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Offline na na

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Is Venus what Earth will be like in future?
« on: 02/05/2008 08:27:00 »
na na  asked the Naked Scientists:
Hi Chris,
   
Thanks for the podcasts; listen to them all the time at work, and trying to convert family too.
   
I've had a hypothesis for a while now, that Venus is Earth in the future. I've been called a doom monger and pessimist amongst other things, but I would like to know how accurate or feasible this is given the right conditions (expanding sun, increasing heat, increasing green-house, oceans eventually suspended in atmosphere leading to crushing sulphuric conditions, etc).
   
Many thanks
Steve
What do you think?


 

Offline Andrew K Fletcher

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Is Venus what Earth will be like in future?
« Reply #1 on: 02/05/2008 10:06:27 »
Hi Steve. I have also been postulating an evolutionary process of planets, perhaps not the same formula as yours, mine is based on planets growing at an infinitesimally slow rate as they attract matter from space due to their mass and gravitational influence of great distances. The larger planets become the more likely they are to scoop up any passing debris from the largest asteroid to sub atomic particulate matter.

The ultimate being a planet expands until it can no longer remain stable and turns into a sun where it decays over many billions of years shedding its particles and feeding the growing planets. A conveyor belt of planets form being very small to becoming massive and gradually heating up as they evolve. Not cooling down from an explosion as presumed.  Exceptions being that suns do become smaller as they burn themselves out and cool down where they then begin the same process over again but have a head start on a virgin planet growing from seed atoms.

Andrew K Fletcher
 

another_someone

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Is Venus what Earth will be like in future?
« Reply #2 on: 02/05/2008 11:46:33 »
There are quite considerable differences between the Earth and Venus, things that go beyond simply its distance from the Sun.

The main thing that makes the Earth so unusual is that it has a very large moon orbiting it (Mars has a small moon, and Venus has no moon).  The way the moon was formed (it is supposed that it was through a major collision with another large body in the early history of the Earth) meant that we also have a very thin crust on the Earth, which allows for plate tectonics to occur on Earth in a way it does not occur on the other rocky planets.

All of this means the way chemicals mix, both in the atmosphere, and between the atmosphere and the rocks of the planet, is very different to the way this happens on the other rocky planets.

Aside from the distance from the Sun (which is the main thing people think about), Venus has about 90 times the atmospheric pressure of Earth, and it has very little nitrogen in the atmosphere (even if all of the Earth's O2 reverted to CO2, it would still amount to about 20% of the atmosphere, since the other 80% still remains to be nitrogen).  Thus, even if one takes the worst case scenario, and converts all of our O2 to CO2, Venus would still have about 430 times the density of CO2 as the Earth.

I would not like to predict what the Earth might be like in the distant future, but I am fairly confident that the differences between the Earth and Venus would mean they would remain looking very different.
« Last Edit: 02/05/2008 11:57:31 by another_someone »
 

Offline JimBob

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Is Venus what Earth will be like in future?
« Reply #3 on: 04/05/2008 04:12:39 »
Not quite correct George. If the water on the earth turned to vapor due to the green house effect then we would have a nitrous-nitric Acid atmosphere while Venus has a sulfuric atmosphere.

Venus has also had some episodes of tectonics as earth has had. Most of the surface is covered by relatively recent lava flows. And:

"Venus is sometimes regarded as Earth's sister planet. In some ways they are very similar:
    * Venus is only slightly smaller than Earth (95% of Earth's diameter, 80% of Earth's mass).
    * Both have few craters indicating relatively young surfaces.
    * Their densities and chemical compositions are similar."

http://www.nineplanets.org/venus.html

IF the green house effect ever takes place then earth could very well look like Venus. That is a big IF.

« Last Edit: 04/05/2008 04:14:34 by JimBob »
 

another_someone

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Is Venus what Earth will be like in future?
« Reply #4 on: 04/05/2008 12:49:23 »
Lava flows do not of themselves prove plate tectonics.  Linear mountain ranges might be better evidence.  In fact, the ultra large volcanoes on Venus is probably an argument against plate tectonics, since on Earth, that volcano would have shifted and created a linear range of smaller extinct volcanoes.  The page you refer me to explicitly states there is no evidence of plate tectonics.

None of this has explained either why Venus has 90 times Earth's pressure.  As you say, if the water on Earth were to evaporate, we would have nitrious acid; but Venus has very little water in its atmosphere (it may possibly once have had, but it certainly does not have now).

Although Venus has a layer of sulphuric acid clouds, its atmosphere is predominantly carbon dioxide - something our atmosphere will not ever be, because of the large predominance of nitrogen (even if we do get a few nitrous oxide clouds, we will still have lots of nitrogen left over).  The small amounts of sulphur locked up sulphuric acid clouds on Venus simply are not comparable to the amounts of nitrogen that exist on this planet.
 

Offline JimBob

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Is Venus what Earth will be like in future?
« Reply #5 on: 04/05/2008 19:13:14 »
Not all of the question about Venus have been answered - I'll agree with you on that. BUT --

WHY do you feel compelled to correct the professionals' current thinking in the xeno-geologic community? The page I referred you to is not the totality of thinking and is not a comprehensive site. It is for the casual browser of the web. To understand the geology of Venus you need to study the raw data. Have you done that?

For example:

http://geopubs.wr.usgs.gov/i-map/i2610/

U.S. Geological Survey
Geologic Investigations Series I-2610
Geologic Map of the Barrymore Quadrangle (V–59), Venus
By Jeffrey R. Johnson, Goro Komatsu, and Victor R. Baker

"The Barrymore quadrangle (V–59) is a predominantly ridged plains region south of Imdr Regio, incorporating portions of Helen, Nuptadi, and Nsomeka Planitiae. The map area extends from lat 50°–75° S. and long 180°–240°, with nearly 70% coverage by cycle 1 synthetic aperture radar (SAR) images (left-look, incidence angles 16°–23°) and complete coverage by cycle 2 images (right-look, incidence angles 20°–25°) (fig. 1). The majority of the map area is covered by regional plains material that may either be smooth or deformed by wrinkle ridges or ridge belts of variable spacing. The difference in elevation between highest and lowest points in the map area is about 2.3 km. A north-south-oriented, 1,375-km linear ridge belt named “Saule Dorsa” is in the center of the region. The southern tip of this [tectonic - JB] belt is intersected by a stratigraphically complicated, east-west-trending intermittent series of disrupted material, arcuate depressions and rises, regional plains, and volcanic centers. This region (hereafter referred to as the “east-west disrupted zone”) lies within a belt between 63°–67° S. extending from Kadlu Dorsa to Moombi Corona. A high concentration of canali-type channels (long sinuous lava channels that may contain subsidiary channels that branch off from the main channel [Baker and others, 1992; Komatsu and others, 1992]) occurs in Nsomeka Planitia. This includes Xulab Vallis and Citlalpul Valles, which form the eastern extent of a 3,000-km-long canali system (Komatsu and others, 1993). Three instances of canali bifurcation from north-south to east-west orientations occur in this region (fig. 2). Several large impact craters with fluidized ejecta blanket (FEB) outflows occur in the map area, along with some impact crater extended deposits (parabolas). The latter are mapped as surficial material using stipple patterns over the plains materials. These surficial deposits show variations in radar backscatter properties between cycle 1 and cycle 2 images related to orientation of aeolian dune or ripple faces (for example, Weitz and others, 1994; table 1). This region provides an interesting geologic setting for interpreting the history of regional and local plains formation and evolution, mainly due to development and subsequent deformation of the areally extensive plains units and accompanying canali (Komatsu and Baker, 1994)."

AND From the Quadrangle discussion:

"STRATIGRAPHY"

"The oldest materials in the map area include volcanically flooded and (or) tectonically deformed remnant
materials. Tessera material (unit t) represents remnant highland, ridge belt, or disrupted corona material and
occurs as isolated hills or larger continuous regions embayed by later lavas or other units. Corrugated ridged
plains material (unit prc) is the oldest unit to embay tessera material, although the stratigraphic history during
the interval between emplacement of the two materials is unclear. The corrugated ridged plains material may
represent compressionally deformed older plains material or possibly the central portion of a former corona
complex (lat 68° S., long 207°; fig. 5), because it is overlain in different areas by either arcuate ridge and
groove material (unit rga) or smooth arcuate ridge material (unit rsa) and is flooded by regional plains material
(unit pr).

"Arcuate ridge and groove material (unit rga) comprises concentric groupings of ridges and fractures elevated
relative to the surrounding terrain and embayed or crosscut by lavas and ridges associated with regional
plains material. The arcuate ridge and groove unit is interpreted as a type of volcanically flooded corona rim. A
similar unit is smooth arcuate ridge material (unit rsa), which encompasses smaller semiparallel, curvilinear,
smooth-topped ridges; this material may represent either ridge belt apices surrounded by volcanically flooded
regions or corona rim remnants (or both).

"Mottled ridged plains material (unit prm) represents old volcanic deposits, some with channelized lava
flows, which deformed contemporaneously with wrinkle ridge formation in the regional plains material. This
material often occurs in “splotchy” patterns with sharp to gradational edges making superposition relations
with regional plains material difficult to discern. However, regional plains material appears to have embayed
mottled ridged plains material. Undifferentiated plains material (unit pu) occurs only in the north-central part of
the map area (type locality at lat 51.5° S., long 209°). This material is distinguished by its embayment by
regional plains material and higher backscatter. It appears to be older lavas originated from the southern rim of
a corona at lat 47.5° S., long 208."

Much more evidence for tectonic activity follows in the USGS discussion.


The point is that that tectonic activity does occur on Venus - A volcano is a tectonic feature and so are the anticlines and synclines found on the map referenced above. The cross-cutting relationships are also indicators of past tectonic activity.


PLEASE DO NOT TELL ME I DON"T KNOW HOW TO INTERPRET THE DATA OF MY PROFESSION. IT IS EXTREMELY RUDE!

As for the atmosphere - at the heat required to cause the oceans to become vapor, acidic conditions would prevail. Venus has a mere 3% acidity in its atmosphere. That percentage would be greater on Earth IF the oceans were vaporized by run-away greenhouse effects. Please, consider all of the problems and possibilities when giving flippant answers.
« Last Edit: 04/05/2008 19:17:09 by JimBob »
 

another_someone

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Is Venus what Earth will be like in future?
« Reply #6 on: 04/05/2008 20:11:03 »
The questions of tectonics, I was quoting from the page that you referred me to where is explicitly stated there was no evidence of plate tectonics.  If you wish to accuse them of being rude, that is your prerogative (but then I would cease quoting those pages if that is how you feel about them).

I said nothing about the atmosphere not being acidic.  I was suggesting that Venus has far more CO2 in its atmosphere than the Earth has - whether CO2 or NOx, it would still be acid - and nowhere did I make any comment to the contrary.

Volcanoes are possible with or without plate tectonics.  I merely said that other features would provide better indications of plate tectonics (such as linear features, of the type you are now saying are there) - it was the page that you referred me to, not my own invention, that stated explicitly that there was no evidence of plate tectonics.
« Last Edit: 04/05/2008 20:13:52 by another_someone »
 

Offline JimBob

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Is Venus what Earth will be like in future?
« Reply #7 on: 04/05/2008 20:54:05 »
Volcanoes are possible with or without plate tectonics. 

By definition volcanoes are tectonic events - you are just plain wrong.
 

another_someone

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Is Venus what Earth will be like in future?
« Reply #8 on: 04/05/2008 21:13:39 »
Volcanoes are possible with or without plate tectonics. 

By definition volcanoes are tectonic events - you are just plain wrong.

I think the key issue here is plate tectonics.

Volcanoes are an upwelling of magma through the crust, but they do not require that the crust itself be in motion, or that the crust be broken up into plates, for this to happen.

To say that a volcano is a tectonic event is merely to say that it is an event in the crust of the planet.  I never questioned that to be the case, and it would be nonsense to question that to be the case.  The question was whether that crust is broken up into plates or not.
« Last Edit: 04/05/2008 21:17:38 by another_someone »
 

Offline turnipsock

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Is Venus what Earth will be like in future?
« Reply #9 on: 04/05/2008 23:55:02 »
I had a similar thought, that is we will all move to Mars when the Sun starts getting bigger and the earth becomes to hot for us. Mars is to cold for us just now, but with the Sun increasing in size there will be a time where is will about right for us.

If we didn't have a moon, we would still have tides beacuse of the infulence of the Sun's gravity.

Mars has two moons, it would be a nightmare working out the tides there.
 

Offline chris

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Is Venus what Earth will be like in future?
« Reply #10 on: 05/05/2008 10:04:59 »
Mmm, interesting thought, but Mars has no magnetic field, which is why it is a dried out husk of a planet: the loss of its magnetism abut 4 billion years ago enabled the solar wind to whip away the majority of the atmosphere and any water that was there. It also means that the surface is basted in large doses of cosmic radiation. This adds up to a pretty harsh environment, even for someone used to living in Basildon (a crappy town in Essex, England). We'd need to find a way around that before we could consider moving there.

Chris
 

Offline na na

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Is Venus what Earth will be like in future?
« Reply #11 on: 06/05/2008 15:00:58 »
Thanks to everyone that have commented on my question. Any feedback is positive whatever its relevance to the question.

I was under the impression that Earth and Venus were sufficiently similar on a global scale. In my question I am enquiring whether this could happen in the very distant future. In that example, the difference in distance (AU) between the Earth and Venus is actually irrelevant due to the sun's eventual expansion. – I suspect it’s a little too late for Venus. ;)

Am I correct to assume that Earths oceans suspended in the atmosphere will increase atmospheric pressure?

Many thanks again...
 

Offline JimBob

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Is Venus what Earth will be like in future?
« Reply #12 on: 07/05/2008 05:50:03 »
Volcanoes are possible with or without plate tectonics. 

By definition volcanoes are tectonic events - you are just plain wrong.

I think the key issue here is plate tectonics.

Volcanoes are an upwelling of magma through the crust, but they do not require that the crust itself be in motion, or that the crust be broken up into plates, for this to happen.

To say that a volcano is a tectonic event is merely to say that it is an event in the crust of the planet.  I never questioned that to be the case, and it would be nonsense to question that to be the case.  The question was whether that crust is broken up into plates or not.

No, it is not. Tectonics are tectonics. It is impossible to prove that plate tectonics do or do not exist on Venus because of the covering of recent volcanic flows which masks the underlying geology. The point is that there is some evidence of plate tectonics that can be inferred from the anticlines, synclines, cross-cutting relationships and faults seen on the very poor resolution radar scans of the surface though the clouds. The radar imagery is not of the quality we can archive at present. It was "flown", I believe in 1994.

The image below shows compressional folding indicate by the white arrow. This is a NASA photograph.  The mechanism for the compression cannot be determined but compressional folding is tectonics.






How the fact the possibility of plate tectonics being part of Venusian history can be disputed is beyond me.
 

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Is Venus what Earth will be like in future?
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