Electric Venus

Historic planetary instability and catastrophe. Evidence for electrical scarring on planets and moons. Electrical events in today's solar system. Electric Earth.

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Re: Electric Venus : electric news dump

Unread postby StefanR » Tue Apr 22, 2008 3:58 pm

http://volcano.und.edu/vwdocs/planet_volcano/venus/Ven_Ref_all.gif
Venus has more volcanoes than any other planet in the solar system. Over 1600 major volcanoes or volcanic features are known (see map), and there are many, many more smaller volcanoes. (No one has yet counted them all, but the total number may be over 100,000 or even over 1,000,000). These volcanoes come in a variety of forms. Most are either Large Shields or Smaller Shield volcanoes, but there are also many Complex Features, several Unusual Constructs, and a few Large Flow Features. None is known to be active at present, but our data is very limited. Thus, while most of these volcanoes are probably long dead, a few may still be active.

Large Shield Volcanoes
Image
This map shows the distribution of large shield volcanoes on Venus. Each red triangle marks the site of a shield volcano over 100 km in size. The background shows local surface heights across the planet. Blues denote smooth lowland plains. Greens mark reg ions 1-2 km higher than average for the planet. Reds and yellows show highlands over 3-4 km higher than the rest of the planet.
Very few large volcanoes are in the lowland plains or in the few highland regions. Rather, most of the large shields lie in the green to light yellow regions. Also note how the volcanoes are clustered into left and right sides of the map (dotted lines). T hese regions contain 2 to 4 times more volcanoes (for their size) than the planet as a whole. The reason for this grouping is not fully known, but it may reflect a cluster of closely spaced hotspots in a region of marked crustal failure. This region conta ins a large network of crisscrossing rifts and major fault zones. (Volcano distribution from data of Head et al. (1992); base map shows cycle 1, 2, 3 Magellan topography data.


Overview
Venus has over 150 large shield volcanoes. These shields are mostly between 100 and 600 km across, with heights between about 0.3 and 5.0 km. The largest shields, however, are over 700 km in diameter and up to 5.5 km in height. For reference, Mauna Loa is ~120 km across at its base, and it has a total height of ~8 km (from the sea floor). Thus, the large Venusian shields are broader, but much flatter then the largest shield volcanoes on Earth. Indeed, the largest shield volcanoes on Venus cover nearly the same area as Olympus Mons, which has a basal diameter of ~800 km. (Note, Olympus Mons is still much bigger than the Venusian shields due to its immense height.)

These large shields all look much like shield volcanoes on Earth. They are mostly covered by long, radial lava flows. They all have very gentle slopes. And most also have some form of central vent or summit caldera. Thus, we think that these shields forme d from basalts, much like the shield volcanoes in Hawaii. The venusian shields, however, show a map pattern which is quite different from that seen on Earth (see reference map). Namely, the shields on Venus are widely scattered, and they show no linear vo lcano chains like those on Earth. This suggests that Venus does not have active plate tectonics, and also that most volcanism on Venus is related to mantle hotspots.


Smaller Shields on Venus
Image
This map shows the placement of large shield volcanoes, smaller (20-100 km) shields and small shield fields on Venus. It also maps the locations of volcanoes which have "Anemone" or flower-like lava flow patterns. Note the relative number of large shields and of shield fields, and the relative rarity of the smaller shields.

This map also shows two clear patterns of volcanism. (1) Very few of the smaller volcanoes lie at high elevations (light green to yellow). Rather, they mostly lie at lower elevations which are colored blue and dark green. (2) Many of the shield fields also seem to cluster around larger shield volcanoes. This may reflect a concentration of volcanic activity in these regions. However, the lack of shield fields in at least some regions may simply mark their burial by thick lava plains. (Data from Head et al, (1992) J. Geophys. Res. vol. 98, p. 13,153; base map of Magellan Topogaphy from NASA JPL .)

Overview
Venus has over 150 large shield volcanoes. These shields are mostly between 100 and 600 km across, with heights between about 0.3 and 5.0 km. The largest shields, however, are over 700 km in diameter and up to 5.5 km in height. For reference, Mauna Loa is ~120 km across at its base, and it has a total height of ~8 km (from the sea floor). Thus, the large Venusian shields are broader, but much flatter then the largest shield volcanoes on Earth. Indeed, the largest shield volcanoes on Venus cover nearly the same area as Olympus Mons, which has a basal diameter of ~800 km. (Note, Olympus Mons is still much bigger than the Venusian shields due to its immense height.)

These large shields all look much like shield volcanoes on Earth. They are mostly covered by long, radial lava flows. They all have very gentle slopes. And most also have some form of central vent or summit caldera. Thus, we think that these shields forme d from basalts, much like the shield volcanoes in Hawaii. The venusian shields, however, show a map pattern which is quite different from that seen on Earth (see reference map). Namely, the shields on Venus are widely scattered, and they show no linear vo lcano chains like those on Earth. This suggests that Venus does not have active plate tectonics, and also that most volcanism on Venus is related to mantle hotspots.


Unusual Volcanoes on Venus
Image
Most of the non-shield volcanoes on Venus are pancake domes, shown here in yellow. Like the shield volcanoes, these domes are widely scattered. They also often form small groups or clusters. Where most venusian shield fields have well over 20 small shields, however, few dome clusters have more than 5 or 6 domes. Further, the pancake domes are rarely found near shield volcanoes on Venus. Instead, many domes lie near corona structures in the lowland plains.
The ticks, shown here in red, show a pattern similar to the pancake domes. Like the pancake domes, most ticks occur in the lowland plains far from the largest shields on Venus. Many are found near the lowland coronas, and some are quite close to one or more pancake domes. The ticks also look something like the pancake domes. Thus, it is thought that many ticks are modified dome features.
Finally, fan-shaped and banded flows are quite rare. They are shown on this map in purple, and most are located in one part of the southern lowland plains. Neither their setting nor their distribution shows any clear trends, so little is known about these flows. Still, they look a lot like the most viscous lava flows on Earth. Thus, they may not have formed from basalt lavas. Instead, they may mark a rare set of granitic or rhyolitic lavas on Venus.

Overview
Most volcanoes on Venus are shields, but a few are not. These volcanoes all formed from very thick, viscous lavas, and they fall into three types. First are the so-called "pancake" domes. Second are a related class of "tick-like" structures. And third are a few volcanoes with thick, fan-shaped or banded flows. Since most basalt lavas are very fluid and fairly thin, these volcanoes do not seem to be made from basalt. Rather, they may mark quartz-rich or granitic lavas. Still, there are theories that gas-rich, "frothy" basalts could produce such viscous lavas. Also, few of these features lie in or near the Venusian highlands. Thus, these three volcano types may differ greatly from the volcanoes seen on Earth's continents.

http://volcano.und.edu/vwdocs/planet_volcano/venus/intro.html
The illusion from which we are seeking to extricate ourselves is not that constituted by the realm of space and time, but that which comes from failing to know that realm from the standpoint of a higher vision. -L.H.
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Re: Electric Venus : electric news dump

Unread postby StefanR » Tue Apr 22, 2008 3:59 pm

We subdivided novae into four topographic classes: (1) upraised, (2) annular, (3) flat and negative, and (4) plateau-like. Novae are located mostly in areas of regional rises and rift zones, with a small number in the lowlands. About one half the novae studied show association with rifts; in some of these the rift troughs surround nova rises and form plateau-like novae. Plateau-like novae may predate, postdate, or form simultaneously with rifts

Novae have multiple evolutionary stages and are long-lived structures. Stratigraphic analysis of all 64 local areas showed a similarity in the sequence of regional geologic units. We found that 40.3% of the novae population started to form before emplacement of regional plains with wrinkle ridges and that 11.3% completed their activity before this time; 88.7% of the population of novae was active after regional plains formation. In contrast to novae, coronae activity was greatest before formation of regional plains, which may be due to thickening of the lithosphere with time. Detailed structural analysis shows that novae evolution does not always lead to the formation of corona-like features.

http://cat.inist.fr/?aModele=afficheN&cpsidt=15249470
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Re: Electric Venus : electric news dump

Unread postby StefanR » Tue Apr 22, 2008 4:00 pm

Pancake Dome Volcanos
Image
These are round volcanoes that literally look like their description: They are domes shaped exactly like pancakes! Pancake domes are unique to Venus and can be found all over the planet in the plains regions, and often around coronae. The domes themselves generally average 24 kilometers across and about 700 meters high. They occur singulary, in pairs, or in clusters.
How pancake dome form is still uncertain.
One idea is that they are made from "andesite," a volcanic lava that is stickier than the usual basalt, so it can't travel far and so piles up into a dome (domes on Earth form by being made from sticky lavas). Another idea is that pancake domes are made from regular basalt, but because the lava is erupted into a massive atmosphere with 90 bars of pressure, the lava still can't travel far and piles up into a dome. Scientists care about this because sticky lavas are silica-rich lavas, formed by lots of recycling of a planet's crust. This means that the results of the debate could affect our understanding of Venus' long-term history.
http://www.adlerplanetarium.org/cyberspace/planets/venus/volcanism.html
Over 152 volcanic domes have been recognized on Venus. Most are circular in form and steep sided, with one or more summit craters and radial fractures. Their upper surfaces, however, vary from convex to exceptionally flat. Venusian domes are much larger than their terrestrial counterparts, with diameters ranging from 20 to 30 km and heights averaging about 300 meters. The flat-topped domes on Venus are sometimes referred to as pancake domes.
The composition of the domes on Venus is unknown.
Although their smooth surfaces are consistent with basaltic compositions, their steep sides suggest that they are composed of viscous lava, consistent with high-silica, rhyolitic compositions. The concentric and radial fracture pattern shown by many domes (see above) is consistent with the stretching of dome surfaces during their formation as lava wells up from interior vents and spreads laterally on the surface.
http://www.geology.sdsu.edu/how_volcanoes_work/venus.html
Pancake Domes in Eistla Regio
Because there is no evidence for plate tectonic movement on Venus, scientists speculate that the lithospheric doming, rifting, and volcanism associated with mantle plumes are the primary way heat is released from within the Venusian interior.
http://wapi.isu.edu/Geo_Pgt/Mod10_Venus/mod10.htm
Image
Image
Domical hills (Tholi), shieldlike in structure, as much as 25 km (15.5 mi) wide and up to 750 m (2,460 ft) high, dot the plains of Alpha Regio. Astrogeologists believe these pancake-shaped features result from upwelling at tubular vents of lavas that spread uniformly in all directions.Here is a closer look at two such domes in Tinatin Planitia; the larger is 65 km wide.

http://www.fas.org/irp/imint/docs/rst/Sect19/Sect19_8.html
The illusion from which we are seeking to extricate ourselves is not that constituted by the realm of space and time, but that which comes from failing to know that realm from the standpoint of a higher vision. -L.H.
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Re: Electric Venus : electric news dump

Unread postby StefanR » Tue Apr 22, 2008 4:00 pm

TICKS
Image
A group of enigmatic volcanic edifices, referred to as ticks, are similar in some respects to volcanic domes in that they are circular, steep-sided, and of similar diameter. They differ, however, in their association with lava flows that breach one or more sides of the structure. The west side of the image shown here, for example, contains dark flows that emanate from a shallow summit crater and traveled west along a lava channel. The origin of these structures is not well understood. Ticks are generally associated with rift zones. One theory suggests that they are generated by dome formation within a rift, followed by localized extrusion of lava along one of the rift fractures. Thus far, about 50 such ticks have been mapped on the surface of Venus.
http://www.geology.sdsu.edu/how_volcanoes_work/venus.html
A variant of the caldera type has been given the descriptive name of "tick volcano" because of its resemblance to the insect of that name. Emanating radially from the crater walls are ridges that form the "tick legs".

http://www.fas.org/irp/imint/docs/rst/Sect19/Sect19_8.html
The illusion from which we are seeking to extricate ourselves is not that constituted by the realm of space and time, but that which comes from failing to know that realm from the standpoint of a higher vision. -L.H.
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Re: Electric Venus : electric news dump

Unread postby StefanR » Tue Apr 22, 2008 4:01 pm

Cone Fields
Image
Cone fields develop when magma rises close to the surface, but can't rise all the way due to pressure from the surface and atmosphere. The magma does bend the surface slightly, however, making little cracks. These small faults become little conduits for magma to reach the surface, and small volcanoes form. Gas and lava seep out in minor eruptions, forming small cinder cones made of ash that are only a couple of hundred feet high at best.
The cinder cones look like pimples covering the plains. Basaltic cinder cones like the one in the image below are common on Earth. Studying them helps us understand the nature of the volcanos on Venus.
http://www.adlerplanetarium.org/cyberspace/planets/venus/volcanism.html
ImageImage
Cinder cones and stratocones (Vesuvius-like) are rare on Venus. Here is one example of a swarm of cones (each about 2 km wide) on the plains that are larger than terrestrial cinder cones but not typical of stratocones.
http://www.fas.org/irp/imint/docs/rst/Sect19/Sect19_8.html
The illusion from which we are seeking to extricate ourselves is not that constituted by the realm of space and time, but that which comes from failing to know that realm from the standpoint of a higher vision. -L.H.
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Re: Electric Venus : electric news dump

Unread postby StefanR » Tue Apr 22, 2008 4:02 pm

Compound Channels
ImageImageImage
Some of the lowland plains on Venus appear very dark in the radar images we have of the surface. Scientists suspect them to be large smooth plains of solidified lava that have erupted and spread out over for hundreds of miles. Some channels on Venus are very complex, consisting of multiple channels that meander and braid together. They resemble streams on Earth. This has led some scientists to theorize Venus may be so hot that lava can flow like water across the surface of the planet!
This makes them the most widespread volcanic feature on Venus. Some systems just form a single long channel (simple channels) while others form multiple ones (compound channels) such as the three images pictured above.

http://www.adlerplanetarium.org/cyberspace/planets/venus/volcanism.html
Image
Flows can sometimes be traced to shield volcanoes (with central calderas) as exemplified by Theia Mons, 4 km high, with a central caldera measuring 75 by 50 km and surrounded by a lava field reaching 800 km in maximum dimension.
http://www.fas.org/irp/imint/docs/rst/Sect19/Sect19_8.html

Simple Channels

There are 2 types of simple channels:
Image
Image
Sinuous Rilles on Venus are similar to ones found on the Moon and Mars. They are deep channels coming out of a depression that spread out over several hundred miles.
Image
http://www.hawastsoc.org/solar/cap/venus/channel.htm
Canali are thin channels that run regularly and evenly for thousands of miles. The longest is a quarter of the width of Venus! On Earth only rivers run that far, but water is unstable on Venus. Scientists believe canali are made of lava, but they're uncertain how the canali formed.
Image
They may be made of an unusual substance, allowing it to flow for a long time before solidifying. Or they could form from lava that melts into the plains and cuts a channel that stays visible even after the lava has drained away.
http://www.adlerplanetarium.org/cyberspace/planets/venus/volcanism.html
Lava Channels

Lava channels extending from hundreds to thousands of kilometers in length are conspicuous on the Venusian plains. Simple channels typically show little or no branching. They include long sinuous forms, termed "canali", and sinuous rilles. Canali are best preserved in regions of subdued relief. They have a high width-to-depth ratio and maintain a remarkably constant width over very long distances. Images reveal the presence of meanders, point bars, cut banks, and abandoned channel segments.

Both the source and the distal ends of many canali are buried or extensively subdued by lava flows younger than those that formed the channels. Measurements have shown considerable relief in longitudinal channel profiles, implying significant tectonic deformation of the plains since the channels formed [Parker et al., 1992]. Wrinkle ridges and ridge belts commonly transect canali. Vertical displacements of hundreds of meters over horizontal distances of a few kilometers are common at ridge crossings.

Sinuous Channel
A Sinuous segment of a simple radar-dark channel about 200 kilometers (120 miles) long and 2 kilometers (1.2 miles) wide is shown in this image. Channel outlines at both ends are indistinct, probably because of infilling by younger lavas. Thin bright returns from channel walls denote steep slopes. A transecting relict channel of approximately similar width is denoted by parallel bright margins (levees) that cross the lava plains in a northwest direction on each side of the radar-dark channel.

Sinuous Rilles
Sinuous rilles emanate from depressions and enlarged fractures south of Ovda Regio. They become progressively narrower and more shallow in the downstream direction. They are typically 1 to 2 kilometers (.6 to 1.2 miles) wide and tens to hundreds of kilometers in length. Channel walls form a distinct boundary between the channel floor and the surrounding terrain. Channel material is similar to that of the surrounding terrain

http://www.iki.rssi.ru/solar/eng/venvolc.htm
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Re: Electric Venus : electric news dump

Unread postby StefanR » Tue Apr 22, 2008 4:02 pm

Image
Magellan carried a microwave experiment (managed at MIT) from which a map of thermal emissivity (see Section 8) could be derived, as shown here. Note that the lowest emissivities (in blue) are found in the highest parts of the venusian surface, implying that the rock types there were other than basalt

http://www.fas.org/irp/imint/docs/rst/Sect19/Sect19_8.html
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Re: Electric Venus : electric news dump

Unread postby StefanR » Tue Apr 22, 2008 4:04 pm

The illusion from which we are seeking to extricate ourselves is not that constituted by the realm of space and time, but that which comes from failing to know that realm from the standpoint of a higher vision. -L.H.
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Re: Electric Venus : electric news dump

Unread postby StefanR » Tue Apr 22, 2008 4:16 pm

Impact Cratering
All craters have material thrown out of the middle to lie strewn about the crater. However, a strange effect occurs on many of Venus' craters: Some of the ejecta travels much farther than the rest causing the crater to have a long finger of ejecta sticking out. Scientists call this a "fluidized ejecta deposit." The extra-long flows are the result of impacts taking place in a hot and heavy atmosphere. A lot of impact material, that would get thrown out in craters on cooler worlds, instead gets melted or boiled so it runs downhill, making the long flow. This crater effect is unique to Venus.

Image
What Impact Craters Can Tell Us About Venus' Past

The crater pattern of Venus is very unusual. Other worlds like Mars or the Moon have a mixture of crater sizes and distributions. Some surfaces are heavily cratered (indicating they are old), while other surfaces are sparely cratered (indicating they are young). Crater size varies from small to giant basins several hundred miles across, especially on the old surfaces.

Venus does not do this. Instead, craters are scattered evenly over the surface of Venus, without the heavy concentration or giant basins that would indicate older areas. This seems to imply that most of Venus' surface is the same age.


Image

http://www.adlerplanetarium.org/cyberspace/planets/venus/cratering.html


3.0 Impact Craters
There are 935 recognized impact craters on Venus (Strom et al., 1994). About half the craters have been formally assigned names; the others remain unnamed. All have been given names after famous women in history, but craters with diameters less than 20 km have been given female common names. Venusian craters range in size from 1.4 km in diameter to 280 km . Crater Mead is the largest impact crater identified on Venus. (See map for the location of this crater and other information available from the crater atlas).

In contrast to Mercury, Mars or the Moon, which are covered with thousands of craters that have accumulated over the last 4 to 4.5 billion years , Venus is scarred by curiously few. Schaber et al. (1992) and Strom et al. (1994) have shown that the spatial distribution of craters is uniform (random and anticlustered) over the entire planet, suggesting that Venus experienced complete global resurfacing in the relatively recent (geologically speaking) past.

In the global resurfacing model , tectonic and volcanic activity affected the entire surface of Venus which obliterated the majority of (if not all) previous impact craters. An observation that lends support to the sudden arrest of these events is the fact that the majority of craters, 84% , do not show any signs of modification (Strom et al., 1994) . This resurfacing activity is thought to have ceased between 300 to 800 million years ago. The uncertainty of the timing lies in the uncertainty of estimating the impact flux.
Types of impact craters
Craters on Venus are recognized by their expression on images and hence classified by their morphology. The high temperture of Venus' surface ( 470 C ) and its thick atmosphere make Venus impact morphology unique among planetary bodies in the solar system ( Ivanov et al., 1992 ). Based on the development of crater floor structures and degree of circularity, Schaber et al. (1992) classified simple craters and five types of complex craters into a six-fold scheme:

* structureless craters are simple craters where the internal floor is flat and featureless. The smallest craters are generally of this type.
* central peak craters (70k gif) have a central uplift that rises above the crater floor. These craters range in size from 8 to 79 km, but are most commonly 16-32 km. Oulining rims are quite circular and often terraced.
* double-ring craters (20k gif) are defined by an outer rim and a circular arrangement of inner peaks and ridges. These craters are typically greater than 40 km.
* multiple-ring craters (168k gif) have two or more concentric ridge structures that rise above the crater floor. The largest craters on Venus, ranging from 86 to 280 km in diameter, are of this type.
* irregular craters have non-circular rim outlines and structural disruptions to otherwise flat crater floors. Almost 1/3 of the craters on Venus are of this type, most of which are less than 16 km across.
* multiple crater formation occurs when a falling body fragments into pieces. Each fragment creates a separate impact crater whose rim may overlap with adjacently formed craters. Individuals of this type are up to 44 km in diameter, but most are less than 11 km.

In general, small diameter craters are flat-floored, have irregular outlines and may be part of multiple-impact event. Complex internal structures occur in large craters and tend to develop progressively as: a central peak, a double-ring, or a multiple-ring, with increasing crater diameter.
Interactive Crater Atlas
You can investigate the relationships between crater size and type, find more information about the names of Venusian craters and look at their distribution on a map by searching the crater database according to crater type and diameter . The current status of the crater database used in making the map can be found in what's new.

As an example of what the crater atlas displays, click on Adivar . A Magellan radar image of this impact crater is displayed below and its features are described.
Image
Crater Adivar
Adivar is a complex crater with a prominent central uplift , and thus, classified as a central peak crater . The bright, irregular ejecta blanket around the crater stands out against the darker background due to the high radar backscatter of the ejecta material (surface roughness is greater). Following an impact, travelling crater ejecta is met with a great resistance from Venus' very dense atmosphere - about 90 times that of Earth's. Consequently, the material does not extend for more than one or two diameters away from the crater edge before settling to the ground.

The crater rim is terraced and extensive collapse of the rim outline can be seen in the SW part of the structure. A dark, V-like indentation of the NW part of the peripheral ejecta blanket suggests that the impactor arrived from that direction (Schultz, 1992) . On the full image of Adivar (88k gif) , a wide parabolic halo of bright material opens westward and extends for many diameters around the impact. Campbell et al. (1992) suggested that this secondary pattern of deposition around the crater is a result of prevailing westward winds at higher altitudes, which carried the fine ejecta downwind following impact.

http://www.gnewton.ca/fov/archive/venus_impact.html
The illusion from which we are seeking to extricate ourselves is not that constituted by the realm of space and time, but that which comes from failing to know that realm from the standpoint of a higher vision. -L.H.
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TERRESTRIAL METEORITE OR VENUS METEORITE

Unread postby StefanR » Tue Apr 22, 2008 4:30 pm

TERRESTRIAL METEORITE OR VENUS METEORITE

Abstract: Present to the reader significant and substantial evidence suggesting a new planetary meteorite type may have been identified with origins strikingly similar to that of Venus. Data collected from remote sensing, satellite flybys, landing modules and the authors own testing will show a remarkable resemblance to this amazing planet.

Catastrophic events along geological timelines were also investigated, but none were found to coincide during the specimens age. At this point, the most satisfactory explanation, whether probable or improbable,and is one that matches what data is available, is a Venusian origin.

This brings us back to our sister planet Venus. Known to the ancient Greeks as Vesper (the evening star) and Phosphor (the morning star). For they believed Venus was actually 2 different stars.


A reasonable question we should ask ourselves would be: Because of the thick atmosphere on Venus, are there any impact craters, or any impact sites that would be large enough to account for our specimens arrival?

Before we answer that question lets examine a few facts that we do know about Earth and Venus.

First of all we do know the surface of Venus has been subjected to imapactors reaching the surface of Venus. On the basis of Magellan mapping, roughly 900 impact craters have been identified on the planets surface.(3) Below are maps showing the association of impact crater density with geologic features found on Venus.(3)


Image
(A) is a smoothed map of crater density and crater locations.
(B) a map of tectonic and volcanic units including 38 million Km2 of tessera, 150,000 linear km of rifts, 364 coronae, 130 arachnoids, 46 novae, 123 calderas, 128 large volcanoes and 48 flood-type lava flow fields. The largest light-gray contains mostly plains consisting of overlapping volcanic flows inferred to be products of a global resurfacing.
(C) a combined map of crater density and geologic features.


Secondly, prior to 2002, 2 terrestrial meteorites were found by USA team members in Antarctica and 1 terrestrial meteorite was discovered by Japanese team members also in Antarctica for a total of 3 terrestrial meteorites(2).

From page 2 we know the escape velocity for Venus is slightly less than that of Earth (10.4 Kms vs. 11.2 Kms).

If we then know that 3 terrestrial meteorites have been found in Antarctica, this fact makes the contention that it would be impossible for rocks to be ejected from the surface of Venus an invalid statement. One that should require no further discussion.

The reasoning is straightforward and simple. It requires less energy to get a rock off the surface of Venus than it does Earth. It would be just as equally plausible to find a Venusian meteorite as it would a terrestrial meteorite, and 3 of those have already been found.

We also know from current cratering calculations that large impacts even on Venus, despite its dense atmosphere, could eject surface rocks into interplanetary space. (15) It should also be recognized that plume-ejection rather than impact ejection is the main mechanism for projecting planetary material into space. (16) These calculations also imply that large impacts on all of the terrestrial planets are thus capable of ejecting lightly shocked surface rocks into interplanetary space. If we then recognize plume-ejection as the dominant mode of getting material into space, could this inversely mean with Venus' thick atmosphere that material might more easily "ride the wave" into interplanetary space from a large impact event?

If we look up above at the altimetric map of Venus. At the top, left of center, we can see Maxwell Montes. Maxwell Montes and two mountainous massifs (Freya Montes and Akna Montes) to the west and north stand out especially on this extensive, pear-shaped plateau stretching more than 5000 Km. This whole mountainous region is isolated from the adjacent lowlands by steep escarpments. One of the summits, in the center of the Maxwell massif, reaches an altitude of 11 Km above the mean surface level, exceeding the highest Earth summit, Mount Everest, by almost one and a half times. On the slope of this mountain at roughly 330 degrees and 65 degrees is a huge double-ringed impact basin, 95 Km in diameter, named Cleopatra Patera (3). This high - located -double-ringed impact basin may have provided us with our candidates.


Image
Impact crater Cleopatra Patera

It may also be noteworthy to mention that Cleopatra Patera does not appear to be a faulted impact crater nor an embayed impact crater. Depending on the geologic activity at this site this may mean Cleopatra Patera is a younger impact crater.

Image
Faulted crater Somerville about 37 Km in diameter
Image
Embayed craters. This Magellan mosiac shows a fractured plains region on Venus, with three large impact craters. The rough ejecta blankets appear radar bright, whereas the craters interior are dark and smooth, having been flooded with lava.(3)

WHERE DO WE GO NOW?

To the best of my knowledge and ability, what the data represents on the available evidence. That which we have seen and that which we have not (i.e. strewn field site, gps coordinates, numerous samples and photos). Results from testing and some tough detective work. It is highly probable that the candidates are meteorites. From where we can only speculate with what data we have.

As of the writing of this article the only definitive test that the candidates are meteorites has not yet been done. It is mandatory that a cosmic radiation analysis be procured somehow. Should the results be positive as I am very confident they would be, and the evidence is strongly suggestive of. It then becomes an exciting and new challenge for the professional scientist to determine a parentage host, and if from Venus, add invaluable knowledge to our understanding of the processes that made Venus the inhospitable planet we know today.

What if they are terrestrial meteorites? This would still be very exciting news for planetary scientists, geologists and vulcanologists. It may lead to new information on a catastrophic event or island forming event that happened 30 million years ago that can be studied in greater detail.

Either way at this point it does not really matter where our candidates came from. What must be done now is to have a cosmic ray exposure analysis completed to validate that they are in fact meteorites. What I have done is try to present what data has been collected, and research that I have accumulated over several years of testing, all at my own time and expense. If a commercial lab were available to conduct the above test I would have this done immediately because I believe enough evidence has been presented that justifies this examination.

Has there ever been or ever will be a closer specimen type which has those compositional characteristics that match that type of rock which is found on Venus equally well as our candidates represent? I know we can recognize a meteorite when we see one and I believe it would also be possible to recognize a terrestrial or a Venusian meteorite.


http://www.venusmeteorite.com/index.html

But maybe this should have it's own thread, it has a nice picture display and research in meteorites??
The illusion from which we are seeking to extricate ourselves is not that constituted by the realm of space and time, but that which comes from failing to know that realm from the standpoint of a higher vision. -L.H.
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Re: Electric Venus : electric news dump

Unread postby StefanR » Tue Apr 22, 2008 4:40 pm

Venera 15/16 Radar Mosaic Browser
http://members.tripod.com/petermasek/venera15.html

Mariner 10 Image Browser and Reconstructor
http://members.tripod.com/petermasek/mariner.html
The illusion from which we are seeking to extricate ourselves is not that constituted by the realm of space and time, but that which comes from failing to know that realm from the standpoint of a higher vision. -L.H.
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Re: Electric Venus : electric news dump

Unread postby seasmith » Tue Apr 22, 2008 7:10 pm

~

Great stuff Stefan.

First thing comes to mind is that those folks are in Desperate Need of a new Venusian geographic lexicon.
The Terrestrial geographic terms, applied to the images above, are Beyond Absurd !

:roll:
~
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Re: Electric Venus : electric news dump

Unread postby davesmith_au » Tue Apr 22, 2008 7:22 pm

seasmith wrote:~

Great stuff Stefan.

First thing comes to mind is that those folks are in Desperate Need of a new Venusian geographic lexicon.
The Terrestrial geographic terms, applied to the images above, are Beyond Absurd !

:roll:
~


Ditto. :mrgreen:

Cheers, Dave Smith.
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THE INTERACTION OF THE SOLAR WIND WITH VENUS (1)

Unread postby StefanR » Wed Apr 23, 2008 2:14 pm

THE INTERACTION OF THE SOLAR WIND WITH VENUS
Originally published in:
Venus
Edited by D.M. Hunton, L Colin, T.M. Donahue, V.I. Moroz, pp. 873-940
University of Arizona Press, Tucson, Arizona, 1983


Venus has been more frequently studied by space missions than any other planet. Consequently, we know more about the solar wind interaction with Venus than with any planet except the Earth. Unlike the Earth, Venus's ionosphere, not a magnetosphere deflects the solar wind flow However, as on the Earth, this deflection is accomplished with the formation of a bow shock, which heats and compresses the solar wind flow The shock is both closer to the planet and weaker than would be expected for an ideal gas dynamic interaction with a perfectly reflecting obstacle. The ionized flow of the magnetosheath can interact directly with the neutral atmosphere through charge exchange and photoionization. The former process removes momentum from the flow; both processes add mass to the solar wind, since the high altitude neutral atmosphere is mainly hot oxygen, not hydrogen. Finally, Venus, like Earth, has a magnetotail but not for the same reason. The mass loading of the flow in the magnetosheath slows the transport of magnetic flux tubes past the planet, while the ends of the tubes continue to travel rapidly in the solar wind. Thus the planet accretes interplanetary magnetic flux. This process is the dominant source for the magnetotail flux, not unipolar induction, although the latter process is present at least when the solar wind dynamic pressure is high. On the whole, the solar wind interaction with Venus is more comet-like than Earth-like.


Image
Basic features of the solar wind interaction with Venus. The solar wind is deflected around Venus by the planetary bow shock. The obstacle is the planetary ionopause; the interface between the magnetic field which piles up in front of the planet and the ionosphere is called the ionopause. At times of low solar wind dynamic pressure the ionosphere is unmagnetized except for the occurrence of twisted filaments of field called flux ropes. Behind the planet a tail is formed by flux tubes which become filled with plasma on the day side and convect around the planet together with some flux tubes which penetrate the ionosphere and become hung up there.
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THE INTERACTION OF THE SOLAR WIND WITH VENUS (2)

Unread postby StefanR » Wed Apr 23, 2008 2:16 pm

I. THE NATURE OF THE OBSTACLE

At the Earth the solar wind is deflected far above the atmosphere by a strong intrinsic magnetic field generated by a dynamo deep in the interior of the Earth. This shielding by the Earth's magnetic field does not prevent solar wind energy from coupling to the Earth's atmosphere. The aurora is one manifestation of this coupling. However, the solar wind does not directly interact with the atmosphere and current rates of loss to the solar wind are thought to play a minor role in the evolution of the terrestrial atmosphere. A similar type of obstacle to the solar wind is found at Mercury, Jupiter and Saturn; we can generally understand the behavior of their magnetospheres in terms of our terrestrial experience.

The earliest measurements suggested that Venus's magnetic field was far weaker than Earth's and possibly even absent, although the latter suggestion evoked some controversy. If the magnetic field were so weak that the solar wind interacted directly with the atmosphere, then a qualitatively different interaction would exist, one more like the interaction of a comet with the solar wind. The fact that the controversy on whether Venus had an intrinsic or induced magnetosphere raged for close to 20 yr shows the limitations of flyby missions for gathering in situ data, especially in situations involving variations in latitude, longitude, altitude, and time.


A. The Search for a Magnetic Moment

Image
The magnetic field measured by Mariner 5 and Venera 4 plotted along their trajectories in solar cylindrical coordinates. For Mariner 5 the 3-dimensional trajectory information is used. For Venera 4 we have only the ecliptic plane projection. Closed triangles mark magnetopause traversals; dots indicate the boundary of a second current layer, possibly the rarefraction wave; the S marks the location of the Mariner 10 shock crossing.

Image
Magnetic field in Venus wake plotted in solar cylindrical coordinates. (a) PVO orbit 65 2/7/79; (b) PVO orbit 72 2/14/79.

Occasionally there werelimited regions of radial field extending apparently through the base of the ionosphere, but the field mainly wrapped around the nightside ionosphere as if the solar wind magnetic field had draped around the planet and was closing behind the obstacle (Russell et al. 1979c, 1980b). There was no obvious sign of a planetary magnetic field. However, it was possible that there was some net flux out of the planet masked by the external currents and their fluctuations. Thus, the average magnetic field over the nightside ionosphere was calculated and inverted to find the best fit for magnetic moment. Using data from two nightside passes the upper limit to the magnetic moment was found to be 4 X 10-5 of the terrestrial moment or <3 X 1021 Gauss-cm3 (Russell et al. 1980a).

The magnetic field strength necessary to deflect the solar wind at 0.72 AU is ~ 100 nT. If the solar wind doubles the planetary field by compression in the interaction, this deflection can be accomplished above the surface of the planet by a magnetic moment only 1/360th of the terrestrial moment. Small as this may be, the actual measured moment is < 1/25000th of the terrestrial moment, and we can conclude that at the present time intrinsic magnetic fields play no significant role in the solar wind- Venus interaction. Venus presents a very different type of obstacle to the solar wind than has been probed at the other planets.


B. Non-Magnetic Barrier Models

Image
Magnetic field lines around a superconducting sphere.

This is the simplest model of the Venus solar windionosphere interaction. However, the region external to the highly (but not infinitely) conducting ionosphere is not a vacuum, but a flowing plasma. Thought of in magnetohydrodynamic terms (as an electrically conducting magnetized fluid) the solar wind has both mass and momentum and an electric field. This flowing plasma has to be deflected by the planet by some pressure wave. The flow introduces day-night asymmetry, and unless the field is flow-aligned there will be asymmetry about the flow direction as well. This superconductor analogy is useful but is only an approximation to the condition of the Venus ionosphere. Furthermore, there are the complications of nonmagnetohydrodynamic processes such as charge exchange and photoioniza- which we ignore for the moment, but will discuss later.
.....
It is important at this point to distinguish between two types of induction. The most familiar type of induction is that associated with a time varying magnetic field, as seen in our case in the reference frame of the planet. This can be caused by propagating waves or by convected structure in the solar wind. The second type of induction is unipolar induction, in which currents are driven in the planetary conductor by the solar wind electric field associated with the moving magnetized highly electrically conducting solar wind. The former type of induction is very important on the moon whose surface, being nonconducting, prevents the latter type from occurring. But it may be important at Venus, and the former is a complication to be avoided in our present observational state.
Image
Fig. 7. Summary of Venus solar wind interaction models by Michel (1971). Profiles of electron concentration, n, magnetic field B, and horizontal flow velocity V are shown as a function of height for the three models. Incident solar wind velocity and field are normalized to unity. (a) Direct interaction model; (b) tangential discontinuity model; (c) magnetic barrier.

We would not need to worry about unipolar induction if the ionosphere were either perfectly conducting or nonconducting. In the former case, the surface of the obstacle would be an equipotential and all flow would be diverted around the planet. In the latter, the flow would all crash into the planet as it does on the lunar surface. In the real world of Venus, the true case is somewhere between. Early investigators proposed a variety of possible scenarios for the solar wind interaction with Venus. Michel (1971) has classified these as the direct interaction model, the tangential discontinuity model, and the magnetic barrier model. These are illustrated in Fig. 7 with altitude profiles of the electron number density, magnetic field strength and horizontal flow velocity.
..............

This discussion concerns only the high-altitude ionopause (altitude 300 km); when the ionopause current is pushed down to lower altitudes it does become significantly resistive and the Cloutier model becomes viable. We defer discussion of the low-altitude ionospheric obstacle for the moment.

The processes of charge exchange and photoionization were mentioned above without much discussion of what these processes do, and without much evidence that they take place. In a charge exchange an electron passes from a neutral atom to an ion. If the neutral atom is cold and the ion hot, the exchange produces a fast neutral and a slow ion. This can be an important process in the solar wind interaction with Venus, because it directly removes momentum from the postshock solar wind and deposits that momentum in the atmosphere. It also decreases the need for solar wind to be deflected by the planet and thus can weaken the shock and change its location, as we discuss in Secs. IV. A and IV. B. Charge exchange occurs most readily, i.e., has the largest cross section between members of the same species, such as H-H. However, proton-oxygen charge exchange is accidentally resonant and Venus has a significant hot neutral oxygen exosphere (Nagy et al. 1981). This charge exchange reaction also adds mass to the postshock solar wind.

Photoionization, by extreme ultraviolet emissions from the Sun, adds mass to the postshock solar wind flow. Photoionization of oxygen is very important because the exosphere is dominantly oxygen in the region of interest and because oxygen ions are much heavier than protons. These processes are important in the formation of the plasma mantle and magnetotail of Venus and will be discussed again in Sec. II.C.


C. The Low-Altitude Barrier

There is a noticeable change in the ionopause at low altitudes (smaller/equal to) 300 km. This change can be seen in Fig. 11, which shows the thickness of the ionopause current sheet as a function of altitude.
Image
Fig. 11. Thickness of the ionopause current sheet as a function of altitude. Thin lines show 2 and 10 gyroradii (Elphic et al. 1981)

The ionopause is typically ~ 30 km thick above 300 km but increases to (smaller/equal to)90 km thick at ~ 250 km (Elphic et al. 1981). We attribute this to the change in conductivity and Joule dissipation with altitude. When the ionopause is low, currents can be driven in the ionosphere as in the Cloutier model.
Image
ig. 12. Altitude profiles of the magnetic field strength and electron density measured by the electron temperature probe for the three passes
In fact, as shown in Fig. 12, the low-altitude ionosphere is magnetized during these periods of low ionopause altitude, which of course are associated with periods of high solar wind dynamic pressure (Luhmann et al. 1980). These high field regions are also more prevalent at low solar zenith angles; this fact is consistent with these high field regions lying along a belt and not covering the entire ionosphere, and is also in accord with Cloutier's model. Suffice it to say that at times when the solar wind dynamic pressure is high the nature of the solar wind interaction with Venus may be significantly different than under typical solarwind conditions.


D. Summary

We now know that for all practical purposes Venus is a nonmagnetic planet and the ionosphere is responsible for deflecting the solar wind flow. At times when the solar wind dynamic pressure is low and the ionopause altitude is above ~ 300 km, a magnetic barrier forms which deflects the solar wind before it directly encounters the ionosphere. At higher solar wind pressures, the ionopause moves to low altitudes, the current layer thickens, and a more direct interaction seems to occur in which currents are driven in the ionosphere by the solar wind electric field, i.e., by unipolar induction.
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