On the one hand, it spins very slowly on its axis, taking 224 terrestrial days and, moreover, it does so in the opposite direction to that of our planet, i.e. from East to West.
Its dense atmosphere of carbon dioxide with surface pressures 90 times that of Earth (equivalent to what we find at 1000 metres below the surface of our oceans), causes a runaway greenhouse effect that raises the surface temperatures up to 450ºC, to such as extent that metals like lead are in a liquid state on Venus. At a height of between 45 km and 70 km above the surface there are dense layers of sulphuric acid clouds totally covering the planet.
It was in the 1960s that they discovered, by means of telescopic observations, that the top level of cloud layers moved very rapidly, orbiting the planet in only four days, compared to the planet’s own orbit of 224 days. This phenomenon was baptised the “superotation” of Venus: the winds carrying these clouds travel at 360 km/h.
The various space missions that explored the planet in the 70s and 80s showed that the “superotation” was a permanent phenomenon and, moreover the probes that descended through its atmosphere indicated that, in a number of places, the winds decreased in speed to zero at Venus’s surface. New observations carried out with the Venus Express mission of the European Space Agency, in orbit around Venus since April 2006, have enabled the team of scientists from the University of the Basque Country (UPV/EHU) to determine in detail the global structure of the winds on Venus at its level of clouds while, at the same time, to observe unexpected changes in the wind speeds, and which helped to interpret this mysterious phenomenon.
The team was led by Agustín Sánchez Lavega with team members being Ricardo Hueso, Santiago Pérez Hoyos and Javier Peralta, from the Planetary Sciences Group at the Higher Technical Engineering School of Bilbao. The article, entitled “Variable winds on Venus mapped in three dimensions”, was published with front page coverage in the Geophysical Research Letters. This journal is published by the US American Geophysical Union (AGU) and is the most prestigious in its sphere of research. Moreover, the article was one of eight selected amongst hundreds for publication by the AGU in all journals as being the most outstanding in the EOS Transactions bulletin – sent to 50,000 AGU members at research centres all over the world.
Novel aspects of the rotation
Using images recorded by both day and night on Venus with the VIRTIS spectral camera on board the Venus Express, the UPV/EHU scientists have succeeded in measuring these clouds over several months and have discovered new aspects of the “superotation”. Firstly, between the equator and the median latitudes of the planet there dominates a superotation with constant winds blowing from East to West, within the clouds decreasing speed with height from 370 km/h to 180 km/h. At these median latitudes, the winds decrease to a standstill at the pole, where an immense vortex forms.
Other aspects of the superrotation that observations with VIRTIS have made possible are that the meridional (North – South) movements are very weak, about 15 km/h, and, secondly, unlike what was previously believed, the superotation appears to be not so constant over time: “We have detected fluctuations in its speed that we do not yet understand”, stated the scientists. Moreover, for the first time they observed “the solar thermal tide” effect at high latitudes on Venus. “The relative movement of the Sun on the clouds and the intense heat deposited on them makes the superotation more intense at sunset than at sunrise”, they stated.
“Despite all the data brought together, we are still not able to explain why a planet than spins so slowly has hurricane global winds that are much more intense than terrestrial ones and are, moreover, concentrated at the top of its clouds” stated Mr Sánchez Lavega. This study has enabled advances to be made in a precise explanation of the origin of superotation in Venusian winds as well as in the knowledge of the general circulation of planetary atmospheres.
Irati Kortabitarte | alfa
Neutron star merger directly observed for the first time
17.10.2017 | University of Maryland
Breaking: the first light from two neutron stars merging
17.10.2017 | American Association for the Advancement of Science
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
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17.10.2017 | Life Sciences
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