From The Reference Frame by Luboš Motl
Five days ago, Stephen Hawking – or someone who has hacked his computerized speech generator – has told us that Donald Trump is a supervillain who will transform the Earth to another Venus with temperatures at 250 °C and sulfuric acid rains.
Wow. Now, every intelligent 10-year-old kid must know why this possibility is non-existent, why the statement is nonsense. Some scientists including Roy Spencer have pointed out how absurd these Hawking’s statements were from a scientific viewpoint.
But lots of the scientists who have paid lip service to the lies about the so-called global warming or climate change in the past have remained silent and confirmed that their scientific dishonesty has no limits. I despise all the climate alarmists who know that statements like that are absurd but who hide this fact because a lie like that could be helpful for their profits or political causes. You know, what these jerks and the people who tolerate these jerks’ existence haven’t quite appreciated is that it is only lies that may be helpful for them.
Now, there are exceptions. Zeke Hausfather, a US Berkeley climatologist, has been an alarmist but he has pointed out that he realizes that Hawking’s statement is just junk:
A good example that even brilliant scientists sometimes say silly things when it’s outside their field of expertise (see Nobel disease) https://t.co/QPsmB1bsv0
— Zeke Hausfather (@hausfath) July 2, 2017
However, I disagree with Hausfather’s assertion that this statement by Hawking’s is outside Hawking’s field of expertise. It is some rather basic physics combined with the basic knowledge of the outer space that should be known to 10-year-old boys who attend physics lectures at the elementary school. It isn’t or shouldn’t be outside Stephen Hawking’s expertise because Hawking is a physicist and one who has studied the outer space. I think it’s right to say that Stephen Hawking has shown a rudimentary ignorance about his field, physics.
A reader has asked me “why Venus is special”. But Venus isn’t special in any general sense. Or if we said that Venus is special, almost every planet would be special. A more sensible assertion is that every planet is completely different. It has a completely different chemistry than others. It has a completely different temperature than others, mostly due to the completely different distance from the Sun.
I really think that it’s a shame that kids and even adults don’t reliably know these basic things.
First, look at the distances of the planets from the Sun, e.g. in this table. Mercury, Venus, and Mars have 38%, 73%, and 152% of the Earth’s distance while Neptune, the most distant planet from the Sun, has 3,000% of the Earth’s distance.
Planets are just rocks that ended up there. But the positions have consequences. The greater the distance is, the cooler the planet will be, at least approximately. Why? Because the amount of solar radiation per unit area goes down as 1/R2<?XML:NAMESPACE PREFIX = “[default] http://www.w3.org/1998/Math/MathML” NS = “http://www.w3.org/1998/Math/MathML” />1/R2 . This incoming radiation has to be equal to the outgoing one which scales like σT4σT4 where TT is the absolute temperature of the planetary surface (i.e. temperature in kelvins). I am neglecting albedo and greenhouse effects and other details. You may see that T∼1/R−−√T∼1/R .
So Venus whose distance from the Sun is 0.73 times greater than the Earth’s (“kk times greater” means “smaller” for k<1k<1 ) should have the temperature that is 1/0.73−−−−√∼1.171/0.73∼1.17 times the Earth’s. If the albedo and greenhouse effect were the same, that would be 1.17×288=3361.17×288=336 kelvins or so. That would be 63 °C or so on the surface and Venus could be a bit warmer but habitable. But the composition of the atmosphere and the albedo etc. are different so Venus ends up much higher than that, well above the boiling point of water. Due to the chemistry and the greenhouse effects etc. that result from it, it’s largely unavoidable.
That’s why we say Venus is barely out of the habitable zone. People usually conclude that Mars is barely inside the habitable zone. The habitable zone is the region of the parameter space, mostly but not necessarily only as a function of the distance from the Sun or another star, where liquid water survives on the surface. Water is good for life.
While Earth and Venus may look like siblings (the radii and distances from the Sun are comparable) and they’re sometimes described in this way, they differ in all the details – especially chemistry – dramatically. In particular, the atmosphere of Venus is almost 100 times denser. Around 95% of it is carbon dioxide so the total mass of Venus’ carbon dioxide is almost 200,000 times greater than the mass of carbon dioxide in the Earth’s atmosphere. There’s just no way to pump this much CO2 into the Earth’s atmosphere because there’s not enough burnable carbon we could access in any imaginable way. At most, if we tried really hard, we could perhaps quintuple the CO2 concentration in the air – which would be a good thing for life on Earth and our economies – but it would be extremely difficult.
Again, the extra greenhouse effect on Venus that adds over 100 °C to the planetary temperature results from the amount of CO2 that is almost 200,000 times greater than that on Earth. Even if we double the CO2 in the atmosphere relatively to now, the ratio would still be almost 100,000. Note that the greenhouse effect due to CO2 on Earth contributes of order several °C so it is significantly greater than the 1/200,000 times the greenhouse effect from CO2 on Venus. It’s because the dependence isn’t linear. It’s sublinear, approximately logarithmic. The more greenhouse gas you have, the less another molecule matters.
If you have never studied the diverse temperatures of the Sun’s eight planets, you are encouraged to spend at least minutes by looking at the Wikipedia pages about these atmospheres:
Mercury: hydrogen, helium, oxygen, sodium, …
Venus: carbon dioxide, nitrogen, sulfur dioxide, argon …
Earth: nitrogen, oxygen, argon, water vapor, …
Mars: carbon dioxide, argon, nitrogen, …
Jupiter: hydrogen, helium, methane, ammonia, …
Saturn: hydrogen, helium, traces of volatiles, …
Uranus: hydrogen, helium, water, ammonia, methane, …
Neptune: hydrogen, helium, methane, …
You see that there are numerous planets – both the distant ones as well as Mercury, the closest one to the Sun (it may be surprising to get it at both extremes) – whose atmospheres are dominated by hydrogen followed by helium – it’s like the early elements in the Cosmos. But the precise compositions are totally different, the following trace elements are different, and the overall pressures of the atmospheres differ by many orders of magnitude.
Read the complete article here.
Venus could have a 100% krypton atmosphere and it would still be the same inferno it is with 96% CO2. From Chapter 3 of my new book on amazon, “In Praise of Carbon”:
3. Venus and Mars
A Pressing Matter
(photo)
The dead planet Venus, shown above left with-out its dense atmosphere in this composite photograph of Venus, Earth, and Mars, is often held up as a poster child for “runaway” greenhouse warming. The average surface temperature of Venus is 462 oC (735K or 864 oF), the highest in the Solar System, surpassing even the hottest spot on Mercury’s midday equator by 35 oC even though Mercury is almost twice as close to Sun as Venus. Whereas Mercury has almost no atmosphere, Venus has a thick atmosphere of almost pure carbon dioxide—96.5 percent—the remaining 3.5 percent being volcanic nitrogen.
The presence of this dense carbon dioxide atmosphere on super-hot Venus has been taken as prima facie evidence that a runaway greenhouse effect is at work on that planet, but in fact it shows nothing of the kind.
To understand this, there are a few other things on the planet Venus that must be taken into account, but that usually aren’t considered in the rush to identify greenhouse conditions there. The first of these is atmospheric pressure at the surface, which is an astonishing 92 bars, or 92 times the pressure of Earth’s surface at-mosphere. There is a well-established relationship between the pressure and the temperature of gases, no matter what kind they are. That relationship is known as Gay-Lussac’s Law, which states that:
P1/T1 = P2/T2
in which P is pressure in some chosen unit, and T is the absolute, or Kelvin, temperature. If P1 is taken to be the pressure of Earth’s atmosphere in bars; T1 is Earth’s temperature of 288 K (interestingly, Earth and Venus have about the same ideal temperature, largely because of Venus’s higher albedo, or reflectivity, which causes it to receive less of Sun’s radiation than it otherwise would, even though it is much closer to Sun than Earth); and P2 and T2 are the equivalent values on Venus, then T2 = T1P2/P1 = 288×92/1 = 26,496 K, or 36 times Venus’s actual surface temperature of 735K and almost five times the temperature of Sun’s surface! Thus, the nearly hundredfold greater pressure alone in Venus’s atmosphere should be sufficient to produce a surface temperature that is much greater than Earth’s.
Using the Arrhenius formula, which specifies a rise of between 4 and 8 oC for each dou-bling of CO2, then Venus’s 96.5 percent CO2 atmosphere should have a temperature equal to Earth’s surface temperature of 288 K plus 18 doublings of 400 ppm (the present concentration of CO2 in Earth’s atmosphere) times (4 to 8K) = 360 to 432K.
So, by Gay Lussac’s Law, the surface of Venus is far colder than it should be, and by the Arrhenius formula, it is three to four hundred K hotter than it should be. What can we tell from this? The answer: absolutely nothing. Looking first at the Gay-Lussac effect, the reason why Venus’s surface temperature is way below what this law predicts it would be is that the atmosphere of Venus is not a confined system. Atmospheric gases are mobile and free to circulate, and as soon as Sun heats up the surface gas, the gas expands, becomes lighter, and rises to higher levels in the atmosphere, where the pressure is much lower, which cools the gas to a temperature far below what it would attain if it were locked in place at the surface. This buoyant rise is the start of the great winds that are known to whip across the face of Venus with constant ferocity.
davidbennettlaing July 10, 2017 at 11:42 am
There is a well-established relationship between the pressure and the temperature of gases, no matter what kind they are. That relationship is known as Gay-Lussac’s Law, which states that:
P1/T1 = P2/T2
You left out the relevant condition: if the mass and volume of the gas are held constant
It also applies to an Ideal gas which CO2 near the surface of Venus certainly is not.
Tx! The atmosphere near the surface of Venus is obviously confined by the overlying layers. The fact that this is a less than effective seal is revealed by the high winds and much lower temperatures than would be expected from the condition of constant mass and volume. The fact that high pressure renders the surface CO2 very non-ideal certainly also contributes to a lower temperature than predicted by the equation.
Prof. Hawking just had an unpleasant dream
“In a deep sleep with a grave nightmare
In which he sees horrifying visions,
That can hardly be defined
Wishing not to see his being in
In his mind a thought came
He has freed himself from this vision;
Ah, but in spite of his most fervent hope
He then sunk himself deep
In the realm of the kingdom of darkness
Sliding down the vista of horrible dreams.”
Apt words of a bishop and ruler of Monte Negro written in 1845, translation may not be perfect, but you may get the idea.
I don’t think Hawking even has the ability to type on his keyboard anymore (for quite some time). So EVERYTHING you hear is done by his handlers, either by “interpreting” Hawking somehow or simply creating it themselves. I think it’s the latter, and if so, it’s a deplorable exploitation of Hawking.
‘A good example that even brilliant scientists sometimes say silly things when it’s outside their field of expertise.’
THANK YOU.
I’ve tried to impress upon people who immediately accede knowledge, and therefore authority, to someone whose profession defines them as a ‘scientist’, that knowledge about one thing does not mean knowledge about anything else. It doesn’t even necessarily mean ‘smart’, ‘intelligent’, and certainly not ‘sensible’.
Often, in fact, specializing tends to minimize collateral awareness.
VENUS:
We don’t live there, there are no humans on it, we do not have years worth of CET temperature date, we do not have analysis of ice cores, tree rings,temperatures of buckets of sea water, etc. We have VERY LITTLE data on VENUS.
But that very little data is MORE THAN ENOUGH to understand the Greenhouse Gas Effect of CO2. Some of the above comments in this thread are 100% correct and some are 100% wrong. Some have an interesting mix of BS and Spot-on Science. I am NOT going to tell you which is which, you need to fire up your own torch and shine it by yourself.
This is not difficult. It is an exercise in relatively simple physical concepts and application of logic. Please, if you have the time and inclination, do the work yourself. Sit down with your paper pencil and calculator and go through it all bit by bit. You know what the AGW/GHG claims are, simply do the calculations and apply them to Venus. Carefully, bit by bit. Make sure each step is 100% logical and consistent.
Good luck with it.
When you are done you will know who is who in this space. You will know which websites and blogs are the REAL science & which are the PRETENDERS. I am not giving you any clues or hints. This really is something you have to do for yourselves.
I honestly think that the person that we know as “Stephen Hawking” is fully incapacitated and acts like a ventriloquest’s dummy to “speak” whatever his left-wing, globalist handlers from Cambridge want him to say.
I am not quite happy with this article, as it misses out on the most relevant subjects. For the sake of comparison, the temperatures on Jupiter, Saturn, Uranus and Neptune are about 550K, 500K and 400-450K respectively at a pressure of 92bar.
So all of these gas giants, which are the only objects to have an atmosphere as “deep” or deeper than Venus, show extremely high temperatures at this pressure level. The physics hereto are well understood and without the slightest doubt, it has nothing to do with a “GHE”, but rather with the adiabatic lapse rate. So how should Venus make an exception from physics and suddenly have a “GHE”?
Also gas giants teach us on the utmost relevant question. What is the surface? We do not have one on a gas giant. Well we can have a beaurocratic answer to it, and say it is were the atmosphere holds the pressure one bar. But it is quite irrelevant.
In reality, the incidental pressence of a firm surface, is just as irrelevant. What matters, is rather the location of radial exchange, which again may span over a certain region of the atmosphere. Or may be limited just to the firm surface, in case there is no atmosphere.
But when we talk of surface temperatures, we must be clear on this subject. Only then, we will finally understand, how 740K or so “surface temperature” on Venus is just irrelevant as the 20.000K it may have around the core Jupiter.
And then, there is another important thing to understand. Clouds will effectively move the surface upward into the atmosphere, heating all what is underneath by the adiabatic lapse rate. So clouds are the one most important “greenhouse factor”, on earth, but also on Venus. Pressure alone can not do it, as long as the atmosphere is widely transparent. And GHG ARE transparent und hardly interfere with radial exchange. So if one could remove the clouds on Venus, temperatures there would drop massively.
“What is the surface? We do not have one on a gas giant.”
The surface on a gas giant like any star, is where the furthest matter away from the core is uniformly connected to the rest.
Albedo is what matters. While Venus is closer and receives twice the w/m2 a 70% albedo means the atmos gets fewer w/m2 than the earth. 2.5 times thicker and half the conductivity and POW 2.6 times the dT to move the energy back to ToA. No RGHE hocus pocus needed.
Pressure is by far the most important part and why Jupiter has temperatures away from it’s surface easily exceeding the surface of the sun. The alarmists have been hugely wrong by this for ages and keep bringing this lie up that it has either little influence or ignore it completely. Albedo of course play it’s part, but the denser the object, the more energy confined to much smaller spaces. Think of it like heat retention of the oceans, but on a much bigger scale. If water could for example retain 92 times more energy per m3 compared to now we would not be alive. (this would be the case also much smaller)
“At the pressure level of 10 bars (1 MPa), the temperature is around 340 K (67 °C; 152 °F). At the phase transition region where hydrogen—heated beyond its critical point—becomes metallic, it is calculated the temperature is 10,000 K (9,700 °C; 17,500 °F) and the pressure is 200 GPa. The temperature at the core boundary is estimated to be 36,000 K (35,700 °C; 64,300 °F) and the interior pressure is roughly 3,000–4,500 GPa”
https://en.wikipedia.org/wiki/Jupiter
Your rant is almost as silly as Hawking’s statements. I’m old enough to remember watching a tv broadcast in which Carl Sagan, the epitome of the orthodox “scientist”, predicted with complete certainty, prior to the arrival of the first Venus space probe, that Venus would have a cold atmosphere, because its clouds blocked the suns rays. He particularly scoffed at the predictions made by Emmanuel Velikovsky that Venus would have a very hot atmosphere consisting of hydrocarbons, due to its being a hot body ejected by Jupiter that had only recently settled into its orbit after multiple close encounters with Earth and Mars (as described in Worlds in Collision, Earth in Upheaval, and Ages in Chaos).
Of course Velikovsky never got credit. Orthodoxy quickly forgets its gaffes and just says “knew it all along”.
Lets not forget the pressure at Venus’s surface is 93 bar. That is enough to explain why it is hotter. A diesel engine compression is 16 bar.
Correction 35 bar (or atmospheres) http://www.ncert.nic.in/html/learning_basket/energy10class/combustion%20engine1.htm
Pressure does not “cause” temperature except in closed system which atmospheres are not. Pressure leads to density which increases thermal resistance which increases the dT required to move energy from hot/high energy “surface” (which not always the ground) and cold/low energy ToA. ToA is where molecules and U A dT stop and S-B radiative balance start. For earth NASA says 100 km & I say 32.
Wrong, a closed system is irrelevant. We as in humans have to create a closed system to increase pressure, as it’s our only way. Nature increases pressure using matter that we can’t replicate because it needs to be so massive. Temperatures increase with more pressure whether in a open or closed system and atmospheres of planets or stars are examples of this. There would be no lapse rate if pressure had no influence with temperature.
Pressure leads to increased density that makes convection that much more difficult. Making convection increasingly difficult doesn’t need a closed system and atmospheres and stars confirm this.
“At the pressure level of 10 bars (1 MPa), the temperature is around 340 K (67 °C; 152 °F)”
Not in a closed system, so why is Jupiter at 10 bars warmer than Earth at 1 bar when albebo is higher and further away from the sun?
If the words were really uttered by the man himself then I mourn the passing of a great intellect. He has forsaken true science and common sense for idiotic alarmism and post normal activism. What a damn shame.
If only he walked up a mountain to realise it gets colder with altitude. Then taken down to huge depths and left to wonder why the lowest places on Earth are the hottest.
It might lend him a basic idea how stars get hot enough to start a fission reaction when compressed from as low as 4 Kelvin in open space.
He might have a brilliant notion this is why the ground temperature of Venus is so high.