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.

astronemma:

The Fornax Cluster of Galaxies 
Image Credit & Copyright: Marco Lorenzi

Explanation: How do clusters of galaxies form and evolve? To help find out, astronomers continue to study the second closest cluster of galaxies to Earth: the Fornax cluster, named for the southern constellation toward which most of its galaxies can be found. Although almost 20 times more distant than our neighboring Andromeda galaxy, Fornax is only about 10 percent further that the better known and more populated Virgo cluster of galaxies. Fornax has a well-defined central region that contains many galaxies, but is still evolving. It has other galaxy groupings that appear distinct and have yet to merge. Seen here, almost every yellowish splotch on the image is an elliptical galaxy in the Fornax cluster. The picturesque barred spiral galaxy NGC 1365 visible on the lower right is also a prominent Fornax cluster member.

nasasapod:

Hyades for the Holidays 
Image Credit & Copyright: Jerry Lodriguss (Catching the Light)

Explanation: Recognized since antiquity and depicted on the shield of Achilles according to Homer, stars of the Hyades cluster form the head of the constellation Taurus the Bull. Their general V-shape is anchored by Aldebaran, the eye of the Bull and by far the constellation’s brightest star. Yellowish in appearance, red giant Aldebaran is not a Hyades cluster member, though. Modern astronomy puts the Hyades cluster 151 light-years away making it the nearest established open star cluster, while Aldebaran lies at less than half that distance, along the same line-of-sight. Along with colorful Hyades stars, this stellar holiday portrait locates Aldebaran just below center, as well as another open star cluster in Taurus, NGC 1647 at the left, some 2,000 light-years or more in the background. Just slide your cursor over the image to identify the stars. The central Hyades stars are spread out over about 15 light-years. Formed some 800 million years ago, the Hyades star cluster may share a common origin with M44 (Praesepe), a naked-eye open star cluster in Cancer, based on M44’s motion through space and remarkably similar age.

sklogw:

Goat Aurora Over Greenland - APOD

Image Credit & Copyright: Juan Carlos Casado (TWAN)

“Sometimes it’s hard to believe what you see in the sky. During the SheliosExpedition to Greenland in late August, even veteran sky enthusiasts saw auroras so colorful, so fast changing, and so unusual in form that they could remember nothing like it. As the ever changing auroras evolved, huge shapes spread across the sky morphed from one familiar form into another, including what looked to be the head of a goat (shown above), the head of an elephant, a strange green-tailed comet, and fingers on a celestial hand. Even without the aurora, the sky would be notable for the arching band of our Milky Way Galaxy and the interesting field of stars, nebulas, and galaxies. In contrast, in the foreground is a farm house in Tasiusaq, Kujalleq. Greenland. The Shelios project exists not only to observe auroras but to motivate students to consider a career in science.”

If you hover over the image here, you can see it with and with out the named galaxies, nebulae, and constellations. 

(via spaceplasma)

thescienceofreality:

Stars in a Dusty Sky - APOD
Image Credit & Copyright: John Davis

“Bright star Markab anchors this dusty skyscape. At the top right corner of the frame, Markab itself marks a corner of an asterism known as the Great Square, found within the boundaries of the constellation Pegasus, the flying horse. The wide and deep telescopic view rides along for some 5 degrees or about 10 times the angular diameter of the Full Moon, with blue reflection nebulae scattered around the scene. And even though this line-of-sight looks away from the plane of our Milky Way galaxy, it covers a region known to be filled with nearby molecular clouds. The associated dust clouds, high latitude galactic cirrus, are less than 1,000 light-years distant. Still apparent, but far beyond the Milky Way, are background galaxies, like the prominent edge-on spiralNGC 7497 near picture center.”

Timelapse from Thierry Legault: One Night on the Pic-du-Midi Observatory

Here’s a really unique video from one of our favorite astrophotographers, Thierry Legault. Thierry sent us a full HD time-lapse of the full sky during one full night (August 7-8) over the Pic-du-Midi Observatory in the French Pyrenees. At 2,877 meters in altitude, this is the highest observatory in France. The video is taken with a fisheye lens, and so the view creates what appears to be a tiny little world (Planet Pic-du-Midi, perhaps?). Visible are Saturn and Mars, then the Moon, Jupiter and Venus. And a passage of the ISS and an Iridium flare complete the planet-like scene. “The rotation of the sky around Polaris is easily noticeable,” Thierry wrote to Universe Today, “as well as the movement of circumpolar constellations such as Big Dipper. The main dome is the 1-meter telescope, I was there with three friends to learn how to use this telescope for future planetary missions. This telescope was used in the 60′s to prepare the Apollo lunar missions because of the quality of its optics and the very good seeing of this site.”

The Pic-du-Midi Observatory has to be one of the most picturesque places in astronomy. You can see a great view of it on Astronomy Picture of the Day. The observatory has three domes that house a 0.6 meter telescope reserved for amateur astronomers, and a Sun-watching telescope called CLIMSO, along with the 1 meter telescope.

Thanks to Thierry for sharing this exceptional video, and as always, check out more of Thierry’s work at his website.

(Source: astrophoto.fr)

astronomer-in-progress:

The Bubbling Cauldron of NGC 3079 

Credit: Gerald Cecil (UNC/Chapel Hill) et al., NASA

Explanation: Edge-on spiral galaxy NGC 3079 is a mere 50 million light-years away toward the constellation Ursa Major. Shown in this stunning false-color Hubble Space Telescope image, the galaxy’s disk - composed of spectacular star clusters in winding spiral arms and dramatic dark lanes of dust - spans some 70,000 light-years. Still, NGC 3079’s most eye-catching features are the pillars of gas which tower above a swirling cosmic cauldron of activity at the galaxy’s center. Seen in the close-up inset at lower right, the pillars rise to a height of about 2,000 light-years and seem to lie on the surface of an immense bubble rising from the galactic core. Measurements indicate that the gaseous pillars are streaming away from the core at 6 million kilometers per hour. What makes this galaxy’s cauldron bubble? Astronomers are exploring the possibility that the superbubble is formed by winds from massive stars. If so, these massive stars were likely born all at once as the galactic center underwent a sudden burst of star formation.

(via astronomerinprogress)

Vincent van Gogh’s Starry Night: Artistic Analogy

Explanation: The painting Starry Night is one of the most famous icons of the night sky ever created. The scene was painted by Vincent van Gogh in southern France in 1889. The swirling style of Starry Night appears, to many, to make the night sky come alive. Although van Gogh frequently portrayed real settings in his paintings, art historians do not agree on precisely what stars and planets are being depicted in Starry Night. The style of Starry Night is post-impressionism, a popular painting style at the end of the nineteenth century. The original Starry Night painting hangs in the Museum of Modern Art in New York City, New York, USA.

Starry Night: Composition Top

The night sky depicted by van Gogh in the Starry Night painting is brimming with whirling clouds, shining stars, and a bright crescent moon. The setting is one that viewers can relate to and van Gogh´s swirling sky directs the viewer´s eye around the painting, with spacing between the stars and the curving contours creating a dot-to-dot effect. These internal elements ensure fluidity and such contours were important for the artist even though they were becoming less significant for other Impressionists. Thus Starry Night´s composition was distinct from the Impressionist technique of the 19th century.

The artist was aware that his Starry Night composition was somewhat surreal and stylized and in a letter to his brother he even referred to “exaggerations in terms of composition. ” The vivid style chosen by van Gogh was unusual - he chose lines to portray this night scene when silhouettes would have been a more obvious choice.

In Starry Night contoured forms are a means of expression and they are used to convey emotion. Many feel that van Gogh´s turbulent quest to overcome his illness is reflected in the dimness of the night sky. The village is painted with dark colors but the brightly lit windows create a sense of comfort. The village is peaceful in comparison to the dramatic night sky and the silence of the night can almost be felt in Starry Night. The steeple dominates the village and symbolizes unity in the town. In terms of composition, the church steeple gives an impression of size and isolation.

In the left foreground is a curvy cypress tree which is typically associated with mourning. It is painted in the same way as the sky with fluid lines which enhances the flow of the Starry Night painting well as its easiness on the eye.

Starry Night: Use of color Top

Van Gogh´s choice of color in Starry Night has been much debated, particularly the dominance of yellow in this and other late works. Some believe van Gogh may have been suffering from lead poisoning or a type of brain disease and that this explains his strange use of color in later paintings.

Van Gogh’s use of white and yellow creates a spiral effect and draws attention to the sky. Vertical lines such as the cypress tree and church tower softly break up the composition without retracting from the powerful night sky depicted in Starry Night.

Vincent van Gogh´s choice of dark blues and greens were complemented with touches of mint green showing the reflection of the moon. The buildings in the centre of the painting are small blocks of yellows, oranges, and greens with a dash of red to the left of the church. The dominance of blue in Starry Night is balanced by the orange of the night sky elements.

Van Gogh paints the rich colors of the night and this corresponds with the true character of this Starry Night, whereby colors are used to suggest emotion.

Starry Night: Use of Light Top

Van Gogh´s passion for nighttime is evident in the Starry Night painting, where the powerful sky sits above the quiet town. It seems that van Gogh is contrasting life and death with luminous stars and a gloomy, peaceful village. The main light sources are the bright stars and crescent moon.

Starry Night: Mood, Tone and Emotion Top

There are various interpretations of Starry Night and one is that this canvas depicts hope. It seems that van Gogh was showing that even with a dark night such as this it is still possible to see light in the windows of the houses. Furthermore, with shining stars filling the sky, there is always light to guide you. It seems that van Gogh was finally being cured of his illness and had essentially found his heaven. He also knew that in death he would be at peace and further portrays this by using bold colors in the Starry Night painting.

In a letter to his brother, Theo, van Gogh comments: “I should not be surprised if you liked the Starry Night and the Ploughed Fields, there is a greater quiet about them than in the other canvases. ” Later in the letter he makes reference to Leo Tolstoys book My Religion and its lack of belief in resurrection. Such fleeting mentions of religion echoed van Goghs feelings towards the subject at this time; he could neither forget it nor totally accept it. Despite this, his use of the word ‘quiet’ and reference to Tolstoys book indicates that the night sky made him feel calm and brought to mind eternity.

Starry Night shows the vast power of nature and the church spire and cypress tree - representing man and nature - both point to the heavens.

Starry Night: Brushstroke Top

In Starry Night van Gogh´s unique, thick brush strokes are very much obvious and it´s possible that his severe attacks further dramatized his brush work. However, there is a consistency to his technique that adds even more depth as well as a rich texture to this work of art.

thescienceofreality:

Conjunction Colours - APOD
Image Credit & Copyright: Phil Hart

“During the past week, nightfall on planet Earth has featured Mars, Saturn, and Spica in a lovely conjunction near the western horizon. Still forming the corners of a distinctive celestial triangle after sunset and recently joined by a crescent Moon, they are all about the same brightness but can exhibit different colors to the discerning eye. This ingenious star trail image was recorded as the trio set on August 12 with a telephoto lens from the shores of Lake Eppalock, in central Victoria, Australia. Focused on foreground eucalyptus trees, the image slightly blurs the trails to show more saturated colors. Can you guess which trail is which? Of course the reddest trail is Mars, with Saturn on the right a paler echo of the Red Planet’s hue. Left is hot and luminousSpica, bluish alpha star of the constellation Virgo.”

APOD Turns Eleven

Credit & Copyright: Herman Serrano

Explanation: The first APOD appeared eleven years ago today, on 1995 June 16. Although garnering only 14 page views on that day, we are proud to estimate that APOD has now served over 400 million space-related images over the last eleven years. That early beginning, along with a nearly unchanging format, has allowed APOD to be a consistent and familiar site on a web frequently filled with change. Many people don’t know, though, that APOD is now translated daily into many major languages. We again thank our readers and NASA for their continued support, but ask that any potentially congratulatory e-mail go to the folks who created the great pictures — many times with considerable effort — that APOD has been fortunate enough to feature over the past year. Many can be contacted by following links found in the credit line under the image. Some of these images are featured in the above spectacular collage of a fantasy sky above Mars submitted by an enthusiastic APOD reader skilled in digital image manipulation. How many APOD images can you identify?

lookatthesefuckinstars:

Jupiter’s Clouds from Cassini

Cassini and Jupiter are two of my favorite things.

<3

(via )