Updates Venus Express News

[Notebook]

http://www.esa.int/esaSC/SEMUKVZNK7G_index_0.html

8 April 2010
ESA’s Venus Express has returned the clearest indication yet that Venus is still geologically active. Relatively young lava flows have been identified by the way they emit infrared radiation. The finding suggests the planet remains capable of volcanic eruptions.

N.

 

[wannacow]

Thats good news to know its geologicallly active

 

[rucinter]

Good news for us, bad news for poor Venusians living near the lava flow...

 

[Notebook]

He's only 39 here, but number one on Venus!:

http://www.empireonline.com/50greatestcomiccharacters/default.asp?c=39

N.

 

[ar81]

Good news for us, bad news for poor Venusians living near the lava flow...

Unless venusians are extremophiles that benefit from lava heat.:thumbup:

 

[Piper]

It's great to see the list of geologically active places in the solar system expanding

 

[Notebook]

Venus Express has completed an 'aerodrag' campaign that used its solar wings as sails to catch faint wisps of the planet’s atmosphere. The test used the orbiter as an exquisitely accurate sensor to measure atmospheric density barely 180 km above the hot planet.

http://www.esa.int/esaCP/SEMUDKF098G_index_0.html

N.

 

[orb]

Venus Express found that Venusian lightnings are similar to Earth's:

• Astronomy Now: Venus' lightning similar to Earth's:
  

  Despite the huge differences between Venus' and Earth's atmospheres, data from ESA's Venus Express satellite finds that the planets produce lightning in surprisingly similar ways.
  
  Although early missions such as Venera, Pioneer Venus and Galileo reported evidence for optical and electromagnetic waves that could be produced by lightning, the topic has been much debated given Venus' very different atmosphere to our own planet's – its surface pressure is nearly 100 times greater than that of Earth and 500 degrees hotter. Now, thanks to Venus Express' magnetometer, scientists have confirmed that lightning is also a common occurrence on our neighbouring planet.
  
  Dr Christopher Russell, who presented the results at the European Planetary Science Congress today, says that the rates of discharge, intensity and spatial distribution of lightning are all comparable to the behaviour of lightning on Earth. "Short strong pulses of the signals expected to be produced by lightning were seen almost immediately upon arrival at Venus, despite the generally unfavorable magnetic field orientation for entry of the signals into the Venus ionosphere at the altitude of the Venus Express measurements," he says.
  ...

• SPACE.com: Lightning on Venus Strikingly Similar to Earth's.
• Universe Today: Lightning Storms on Venus Similar to Those On Earth.
• ScienceDaily: Earth and Venus Lightning: Similar Mechanisms on the Two Planets.

---------- Post added 24th Sep 2010 at 01:19 ---------- Previous post was 23rd Sep 2010 at 11:14 ----------

Astronomy Now: Venus polar vortex all shook up:

New animations created from ESA's Venus Express mission show striking changes in the vortex that rides around the planet's south pole, its double-eyed feature currently absent.

Three-dimensional perspective view of the south polar vortex in its present state (left)
and in a dipole configuration (right). Image: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA.​

Since Venus Express' arrival at our neighbouring planet in 2006, the VIRTIS (Visible and InfraRed Thermal Imaging Spectrometer) instrument has been collecting data on the temperature of the planet's atmosphere and cloud decks, finding that the polar region's dynamics follow rules of their own.

A north polar vortex was observed as early as the 1979 Pioneer Venus mission, but Venus Express soon found its double-eyed southern hemisphere twin. Covering a diameter of around 3,000 kilometres, it rotates almost like a solid body. As the Venus Express mission progressed, however, a variety of vortex shapes have been seen, with the double-eye feature now having apparently disappeared.
...

Dynamics within the south polar vortex are extremely complex.
The animation below shows atmospheric flow in different directions and at different speeds:

Image: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA/Univ. of Oxford.

 

[Orbinaut Pete]

The Strength of Venus Lightning Sparks Interest in the Scientific Community.

Despite the great differences between the atmospheres of Venus and Earth, scientists have discovered that very similar mechanisms produce lightning on the two planets. The rates of discharge, the intensity and the spatial distribution of lightning are comparable, thus scientists hope to be able to better understand the chemistry, dynamics and evolution of the atmospheres of the two planets. These results will be presented by Dr. Christopher Russell at the European Planetary Science Congress, on Thursday 23d September.

Early missions, such as the Venera orbiters and probes, followed later by the Pioneer Venus Orbiter and more recently by the Galileo spacecraft, have reported evidence for optical and electromagnetic waves from Venus that could be produced by lightning. This was also confirmed by ground telescopes capturing lighting flashes at Venus. Yet the differences in the two atmospheres led some to claim that lightning on Venus would be unlikely and the topic became controversial. The launch of Venus Express with its magnetometer built by the Space Research Institute in Graz, Austria, has provided a great opportunity to unambiguously confirm the occurrence of lightning on Venus and to study in detail its magnetic field at altitudes between 200 and 500 km.

“Short strong pulses of the signals expected to be produced by lightning were seen almost immediately upon arrival at Venus, despite the generally unfavorable magnetic field orientation for entry of the signals into the Venus ionosphere at the altitude of the Venus Express measurements,” says Dr. Russell of the University of California, USA. The electromagnetic waves that Dr. Russell and his team observed are strongly guided by the Venusian magnetic field and they can only be detected by the spacecraft when the magnetic field tilts away from the horizontal by more than 15 degrees. This is quite unlike the situation on Earth, where the lightning signals are aided in their entry into the ionosphere by the nearly vertical magnetic field.

When clouds form, on Earth or Venus, the energy that the Sun has deposited in the air can be released in a very powerful electrical discharge. As cloud particles collide, they transfer electrical charge from large particles to small, and the large particles fall while the small particles are carried upward. The separation of charges leads to lightning strokes. This process is important for a planetary atmosphere because it raises the temperature and pressure of a small portion of the atmosphere to a very high value so that molecules can form, which would not otherwise occur at standard atmospheric temperatures and pressures. This is why some scientists have speculated that lightning may have helped life to arise on Earth.

On our planet occur about 100 lightning discharges per second, but from any one location we see far fewer. Similarly on Venus we do not see the entire planet and we have to estimate the total occurrence rate with some assumptions about how far one can see. Thanks to the new datasets from Venus Express, Dr. Russel and colleagues were able to show that lightning is similar in strength on Earth and Venus at the same altitudes. “We have analyzed 3.5 Earth-years of Venus lightning data using the low-altitude Venus Express data (10 minutes per day). By comparing the electromagnetic waves produced at the two planets, we found stronger magnetic signals on Venus, but when converted to energy flux we found very similar lightening strength,” reports Dr. Rusell. Also it seems that lightning is more prevalent on the dayside than at night, and happens more often at low Venusian latitudes where the solar input to the atmosphere is strongest.

“Venus and Earth are often called twin planets because of their similar size, mass, and interior structure. The generation of lightning is one more way in which Venus and Earth are fraternal twins,” concludes Dr. Russell.

IMAGES

Press release images available at: ftp://igpp.ucla.edu/pub/out

ADDITIONAL INFORMATION

www-ssc.igpp.ucla.edu/VenusLightning/Strength_Venus_Lightning.pdf
Venus lightning: Comparison with terrestrial lightning, C.T. Russell, R.J. Strangeway, J.T.M. Daniels, T.L. Zhang, and H.Y. Wei, 2010, Planetary and Space Science (in press).

The Venus Express mission was launched and is operated by the European Space Agency. The magnetic field instrument was built by the Space Research Institute of the Austrian Academy of Sciences under the leadership of T.L. Zhang. C.T. Russell is supported by NASA’s Venus Express Participating Scientist Program.

---------- Post added at 04:17 AM ---------- Previous post was at 04:08 AM ----------

The Many Faces of the Venus Polar Vortex.

A new animation using data from ESA's Venus Express spacecraft shows that the double eye of the giant vortex at Venus's South pole has disappeared. Results of a study that shows the complex, variable dynamics at the venusian south pole will be presented by Dr. Giuseppe Piccioni at the European Planetary Science Congress, on Thursday 23d September.

Orbiting around Venus since April 11 2006, the ESA mission Venus Express, in particular the VIRTIS (Visible and InfraRed Thermal Imaging Spectrometer) instrument on board, is providing an extensive and unique dataset of great scientific importance, spanning from the surface to the atmosphere and its interaction with the solar wind. VIRTIS is perfectly suited to study Venus from orbit through so called infrared atmospheric windows (very narrow holes at selected wavelengths almost transparent and thus able to transmit the thermal radiance from very deep regions into the Venusian atmosphere). Also, it provides information about temperature of the atmosphere and the clouds’ top, from which it is possible to study its dynamics and in particular the polar vortex.

The Pioneer Venus mission observed for the first time in 1980 the elliptical shape of a polar vortex with two apparent centres of rotation, in the Venusian northern hemisphere labelling it the dipole of Venus. The VIRTIS instrument, right at the beginning of the Venus Express mission, observed for the first time a very similar shape in the southern hemisphere. This discovery revealed a North-South symmetry on Venus and, at a first glance, confirmed the stability of the dipole. However, in the course of the mission, systematic observations with VIRTIS showed a large number of different shapes of the vortex, complex configurations with a not well identified stable feature.

“We had ironically observed it in a dipole configuration right at the beginning of the mission. But we soon discovered that this was just a coincidence, since the dipole in reality is not a stable feature on Venus but just one shape among others,” says Dr. Piccioni.

Dr. Piccioni and colleagues also tracked the clouds in the Venusian atmosphere in order to measure the wind speeds of the significant atmospheric “super-rotation” rotating 60 times faster than its solid body. Measuring the solar light as is reflected or transmitted at different wavelengths they were able to probe different altitude levels within the atmosphere. “We found a significant vertical shear (change of winds with height) at low latitudes, with winds doubling from the lower clouds to the clouds’ top,” says Dr. Piccioni. “However, the shear disappeared at higher latitudes, in combination with a decreasing wind speed toward the pole” he adds.

In fact, the polar region of Venus is known for its very peculiar dynamics, quite different than the rest of the planet. A permanent giant vortex, extending more than 3000 km, dominates its dynamics with, on average, an almost solid body rotation. This is quite contrary to the vertical shear in the mid-to-low latitudes, observed by Dr. Piccioni’s team. The ring surrounding the polar region, known as cold collar, acts as a real barrier of separation between the two rotation zones.

Starting from this December, Venus Express will not be alone any more orbiting around Venus, because the Japanese mission Planet-C, launched last May, will join it into the adventure of exploring the mysterious sister planet.

Images and Movies

Image 1: Comparison of 3D prospective views of the Venus’ south polar vortex showing the vortex as it is now (left) and with the dipole configuration (right).. The vertical scale represents the temperature of the clouds’ top, correlated with its altitude. The centre of the vortex is the deepest zone, estimated to be a few km lower than its surroundings. Credits: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA

Animation 1 (gif): A 3D prospective view of the Venus’ south polar vortex at 3.8 microns acquired by VIRTIS. The vertical scale represents the temperature of the clouds’ top, correlated with its altitude. The centre of the vortex is the deepest zone, estimated to be a few km lower than its surroundings. Credits: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA

Animation 2 (gif): A 3D prospective view of the Venus’ south polar vortex with the dipole configuration. The vertical scale represents the temperature of the clouds’ top, correlated with its altitude. The centre of the vortex is the deepest zone, estimated to be a few km lower than its surroundings. Credits: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA

Image 2 (tif): A set of images of the Venus south polar vortex at 3.8 microns acquired by VIRTIS. The images show the temperature of the clouds top at about 65 km altitude. A darker region corresponds to higher temperature and thus lower altitude. The centre of the vortex, approximately at a temperature of about 250K, is the deepest zone, exhibiting the highest temperature of the Venus clouds’ top. Credits: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA


Animation 3 (gif): A movie of the Venus south polar vortex at 3.8 microns acquired by VIRTIS. The set of images show the temperature of the clouds’ top. A darker region corresponds to higher temperature and thus lower altitude. The temperature contrast is the reason of the three dimensional effect of the images. Credits: ESA/VIRTIS/INAF-IASF-/Obs. de Paris-LESIA


Animation 4 (gif): A movie of the Venus’ south polar vortex at 3.8 microns acquired by VIRTIS. The set of images are projected and compensated for the vortex rotation, to show the dynamics within the vortex, which is very complex. It is thus possible to see atmospheric flow with different direction and speed. Credits: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA/Univ. of Oxford


Figure 5 (gif): A movie of the Venus’ south polar vortex at 3.8 microns acquired by VIRTIS. The set of images are projected and compensated for the vortex rotation, to show the dynamics within the vortex, which is very complex. It is possible to see some structure of planetary waves rotating around the vortex. Credits: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA/Univ. of Oxford

 

[Keatah]

Damn, those are spooky clouds.

 

[orb]

Astronomy Now: Venus Express skims through planet's upper atmosphere.

 

[Orbinaut Pete]

ESA: "Venus Express finds planetary atmospheres such a drag".

SPACE.com: "Venus' Atmosphere Proves a Real Drag, Leading to a Discovery".

 

[Orbinaut Pete]

ESA: "Venus Express probes the planet's atmosphere by flying through it".

 

[orb]

Astronomy Now: Venus Express carries warning for Earth engineers:

ESA's Venus Express satellite has reported an unexpected, high altitude layer of sulphur dioxide in the planet's upper atmosphere that could act as a warning against plans to mitigate climate change on our own planet by injecting the Earth's atmosphere with sulphur droplets.
{...}

________________________________________


ESA:
Venus holds warning for Earth

30 November 2010

A mysterious high-altitude layer of sulphur dioxide discovered by ESA’s Venus Express has been explained. As well as telling us more about Venus, it could be sending a warning to those on Earth seeking to inject our atmosphere with sulphur droplets in an attempt to mitigate climate change.

Venus is blanketed in sulphuric acid clouds that block our view of the surface. The clouds form at altitudes of 50–70 km when sulphur dioxide from volcanoes combines with water vapour to make sulphuric acid droplets. Any remaining sulphur dioxide should be destroyed rapidly by the intense solar radiation above 70 km.

So the detection of a sulphur dioxide layer at 90–110 km by ESA’s Venus Express orbiter in 2008 posed a complete mystery. Where did that sulphur dioxide come from?

Now, computer simulations by Xi Zhang, California Institute of Technology, USA, and colleagues from America, France and Taiwan show that some sulphuric acid droplets may evaporate at high altitude, freeing gaseous sulphuric acid that is then broken apart by sunlight, releasing sulphur dioxide gas.

Close-up on venusian cloud structures at the south pole

“We had not expected the high-altitude sulphur layer, but now we can explain our measurements,” says Håkan Svedhem, ESA’s Venus Express Project Scientist.

“However, the new findings also mean that the atmospheric sulphur cycle is more complicated than we thought.”

As well as adding to our knowledge of Venus, this new understanding may be warning us that proposed ways of mitigating climate change on Earth may not be as effective as originally thought.

Nobel prize winner Paul Crutzen has recently advocated injecting artificially large quantities of sulphur dioxide into Earth’s atmosphere at around 20 km to counteract the global warming resulting from increased greenhouse gases.

Venus Express

The proposal stems from observations of powerful volcanic eruptions, in particular the 1991 eruption of Mount Pinatubo in the Philippines that shot sulphur dioxide up into Earth’s atmosphere. Reaching 20 km in altitude, the gas formed small droplets of concentrated sulphuric acid, like those found in Venus’ clouds, which then spread around Earth. The droplets created a haze layer that reflected some of the Sun’s rays back into space, cooling the whole planet by about 0.5°C.

However, the new work on the evaporation of sulphuric acid on Venus suggests that such attempts at cooling our planet may not be as successful as first thought, because we do not know how quickly the initially protective haze will be converted back into gaseous sulphuric acid: this is transparent and so allows all the Sun’s rays through.

“We must study in great detail the potential consequences of such an artificial sulphur layer in the atmosphere of Earth,” says Jean-Loup Bertaux, Université de Versailles-Saint-Quentin, France, Principal Investigator of the SPICAV sensor on Venus Express. “Venus has an enormous layer of such droplets, so anything that we learn about those clouds is likely to be relevant to any geo-engineering of our own planet.”

In effect, nature is doing the experiment for us and Venus Express allows us to learn the lessons before experimenting with our own world.

 

[orb]

SPACE.com: Bizarre Vortex on Venus Changes Shape Every Day:

A giant vortex at the south pole of Venus is actually a shape-shifter that changes form at least once a day, at times bizarrely taking on the appearance of a giant letter "S" or the number "8," a new study reveals.

{...}

Past images suggested the roughly 1,200-mile-wide (2,000-kilometer) southern polar vortex was only a spinning oval shape. However, new infrared pictures from the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on the European Space Agency's Venus Express mission revealed far more detail than past images, showing that the vortex's internal structure changes shape at least every 24 hours.

{...}

 

[orb]

ESA: ESA finds that Venus has an ozone layer too:

6 October 2011

ESA’s Venus Express spacecraft has discovered an ozone layer high in the atmosphere of Venus. Comparing its properties with those of the equivalent layers on Earth and Mars will help astronomers refine their searches for life on other planets.

Venus Express made the discovery while watching stars seen right at the edge of the planet set through its atmosphere. Its SPICAV instrument analysed the starlight, looking for the characteristic fingerprints of gases in the atmosphere as they absorbed light at specific wavelengths.

The ozone was detectable because it absorbed some of the ultraviolet from the starlight.

{...}

 

[Cairan]

I guess that comes from the more intense sunlight at Venus splitting enough CO and CO2 molecules long enough so they can form O3 high in the atmosphere...

 

[orb]

ESA:
Could Venus be shifting gear?

10 February 2012

ESA’s Venus Express spacecraft has discovered that our cloud-covered neighbour spins a little slower than previously measured. Peering through the dense atmosphere in the infrared, the orbiter found surface features were not quite where they should be.

Click for Animation of Venus (FLASH) / High Resolution WMV​

This animation shows Venus, a planet very similar to Earth in mass and size, but with a crushing atmosphere, sulphuric acid clouds and surface temperatures in excess of 460ºC. Venus Express is helping scientists to understand how a planet with similar physical characteristics to Earth evolved in a way so fundamentally different.

Credits: ESA - C. Carreau​

​

Using the VIRTIS instrument at infrared wavelengths to penetrate the thick cloud cover, scientists studied surface features and discovered that some were displaced by up to 20 km from where they should be given the accepted rotation rate as measured by NASA’s Magellan orbiter in the early 1990s.

These detailed measurements from orbit are helping scientists determine whether Venus has a solid or liquid core, which will help our understanding of the planet’s creation and how it evolved.

If Venus has a solid core, its mass must be more concentrated towards the centre. In this case, the planet’s rotation would react less to external forces.

The most important of those forces is due to the dense atmosphere – more than 90 times the pressure of Earth’s and high-speed weather systems, which are believed to change the planet’s rotation rate through friction with the surface.

Earth experiences a similar effect, where it is largely caused by wind and tides. The length of an Earth day can change by roughly a millisecond and depends seasonally with wind patterns and temperatures over the course of a year.

In the 1980s and 1990s, the Venera and Magellan orbiters made radar maps of the surface of Venus, long shrouded in mystery as well as a dense, crushing and poisonous atmosphere. These maps gave us our first detailed global view of this unique and hostile world.

Over its four-year mission, Magellan was able to watch features rotate under the spacecraft, allowing scientists to determine the length of the day on Venus as being equal to 243.0185 Earth days. .

However, surface features seen by Venus Express some 16 years later could only be lined up with those observed by Magellan if the length of the Venus day is on average 6.5 minutes longer than Magellan measured.

This also agrees with the most recent long-duration radar measurements from Earth.

Click on image to enlarge​

Topographic maps from Magellan and Venus Express clearly show the 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 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.

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

“When the two maps did not align, I first thought there was a mistake in my calculations as Magellan measured the value very accurately, but we have checked every possible error we could think of,” said Nils Müller, a planetary scientist at the DLR German Aerospace Centre, lead author of a research paper investigating the rotation.

Scientists, including Özgur Karatekin of the Royal Observatory of Belgium, looked at the possibility of short-term random variations in the length of a Venus day, but concluded these should average themselves out over longer timescales.

On the other hand, other recent atmospheric models have shown that the planet could have weather cycles stretching over decades, which could lead to equally long-term changes in the rotation period. Other effects could also be at work, including exchanges of angular momentum between Venus and the Earth when the two planets are relatively close to each other.

“An accurate value for Venus’ rotation rate will help in planning future missions, because precise information will be needed to select potential landing sites,” noted Håkan Svedhem, ESA’s Venus Express project scientist.

While further study is needed, it’s clear that Venus Express is penetrating far deeper into the mysteries of this enigmatic planet then anyone dreamed.

{...}



Universe Today: Is Venus’ Rotation Slowing Down?

 

[orb]

SPACE.com: Raging Solar Storm 'Blinds' Venus Spacecraft:

Strong radiation from one of the most intense solar storms in the past five years has temporarily "blinded" a European spacecraft in orbit around Venus, and mission controllers are now racing to fix the problem.

{...}

 

[orb]

Parabolic Arc: Venus Express star trackers recovered

Discovery News: Venus Spacecraft Punched, Blinded by Solar Radiation