* Astronomy

Blobrana · L

RE: Venus

Blobrana · L

One of the many mysteries of Earth's nearest planetary neighbour Venus has been cracked, Nature journal reports.
Scientists have long puzzled over conspicuous patches in the Venusian clouds that appear dark at ultraviolet (UV) light wavelengths.
They now think these are solid particles or liquid droplets that get transported from deep in the atmosphere up to the planet's cloud tops.
But a riddle remains: scientists still don't know what they are made up of.
The features are distributed within the thick clouds of sulphuric acid and sulphur dioxide that shroud the hothouse planet.

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Blobrana · L

A pale dot to the human eye, Venus, Earth's twin planet comes to life in the ultraviolet and the infrared. New data and images from the Venus Express spacecraft reveal a clearer picture of the atmosphere of the planet, showing temperature, conditions, cloud structure and dynamics. The observations by D. Titov of the Max Planck Institute for Solar System Research and colleagues ('Atmospheric structure and dynamics as the cause of ultraviolet markings in the clouds of Venus'), published in the 4 December 2008 issue of Nature, will enable scientists to better understand the meteorology of Venus and compare it to that of Earth.
Using Venus Express, it is possible to compare what the planet looks like in different wavelengths, giving scientists a powerful tool to study the physical conditions and dynamics of the planet's atmosphere.
Observed in the ultraviolet, Venus shows numerous high-contrast features. The cause is the inhomogeneous distribution of a mysterious chemical in the atmosphere that absorbs ultraviolet light, creating the bright and dark zones. The ultraviolet reveals the structure of the clouds and the dynamical conditions in the atmosphere, whereas the infrared provides information on the temperature and altitude of the cloud tops.
With data from Venus Express, scientists have learnt that the equatorial areas on Venus that appear dark in ultraviolet light are regions of relatively high temperature, where intense convection brings up dark material from below. In contrast, the bright regions at mid-latitudes are areas where the temperature in the atmosphere decreases with depth. The temperature reaches a minimum at the cloud tops suppressing vertical mixing. This annulus of cold air, nicknamed the 'cold collar,' appears as a bright band in the ultraviolet images.
Observations in the infrared have been used to map the altitude of the cloud tops. Surprisingly, the clouds in both the dark tropics and the bright mid-latitudes are located at about the same height of about 72 km. At 60 south, the cloud tops start to sink, reaching a minimum of about 64 km, and form a huge hurricane at the pole.
This study has revealed that variable temperature and dynamical conditions at the Venus cloud tops are the cause of the global ultraviolet pattern.
But the exact chemical species that creates the high-contrast zones still remains elusive, and the search is on.

Source: European Space Agency

Blobrana · L

Team led by scientists from University of the Basque Country manage to measure wind details of Venus

Venus is a planet similar in size to the Earth. Nevertheless, it is quite different in other aspects. 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 planets own orbit of 224 days. This phenomenon was baptised the superotation of Venus: the winds carrying these clouds travel at 360 km/h.

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Title: Magnetic Fluctuations and Turbulence in the Venus Magnetosheath and Wake
Authors: Z. Vörös, T.L. Zhang, M.P. Leubner, M. Volwerk, M. Delva, W. Baumjohann, K. Kudela

Recent research has shown that distinct physical regions in the Venusian induced magnetosphere are recognizable from the variations of strength and of wave/fluctuation activity of the magnetic field. In this paper the statistical properties of magnetic fluctuations are investigated in the Venusian magnetosheath, terminator, and wake regions. The latter two regions were not visited by previous missions. We found 1/f fluctuations in the magnetosheath, large-scale structures near the terminator and more developed turbulence further downstream in the wake. Location independent short-tailed non-Gaussian statistics was observed.

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Blobrana · L

As ESA's Venus Express orbits our sister planet, new images of the cloud structure of one of the most enigmatic atmospheres of the Solar System reveal brand-new details.
Venus is covered by a thick layer of clouds that extends between 45 and 70 km above the surface. These rapidly-moving clouds are mainly composed of micron-sized droplets of sulphuric acid and other aerosols (fine solid or liquid droplets suspended in a gas), the origin of which is unknown.
Earlier missions have shown that the clouds resemble Earth's light fogs, but their thickness creates an impenetrable veil.

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Southern hemisphere of Venus in the ultraviolet

Southern hemisphere of Venus in the ultraviolet

This beautiful, false-colour ultraviolet image of the Southern hemisphere of Venus was obtained by the Venus Monitoring Camera (VMC) on board ESAs Venus Express on 27 July 2007. It was taken from a distance of 30 000 km from the planets surface at a wavelength of 365 nanometres. The planet is seen from the southern hemisphere: the south pole is at the bottom, while equator is at the top.

Blobrana · L

Venus Express has detected the molecule hydroxyl on another planet for the first time. This detection gives scientists an important new tool to unlock the workings of Venuss dense atmosphere.
Hydroxyl, an important but difficult-to-detect molecule, is made up of a hydrogen and oxygen atom each. It has been found in the upper reaches of the Venusian atmosphere, some 100 km above the surface, by Venus Expresss Visible and Infrared Thermal Imaging Spectrometer, VIRTI

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Blobrana · L

In the twilight sky, low on the horizon, glows a brilliant body. Occasionally mistaken for a UFO, the planet is actually our nearest neighbour and Earths twin: Venus. Earth and Venus share a similar mass, volume and distance from the sun. Scientists even think the two planets were birthed from the same parent material some 4.5 billion years ago. But while Earth was developing into a thriving planet filled with life, Venus went down a wayward path, becoming Earths evil twin: a hellishly hot world enveloped by a thick, toxic atmosphere.

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Blobrana · L

The planet Venus, hellishly hot and as written off as a habitat of any life, in recent times, could be, is afterall harboring microbial life in its cloudy upper atmosphere.
Professor Chandra Wickramasinghe of Cardiff University, the worlds leading authority on the theory of Panspermia, which says life on earth originated in deep space and travelled here hitchhiking on comets, said according to the latest researches of me any my daughter, Janaki Wickramasinghe, the planet Venus has a microbial ecology high in its atmosphere.

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Blobrana · L

A mega-collision between two large embryonic planets could have created Venus as we know it, according to a new paper by a Cardiff University scientist.
Venus is a sister planet to Earth. It is nearly the same size and density yet it has a surface temperature of 720 K, an atmosphere dominated by carbon dioxide and no evidence of oceans or ridges. It has been described as Earths evil twin.
Dr Huw Davies, of the School of Earth and Ocean Sciences argues that a mega-collision could explain these differences. In particular the collision could explain why the interior of Venus is dry, the odd rotation of the planet and the carbon dioxide atmosphere.

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