Why is Venus so hot?

Continuing in the correct tradition, Venus is hot MOSTLY due to geothermal reasons – and NASA knows it.

https://www.nas.nasa.gov/SC13/assets/images/content/33_Smrekar_S_Figure7_SC13_big.jpg

Duh!

No stupid runaway greenfraud effect necessary.

-Zoe

This article is dedicated to Hans Schreuder, R.I.P.

Update – 2020/01/14

Somebody complained that NASA’s diagram shows geothermal as being a little over 500K, which is not enough for Venus.

This has no credibility. Here is a zoom-in of the diagram:

Treating the 500 marking as pixel 0, the 2500 marking appears at pixel 546. This means that each pixel represents 2000 / 546 = 3.663 Kelvin

The center of the dark black geothermal line falls at pixel 65.

500 + 65 * 3.663 = 738.095

According to NASA, Venus’ surface is: 737K

27 thoughts on “Why is Venus so hot?

  1. As in, outgoing radiation. I don’t care too much how much radiation is bounced around, absorbed, whatever. At the end of the day, how much is getting out? If it is significantly less than 16000, say, 10000, then how can that be explained?

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    1. Venus appears colder than Earth from space.

      Sun is theorized to be a gas. So why can’t we see emission from the 15,000,000K degree core? Why we get only 5778K? Same reason.

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      1. “If it is significantly less than 16000, say, 10000, then how can that be explained?”
        “Why we get only 5778K (out of 1.5e7 K)? Same reason.”
        And that is?

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      2. Dissipation of the Sun’s fusion is mostly via the strong and weak interactions, not electromagnetic – i.e., the emission of particles, not radiation.

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  2. This is part of the answer. Venusian clouds are sulfuric acid, the cloud droplets will coalesce, fall to the surface, and decompose by the volcanic heat to sulfur dioxide and water; the dioxide will oxidize to the trioxide by dust in the atmosphere, combine with water, with the release of an immense amount of heat. In this manner, volcanic heat becomes a permanent part of the Venusian atmosphere. The clouds are certainly not a static thing, they are continually formed and decompose. All of the free energy changes to this sequence are favorable at the T and P of Venus.

    Hansen wouldn’t think of it because he wasn’t a chemist.

    Liked by 1 person

    1. This is the full answer. I have searched the journals for diurnal changes at the surface. There is none. A few kilometers up, there is a little bit. This suggests to me that the surface is entirely geothermally controlled.

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        1. Just a brief thought without much time going over any math or physical theory. So please cut me some slack.

          Because I am not as smart as you guys let me go through my thought process and work things out. Again, if you see a problem, please point it out.

          Let me begin by looking at the word temperature. I was always taught that this meant some measure of the warmth or coldness of something in reference to some standard value. That value is usually determined by a process like the freezing of water at a particular pressure.

          But this does not tell me very much. When you say that the atmosphere is ‘hot’ you are referring to the kinetic motion of the atoms that make up that atmosphere. But ‘hot’ compared to what? Note the need for a proper comparison here. The Earth’s atmosphere is not very impressive when compared to what we see on Venus. To get the same pressure on Earth as we have on the surface of Venus we need to be up around 50 to 60 km. Given that Venus is closer to the sun, I would expect that it would be heated more than Earth. But given those white sulfuric acid clouds, I doubt that any of the sunshine gets all that close to the surface.

          It seems to me that we need to figure out what the temperature of Venus is at altitudes where it approximates terrestrial surface pressures. We then need to go to the surface and imagine what terrestrial temperatures would be if the atmosphere were the same thickness. Sorry but I don’t see the Venus hype as much more than that; hype.

          What did I miss?

          Liked by 1 person

        2. There is indeed a link between pressure and temperature, but the cause is temperature to pressure. Gravitational Pressure is counterbalanced by Atmospheric Pressure – which is an outward force caused by kinetic energy (Temperature).

          Pressure itself can only raise temperature once. Gravity wants to crush all the molecules to the surface, but Temperature (kinetic energy) won’t let it.

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  3. Zoe, Venus is one strange place. I get the geothermal temperature of the surface of Venus. The gas laws also give approximately the same temperature. I assume that the think atmosphere on Venus is due to previous volcanic activity. While the slow rotation of Venus doesn’t produce a magnetic field, there is a magnetic field from the interaction of the upper atmosphere with the solar wind. Gravity on Venus is about the same on the Earth. Gravity working on the relatively heavy CO2 molecules allows Venus to keep much of its atmosphere despite a weak magnetic field. While most of the sunlight striking Venus doesn’t make it to the surface, some does. I am surprised that there doesn’t seem to be a role of the sun in determining the surface temperature. I am always puzzled when I see people explain that Venus is hot due to a strong greenhouse effect.

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    1. Venus is a new planet, so it defies NASA creation myths. Some of us think that these planets can come from huge comets, and the act of a huge comet breaking into the inner solar system will tend to create a lot of heat energy.

      If you look at comets you see all these extra neutrons in the the atoms of the entourage, that is dragging behind them. The oxygens will have these extra neutrons, there is deuterium in the water vapour, the carbon atoms will be highly isotopic, and if we could look at the rocks flying behind that nucleus we can expect all this helium 3 and other isotopes of metals on the surface of these rocks.

      So when this is all amalgamated together, in a new planet, then there is likely to be a lot of heat, and a great deal of heat creation, within the centre of the new planet. But if you accept the NASA dust amalgamation creation myths, then you are unlikely to give the new planet story a fair go.

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    2. Gas Laws:

      https://en.m.wikipedia.org/wiki/Gay-Lussac%27s_law

      “Gay-Lussac’s law states that the pressure of a given mass of gas varies directly with the absolute temperature of the gas”

      https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Book%3A_Introductory_Chemistry_(CK-12)/14%3A_The_Behavior_of_Gases/14.05%3A_Gay-Lussac's_Law

      “Gay-Lussac’s Law states that the pressure of a given mass of gas varies directly with the absolute temperature of the gas”

      All 3 sources say that P is dependant on T, not vice versa.

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      1. Zoe, while all of these laws hold under various conditions, the atmosphere of a planet is tricky. None of these laws explicitly deal with gravity. Why? Because they were developed by observing properties of gas in laboratory conditions. If you fix the volume, the pressure obviously increases when you increase temperature. Increased temperature is nothing more than increased motion and increased motion causes greater hits to the side of the container increasing pressure. Pressure is nothing more that the number of molecules hitting the pressure gauge.

        The atmosphere of a planet is tricky as you know. You have to consider gravity that increases pressures the closer you are to the surface, which in turn increases temperatures. The 3 sources you cite for P being dependent on T don’t generalize to the atmosphere where autocompression is at work. The set up for Gay-Lassac’s law leaves only temperature as a way to effect pressure.

        Whats interesting about the ideal gas law and combined gas law are that they include V, T and P. This is why they have some use in describing temperatures we observe on planets with atmospheric pressures above some minimal amount. A planet without an atmosphere with mass has little surface pressure. Why? There is no mass for autocompression from gravity to work on.

        Getting back to Venus. If the atmosphere of Venus was blown away, the surface temperature would not stay the same. The surface on the dark side would drop. THe geothermic gradient would still be at work, but the cold from space would drive surface temperature well below what the current thermal gradient shows. Much like in winter where the temperature can be well below freezing for several feet below the surface. The frost line changes with latitude, getting deeper the further north you go. Even so, you don’t have to go under very far until the geothermal forces dominate. I have done a lot of caving in WVA. In the coldest days of winter, you still get nice 55 degree temperature once you down a cave like Senate.

        While I think we basically agree, I don’t think the gas laws that just have 2 of P,V and T are much use for understanding temperatures on a planet with an atmosphere that can expand and contract. To me, the biggest failure of the CO2 crowd is to ignore convective forces, which dominate heat transfer in the Troposphere. By the same reasoning, I find that models that use averages for insolation worthless. The convective forces are unleased by differential radiative effects by latitude combined with the spinning earth that causes longitudinal differences at the same time. The surface at the equator receives about 800 w/M^2 at noon from the sun and none at night. Hadley Cells, Ferrell cells, jet streams, trade winds , EPO, WPO, NAO, ENSO, the various ocean current are all a result. The few watts per meter squared from doubled CO2 are at best 3rd order effects in this world.

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      2. Careful. Venus has a huge amount of gas in its atmosphere and T varies by altitude. We need to compare temperatures at the same pressure so we get the same values for both the Earth and Venus. Give the Earth the same number of molecules in its atmosphere and the temperature at the surface would be similar. There is a lot of complexity to sort through and most of the smart people here have a tendency to underestimate all of the factors that need to be accounted for.

        ______

        “Gay-Lussac’s law states that the pressure of a given mass of gas varies directly with the absolute temperature of the gas”

        Venus has a great deal more mass of gas than Earth.

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        1. That begs the question. Why does Venus have a thick atmosphere? Because it’s hotter.

          You just stated Gay-Lussac’s Law. It specifically tells you causation: Temperature -> Pressure, and not vice versa.

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      3. They are interdependent. T is most certainly dependent on P. If you compress a gas, its temperature will rise. If you expand a gas, its temperature will fall. This is taught in 1st semester chemistry.

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  4. “If the atmosphere of Venus was blown away, the surface temperature would not stay the same. The surface on the dark side would drop.”

    Supposing that only some of the atmosphere was blown away. And that Venus was left with an atmosphere not too much thicker than earths. Its still going to take a very long time for Venus to cool down. Being heated from the inside out. Sure the massive atmosphere slows the process. But its still going to be a slow process.

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    1. Yes. Hard to know what to make of that exactly. We may wish to be comparing the moons of Saturn and Jupiter and see what the comparisons will yield. Although even there we have complications. Both Jupiter and Saturn have a proton wind. When I see that I assume electrical transfer and these two will be producers of light radiation as well.

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