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| Piú votate - Venus |
Venus-PIA10123.jpgApproaching Venus54 visiteCaption NASA:"On Oct. 24, 2006, the MESSENGER Spacecraft came within 2990 Km (such as about 1860 miles) of Venus during its second planetary encounter.
Twenty days before closest approach to Venus the MESSENGER Dual Imaging System snapped pictures of the Planet from a distance of about 16,5 MKM (about 10,3 MMs). Despite the low resolution of the image on the left, one can see that Venus is shrouded in a thick blanket of clouds that hides its surface.
The picture on the right is the same image expanded 4 times, clearly showing the dense Venusian cloud cover".MareKromium
(3 voti)
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South_Polar_Regions-0.gifVenusian South Polar Vortex through Venus Express (1)54 visiteThis composite video sequence was obtained by the Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) on board ESA’s Venus Express.
The single images were taken from 7 to 11 April 2007 over 5 different orbits. In each orbit the images were collected over a time span of 8 hours and were separated by about half an hour. The average distance from the Planet was about 65.000 Km.
The Latitude of the observed area spans 50 to 90° South. The Longitude spans about 20 to 150° East.
The video shows details of the Planet’s South Pole in RGB colour. The data obtained at 1.7 microns is shown in blue, while those obtained at 3.8 microns is represented in red.
Using specific wavelengths (3.8 and 1.7 microns, respectively), the observations allowed the imaging of the day and night areas around the South Pole simultaneously, at different depths (at about 65 Km and below the cloud deck, respectively) simultaneously. The intersection between the polar atmospheric structures seen at different wavelengths is visible well, due to the optical properties of the clouds.
MareKromium
(3 voti)
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South_Polar_Regions-1.gifVenusian South Polar Vortex through Venus Express (2)54 visiteThis composite video sequence was obtained by the Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) on board ESA’s Venus Express.
The single images were taken from 7 to 11 April 2007 over 5 different orbits. In each orbit the images were collected during a time span of 8 hours and were separated by about half an hour. The average distance from the Planet was about 65.000 Km.
The Latitude of the observed area spans from 90 to 50° South. The Longitude spans from about 20 to 150° East.
The video shows details of the Planet’s South Pole with edge-enhanced contrast.
Using specific wavelengths (3.8 and 1.7 microns, respectively), the observations allowed the imaging of the day and night areas around the South Pole simultaneously, at different depths (at about 65 Km and below the cloud deck, respectively) simultaneously. The intersection between the polar atmospheric structures seen at different wavelengths is visible in good detail, due to the optical properties of the clouds.MareKromium
(3 voti)
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Z-Venus~1.jpgIs there Life on Venus?112 visitePotential signs of life on Venus are fading as astronomers downgrade their original claims.
"The announcement in September 2020 took the World by storm: Researchers using two radio telescopes found signs that the clouds of Venus were harboring phosphine, a toxic compound that on Earth is only made in significant quantities by microbes and chemists. The unexpectedly high levels detected on Venus could point to a floating microbial biosphere, the researchers suggested in a paper published in Nature Astronomy. But almost immediately, other astronomers began to criticize the results, with four independent studies pointing out questionable methods or failing to reproduce the results.
Now, after reanalyzing their data, the original proponents are downgrading their claims. Even the most favorable interpretation of their data now suggests phosphine levels are at least seven times lower than first reported, making it a much more tentative finding, the authors reported in a preprint posted on 17 November to arXiv. But the team still believes the gas is there, with the possibility that local pockets rise to higher levels, said Jane Greaves, an astronomer at Cardiff University who led the work, in a talk today to NASA’s Venus Exploration Analysis Group (VEXAG). “We have again a phosphine line.”
Lets hope more research and study provide the necessary data to prove one way or another!".MareKromium
(2 voti)
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Venus_Clouds_-_Akatzuki_960.jpgVenusian Clouds145 visitenessun commentoMareKromium
(2 voti)
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Volcanoes-Sapas_Mons-PIA00099-PCF-LXTT-IPF.jpgThe Eastern Flank of Sapas Mons (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)80 visiteThis NASA - Magellan Spacecraft's image - centered near 9,6° North Latitude and 189,5° East Longitude - covers an area of approx. 140 Km (such as about 86,94 miles) by approx. 110 Km (such as aabout 68,31 miles) and shows us part of the Eastern Flank of the Venusian Volcano known as Sapas Mons, which is located on the Western Edge of Atla Regio.
The bright Lobate Surface Features visible along the Southern and Western portions of the image, oriented in a North/East to South/West directions, are huge Lava Flows. These Flows range, in width, from approx. 5 to 25 Km (such as from about 3,1 to 15,525 miles), with lengths going from about 50 to approx. 100 Km (such as from about 31,05 to 62,1 miles), and they seem to extend themselves way off the area shown here. Additional Radar-Dark (---> Smooth) Flows are also present. The Radar-Bright Linear Structures found in the North/Western portion of the frame are interpreted to be (relatively) shallow Faults and Fractures, which could possibly be associated with the emplacement of Magma in the Sub-Surface.
Furthermore, located near the center of the image, there is an Impact Crater whose diameter is roughly 20 Km (such as about 12,42 miles). This Impact Crater is superimposed on a North/East-to-South/West trending Fracture, while the Southern Side of the Crater's Ejecta Blanket is covered by an approx. 6 Km (such as about 3,72 miles) wide Radar-Bright Lava Flow. These (just apparently) complicated relations indicate that the Crater post-dates an episode of Fracturing and that is older than the Lava Flows covering its Southern Edge.
Last, but not least, this is one of only a few places on Venus where an Impact Crater is seen to be covered by Volcanic Deposits.
This frame (which is an Original NASA - Magellan Spacecraft Radio-Image-Mosaic published on the NASA - Planetary Photojournal with the n. PIA 00099), since it is just a Radio-Image of the Venusian Surface and NOT a real view of it, has been colorized, according to an educated guess carried out by Dr Paolo C. Fienga (LXTT-IPF), in what they could reasonably be its possible Absolute Natural Colors (such as the colors that a human eye would perceive if someone were onboard the NASA - Magellan Spacecraft and, once the thick layer of Venusian Clouds and Fogs is completely overcome, looked down, towards the Surface of Venus itself), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.MareKromium
(2 voti)
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Craters-Ghost_Crater_in_Lakshmi_Region-PIA00477-PCF-LXTT-IPF.jpgPossible "Ghost Crater" in Lakshmi Region (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)76 visiteThis NASA - Magellan Spacecraft image covers an area of approximately 100 by 120 Km (such as 62,1 by 74,5 miles) and is located in the Lakshmi Region of Venus, at 47° North Latitude and 334° East Longitude. Due to the extremely dense Venusian Atmosphere, primary Impact Craters of less than a 3 Km (such as 1,863 mileS) diameter are, in fact, nonexistent on the Surface of this Planet. However, the Dark Circular Region and the associated Central Bright Feature visible in this frame are reasonably thought to be the remnants of a Meteoroid that was smaller than the size necessary to create an actual Impact Crater but, anyway, that was big enough to leave some scars on the Venusian Surface.
Entering the Venusian Atmosphere at a low velocity (approximately 350 meters/second - such as about 1260 Km per hour) the Central Bright Feature appears to be a Cluster of Small Secondary Impacts, Ejecta and Debris from the original Meteor that broke up in the Atmosphere and, litterally, fell down in pieces. Even though most of the Meteorite did not hit the Surface, the Atmospheric Shock Wave/s that were generated by the Impact Event, could have been great enough to modify the surrounding Region. One explanation for this radar Dark Circular Formation - called "Dark Margin" -, could be that the Shock Wave/s was/were energetic enough to pulverize some portion of the Venusian Surface (remember that smooth surfaces generally appear radar dark).
Another explanation is that the Surface nere, could be blanketed by a fine material that was formed by the original Meteor's break up through the Atmosphere. Just out of curiosity, more than half of the Impact Craters found on Venus have associated "Dark Margins", and most of them are prominently located left of center of the Craters themselves.
This frame (which is an Original NASA - Magellan Spacecraft Radio-Image published on the NASA - Planetary Photojournal with the n. PIA 00477), since it is just a Radio-Image of the Venusian Surface and NOT a real view of it, has been colorized, according to an educated guess carried out by Dr Paolo C. Fienga (LXTT-IPF), in what they could reasonably be its possible Absolute Natural Colors (such as the colors that a human eye would perceive if someone were onboard the NASA - Magellan Spacecraft and, once the thick layer of Venusian Clouds and Fogs is completely overcome, looked down, towards the Surface of Venus itself), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.MareKromium
(2 voti)
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Venus-Southern_Vortex-ESA-VE.jpgVenus' South Polar Vortex115 visiteCaption NASA:"What's happening over the South Pole of Venus?
To find out, scientists have been studying images taken by the robotic Venus Express spacecraft when it passes over the lower spin axis of Earth's overheated twin. Surprisingly, recent images from Venus Express do not confirm previous sightings of a double storm system there, but rather found a single unusual swirling cloud vortex.
In the above recently released image sequence taken in IR 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 (Eddy - plur. Eddies ---> vortice/i, mulinello/i) 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. In three months, the European Venus Express spacecraft will be joined around Venus by the Japanese Akatsuki satellite".MareKromium
(2 voti)
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Craters-Barton_Crater-PIA00463.jpgBarton Crater (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)56 visiteDuring orbits 404 through 414 on 19-20 September 1990, the Magellan Probe imaged a Peak-Ring Crater that is about 50 Km in diameter located at Latitude 27,4° North and Longitude 337,5° East. The name "Barton" has been proposed by the Magellan Science Team for this Crater, after Clara Barton, founder of the Red Cross; however, the name is tentative pending approval by the International Astronomical Union.
Barton is just at the diameter size that Venus Impact Craters appear to begin to possess Peak-Rings instead of a single Central Peak or Central Peak complex like does about 75% of the craters with diameters between about 50 and 15 Km.
The floor of the Crater is flat and radar-dark, indicating possible infilling by volcanic deposits sometime following the impact event. Barton's Central Peak Ring is discontinuous and appears to have been disrupted or separated during or following the cratering process. The extremely blocky crater deposits (ejecta) surrounding Barton appear to be most extensive on the South-West to South-East (lower left to right) side of it.MareKromium
(2 voti)
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Lakshmi_Planum-PIA00249.jpgDanu Montes and Lakshmi Planum (possible Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)56 visiteSouthwest Lakshmi Planum is bounded on the South by the Danu Montes.
Lakshmi Planum is an elevated plateau plain that is bounded on all sides by mountain chains. Here, the Danu Mountains have an angular fractured appearance. Chasms slice diagonally across the mountains in the lower left (South-West) corner of the image. Because of the steep slopes and the local relief of the mountains of several kilometers (2-3 miles, these fault-bounded troughs appear to zig-zag through the mountains when, in fact, they are probably straight if viewed from above.
The radar view provides a perspective that would place the viewer's eye to the right, 27° above the Horizon. Thus, slopes facing to the right can be seen completely, though dark, and slopes facing away to the left appear shortened, often seen only as thin bright lines. In the center of the image is a low volcanic dome (approx. 20 Km - about 12 miles - in diameter).
This type of volcanic feature frequently occurs on the low plains. This dome on the edge of Lakshmi is deformed and faulted where it has been affected by the forces that created the Danu mountains.
The image is approx. 75 Km (about 46 miles) on a side. The center is at 60° North Latitude and 324,5° East Longitude.MareKromium
(2 voti)
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Venusian_Clouds_Altimetry-2008-04-03438_Figure_3_H.jpgAltimetry of Venus Clouds' Top54 visiteCaption ESA:"A Venus Monitoring Camera UltraViolet image with a superimposed colour mosaic, showing the altitude of the cloud tops.
The colour mosaic was derived from simultaneous pressure measurements by the Visible and Infrared Thermal Imaging Spectrometer".MareKromium
(2 voti)
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Montes-Akna_Montes-PCF-LXTT.jpgAkna Montes (Natural Colors; credits: Lunar Explorer Italia)66 visitenessun commentoMareKromium
(2 voti)
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