Venus temperature

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19 years 11 months ago #12070 by tvanflandern
<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by EBTX</i>
<br />I read (in WIRED magazine or maybe Popular Science) that the heat emitted by Venus is 17 times greater than what it receives from the sun.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">The net heat flux from Venus is difficult to measure and has long remained uncertain. I have not seen any widely accepted or independently confirmed value. But a factor of 17 seems well outside the range of all data I've heard of.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">The writer went on to state that this is the effect of global warming on Venus due to greenhouse gases.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">The greenhouse effect is the usual explanation for why Venus is so warm (trapping of heat by CO2 in its atmosphere). That model assumes thermal equilibrium, and has nothing to do with excess heat flow.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Obviously, that would be nonsense as stated because it constitutes a thermodynamic impossibility. Venus (or any other body) can't radiate more energy than it receives.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Surprisingly, excess heat flow is the norm, not the exception. The gas giants Jupiter through Neptune all have excess heat flows up to a factor of two or so. The only other reliable heat flow numbers are for the relatively small bodies Earth and Moon, and the heat outflow exceeds the arriving solar heat by just a tiny fraction.

The reason why is not well understood, but is usually attributed to heat from internal radioactivity (e.g., decay of uranium near the core, etc.). But excess heat flow is obviously the norm for most visible astrophysical bodies, which are the stars and supposedly radiate from internal thermonuclear fusion. I've mentioned meteoritic heating as another possible contributor to heat flows in large planets.

But it may be that absorption of gravitons is a major source of heat for all these bodies. This mechanism and a table of observed heat flows appears in my chapter in <i>Pushing Gravity</i>. -|Tom|-

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19 years 11 months ago #11815 by Jim
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This topic has not been explained as yet by science. The fact is all planets radiate much more energy than they receive from outside sources. The Venus energy balance is a small mater compared the the energy balance of Earth. The Earth radiates at a temperature of 288k and the solar income is only about 250 watts per square meter which would mean the Earth should radiate at ~235k. The extra energy needed to cause Earth to radiate as it does has to come from the mantle and yet everyone will tell you the mantle flux is a few milliwatts. Go figure that one! And then they tell us greenhouse gases cause the Earth to be warmer. It is nuts.

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19 years 11 months ago #11817 by Leland
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I’ve never fully understood the details on this topic but it seems to me that the contribution of gravity pressure on the atmosphere might be left out.? They way I understand how Jim has explained it is that heat measured at the ground is less than measured at altitude. Is this correct? If so the small amount that would occur in the air under pressure without any solar input or conduction from the ground may explain it. I have never considered it sensible that heat left over from the formation of the earth would at any time be a factor. These days I favor the earth and all bodies as growing (like everything else) just over a much longer time span. The more recent trend in science toward all things flowing (glass, solid rock and the human belly) may someday be all things growing as well.

Leland

There is only one kind of stuff!

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19 years 11 months ago #12003 by Jim
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Leland, My point about this detail about how planets are heated is that we are told the Earth(or Venus or Jupiter) receive energy from the sun and not from the interior of the planet. This is not true in my opinion the planets do in fact generate energy in some unknown manner. It is totally unacceptable to the established models that a planet can generate energy. To me this kind of faith in a model is as silly (and even more so since the people having faith in a BB or MM model are exalted) than belief in the Flat Earth model. The current belief system holds many false ideas about how stars and planets work. The people who believe have absolute faith they are right about these ideas. So, if it can be established that planets do in fact generate energy and we don't know how the energy is being produced then maybe some real progress can be made.

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19 years 11 months ago #11853 by GD
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Why not consider the position of matter in a system as being the cause of this radiation or heat ?

Venus, Earth and Mars are relatively the same size. Could their position in the solar system (apart from receiving the sun's influx of energy) be a cause.
Is this not why the center of the earth radiates more energy than at the surface ?

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19 years 11 months ago #11914 by Jim
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If the center of Earth radiates more energy than the surface where or how is the excess energy of the center being used? The surface radiates to space but the center radiates or conducts energy to the surface. And by the way that is how the suface stays warm-by getting enough energy from the interior to maintain an ideal temperature at the surface even as the energy is radiated into space. If there was no energy flux from the interior the surface of Earth would be about 240kelvin and frozen solid.

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