Why Is Venus So Hot?

“It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.”

Richard P. Feynman


About Tony Heller

Just having fun
This entry was posted in Uncategorized. Bookmark the permalink.

17 Responses to Why Is Venus So Hot?

  1. Disillusioned says:

    Excellent. Thank you Tony!

  2. Bob G says:

    I recently came across an interesting table which listed how many 90° days Minneapolis Minnesota has had every year going back to 1891. you would expect a trend towards more hot days even if it’s just caused by the growth of the Minneapolis Urban heat island. or maybe from the growth of CO2 which has gone up over 40% over that time period. but no, there were more 90° and above days in the first half of the historic record than the second half – the warmest Summer’s easily being in the 1930s. the politicians and the highly paid actors keep telling us we’re experiencing some kind of new climate calamity but the record says we are not. https://www.extremeweatherwatch.com/cities/minneapolis/yearly-days-of-90-degrees. FYI Minneapolis has had no 90° temps this year, so far, and none are in the June forecast

    • Conrad Ziefle says:

      Yeah, well, they haven’t been able to corrupt all of the temperature databases. Yes, one would expect that if the temperature were increasing (due to global warming), then 100F days should also be increasing, and 90F days should also be increasing. This is not absolutely necessary, but it is a pretty good hypothesis, one which for me doesn’t need to be scientifically verified. AND, when they say that the average global temperature is increasing, yet the data shows decreasing number of 90F and 100F days, I don’t think, “Oh my God” the mean temperature and all the temperatures one standard deviation above the mean are increasing, while those higher than that are decreasing. Instead, I think they are simply lying and doing a very bad job of it.

  3. Check out Nikolov and Zeller’s paper, in which they show, purely from empirical observation, that the radiative properties of the atmospheric gases have nothing to do with the surface temperature.

    The community still claims that gravitational compression does not determine surface temperature, which is curious because without it interstellar gas could never compress to initiate thermonuclear reactions. In other words, without gravitational compression, none of the stars would shine.

    The ‘debunk’ rests on the notion that the atmospheric gas rests in isothermal layers, and doesn’t circulate; which is arrant nonsense. The troposphere is characterised by circulation because it is impossible for gas to rest in stratified layers in a negative temperature gradient.

    The ideal gas equation can only be applied to a package of gas which is undergoing adiabatic expansion and compression as it circulates. The gas is circulating, ergo it is valid to apply the ideal gas equation.

    Is it coincidence that Hawking made his pronouncement after a visit to Epstein Island?

    • Just a minor point, the ideal gas equation is inaccurate at the extreme pressures at the Venusian surface, but remains valid qualitatively. Temperature does not depend on the equation of state, but is directly derivable from the First Law of Thermodynamics from the exchange of thermal and gravitational potential energy, independent of the ideal gas equation. The alarmists cannot tell the difference between enthalpy and internal energy, hence they confuse temperature with energy, amongst their many other failings.

  4. William says:

    I am unaware of any significant contributions to science made by Sagan. But he was the first celebrity “scientist” and therefore in a position to promote CO2 alarmism to the masses. Which he did with his preposterous “runaway greenhouse effect” science fiction nonsense. Repeated endlessly, it has been collectively internalized. In the final analysis he was a front man, a salesman, for the globalist agenda of dismantling civilization and reducing global population drastically. Hawking made his contributions but in the end couldn’t stand up to globalist power politics. Perhaps he was coerced. “They” play for keeps

  5. Conrad Ziefle says:

    The pressure on the surface of Venus is 80 atms, or about 1200 lbs/in^2. That’s the pressure at 2640 feet below the surface of the ocean. While the ideal gas law may not be accurate at that great a pressure, there are gas tables available, which have been verified experimentally, and show that adiabatic compression (without any heat being added) to those pressures yields very high temperatures.

  6. Peter Carroll says:

    Compare the surface temperatures of Venus and Mars. Both planets have an atmosphere of approximately 95% CO2. The mean surface temperature of Mars is -63C, with a mean surface atmospheric pressure of only 0.006 bar. (QED?)

  7. For adiabatic expansion, the First Law becomes:
    where p is pressure, u specific volume and u the internal energy. (CvdT) where Cv is the specific heat at constant volume and T absolute temperature.

    The enthalpy is the work done in a constant pressure expansion plus the internal energy,
    dh =pdv+vdp+du=vdp

    The pressure variation with height is given by the hydrostatic equation;
    dp=-g dz/v
    where g is the acceleration of gravity and z is the change of height during the flow process
    dh=-g dz
    The enthalpy may be made up of so called ‘sensible heat’ and latent heat of condensation. If the gas is dry, we have:
    dh=Cp dT=-g dz
    where Cp is the specific heat at constant pressure.
    This implies a temperature lapse rate of:

    The tropopause temperature of Venus is 204K, Cp is a function of temperature, but averages at about 900 J/kg K and g is 8.2 m/s/s so the lapse rate is 9.1 K/km. The troposphere depth is 60km, hence the surface temperature is: 204+60*9.1=750K

    The equation of state does not come into the calculation, but is needed to calculate density and pressure.

    Now the alarmist ‘debunk’ essentially claims dz=0, and the gas stays in stratified layers which is arrant nonsense.

    • Conrad Ziefle says:

      For those who don’t think in Kelvin, absolute temperature, 273 K is 0 C, or the freezing point of water. 204K us therefore -69C . Then at the surface of Venus, 750K is 477C or almost 5x the temperature of boiling water. In Fahrenheit, top and bottom temperatures are -92F and 890F, respectively. I believe that ideal gas laws vary with larger molecules and high pressures due to inter-molecular forces. I believe this is all accounted for in other equations, data, etc. developed to handle these situations, notably in the oil industry.

      • The ideal gas equation yields surface pressure which is about 20% greater than the observed value of 90 atmospheres, The van der Waals Equation, which takes account the volume taken up by the molecules and the attractive force between molecules is a lot better. However, the pressure gradient near the surface is also enormous, so the measured ‘surface pressure may vary significantly over the elevation of the landing sites.

  8. Allan Shelton says:

    Thanks Tony..
    An excellent video for everyone, no matter what your education level is.

  9. Solar Mutant Ninjaneer says:

    Actually, gravitational compression has only a minor impact on the lapse rate. This is because the atmosphere is not adiabatic. Just like the bicycle tire, the atmosphere after undergoing compression or expansion, will exchange heat with its surroundings. The atmosphere is not warmer towards the surface because it is at a higher pressure. If that were true, thermal inversions would not occur. The atmosphere is warmer towards the surface because of heat transfer. It is warmer at the bottom of the Grand Canyon because there is more atmospheric insulation between the bottom (where solar flux is thermalized) and the cold sink of space than at the rim.

    The surface temperature of Venus is high because of its thick atmospheric insulation, something like 80 times that of Earth. In addition, Venus does not have two-phase heat transfer like on Earth. Water evaporated at earth’s surface is transported to the upper troposphere, where it condenses liberating the heat of condensation. This two-phase convective heat transfer is responsible for nearly half of the heat transferred between earth’s surface and the top of the atmosphere where it is radiated to space. Venus has nothing like that.

    BTW climate models fail to properly account for convective transfer. Any warming from increased CO2 concentrations in the atmosphere will be mitigated by increased convection as well as increased surface radiation. This omission results in overestimating CO2 driven equilibrium climate sensitivity by more than a factor of two.

  10. Jay Owens says:

    As Heller should know the ideal gas law is an approximation of the behavior of real gases. At the surface of Venus (460 oC, 92 bar) a far better (though still not exact) equation would be the van der Waals equation.

    We do need real scientists. On that we agree. Having said that, it is the experts on climate science whose opinion should carry more weight. Most of those experts believe the current warming is real, and most believe it is primarily anthropogenic. While questions of science are not decided by vote, it is generally better to believe the consensus opinion of experts in a field rather than fringe beliefs. When those beliefs are offered up by those who don’t publish research in recognized scientific journals my level of skepticism increases.

    A good place to go concerning the beliefs of working climate scientists is the paper by Stenhouse and coworkers, appearing in the Journal of the American Meteorological Society (2014). In their discussion section they state the following: “Our findings regarding the degree of consensus about human-caused climate change among the most expert meteorologists are similar to those of Doran and Zimmerman (2009): 93% of actively publishing climate scientists indicated they are convinced that humans have contributed to global warming. Our findings also revealed that majorities of experts view human activity as the primary cause of recent climate change: 78% of climate experts actively publishing on climate change, 73% of all people actively publishing on climate change, and 62% of active publishers who mostly do not publish on climate change. These results, together with those of other similar studies, suggest high levels of expert consensus about human-caused climate change (Farnsworth and Lichter 2012; Bray 2010).”

Leave a Reply

Your email address will not be published. Required fields are marked *