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Andre
Joined: 21 Jul 2007
Posts: 298
Location: Germany - The Nederlands
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 Posted: Mon Aug 20, 2007 8:27 pm Post subject: |
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Interesting, BW, Thanks,
Obviously there have been spectacular cosmic displays in the night sky, causing all kind of specultations by the spectators, ultimately resulting in those myths.
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Baywax
Joined: 23 Jul 2007
Posts: 113
Location: Pacific West Coast
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| Posted: Mon Aug 20, 2007 10:50 pm Post subject: |
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Thanks Andre,
To me, she still looks pretty young!
http://www.universetoday.com/2007.../messengers-farewell-venus-video/
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scpg02
Joined: 22 Jul 2007
Posts: 221
Location: Sacramento
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| Posted: Mon Aug 20, 2007 11:19 pm Post subject: |
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| Quote: | | To me, she still looks pretty young! |
Thank you.  |
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Andre
Joined: 21 Jul 2007
Posts: 298
Location: Germany - The Nederlands
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| Posted: Tue Aug 21, 2007 11:30 am Post subject: |
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| scpg02 wrote: | | Quote: | | To me, she still looks pretty young! |
Thank you. |
 
Okay, I'm getting the message. Don't take a sip of coffee when opening the earth forums. When Maggie posts, you may have to clean out the keybord from the coffee.
Such a spill. 
Anyway, i don't know how to put it. i'm sure that Maggie looks great, but this is how that particular planet looks like naked:
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Baywax
Joined: 23 Jul 2007
Posts: 113
Location: Pacific West Coast
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| Posted: Tue Aug 21, 2007 3:45 pm Post subject: |
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That's the infared shot of her, yes. They call some of the blotches impact craters and some of them volcanic sites. More like an adolescent portrait of her surface.
Its hard to tell what's going on in that photo. Eruptions or very few impacts....... (possibly residual scars from an encounter with Mars)... all in all she's still young with all that "magma" still flowing!
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Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory. Leonardo Da Vinci
Time flies like an arrow, fruit flies like a banana.
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Andre
Joined: 21 Jul 2007
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Baywax
Joined: 23 Jul 2007
Posts: 113
Location: Pacific West Coast
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| Posted: Wed Aug 22, 2007 2:52 am Post subject: |
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These articles look really good Andre.
The PPT is good and to the point.
There appears to be remaining undecidedness about Venus and her whole morphology, history etc......
You may still sway me to believe that craters can be used as a dating technique. But I will have to find some stuff about that on my own....
here's something of interest concerning the controversy surrounding the age and morphological structure of Venus's surface,
| Quote: | Models for the surface age of Venus can be considered as lying in between two extreme, or end-member models. In one extreme, the crater data can be interpreted to indicate that all significant geologic activity ceased on Venus as of 300--500 Ma (million years ago), and that prior to that time, activity was rapid and no craters from this previous epoch survive on the surface today. The other end-member model suggests that geologic activity is ongoing and that no steep decline in rates of tectonism and volcanism is required.
Noting the spatial randomness and the unmodified appearance of impact craters, Schaber et al. [1992; also Strom et al., 1994] suggest that they represent a production population, one that has undergone little or no modification due to volcanism or tectonism. Prior to Ma, they suggest that the rate of volcanic and tectonic activity was high in comparison to the cratering rate. This activity constitutes global resurfacing, and may be a recurring event in Venus history [ Arkani-Hamed et al., 1993; Parmentier and Hess, 1992]. Subsequent to resurfacing was a short period (approximately 10 m.y.) of steep decline in the rate of geologic activity. Geologic activity since the end of this ``great decline'' has been comparatively minor.
Phillips et al. [1992] argue against an end-member global resurfacing model for reasons that involve spatial correlation of modified craters with geological features or with one another. These workers formulated an equilibrium resurfacing model which considered a characteristic area and recurrence interval for resurfacing events. The model only satisfies the requirement of spatial randomness for events covering less than 140,000 km (0.03% of Venus' surface) that recur at intervals of less than 150,000 years or for events covering more than 10% of the planet ( km) |
http://www.agu.org/revgeophys/bindsc01/node2.html
Its interesting to note that there are questions surrounding the volcanism and the craters and the age of the surface in general. The craters show no signs of disturbance yet there are active flows everywhere. The photos of the craters are astounding and the debris fields are almost symetrical with a very "fresh" look to them. 
Dating Craters (during high school  )
| Quote: | | We suggest a crater dating technique that correlates morphometric indices of simple impact craters to their age. We examine populations of craters from several Martian terrains of known age and, using the Mars Orbiter Laser Altimeter (MOLA) topographic dataset, we compute their rim-to-diameter ratio, depth-to-diameter ratio, slope, and eccentricity. Since these parameters will be systematically affected by the degree of degradation by erosional and depositional processes, they can be useful metrics for characterizing crater degradational process and also for estimating crater age. By considering the youngest surfaces on Mars, those of Amazonian age (< ca. 250 Ma), and sequentially examining surfaces of progressively older age (e.g. Herperian and Noachian), we characterize age populations of simple craters according to their degradational morphology. This is then used to calibrate a model for the degradational history of simple craters on Mars that can be used for geochronologic purposes. In addition, we can use the data to estimate the density of craters (craters/km2) of a given size and age expected on a surface. The applications of this statistical study of crater morphology include planetary geochronology and the identification of resurfacing events. |
http://adsabs.harvard.edu/abs/2006AGUFM.P31B0146C
| Quote: | | "We examine populations of craters from several Martian terrains of known age |
How does someone arrive at the "known age" of a terrain on Mars? And how does that "known age" help date a crater on the other side of the planet or even a few km from the "known terrain"??
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Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory. Leonardo Da Vinci
Time flies like an arrow, fruit flies like a banana.
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Andre
Joined: 21 Jul 2007
Posts: 298
Location: Germany - The Nederlands
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| Posted: Wed Aug 22, 2007 8:43 pm Post subject: |
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I think this the key paper here:
http://adsabs.harvard.edu/abs/1998JGR...103.8531B
Basilevsky, A.T. Head, J.W. 1998 The geologic history of Venus: A stratigraphic view: Journal of Geophysical Research, Volume 103, Issue E4, p. 8531-8544
| Quote: | Abstract
On the basis of regional and global stratigraphic analyses, we outline the major events in the geologic history of Venus determined by photogeological study of surface features. Because the morphological signatures of terrain emplaced prior to the time of tessera formation are not preserved, the stratigraphic record presented comprises only the last 10-20% of the total history of Venus. The estimated range of the mean crater retention age of the surface (from ~200 to 1600 million years) leads us to describe the timing and duration of different events in terms of fractions of the mean surface age T. The beginning of the observed history of Venus was characterized by intensive tectonic deformation of global or semi-global scale which formed the tessera terrain. Termination of the compressional stage is estimated to have occurred at about 1.4T while the tensional stage lasted for another 0.1-0.2T. After tessera formation, several stages of extensive volcanism occurred, burying vast areas of tessera and forming what are now observed as regional plains. The combined duration of the emplacement of these plains is estimated to be about 0.2-0.3T, with an implied average global rate of volcanism of a few cubic kilometers per year. Regional plains-forming materials can be subdivided and are separated from each other, and from underlying and overlying units, by unconformities. These unconformities are formed, from oldest to youngest, by tessera-forming deformation, dense fracturing, broad ridging, and, finally, wrinkle ridging. These tectonic episodes are interpreted to be generally globally synchronous and to represent successive episodes characterized by the dominance of compression, then tension, then again compression, and, finally, tension. The last global-scale tectonic episode, extensive wrinkle ridging, happened at about time T, which was very close in time to the emplacement of the most areally abundant plains unit. This marked the transition to the present stage of the history of Venus, which is characterized by a predominance of regional rifting and related volcanism. This stage appears to have lasted from about time T to the present, making it the longest time duration among the stratigraphic units considered, although the resulting tectonic and volcanic features and deposits cover only 10-20% of the surface of Venus. These observations mean that the general intensity of tectonics and the flux of volcanism (a few tenths of a cubic kilometer per year) in this latest period were much lower than those in earlier times. In summary, the morphologically observable part of the history of Venus was characterized by two key characteristics that stand in contrast to the comparable period of Earth history (approximately the Phanerozoic) when global geodynamic processes were dominated by plate tectonics: (1) Venus shows no signature of plate tectonics; instead, its global tectonic environment passed from an initial dominance of compression, through tension, then again compression, and finally tension, with the density of deformational structures and the strain rate declining with time. (2) In the beginning of this period of time on Venus, plains-forming volcanism occurred at a rate comparable to volcanism at mid-ocean ridges but was emplaced in an entirely different style. The predominant component of volcanism on Earth during this time was the extrusive volcanism at mid-oceanic ridges. For the last few hundred million years, Venus has been dominated primarily by rift-associated volcanism emplaced at a production rate comparable to or even lower than present intraplate volcanism production rates on Earth. |
It's interesting what T is exactly, 500My or 1By, the ratio of event. Note the declining volcanism and other activities. Seen a PhD thesis on the impact craters, the freshness, lava filling etc. Only a few are. Therefore it is thought that the volcanism declined overall. This is exactly in line with my little pet idea that is a bit in the freezer right now. But it will come out again when the Venus express acknowledges that.
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Baywax
Joined: 23 Jul 2007
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| Posted: Wed Aug 22, 2007 10:02 pm Post subject: |
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You're rapidly deflating any possibility of Venus being 3600 years old...  ... at least by siting these damn Harvard fellows....
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Andre
Joined: 21 Jul 2007
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| Posted: Thu Aug 23, 2007 10:00 am Post subject: |
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I'm sorry about that. That extremely effective Magellan radar imaging satellite spoiled the romantic musing about Venus. Well science progresses and we have to move on I guess.
I'd like to explore that later after the isotopes.
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Baywax
Joined: 23 Jul 2007
Posts: 113
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| Posted: Thu Aug 23, 2007 5:30 pm Post subject: |
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Its ok Andre... you always seem to come up with good evidence!
I am still somewhat optimistic, given how researchers and instruments and interpretations can be incorrect. For instance with the fact that
| Quote: | | There are few impact craters on Venus, suggesting that the surface is, in general, geologically young - less than 800 million years old. |
http://www2.jpl.nasa.gov/magellan/fact.html (your source)
this "less than 800 million years old" could be as young as 3600 years old.... in literal terms....
In the model of Venus being expunged from Jupiter we have to remember that the interior of Venus would be as old as Jupiter while the surface would appear "young" as has been demonstrated.
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Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory. Leonardo Da Vinci
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Baywax
Joined: 23 Jul 2007
Posts: 113
Location: Pacific West Coast
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| Posted: Tue Aug 28, 2007 4:12 pm Post subject: |
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Here is a summary of Immanuel Velikovsky's theories concerning Venus, Jupiter, Earth, Mars and the record of events that allegedly took place between these planetary bodies.
| Quote: | Immanuel Velikovsky has a theory about (Jupiter/Venus) in his book Worlds in Collision......
Core ideas
"Worlds in Collision is a book of wars in the celestial sphere that took place in historical times. In these wars the planet earth participated too. [...] The historical-cosmological story of this book is based in the evidence of historical texts of many people around the globe, on classical literature, on epics of the northern races, on sacred books of the peoples of the Orient and Occident, on traditions and folklore of primitive peoples, on old astronomical inscriptions and charts, on archaeological finds, and also on geological and paleontological material." - Worlds in Collision, Preface.
The book proposed that around the 15th century BC, a comet or comet-like object (now called the planet Venus), having originally been ejected from Jupiter, passed near Earth (an actual collision is not mentioned). The object changed Earth's orbit and axis, causing innumerable catastrophes which were mentioned in early mythologies and religions around the world. Fifty-two years later, it passed close by again, stopping the Earth's rotation for a while and causing more catastrophes. Then, in the 8th and 7th centuries BCE, Mars (itself displaced by Venus) made close approaches to the Earth; this incident caused a new round of disturbances and disasters. After that, the current "celestial order" was established. The courses of the planets stabilized over the centuries and Venus gradually became a "normal" planet.
These events lead to several key statements that were claimed in the book:
Venus must be still very hot as young planets radiate heat.[3]
Venus must be rich in petroleum gases, and hydrocarbons.[4]
Venus has an abnormal orbit in consequence of the unusual disasters that happened.
Velikovsky suggested some additional ideas that he said derived from these claims, including:
Jupiter emits radio noises.[5]
The magnetosphere of Earth reaches at least up to the moon.
The sun has an electric potential of approximately 10^19 volts.
The rotation of earth can be affected by electromagnetic fields.
Velikovsky arrived at these proposals using a methodology which would today be called comparative mythology - he looked for concordances in myths and written history of unconnected cultures across the world, in particular following a rather literal reading of their accounts of the exploits of planetary deities. In this book, he argues on the basis of ancient cosmological myths from places as disparate as India and China, Greece and Rome, Assyria and Sumer. For example, ancient Greek mythology asserts that the goddess Athena sprang from the head of Zeus. Velikovsky identifies Zeus (whose Roman counterpart was the god Jupiter) with the planet Jupiter. Velikovsky identifies Athena with the planet Venus, although the Greek counterpart of the Roman Venus was Aphrodite and not Athena. This myth, along with others from ancient Egypt, Israel, Mexico, etc. are used to support the claim that "Venus was expelled as a comet and then changed to a planet after contact with a number of members of our solar system" (Velikovsky 1972:182). |
http://ca.answers.yahoo.com/quest...dex.php?qid=20070825094022AAVIpQb
Just a note that Velikovski wrote these claims before there was much scientific information about Venus.
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Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory. Leonardo Da Vinci
Time flies like an arrow, fruit flies like a banana.
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Baywax
Joined: 23 Jul 2007
Posts: 113
Location: Pacific West Coast
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| Posted: Tue Nov 13, 2007 8:03 pm Post subject: |
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OK, as long as there's very few people commenting on this idea I have another "out-there" one for Jupiter.
For some reason there's a big rumour and hub-bub going on on the web about Jupiter becoming another sun in our solar system.
Does anyone have scientific data to back this rumour up?
If its a reality... that could also explain the warming taking place not only on Earth but the other planets.
| Quote: | | There are many things the old Greeks did not know about this great light of heaven, but the more we study it the more appropriate it seems that they named it as they did. Jupiter has a diameter about 12 times that of Earth, yet it rotates on its axis more than twice while Earth rotates once. Jupiter has nearly 318 times more mass than Earth: indeed nearly three times more mass than all the other planets combined. Except for the Sun itself, Jupiter is the giant of the Solar System. It is nearly large enough to have become a star. Think about that. If Jupiter had been a bit more massive we would be living in a binary star system. Or would we? If Jupiter had become a star, would life have been possible on Earth? Probably so, for Jupiter would have been a dim star, orbiting 5 times farther out from the Sun than Earth is. For us, its distance constantly changes between 4 and 6 times the solar distance. As Earth sweeps between Jupiter and the Sun it is 4 times farther away than the Sun, and when Jupiter is beyond the Sun, on the far side of its orbit it is 6 times farther from us than the Sun. Thus, if Jupiter had been a star, orbiting just as it currently does, it would be an extremely bright, but constantly changing, light. How different things would be. We would not have had nearly as much darkness, for whenever Jupiter would be in the sky it would cast its much greater brilliance into our otherwise night--far more light than the full moon we know. The famous science fiction author, Arthur C. Clarke, included the idea of Jupiter becoming a star in his series of books, 2001, 2010, 2061, and 3001. |
http://www.clarkfoundation.org/astro-utah/vondel/jupiter.html
and
| Quote: | Warming On Jupiter, Mars, Pluto, Neptune's Moon & Earth Linked to Increased Solar Activity, Scientists Say
IN CASE YOU MISSED IT...
Bright sun, warm Earth. Coincidence?
By Lorne Gunter
National Post
Link to Article
Monday, March 12, 2007
Mars's ice caps are melting, and Jupiter is developing a second giant red spot, an enormous hurricane-like storm.
The existing Great Red Spot is 300 years old and twice the size of Earth. The new storm -- Red Spot Jr. -- is thought to be the result of a sudden warming on our solar system's largest planet. Dr. Imke de Pater of Berkeley University says some parts of Jupiter are now as much as six degrees Celsius warmer than just a few years ago.
Neptune's moon, Triton, studied in 1989 after the unmanned Voyageur probe flew past, seems to have heated up significantly since then. Parts of its frozen nitrogen surface have begun melting and turning to gas, making Triton's atmosphere denser.
Even Pluto has warmed slightly in recent years, if you can call -230C instead of -233C "warmer."
And I swear, I haven't left my SUV idling on any of those planets or moons. Honest, I haven't.
Is there something all these heavenly bodies have in common? Some one thing they all share that could be causing them to warm in unison?
Hmmm, is there some giant, self-luminous ball of burning gas with a mass more than 300,000 times that of Earth and a core temperature of more than 20-million degrees Celsius, that for the past century or more has been unusually active and powerful? Is there something like that around which they all revolve that could be causing this multi-globe warming? Naw! |
http://epw.senate.gov/public/inde...DD8F9-802A-23AD-4459-CC5C23C24651
I know I shouldn't put too much faith in Arthur C. Clarke's predictions and fictions, but, in the least we could say Jupiter does contribute to the general "atmosphere" of our little solar system.!
.
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Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory. Leonardo Da Vinci
Time flies like an arrow, fruit flies like a banana.
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