Venus

[m1omg]

This is my opinion on the evolution of Venus:

1.Hadean -

Like Earth, Venus was constantly bombarded by large meteorites and some big asteroids.The sufrace was very hot, and there was a lot of volcanism.

2.Archean-

Venus was fully formed now, not so much meteorite impacts, but there were alredy flaws what later contributed to Venus fate;

1.The core was not properly formed, there was no convection and no liquid-solid core differentiation.This contributed to the extreme geology of Venus.

2.The plate tectonics failed to develop properly, Venus with its fully liquid core cannot sustain normal plate tectonics.Instead, pressure under the crust slowly builds up and than wave of resurfacing and volcanic activity wil occur, releasing colosal amount of greenhouse and toxic gases.

Oceans were formed, minerals from volcanos and black smokers were dissolved in the warm oceans, complex molecules were present, primitive anaerobic life then evolved.

3. Paleoproterozoic-
The waves of volcanic activity resurfaced the Venus , emited colossal amounts of greenhouse gases and hindered the life evolution to plants producing oxygen.Instead of shift to oxygenated atmosphere,temperature increased, the atmosphere was becoming more dense and was full of sulfur and carbon gases + traces of HCl.Life became completely extint at the end of Paleoproterozoic on Venus.Percipation stopped almost entirely

4.Mesoproterozoic and Neoproterozoic-
The temperature was slowly increasing to the boiling point of water, because of ill plate tectonics.Runaway greenhouse effect started, release of the water vapor caused release of more water vapor.Water vapor is of cource a powerful greenhouse gas, so at the end of proterozoic, there was a dense atmosphere composed mainly of CO2 and steam.However, some water was still liquid because of pressure keeping the water liquid even at high temperatures.But not for long.

5.The begining of Phanerozoic to present-
Solar output was much more powerful that in the good old Archean days.Water was now present only in gaseous form.There was a 9MPa atmosphere of CO2 and steam.At these times, Venus has complete water cloud cover and was even brighter than today.But water slowly dissociated in the glare of the Sun UV, because of absence of any ozone layer (that shouldnt develop because there was no oxygen)Cycles of resurfracing and volcanic hell were repeating, slowly, water dissociated to O2 and H2.Hydrogen escaped to space and oxygen recombined with sulfur from volcanoes, making this planet even more hostile because now the clouds were not familiar H2O variety, but composed of corrosive and toxic sufluric acid.Venus became slightly fainter, because of yellowish suflur and H2SO4 clouds, which were fainter than H2O, but Venus is, of course, still very bright.

Nowadays, Venus is a hostile barren wasteland with temperature, pressure and chemical extremes and bear no resemblence to once beatiful blue Earth's sister planet, like it was in Archean times of simplicity.

I think that is a more reasonable and logical assumption that simply babbling out "Venus was too close to sun..".Actually, I think that Venus might well may be a tropical paradise if some imperfections did not doom it.

Maybe God wanted only one habitable planet with complex life in this Solar system...

Imagine, multiple civilizations in the same Sol system...

P.S: I am not a Creationist, just I belive that cosmos is logical and nature is in fact God, who makes the best decisions.
Otherwise, will will be not here.

[redshifter]

I suppose one could argue that if god is nature, and nature makes the 'best' decisions, we would've been wiped out long ago.

[korjik]

do you have any references for your assertions? Why are you using Earths time divisions instead of just using years?

Alot of Venus' development can probably be attributed to its slow rotation. With the slow rotation, there would be no magnetosphere, and any primordial ocean would be rapidly heated with the extremely long days.

You could have still had developed plate tectonics, getting the equvalent of ancient cratons formed, if the water lasted long enough, but when the water dried out, the tectonics may have shifted from plates (as they locked up against one another) to the full surface repaving we see today.

With current theory estimating a crust age of 100 million years or less (if I remember right) I think your assertion that Venus never internally differentiated may be wrong. There must be a large amount of heat to cause the current volcanism, and I dont think that Venus' composition is so much different from the Earth's that the volcanism comes from a different source.

[eburacum45]

m1omg's ideas sound similar to David Grinspoon's ideas from a few years back; see here for instance
Venus possibly habitable for billions of years

but I would prefer to see more results from the Venus Express before totally agreeing with him.

[R.A.F.]

m1omg, the idea that "god did it" will be challenged, particularly on a science board.

I guess it's kinda pointless to ask if you have any evidence for your claims...

[north]

This is my opinion on the evolution of Venus:

1.Hadean -

Like Earth, Venus was constantly bombarded by large meteorites and some big asteroids.The sufrace was very hot, and there was a lot of volcanism.

2.Archean-

Venus was fully formed now, not so much meteorite impacts, but there were alredy flaws what later contributed to Venus fate;

1.The core was not properly formed, there was no convection and no liquid-solid core differentiation.This contributed to the extreme geology of Venus.

2.The plate tectonics failed to develop properly, Venus with its fully liquid core cannot sustain normal plate tectonics.Instead, pressure under the crust slowly builds up and than wave of resurfacing and volcanic activity wil occur, releasing colosal amount of greenhouse and toxic gases.

Oceans were formed, minerals from volcanos and black smokers were dissolved in the warm oceans, complex molecules were present, primitive anaerobic life then evolved.

3. Paleoproterozoic-
The waves of volcanic activity resurfaced the Venus , emited colossal amounts of greenhouse gases and hindered the life evolution to plants producing oxygen.Instead of shift to oxygenated atmosphere,temperature increased, the atmosphere was becoming more dense and was full of sulfur and carbon gases + traces of HCl.Life became completely extint at the end of Paleoproterozoic on Venus.Percipation stopped almost entirely

4.Mesoproterozoic and Neoproterozoic-
The temperature was slowly increasing to the boiling point of water, because of ill plate tectonics.Runaway greenhouse effect started, release of the water vapor caused release of more water vapor.Water vapor is of cource a powerful greenhouse gas, so at the end of proterozoic, there was a dense atmosphere composed mainly of CO2 and steam.However, some water was still liquid because of pressure keeping the water liquid even at high temperatures.But not for long.

5.The begining of Phanerozoic to present-
Solar output was much more powerful that in the good old Archean days.Water was now present only in gaseous form.There was a 9MPa atmosphere of CO2 and steam.At these times, Venus has complete water cloud cover and was even brighter than today.But water slowly dissociated in the glare of the Sun UV, because of absence of any ozone layer (that shouldnt develop because there was no oxygen)Cycles of resurfracing and volcanic hell were repeating, slowly, water dissociated to O2 and H2.Hydrogen escaped to space and oxygen recombined with sulfur from volcanoes, making this planet even more hostile because now the clouds were not familiar H2O variety, but composed of corrosive and toxic sufluric acid.Venus became slightly fainter, because of yellowish suflur and H2SO4 clouds, which were fainter than H2O, but Venus is, of course, still very bright.

Nowadays, Venus is a hostile barren wasteland with temperature, pressure and chemical extremes and bear no resemblence to once beatiful blue Earth's sister planet, like it was in Archean times of simplicity.

I think that is a more reasonable and logical assumption that simply babbling out "Venus was too close to sun..".Actually, I think that Venus might well may be a tropical paradise if some imperfections did not doom it.

Maybe God wanted only one habitable planet with complex life in this Solar system...

Imagine, multiple civilizations in the same Sol system...

P.S: I am not a Creationist, just I belive that cosmos is logical and nature is in fact God, who makes the best decisions.
Otherwise, will will be not here.

if the cosmos is logical and Nature is in fact god , then why destroy , by Nature , ANY church of god? ( tornados )?

[hhEb09'1]

just I belive that cosmos is logical and nature is in fact God,

m1omg, the idea that "god did it" will be challenged, particularly on a science board.

I guess it's kinda pointless to ask if you have any evidence for your claims...

there seems to be a terminology issue...

[John Mendenhall]

Offhand, I can't think of any way to ever get Venus cool enough to support oceans.

Good point in previous post about the rotation and rate and the magnetic field.

[Walker59]

But for terraforming it might be more ideal than Venus. Bringing down atmospheric pressure is much easier than raising it. Raid the Jovian systems for some nice size ice asteroids and shake and bake it. Well. Maybe not that simple.

[hhEb09'1]

Good point in previous post about the rotation and rate and the magnetic field.

Took me a little while, but I think that this comment was about this post in the Flux tubes, geodynamos and our planets.... thread. Shouldn't there be a note when a sub-thread is split out?

[m1omg]

do you have any references for your assertions? Why are you using Earths time divisions instead of just using years?

Alot of Venus' development can probably be attributed to its slow rotation. With the slow rotation, there would be no magnetosphere, and any primordial ocean would be rapidly heated with the extremely long days.

You could have still had developed plate tectonics, getting the equvalent of ancient cratons formed, if the water lasted long enough, but when the water dried out, the tectonics may have shifted from plates (as they locked up against one another) to the full surface repaving we see today.

With current theory estimating a crust age of 100 million years or less (if I remember right) I think your assertion that Venus never internally differentiated may be wrong. There must be a large amount of heat to cause the current volcanism, and I dont think that Venus' composition is so much different from the Earth's that the volcanism comes from a different source.

You are completely wrong.Modern science theories belives that Venus thick 90bar CO2 atmosphere stopped and eventually turned Venus rotation to retrograde by its friction.Any other theory about Venus unnatural rotation, axial tilt?

[m1omg]

And references;I have read it from the same source as eburacum45.

[JonClarke]

You are completely wrong.Modern science theories belives that Venus thick 90bar CO2 atmosphere stopped and eventually turned Venus rotation to retrograde by its friction.Any other theory about Venus unnatural rotation, axial tilt?

First I have heard of it. Any references, links, to support this? The standard explanation I have heard for axial tilt and rotation are due to giant impacts early in the planet's history.

Jon

[korjik]

And references;I have read it from the same source as eburacum45.

If you read the link eburacum45 provided, and read my post, how am I totally wrong?

As for the atmo stopping the rotation, yes I have heared that, but I seem to remember that that force isnt enough to stop a planet rotating at Earth's angular momentum.

[cjl]

Any force is enough to stop any momentum, given enough time.

[m1omg]

First I have heard of it. Any references, links, to support this? The standard explanation I have heard for axial tilt and rotation are due to giant impacts early in the planet's history.

Jon

No giant impact my friend;

http://en.wikipedia.org/wiki/Venus#Orbit_and_rotation

"Venus rotates once every 243 days – by far the slowest rotation period of any of the major planets. A Venusian sidereal day thus lasts more than a Venusian year (243 versus 224.7 Earth days). However, the length of a solar day on Venus is significantly shorter than the sidereal day; to an observer on the surface of Venus the time from one sunrise to the next would be 116.75 days.[21] The Sun would appear to rise in the west and set in the east. At the equator, Venus' surface rotates at 6.5 km/h; on Earth, the rotation speed at the equator is about 1,600 km/h.

If viewed from above the Sun's north pole, all of the planets are orbiting in a counter-clockwise direction; but while most planets also rotate anticlockwise, Venus rotates clockwise in "retrograde" rotation. The question of how Venus came to have a slow, retrograde rotation was a major puzzle for scientists when the planet's rotation period was first measured. When it formed from the solar nebula, Venus would have had a much faster, prograde rotation, but calculations show that over billions of years, tidal effects on its dense atmosphere could have slowed down its initial rotation to the value seen today.[22][23]"

Maybe yes, but its a more doubtful new theory;

"Venus is currently moonless, though the asteroid 2002 VE68 presently maintains a quasi-orbital relationship with it.[25] According to Alex Alemi and David Stevenson of the California Institute of Technology, their recent study of models of the early solar system shows that it is very likely that, billions of years ago, Venus had at least one moon, created by a huge impact event.[26][27] About 10 million years later, according to Alemi and Stevenson, another impact reversed the planet's spin direction. The reversed spin direction caused the Venusian moon to gradually spiral inward[28] until it collided and merged with Venus. If later impacts created moons, those moons also were absorbed the same way the first one was. The Alemi/Stevenson study is recent, and it remains to be seen what sort of acceptance it will achieve in the scientific community."

[JonClarke]

No giant impact my friend;

http://en.wikipedia.org/wiki/Venus#Orbit_and_rotation

Actually my friend, the giant impact idea has been round for more than a decade. It is only the impacting moon variant that is new.

Jon

[m1omg]

Humans tries to explain everything with some great cataclysms.Bad things can happen slowly and there are currently 6 such things here on Earth on the progress and if humans does not became more clever , our planet will became, after a few millenias; an radioactive place with temperatures of 200 degress, with sufluric acid rain, with UV levels extremly high and there will be ruins scattered, of the past human civilization, most of them molten by nuclear explosions.Maybe some alien civilization in the future will explore that Earth, and say; "This planet was devastated by a some pseudointelligent brutal noncivilization".So we,before terraforming other places, must save our Earth and made humanity a real humanity.
I dont think that a giant impacts are the most sensible way of explaining anything.I think that slowdown of the Venus rotation was very slow, and started when the Venus became a toxic, uninhabitable, hot place.

[JonClarke]

Nobody is saying that giant impacts are the cause over everything. However there isa evidence that such impacts have occurred and it is reasonable to explore the possibility as to whether they had a role in things like the unusual rotation of Venus.

What is your evidence that the rortation of Venus occurred slowly and that it had a connection with the current runaway greenhouse conditions on the planet?

Jon

[m1omg]

Because the friction of atmoshere over time.
And any evidences of the giant impact?

[Nereid]

do you have any references for your assertions? Why are you using Earths time divisions instead of just using years?

Alot of Venus' development can probably be attributed to its slow rotation. With the slow rotation, there would be no magnetosphere, and any primordial ocean would be rapidly heated with the extremely long days.

You could have still had developed plate tectonics, getting the equvalent of ancient cratons formed, if the water lasted long enough, but when the water dried out, the tectonics may have shifted from plates (as they locked up against one another) to the full surface repaving we see today.

With current theory estimating a crust age of 100 million years or less (if I remember right) I think your assertion that Venus never internally differentiated may be wrong. There must be a large amount of heat to cause the current volcanism, and I dont think that Venus' composition is so much different from the Earth's that the volcanism comes from a different source.

You are completely wrong.Modern science theories belives that Venus thick 90bar CO2 atmosphere stopped and eventually turned Venus rotation to retrograde by its friction.Any other theory about Venus unnatural rotation, axial tilt?

And references;I have read it from the same source as eburacum45.

I'm not sure that korjik's questions (do you have any references for your assertions? Why are you using Earths time divisions instead of just using years?) have been answered.

Do you have any references to support the assertions you make in the OP?

Why are you using Earth geological time divisions instead of years?

[m1omg]

I'm not sure that korjik's questions (do you have any references for your assertions? Why are you using Earths time divisions instead of just using years?) have been answered.

Do you have any references to support the assertions you make in the OP?

Why are you using Earth geological time divisions instead of years?

Please, 1st. explain to me what is OP?
2nd., because then it can be easily compared to Earths developement, geological epochs makes more sense to me than some bunch years.

[Noclevername]

OP = Original Post, the premise you started the thread with.

[Nereid]

Please, 1st. explain to me what is OP?
2nd., because then it can be easily compared to Earths developement, geological epochs makes more sense to me than some bunch years.

Noclevername has answered your question*.

Thanks for the answer to the second question.

Now that you know what "OP" stands for, when may we expect some answers?

*You can also use 'opening post'. Myself, I think its a common abbreviation in internet discussion fora (so I don't usually spell it out); but, sometimes, I make one assumption too many.

[JonClarke]

Because the friction of atmoshere over time.
And any evidences of the giant impact?

Friction of the atmosphere against what?

[korjik]

Friction of the atmosphere against what?

against the surface of the planet. IIRC a slow rotating planet with an atmo has atmospheric currents set up that basically go night to daysside, or vice versa. Since the atmo currents are decoupled from the rotation, the atmo acts like a brake due to friction. Kinda like a ball in still air in the earth.

[korjik]

Please, 1st. explain to me what is OP?
2nd., because then it can be easily compared to Earths developement, geological epochs makes more sense to me than some bunch years.

The paper eburacum45 referenced heavily implies that you should use a Venus timescale instead of the Earths. If they are right, and Venus was wet till around 700 million years ago then a more reasonable scaleing is somthing like

4.5 billion till ~1 billion : hot Earthlike
~1 billion till 700 million: boiling Earthlike
700 million till present: Venusian

Note that the ~1 billion is a WAG

hot earthlike is where the enviro is still similar to earth, just hotter
Boiling is where the evaporation effects on the oceans becomes important

[JonClarke]

against the surface of the planet. IIRC a slow rotating planet with an atmo has atmospheric currents set up that basically go night to daysside, or vice versa. Since the atmo currents are decoupled from the rotation, the atmo acts like a brake due to friction. Kinda like a ball in still air in the earth.

What evidence is there that this process is effective enough to slow the rotation of Venus to present levels? How does this explain retrograde rotation?

Jon

[korjik]

Dont think there is any. Venus' rotation rate is mostly set by initial angular momentum from collisions. I think that the atmosphereic effect is only thought to have maybe changed a very slow prograde rotation to a very slow retrograde rotation.

[JonClarke]

How does that work (getting retrograde from prograde rotation via tidal friction)?

Jon