be expected that the remaining propellant would be exhausted during this period, but we are pleased to have been pushing the boundaries right down to the last drop.”

“During its mission at Venus, the spacecraft provided a comprehensive study of the planet’s ionosphere and atmosphere, and has enabled us to draw important conclusions about its surface,” says Håkan Svedhem, ESA’s Venus Express project scientist.

Venus has a surface temperature of over 450°C, far hotter than a normal kitchen oven, and its atmosphere is an extremely dense, choking mixture of noxious gases.  

One highlight from the mission is the tantalising hint that the planet may well be still geologically active today. One study found numerous lava flows that must have been created no more than 2.5 million years ago – just yesterday on geological timescales – and possibly even much less than that.

Indeed, measurements of sulphur dioxide in the upper atmosphere have shown large variations over the course of the mission. Although peculiarities in the atmospheric circulation may produce a similar result, it is the most convincing argument to date of active volcanism.

Even though the conditions on the surface of Venus are extremely inhospitable today, a survey of the amount of hydrogen and deuterium in the atmosphere suggests that Venus once had a lot of water in the atmosphere, which is now mostly gone, and possibly even oceans of water like Earth’s.

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Is Venus volcanically active?
Also just like Earth, the planet continues losing parts of its upper atmosphere to space: Venus Express measured twice as many hydrogen atoms escaping out of the atmosphere as oxygen atoms. Because water is made of two hydrogen atoms and one oxygen atom, the observed escape indicates that water is being broken up in the atmosphere.

Studies of the planet’s ‘super-rotating’ atmosphere – it whips around the planet in only four Earth-days, much faster than the 243 days the planet takes to complete one rotation about its axis – also turned up some intriguing surprises. When studying the winds, by tracking clouds in images, average wind speeds were found to have increased from roughly 300 km/h to 400 km/h over a period of six Earth years.

At the same time, a separate study found that the rotation of the planet had slowed by 6.5 minutes since NASA’s Magellan measured it before completing its five-year mission at Venus 20 years ago. However, it remains unknown if there is a direct relationship between the increasing wind speeds and the slowing rotation.

“While the science collection phase of the mission is now complete, the data will keep the scientific community busy for many years to come,” adds Håkan.

“Venus Express has been part of our family of spacecraft in orbit since it was launched in 2005,” says Paolo Ferri, Head of ESA Mission Operations.

“It has been an exciting experience to operate this marvellous spacecraft in the Venus environment. The scientific success of the mission is a great reward for the work done by the operations teams and makes us more proud than sad in this moment of farewell.”

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Venus, southern hemisphere
“While we are sad that this mission is ended, we are nevertheless happy to reflect on the great success of Venus Express as part of ESA’s planetary science programme and are confident that its data will remain important legacy for quite some time to come,” says Martin Kessler, Head of ESA Science Operations.

“The mission has continued for much longer than its planned lifetime and it will now soon go out in a blaze of glory.”

“Venus Express was an important element of the scientific programme of ESA and, even though mission operations are ending, the planetary science community worldwide will continue to benefit from more than eight years of Venus Express data and major discoveries which foster the knowledge of terrestrial planets and their evolution,” says Alvaro Giménez, ESA’s Director of Science and Robotic Exploration.

Notes for Editors:

Summary of the first science results from the aerobraking campaign:

Eight mission highlights for eight years in orbit – read more about key mission discoveries:

Shape-shifting polar vortices:

Recent volcanism?:

Spinning Venus is slowing down:

Super-rotation is speeding up:

Snow on Venus?:

Ozone layer:

Water loss:

A magnetic surprise:

Images, Text, Credits: ESA/C. Carreau/MPS/DLR/IDA, M. Pérez-Ayúcar & C. Wilson/VIRTIS-VenusX IASF-INAF, Observatoire de Paris (R.Hueso, Univ. Bilbao).

Best regards,
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Topographic maps of Venus from Magellan (1990-1994) and Venus Express (2006-ongoing) clearly show a shift in surface features. At infrared wavelengths Venus Express was able to peer through the dense atmosphere and map surface features observed from both Earth-based radar imaging and with the Russian Venera 15 and Venera 16 missions as well as NASA’s Magellan spacecraft. By comparing the currently accepted rotation rate value for the planet from the Magellan mission, scientists discovered a ‘shift’ in surface features of up to 20 km caused by what they believe is a change in the rotation rate of the planet.

credit: NASA/JPL/Magellan/P. Ford/ESA/Venus Express/P. Drossart/G. Piccioni

When a planet behaves like a comet

Venus Express has discovered that our sister planet’s ionosphere balloons out like a comet’s tail on its nightside.

The European Space Agency’s (ESA) Venus Express has made unique observations of Venus during a period of reduced solar wind pressure, discovering that the planet’s ionosphere balloons out like a comet’s tail on its nightside.

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Venus Can Have'Comet-Like’ Atmosphere

The planet Venus sometimes looks less like a planet and more like a comet, scientists say.

Scientists with the European Space Agency have discovered that a part of the upper atmosphere of Venus — its ionosphere — acts surprisingly different depending on daily changes in the sun’s weather. The side of Venus’ ionosphere that faces away from the sun can billow outward like the tail of a comet, while the side facing the star remains tightly compacted, researchers said.

The discovery was made using ESA’s Venus Express spacecraft, which observed Venus’s ionosphere during a period of low solar wind in 2010 to see exactly how the sun affects the way the planet’s atmosphere functions. In 2013, the sun is expected to reach the peak of its 11-year solar activity cycle.

“As this significantly reduced solar wind hit Venus, Venus Express saw the planet’s ionosphere balloon outwards on the planet’s ‘downwind’ nightside, much like the shape of the ion tail seen streaming from a comet under similar conditions,” ESA officials said in a statement today (Jan. 29).

It only takes 30 to 60 minutes for the planet’s comet-like tail to form after the solar wind dies down. Researchers observed the ionosphere stretch to at least 7,521 miles (12,104 kilometers) from the planet, said Yong Wei, a scientist at the Max Planck Institute in Katlenburg, Germany who worked on this research.

Earth’s ionosphere never becomes comet-like largely because the planet has its own magnetic field that balances out the sun’s influence on the way the atmospheric layer is shaped. Venus, however, doesn’t have its own magnetic field and is therefore subject to the whims of the sun’s solar wind.

Researchers think that Mars behaves in much the same way. The Red Planet doesn’t have a magnetic field to mitigate the influence of the sun’s wind either.

The Venus Express spacecraft launched in 2005 and has been orbiting the second planet from the sun since 2006. The spacecraft is equipped with seven instruments to study the atmosphere and surface of Venus in extreme detail. The spacecraft is currently in an extended mission slated to last until 2014 .

image: When the solar wind dies down, an outer layer of Venus’s atmosphere billows outward (illustrated on right), making the second planet from the sun look like a comet.
CREDIT: ESA/Wei et al.


Takayama Shinobu Artbook for Venus Express (Kinsei Tokkyuu) a light novel series by Ureshino Kimi

Okay, so I couldn’t resist buying this artbook book because Takayama Shinobu!!!!!!!! Who cares if I’ve never read the series the art is from.

I’m pretty sure if you’ve read the series, this thing is a goldmine. It’s already awesome as a standalone.

The first section has color illustrations, the second has black and white illustrations, the third has comics, and the fourth has rough sketches and a short story.

I took some pictures to give you an idea of what’s inside it. The color illustrations are especially beautiful. \o/

hekate: Cloudtops of Venus, photographed by Venus Express, 23rd September 2010.

The camera looks down into a rift between clouds then moves away over the cloudtops, now looking backward. When the spacecraft takes its closest look into the rift, the image is about 460km across.

This gif covers about 9 minutes of real time, ending 8 minutes before the spacecraft reached that orbit’s closest encounter with Venus. 

From orbit 1616.

Image credit: ESA/MPS/DLR/IDA. Animation: AgeOfDestruction.

Weird ‘Gravity Waves’ in Venus Clouds Spotted by Spacecraft

A European spacecraft circling Venus has captured high-resolution images of strange waves in the clouds whirring above Earth’s nearest neighbor. These ripples could help scientists understand how Venus’ hellish surface shapes its atmosphere.

On Venus, mountains and volcanoes rise above vast lava plains and temperatures are hot enough to melt lead. But this hostile landscape is largely obscured by the planet’s dense, toxic atmosphere with clouds blown by winds up to 186 to 248 mph (300 to 400 km/h).

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Are Venus’ Volcanoes Still Active?

image 1: Artist’s impression of an active volcano on Venus (ESA/AOES)
image 2: 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. Credits: Data: E. Marcq et al. (Venus Express); L. Esposito et al. (earlier data); background image: ESA/AOES

Incredibly dense, visually opaque and loaded with caustic sulfuric acid, Venus’ atmosphere oppresses a scorched, rocky surface baking in planet-wide 425 ºC (800 ºF) temperatures. Although volcanoes have been mapped on our neighboring planet’s surface, some scientists believe the majority of them have been inactive — at least since the last few hundreds of thousands of years. Now, thanks to NASA’s Pioneer Venus and ESA’s Venus Express orbiters, scientists have nearly 40 years of data on Venus’ atmosphere — and therein lies evidence of much more recent large-scale volcanic activity.

The last six years of observations by Venus Express have shown a marked rise and fall of the levels of sulfur dioxide (SO2) in Venus’ atmosphere, similar to what was seen by NASA’s Pioneer Venus mission from 1978 to 1992.

These spikes in SO2 concentrations could be the result of volcanoes on the planet’s surface, proving that the planet is indeed volcanically active — but then again, they could also be due to variations in Venus’ complex circulation patterns which are governed by its rapid “super-rotating” atmosphere.

“If you see a sulphur dioxide increase in the upper atmosphere, you know that something has brought it up recently, because individual molecules are destroyed there by sunlight after just a couple of days,” said Dr. Emmanuel Marcq of Laboratoire Atmosphères in France, lead author of the paper, “Evidence for Secular Variations of SO2 above Venus’ Clouds Top,” published in the Dec. 2 edition of Nature Geoscience.

“A volcanic eruption could act like a piston to blast sulphur dioxide up to these levels, but peculiarities in the circulation of the planet that we don’t yet fully understand could also mix the gas to reproduce the same result,” added co-author Dr Jean-Loup Bertaux, Principal Investigator for the instrument on Venus Express.

Because Venus’ dense atmosphere whips around the planet at speeds of 355 km/hour (220 mph), pinpointing an exact source for the SO2 emissions is extremely difficult. Volcanoes could be the culprit, but the SO2 could also be getting churned up from lower layers by variations in long-term circulation patterns.

Venus has over a million times the concentration of sulfur dioxide than Earth, where nearly all SO2 is the result of volcanic activity. On Venus it’s been allowed to build up, kept stable at lower altitudes where it’s shielded from solar radiation.

Regardless of its source any SO2 detected in Venus’ upper atmosphere must be freshly delivered, as sunlight quickly breaks it apart. The puzzle now is to discover if it’s coming from currently-active volcanoes… or something else entirely.

“By following clues left by trace gases in the atmosphere, we are uncovering the way Venus works, which could point us to the smoking gun of active volcanism,” said Håkan Svedhem, ESA’s Project Scientist for Venus Express.

Read more on the ESA release here.