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No moon

I vote the fact that Venus has no moon should be mentioned explicitly and relatively early on in the introduction.--Cancun771 (talk) 10:17, 30 October 2013 (UTC)

I disagree. That isn't a particularly notable fact; maybe just notable enough to stay in the lead, but definitely not notable enough to be second sentence. — Reatlas (talk) 03:19, 31 October 2013 (UTC)

I strongly agree with Reatlas, the absence of a moon is definitely not notable enough to be the second sentence in the lead, and certainly not in the bald way it has been added. I do not object in principal to mentioning the lack of a natural satellite in the lead, but it should come after the sentence 'However, it has also been shown to be very different from Earth in other respects'. Also while saying 'the Moon' might be slightly ambiguous Earth's Moon is the only moon that qualifies for either the definite article or a capital 'M' so I'm not sure about the addition of the qualifier 'Earth's' to 'the Moon' is necessary either. Physdragon (talk) 18:23, 27 November 2013 (UTC)

Axial tilt 177° or 3°

In the "Infobox planet" box, on the right top side of this Misplaced Pages article, the axial tilt of Venus is given as 177.36° but in the main body of the article, under the "Atmosphere and climate section", the fifth paragraph down, it says in complete contradiction to that reasonable sounding value, "The planet's minute axial tilt—less than 3°, compared to 23° on Earth—also minimizes seasonal temperature variation." Which figure is correct, 177.36° or 3°? I am guessing that there was a misprint in the source from where the 3° figure was quoted from. Someone who drew up that NASA page probably got Jupiter and Venus somehow mixed up as Jupiter does have an axial tilt of around 3°. I do realise that obviously 180° - 177.36° is roughly 3° but so what?! Either Venus has a 177.36 degrees over its 224.701 day year which would make for extreme seasonality if it wasn't for its thick carbon dioxide atmosphere or it tilts by only 3 degrees over its 225 day year and wouldn't experience much seasonality even if it didn't have 89 atmospheres of carbon dioxide blanketing/smothering it so completely. — Preceding unsigned comment added by 86.163.137.155 (talk) 03:38, 15 November 2013 (UTC)

Technically, 177.36° is correct, because Venus rotates in the opposite direction compared with its orbital motion. However, to explain to the layman what this means, one can say an axial tilt of 2.64° (3° if rounded) and rotating in the opposite direction. --JorisvS (talk) 15:33, 15 November 2013 (UTC)

Untitled

On the 3rd February experimental film researcher Vincenzo Giovanni Ruello and his wife Melaia Ruello photographed the first ever graphic photo of an HFA...Hot Flow Anomalie explosion eruption on the surface of Venus. The massive eruption at the top of the planet is unprecedented the images are being investigated by Nasa and can be seen t youtube http://www.youtube.com/watch?v=0bluKP9aW5w — Preceding unsigned comment added by 101.174.151.68 (talk) 13:39, 3 February 2014 (UTC)

Semi-protected edit request on 4 February 2014

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Venus retrogrades like uranus and pluto and isnamed after roman goddess, Venusand in greek aphrodite

please put thisin thx 99.112.136.195 (talk) 06:18, 4 February 2014 (UTC)

 Not done All of those basic facts are already in the article if you actually read it. Cadiomals (talk) 18:44, 4 February 2014 (UTC)

Active Volcanoes Revealed on Venus

Just dropping off some newly published info on Venus. If the link doesn't post, just look for "Active Volcanoes Revealed on Venus" at space dot com. — Preceding unsigned comment added by 83.180.201.142 (talk) 16:16, 19 March 2014 (UTC)

Greenhouse effect on Venus not substantiated by valid physics

It cannot be substantiated with standard physics that the surface of Venus is kept hot by radiation from the colder carbon dioxide atmosphere. The small solid core of Uranus (55% the mass of Earth) has a surface temperature several times that of the Venus surface, and yet only about as much methane as Earth has water vapor. Uranus is nearly 30 times further from the Sun than Earth is, and thus receives little more than 0.1% of incident solar radiation.

In fact the surface temperature of Venus rises by about 5 degrees (from 732K to 737K) during the four-month-long day and so this requires an input of thermal energy, which cannot be coming by way of radiation from the colder atmosphere because, if it were, entropy would be decreasing.

Venus cools by 5 degrees at night, and so it could easily have cooled right down over the life of the planet if the Sun provided no insolation. So we can deduce that it is energy from the Sun which is gradually raising the temperature of the Venus surface during those four months of Earth time. But less than 20 watts per square meter of solar radiation gets through to the surface because carbon dioxide actually absorbs incident solar radiation.

If one tries to explain the 5 degree difference with Stefan-Boltzmann calculations for radiation, there is a difference of about 450 watts per square meter just between the two temperatures 732K and 737K, and so this is not supplied from the direct solar radiation which is only about one tenth of that which reaches Earth's surface.

Hence there is no scientific basis for assuming that direct radiation to the surface is the cause of the high surface temperatures on Venus, and thus there is no "runaway greenhouse effect."

Douglas Cotton (talk) 02:16, 1 April 2014 (UTC)

There is no room for fringe ill-informed refutable claims against a consensus by 99.9% of qualified scientists. If another user feels this topic violates WP:TALK guidelines since it does not directly discuss improvements to the article, they can remove it from this page and I would back them up. Cadiomals (talk) 03:01, 1 April 2014 (UTC)

This sounds like a lot of original research and thought that's not supported by all scientific material. We go with what the scientists and sources say. Scarlettail (talk) 03:08, 1 April 2014 (UTC)

Response to comments

You cannot prove with valid physics that direct radiation reaching the Venus surface (measured by the Russian probes and estimated not to exceed a mean of 20 watts per square meter) can raise the temperature from 732K to 737K. None of your claimed 99.9% have proved that a radiative greenhouse effect can operate on Venus. Where is a citation to an energy budget, for example, with Stefan-Boltzmann calculations matching the flux shown? Which article on Misplaced Pages supposedly cites any valid proof? I will easily show you what's wrong with it if one exists. You cannot prove that radiation from the far less hot carbon dioxide can raise the Venus surface temperature. Nor can you explain how the surface is maintained at anything like the temperature that has been measured. Nor can you explain why the surface of the solid core of Uranus is about 5,000K, far hotter than Venus, and a lot further from the Sun. So your greenhouse conjecture simply does not work on other planets like these.

This is not discussing some unique theory of mine: it is merely pointing out, in a way that any physicist should recognize to be valid, that what is written in this article is not in agreement with the laws of physics. Douglas Cotton (talk) 08:01, 1 April 2014 (UTC)

Nothing you say matters to anyone here at all if you can't find reliable mainstream sources and scientific journals to back up your assertions. And that's that. Misplaced Pages conforms to the mainstream, it is not the proper place to push original research or fringe unsourced claims. Start your own blog for that. This is my last reply as fringe beliefs should not be elevated with further attention. Cadiomals (talk) 09:00, 1 April 2014 (UTC)

I am merely refuting this Misplaced Pages article, not any valid article anywhere that can be shown to be based on correct physics.

The article does not quote any valid "mainstream scientific journal" that contains a valid article "that backs up" the article's implied assertion (which amounts to a violation of the Second Law of Thermodynamics) that the warming of the Venus surface (by about 5 degrees in 4 months) can in any way be the result of incident radiation from the colder atmosphere striking that surface.

The only references to greenhouse effect cited in the article are ...

(1) http://www.cambridge.org/au/academic/subjects/astronomy/planetary-science/new-solar-system-4th-edition?format=PB

This is a book costing around $100 with not a single review since 1999. Nothing from it was actually quoted and it is out of print.

(2) http://burro.cwru.edu/stu/advanced/venus.html

This just makes these assertive statements ...

(a) "Venus is the case of a runaway greenhouse effect."

(b) "This process is a runaway one in that once less water is available to wash CO2 from the atmosphere, the CO2 level rises. This results in a stronger greenhouse effect, so the temperature rises."

(3) http://www.chriscunnings.com/uploads/2/0/7/7/20773630/runaway_greenhouse_venus.pdf p.483

This actually concludes ...

"however CO2 increases alone are not able to trigger a runaway greenhouse"

I put it to you that the references to greenhouse effects in this article are unnecessary, unsupported and ought to be deleted.

Douglas Cotton (talk) 10:54, 1 April 2014 (UTC)

I put it to you that you're taking a lot of stuff out of context. It's true CO2 alone is not able to trigger a runaway greenhouse effect... other greenhouse gasses are needed. So it's still just a pure greenhouse gas. But I'll leave you with WP:NOTESSAY and WP:NOR (no original research). If you want to conduct your own "research" that's your prerogative, but[REDACTED] isn't the place to publish it. Sailsbystars (talk) 13:38, 1 April 2014 (UTC)

You probably misunderstand what greenhouse effect is. It is actually a consequences of (near) complete opacity of the Venusian atmosphere to the thermal radiation. Since the radiation is completely trapped, the radiative cooling of the surface is impossible and, in such circumstances, the only process that can remove heat from the surface is convection. However convection can only function if the temperature decreases with altitude adiabatically or faster. In practice it means that the temperature profile will be forced to become adiabatic. Now consider that the temperature in the upper atmosphere of Venus is determined by the balance of the absorbed solar light and thermal radiation escaping into the space. For the highly reflective Venusian clouds this means that the upper atmosphere temperature is around 200 K (at pressure around 0.1 bar). This temperature must grow as the altitude decreases following the adiabatic curve. Taking into account that the surface pressure is 95 bar, this will lead to a very high surface temperature. The amount of solar energy that reaches the surface does not really matter: it can be 20 W or 1 W—the result will be the same. Ruslik_Zero 19:45, 1 April 2014 (UTC)

Ruslik: Says "other GH gases are needed" - well carbon dioxide is over 96% of the Venus atmosphere, so the "other gases" have a lot of work to do. In any event, because over 95% of the incoming solar radiation is absorbed by the carbon dioxide and a few other gases in the Venus atmosphere, and the radiation back to space is roughly in balance, it should be obvious that carbon dioxide is leading to lower temperatures at the Venus surface which, by the way, receives less than 10% of the direct solar flux that Earth's surface receives. In that this has been measured by the Russian probes dropped onto the Venus surface, why is such information not in this cherry-picking article? A surface at the temperature of Venus could very readily shed far more than the 20 watts per square meter of radiative flux that it receives by conduction, diffusion, convection and advection into and within the atmosphere. In fact, at night the Venus surface and the whole troposphere cool by 5 degrees in 4 months. So how does the Venus surface warm again from 732K to 737K over the 4 months of sunshine? Although I can answer that with valid physics, I doubt that you can explain it any other way. You are correct in saying convection can only operate (upwards) if the thermal gradient exists. That is the gravito-thermal effect in operation forming that gradient, as can be proved with valid physics. And when new solar energy is absorbed at the top of the troposphere, convection goes downwards, restoring the disturbed state of thermodynamic equilibrium which is the thermal gradient you spoke of. This is nothing more nor less than a correct application of the Second Law of Thermodynamics, the entropy conditions in which you may not fully understand. I suggest you refer to my "talk" on the Second Law. You write about the "adiabatic curve" without realizing that it is the state of thermodynamic equilibrium described in statements of the Second Law. And, no, high pressure does not cause or maintain high temperatures. The force of gravity acting upon molecules in free path motion sets up, in accord with the Second Law, both a density gradient and a temperature gradient. These are the independent variables, and pressure is merely the result thereof, being proportional to the product of density and temperature. If you want a better understanding of thermodynamics I can help you (as I have helped many undergraduates over the course of nearly 50 years) but you need to be willing to learn.

Douglas Cotton (talk) 22:14, 1 April 2014 (UTC)

Douglas Cotton really does not know what he is talking about because his comparison between the rocky body of Venus and the rocky core of Uranus is fallacious. The solid body of Venus at a surface temperature of ca. 750K is enveloped in its atmosphere of mostly carbon dioxide versus the tiny, rocky core of Uranus which is covered by a thick mantle of water, ammonia, and methane ices under a thick atmosphere of mostly hydrogen, helium, and methane gases. As is the case with Jupiter, Uranus does not possess a well-defined solid surface. The high 5000K temperature of the solid, rocky Uranus core under its thick, insulating blanket of the icy mantle could easily be the result of heat from radioactive decay in concert with residual, primordial natal heat. I suggest Cotton read the "Internal Structure" section of the Uranus entry for meaning. Phaedrus7 (talk) 20:00, 1 April 2014 (UTC)

Phaedrus: I acknowledge loose use of the word "surface" by which I of course meant the rather ill-defined boundary between the Uranus core and its mantle, this boundary having roughly 25% the radius of the whole planet. However, you do not seem to be aware that Uranus is unique, being different from the collapsing gaseous planets like Neptune and Jupiter. Because of the solid core in Uranus, there is no evidence of internal energy coming from the reduction in gravitational potential energy in a collapsing atmosphere. Nor is there convincing evidence of significant net energy loss at top of atmosphere that might indicate much nuclear decay. In the simple Misplaced Pages article on the GH effect there is a comparison made between Venus and Mercury, as if that proves the Venus temperature has something to do with CO₂ but in reality it has only to do with the height of the atmosphere, as is further confirmed with Uranus, which that article did not mention.

I can explain with valid physics why the gravito-thermal effect is a reality (backed up by evidence in a Ranque-Hilsch vortex tube) and I can then explain how the required energy gets down into planetary atmospheres, crusts, mantles and cores in order to balance the energy losses. See my reply to Ruslik just above and think about the issue as to how the necessary thermal energy actually gets into the Venus surface to raise its temperature by 5 degrees in its four-month-long daytime. I am not inventing some new science: I am using well established thermodynamics which, unlike most who don't understand it, I do.

TO ALL READERS:

The argument that planets are still cooling off, or are somehow generating internal energy that maintains their existing temperature is not valid because ...

(1) Every planet cools on its dark side at a rate which could easily have enabled it to cool right down (even in its core) to about the temperature supported by any external radiation. Venus cools about 5 degrees in 4 months, Earth cools by about 10 degrees in 12 hours etc. In other words, if the Sun existed but emitted no significant energy, it would appear that all planets in our Solar System could have cooled down close to absolute zero.

(2) So it must be energy from the Sun which is maintaining the existing temperatures on all planets and satellite moons, even down to their cores, and it must be doing so by raising the temperatures back up again by the amount equal to the cooling the night before. Why, for example, is the core of our Moon so much hotter than the surface ever is?

(3) Hence we require an explanation as to how the necessary energy gets into the lower troposphere, the surface and even below the surface of a planet or moon in order to maintain the current temperatures. In general, radiation from a colder atmosphere cannot actually add net thermal energy to a warmer surface and thus contribute to raising its temperature, because that would decrease entropy. This is established by the Second Law of Thermodynamics.

(4) The original NASA net energy budgets for Earth did not show radiative energy transfers by the atmosphere to the surface, but they then found that the radiation from the Sun alone does not explain the mean surface temperature when using Stefan-Boltzmann calculations. Such calculations are inappropriate anyway, because what is effectively "the surface" is a very thin layer (let's say 1cm thick) and about 70% of this thin 1cm layer is transparent water. A black or gray body is not transparent by definition, and so S-B should not be applied to a thin 1cm layer of transparent water. The mean temperature of the ocean thermocline (all of which is absorbing the solar radiation but not back radiation) is about 8 to 10 degrees below the mean surface temperature.

(5) Whilst for Earth climatologists and IPCC authors then claimed to overcome this shortage of direct solar radiation by adding back radiation, you cannot possibly imagine that this would "work out" on Venus. Such back radiation cannot participate in any raising of the temperature of the Venus surface and, even if you think it could, you would have to explain how it could be over 16,000 watts per square meter, somehow multiplying the energy in the incident solar radiation (20 watts per square meter at the surface) by nearly 1,000-fold. If you shine a light such that it reflects multiple times between parallel mirrors, do you create more energy? That is what the radiative greenhouse conjecture is implying can happen with radiation back and forth between the surface and the atmosphere.

(6) Between the base of the nominal Uranus troposphere and the TOA there is a mean thermal gradient which is very close to the usual calculated value (for the "Dry adiabatic lapse rate") which is the negative quotient of the acceleration due to gravity and the weighted mean specific heat of the gases. On Venus (as on Earth) the effective (environmental) lapse rate (thermal gradient) is reduced by about 25% to 35% by inter-molecular radiation between carbon dioxide molecules on Venus, and water molecules on Earth, together with some release of latent heat on Earth which may play a small part in producing the "wet adiabatic lapse rate" though not the major part. So, why is it so? Is it just a coincidence that the base of the nominal Uranus troposphere is 320K (hotter than Earth's surface) which is just the right amount for the correct thermal gradient to exist in the 350Km of troposphere above, such that the temperature at the so-called radiating altitude is just right at around 60K? Likewise on Venus and other planets?

Douglas Cotton (talk) 00:16, 2 April 2014 (UTC)

SUMMARY of DISPUTE regarding VENUS article:

Fact 1: The temperature of the Venus surface (and its troposphere) rise by about 5 degrees (from 732K to 737K) during the course of its four-month-long day. There is cooling of about 5 degrees at night, so Venus could easily have cooled right down but for new energy that must be coming from the Sun.

Fact 2: As determined from measurements made by Russian probes dropped to the surface of Venus, the mean incident solar radiation reaching the surface is less than 20 watts per square meter, because the CO₂ absorbs most incident solar radiation and radiates energy back to space.

Fact 3: If one applies Stefan-Boltzmann calculations for 732K and 737K the difference is about 450 watts per square meter, and so it cannot be direct solar radiation or radiation from the colder atmosphere which is supplying the extra energy into the surface that would be required to raise the surface temperature by 5 degrees.

Hence there is no radiative greenhouse effect on Venus which can be explained with any valid energy budget and corresponding Stefan-Boltzmann calculations. (There is a totally different and valid explanation based on standard physics and supported by evidence such as in the Ranque-Hilsch vortex tube but this is not the issue in this dispute.)

Douglas Cotton (talk) 23:20, 1 April 2014 (UTC)

Douglas Cotton (talk) 22:51, 1 April 2014 (UTC)

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