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.
Give Stephen Hawking a break. He’s old and sick.
That is not an excuse. He pronouncements carry weight is some circles and if they are nonsensical they need to be countered.
They played his “voice” on CNN, and they took it as Gospel – didn’t dispute his claim…
CNN is the only news channel I get here in Mexico on Dish network.
I have to go to USTVNOW to get other US news channels on my laptop…
he is one of 10 in “dire need of a blow job than any white man in history.”
Hawking should keep his mouth shut about subjects that he knows nothing about. He should stick to his silly theoretical nonsense that got him further than he deserved to go.
I believe he’s probably on the payroll as a “consultant” to the BBC, The Guardian, etc. Everyone needs money, and CAGW “precautionary principles” are seen as a harmless, politically correct virtue-stance.
It’s up to the “journalists” to determine the credibility of their sources. Unfortunately, Hawking has not been the same man for the past few years and the not-so-bright have not caught on to this yet.
‘That is not an excuse. He pronouncements carry weight is some circles and if they are nonsensical they need to be countered.’
I agree. He has become one of the Progressive Left’s ‘characters’ – the ‘super-smart guy’ who knows everything. AND the victim of a debilitating ailment, and therefore immune from criticism.
As Lubos will tell you, this comment is about in line with his recent history of science papers. I suspect he has an undiagnosed condition because he has lost much of his basic physics knowledge. I think after one paper he described him as a “silly old fool in a wheelchair” because it was so flawed.
What’s that old saying “Better to say nothing and be thought a fool than to say something and prove it”! Of course he is known to be handicapped, and I’m sure we all sympathise, but such idiotic statements should not be allowed to persist just because of that. Some people might actually believe him – probably those of a green hue!
Every wrong public statement should be corrected. I just say give “him” a break. There is no point in attacking an old handicapped brilliant scientists. I didn’t like it when I have seen it done to Freeman Dyson or other skeptic old scientists, and I don’t like it either for Hawking. Being wrong is also a right.
Is Hawking brilliant?
He’s famous for “Hawking” radiation, for the existence of which hypothetical phenomenon he provided a theoretical argument in 1974. But Hawking got the idea from Mexican-Israeli theoretical physicist Bekenstein, Belarussian physicist Zeldovich and his Russian student, astrophysicist and cosmologist Starobinsky.
Despite more than 40 years of looking for it, “Hawking” radiation has yet to be definitely detected.
Gabro, very good point. I’ve often wondered why in the H**l anyone believes he’s exceptionally “brilliant”. A smart man, yes.
Eck,
His affliction gained him notoriety.
IMO, he wouldn’t make it on any legitimate list of the Top Twenty British Physicists, let alone world. Maybe not even English, depending upon whether scientists born abroad, like Rutherford, are allowed.
Then there are definitional questions. Do physical chemists count? Astrophysicists? I guess Hawking himself might count as one of the latter.
He’s definitely not on the British Top Ten list. Most here could probably name those guys, and they are all guys.
After he goes to his reward, his memory will fade. More of a scientific celebrity than an important scientist.
Then there is always the issue of applied vs. basic science. And of place of birth and place of work, ie do applied physicists Marconi and A. G. Bell count as British?
IMO Watson-Watt, pioneer of RDF and radar, deserves a spot on the Top Ten list. He worked back when the Met Office did actual science.
After the Top Five or so slots (by importance) for British physicists, the list could become contentious. In chronological rather than ranked order:
1) Gilbert
2) Hooke
3) Newton
4) Faraday
5) Kelvin (Thomson)
6) Maxwell
7) J, J, Thomson (no kin to Kelvin, but son was a Nobel laureate physicist)
8) Rutherford (born NZ)
9) Chadwick
10) Dyson
11) Higgs (if Rutherford be excluded)
Although my list is missing Watson-Watt!
Hawking isn’t worthy even to dust the lab equipment of the truly great British physicists. I’m in awe that such a small island nation (or nations) could have achieved so much. Kelvin was from Northern Ireland and Maxwell Scotland.
In Gilbert, Faraday and Maxwell you have magnetism, electricity and electromagnetism. In Hooke and Newton, gravity. In Newton, also light. In Kelvin, the laws of thermodynamics. After him, the men who discovered the structure of the atom, then subatomic particles: Thomson the electron, Rutherford the proton, Chadwich the neutron, Higgs the theory behind an important subatomic particle. Experimentalists and theoreticians both, sometimes in the same person.
We have Brits to thank for all four forces, ie gravity, electromagnetism, strong and weak. Among other breakthroughs.
Yet Hawking gets the ink, thanks not to his work but his disability.
Mikelowe:Do you supposed he wheeled himself over to BBC to rant about Trump? He is ill with a degenerative disease and these amoral champagne soshulusts badgered the poor fellow while he still enjoys stature among the ordinary folk. It’s despicable and shameful to exploit this great man at this time. Boy they really took the late Schneider’s ends justify the means admonition to heart!
Javier says, ” . I didn’t like it when I have seen it done to Freeman Dyson or other skeptic old scientists, and I don’t like it either for Hawking. ”
It is not the same, as the Freeman Dyson’s comments and skeptcism are in fact solidly supported by science.
This article does not call Hawking a senile old man, it simply points out the absurdity of his comments. Hawking discredits himself here. His innane comments marginalize his credibility.
Gabro – You missed out Oliver Heaviside.
Martin,
Again, a hard choice, but I inclined toward basic more than applied scientists.
he’s always been “sick” … that’s no excuse …
He’s not old and sick; he died years ago. The sad thing they trot it is a carnival dummy with an A.I. programmed by a far left wing staff which has it spewing things that the real Stephen Hawking would never have said.
It’s a sick sideshow act, nothing more.
Shades of the stuffed remains of Jeremy Bentham trundled out for meetings of the board of directors of University College London.
Or Lenin’s Tomb.
http://www.critical-theory.com/wp-content/uploads/2013/07/bentham-corpse.jpg
I think Dr. Hawking still has a sense of comedic humor. Obviously, he knows what he is saying, and he is playing with the alarmists for the foolish drivel they come up with about predicting global climate and temperatures a 100 years in the future. Or that humans now drive the climate through GHG emissions. It is almost funny to hear such a statement from a brilliant mind, since everyone including the most ardent alarmist wouldn’t dare try and protect such a ludicrous statement. He is even playing us for fools in getting us to denounce him, or claim his handlers are now ‘speaking’ for him. Keep up the good work Dr. Hawking, and it sure is nice once and awhile to have some comedic relief from all this CAGW madness/seriousness.
I don’t think we need too many violins. I met him briefly back in 1967 and he still looks much the same.
Observation is an important part of science.
Then he should shut up and not invite criticism by making absurd statements.
I’m kinda happy that Hawkins wrote this. More and morte alarmists seem to try to remove themselves from the predictions of doom and glooom these days, claiming that scientists don’t take part in that. Then it is nice to be able to quote Hawkins.
Tell it to those who keep trotting him out to deliver what amounts to complete nonsense. They are using him to spout Warmunist propaganda. Shameful.
Fidel Castro was old and sick when he gave his last speech.
Can someone please explain how or why the venusian atmosphere is ‘100xdenser’ than that of earthair ,if it is composed of 96percent of co2 ,3.5/100argon(density less than co2) &the rest minute amounts of trace gases….Co2 is 1,67xdenser than air at stp , as far as i can find out .so what causes it to be so much denser .?as venus is said to be about 500c at the surface,gas density falls when hotter ,
“Can someone please explain how or why the venusian atmosphere is ‘100xdenser’ than that of earthair ”
It isn’t 100 times denser.
It is close to 100 times the air pressure of Earth.
Earth pressure at sea level is called 1 atm. Or it’s 14.7 psi. 10 meter depth of water is also 1 atm
of pressure.
It should be noted that Venus has no sea level, so when someone give the pressure of Venus it’s related average surface elevation. Or on earth there is lower pressure on mountain top as compared to deep valley.
Venus:
“Surface pressure: 92 bars ”
https://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html
1 Bar = 1 atm of pressure
sometimes it’s said to be 94 bars or atm.
Anyhow, it’s density is:
“Surface density: ~65. kg/m3”
[same ref]
Earth’s density depends air temperature, but it’s about 1.2 kg per cubic meter or
~1 kg per cubic meter
Or Venus surface has about 67 times more air density as Earth’s surface air.
Thanks Lubos..and CTM
…it’s a shame, makes you question everything the man has said
Won’t be the first time he was wrong, and with respect to his own specialty:
https://www.universetoday.com/108870/why-hawking-is-wrong-about-black-holes/
Lots of far greater physicists than he have been wrong, too, of course. Copernicus thought planetary orbits were circular; Galileo was mistaken about tides, and Newton thought that space and time were absolute, rather than relative, and that gravity worked at a distance instantaneously.
But no scientist with any claim to fame has ever been as ludicrously wrong about anything as Hawking about Venus. If he did indeed really perpetrate this laughable error.
Gabro July 9, 2017 at 5:23 pm
… and Newton thought that … gravity worked at a distance instantaneously.
Gravity does work instantaneously. We are 8 light-minutes from the sun and travelling at 19 miles per second perpendicular. The sun, relatively, is travelling at 19 miles per second opposite. Gravity curves our path from where the sun is Now, not where it was 8 minutes ago.
That’s one of the proofs of general relativity.
Nope.
https://einstein.stanford.edu/content/relativity/q1510.html
The sun’s mass sets up the gravitational field. The field determines where we go, and that field has the sun as its center. The sun could blink out, disappear from the universe as things do when they drop into a black hole and leave their fields behind, and we would still be curving to where the sun disappeared.
I don’t wish to be rude, but if you don’t grasp that gravity works at the speed of light, then you don’t understand Einstein’s theories of relativity and really ought not to comment upon them.
One of the basic tenets of general relativity, confirmed by actual observations, is that gravity propagates at the speed of light; that is, the motion of a massive object creates a distortion in the curvature of spacetime which moves outward at light speed. Hence, without the sun’s mass to distort spacetime, its gravitational effect wouldn’t exist.
Dunno where you got your opinions about general relativity, but they could not possibly be more wrong. Sorry.
Mike,
Dude, seriously, wherever you studied physics, ask for your money back.
Wrong is too strong! Without Newton, Maxwell… Einstein may have remained a patent clerk.
I’ve replied, but it ended up down below at
Mike McMillan
July 9, 2017 at 9:38 pm
Oh, and where I studied physics, you paid for. 😉
I copied my misplaced post to here so we can keep the instruction period together.:
July 9, 2017 at 9:38 pm
Hate to have to educate more than one of us on gravity and light. First off, the sun is not moving in its gravitational field. It established that field long before any of us, even Willis, were born. The field does not depend on constant reinforcement from gravity beams radiating from the sun. It the sun does something different, then the field will adjust to it, but that hasn’t happened recently.
We travel thru this static field, adding our own little bit of gravity, but that hasn’t changed recently either. The question here is whether our centripetal acceleration is aimed at where the sun is now, or where the sun was 8 minutes ago. A steady orbit requires the former.
A centripetal acceleration toward the 8 minute old spot, something over a 9 thousand miles offset, would produce a small offset component that would, over time trash our orbit. I can’t say right offhand whether it would drag us in, or toss us out. I’d suspect out.
Gravity waves and light waves travel the same speed, so where we See the sun should be the same place we Feel gravity emanating from, n’est ce pas? Well, we see the sun where it Is now, although we see What it was doing 8 minutes ago. Basic astronomy, that part.
“Well, we see the sun where it Is now, although we see What it was doing 8 minutes ago. ”
Golly, not to pile on Mike, but seriously?
The light we see came from the sun 8 minutes ago, where it was then.
So we see where it was THEN, not NOW.
We see it eight minutes ago…where it is AND what it was doing.
I have wondered about whether gravity was instantaneous or travelled at the speed of light.
Obviously this has implications for astronomical observations and for cosmological questions.
It may even bear on the question of the so called missing mass, which causes the discrepancy on the rotational rate of galaxies.
In any case, in 2012 some guys supposedly proved that gravity travels at the speed of light, using studies of tides:
“In December 2012, a research team in China announced that it had produced measurements of the phase lag of Earth tides during full and new moons which seem to prove that the speed of gravity is equal to the speed of light.[36] This means that if the Sun suddenly disappeared, the Earth would keep orbiting it normally for 8 minutes, which is the time light takes to travel that distance. The team’s findings were released in the Chinese Science Bulletin in February 2013″
” The sun could blink out, disappear from the universe as things do when they drop into a black hole and leave their fields behind, and we would still be curving to where the sun disappeared.”
Yes…for the same 8 minutes or so it takes for the light from it to reach us.
https://en.wikipedia.org/wiki/Gravity
Frame dragging, perihelion precession of Mercury…etc.
Confirmed.
Why do you think gravity is instantaneous?
You say you studied this stuff…but when?
See here:
https://en.wikipedia.org/wiki/Speed_of_gravity
Did you know that gravity waves have been detected?
I do not think anyone claims to have seen a graviton, but that boson is thought to exist by many.
If not, what is the vector of the force of gravity?
Which leads to the whole question of quantum gravity…
Mike,
You have the right to be wrong, but you are wrong as wrong can possibly be.
Preposterous that you assert totally contrary to reality that Einstein says gravity is instantaneous. At the very core of his insight was that it is not. You could not possibly be more wrong.
Clearly, you have never actually read Einstein. So here is yet another explication of his insight:
http://www.einsteins-theory-of-relativity-4engineers.com/speed-of-gravity.html
Another misplaced post, sigh, so here’s a copy for your enlightenment.:
July 9, 2017 at 11:55 pm
Okay, folks. Education, this time involving only arithmetic.
We see the sun Doing what it was doing 8 minutes ago. Consensus. No problemo.
We see the sun Where it is Now, not where it was 8 minutes ago.
What?! Impossible!! Crazy, absolutely off his rocker.
I said simple astronomy. It’s an effect called stellar aberration, discovered by James Bradley in 1727. Since we’re moving around the sun, the sun will appear swept ahead of the position we’d see it if we were not moving.
All stars located normal to the direction of our orbit will appear swept ahead 20.2 seconds of arc. Six months later, when we’re headed the opposite direction in our orbit, they will appear swept 20.2 seconds the other way. Indeed, if you watch a star normal to the plane of our entire orbit, you will see it trace out a donut in the sky, always leading our present path.
Here’s where the arithmetic comes in.
At our speed, we will move something over 9,000 miles in those 8 minutes, and relatively to us, the sun will have moved that distance. So we’d need something over 9,000 miles of stellar aberration to move our view of the sun to where it actually is.
60 sec times 60 minutes times 360 degrees gives 129600 seconds per circle. Store in calculator memory.
93000000 miles to the sun times 2 radiuses times Pi gives 584336233 miles per circle.
Divide by 129600 seconds gives 450.8767 miles per second, times 20.2 seconds gives 9,107.7 miles of stellar aberration, just about enough to put the sun back in its rightful place in the sky.
So we see it When it was Where it is.
Dude, you are seriously mixed up.
Even the article you site should make you understand that what you are saying it ridiculous.
It even has a GIF animation showing that you are exactly the opposite of correct!
Look, I am not going to check your math, but you should realize from what you wrote that when the earth is moving in the same direction in it’s orbit as the sun is moving in the galaxy…we are moving right along with the sun! We are in the same reference frame with respect to the Sun!
That was the whole point of the article…reference frames.
The Sun is 8 light minutes ahead of where it appears to us…because we are seeing the light from 8 minutes ago! The earth has moved in it’s orbit for 8+ minutes in the time the light takes to get here.
But all of this is in the solar reference frame…it has nothing to do with the motion of the sun in the milky way.
Six months from now, we are heading in the opposite direction with respect to the inertial reference frame of the Sun, but it is still 8 light minutes ahead of where we see it.
How can you not understand this?
You are completely missing the point of the whole aberration article…and it even has a section saying exactly what I said above…without needing to look anything up!
“A special case of annual aberration is the nearly constant deflection of the Sun from its position in the Sun’s rest frame by κ {\displaystyle \kappa } \kappa towards the west (as viewed from Earth), opposite to the apparent motion of the Sun along the ecliptic (which is from west to east, as seen from Earth). The deflection thus makes the Sun appear to be behind (or retarded) from its rest-frame position on the ecliptic by a position or angle κ {\displaystyle \kappa } \kappa .”
Key phrase: “apparent motion of the Sun along the ecliptic ”
Apparent, not real, caused by the motion of the Earth.
Look carefully at this…the star has moved by the time we see the light…it is no longer where it appears to be by the time we see the light.
The article even explains that the sun is a special case because it is so close.
But besides for that misdirection…what has that got to do with the speed of gravity?
Nothing.
You need to reread this article a few times until you understand what it is saying…it has to do with the speed of the earth in it’s orbit, and the speed of light.
At the most basic level, what Einstein said is that we cannot know anything other than what the light that we see tells us. If we look at the sun, we see it as it was then from where we are now.
We cannot even know if it still exists…all we know is it existed 8 minutes ago. Even gravity cannot tell us.
If the speed of gravity was instantaneous, we would know immediately it was gone…impossible according to Einstein.
Now, quantum entanglement may say something different, but Einstein resisted what Heisenberg was telling him about quantum mechanics.
Einstein: “God does not play dice with the Universe!”
Heisenberg: “Stop telling God what to do!”
The aberration of light requires you to aim the telescope ahead of where the object actually is, otherwise the photons would hit the inside wall of the telescope instead of the base due to the motion of the telescope. I’ve exaggerated the amount of aberration for ease of understanding.
Ah, so much misunderstanding. We’ll have to take this up again in some future, more current thread.
To Menicholas’ points:
First off, stellar aberration is not a relativistic effect, no more than riding in a car or flying an airplane. If you’re driving at a relativistic speed, you have to apply a relativistic correction, but 19 mps is nowhere near that neighborhood. Ahalda, the GIF author, didn’t have a handle on that when he made the animation. First clue was the green arrow with the words “Lorentz Transform (Beaming).” Beaming is a classy term for the headlight effect, which only happens with relativistic emitters, and the Lorentz Transform in the sun’s slowpoke case is a waste of time.
The Wiki article says the aberration of the sun is always westward. That’s correct. When we face the sun, we’re moving westward. And we can consider the earth’s motion to be unaccelerated, since we’re in free fall in the sun-earth gravitational field, and the field is so weak it takes all day to change our path one degree.
The sun is a “special case” compared to the fixed stars only in that we change orientation by about 2 seconds of arc in the 8 minutes, which keeps the sun in the same spot as we orbit. Aberration from the earth’s rotation is only a tenth of that. So we’re seeing the sun where it is, not where it was, and the gravity field is also relative to where the sun is now. For a stable orbit, it cannot be where the sun was 8 minutes ago.
Folks still have trouble with the concept of curved spacetime and the gravity field. It’s hard to let go of the feeling that the sun has a force pulling us toward it, and with the 8 minute delay it’s from a position 9,000 miles to the left of where it really is. The actual case is that the sun’s mass has shaped a gravitational field about itself, with the sun in the center. The field will always cause an acceleration directly toward the sun without any time delay or 9,000 mile offset. Any time delayed gravitational effect doesn’t change anything; it merely reaffirms the present curvature of the field.
The earth moves in response to the gravitational field it is immersed in, instantly, not to a gravitational force that takes 8 minutes to reach it.
Here’s a slightly different take on the subject (I know one of the authors):
http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_speed.html
ferdberple July 10, 2017 at 6:01 am
The aberration of light requires you to aim the telescope ahead of where …
True. Here’s a problem in aberration that I thunk up some 20 years ago when I began studying relativity:
The telescope angle comes from a right triangle with the speed of light as one side of the right angle and the speed of the observer as the other side. Suppose we had a telescope that was solid glass along its length. The speed of light is lower in glass. Does that change the aberration angle?
I don’t know the answer.
Does that change the aberration angle
=======
No, which is one of the many puzzling results in physics and was one of the nails in the coffin for the aether.
Mike is channeling discredited kook Van Flandern:
https://en.wikipedia.org/wiki/Tom_Van_Flandern#Le_Sage.27s_theory_of_gravitation_and_the_speed_of_gravity
Mike,
This might help you out:
https://www.forbes.com/sites/startswithabang/2016/04/28/why-does-gravity-move-at-the-speed-of-light/#4bf43b1f6211
Observations show that the speed of gravity is at the very least close to the speed of light. It certainly isn’t instant or tens of billions of times faster than light.
Instantaneous anything removes causality from the universe.
It does not happen.
Sounds like you all still believe in action at a distance rather than curved spacetime.
Latitude, agree on both counts. Motl, physicist, takes Hawking, former famous physicist, to task. Hawking absolutely embarassed himself. Glad a peer took him on.
Wasn’t just a little while ago Hawking said something about 100 years to get out of here…colonize another planet…something like that?
Lat,
Just four years ago:
https://www.space.com/20657-stephen-hawking-humanity-survival-space.html
I do hope that some prankish, pimplish Brit undergrads have hijacked his voice synthesizer, but fear that’s not the case.
I do not understand Hawking’s rush to leave the planet either because either “we” are destroying it, or Earth may be struck by cosmic debris. Other places (e.g., Mars, moon) are already “destroyed” by comparison and are just as likely to collide with another object. The idea that we can simply colonize another planet is ridiculous – especially ones without protective magnetic fields.
I’m afraid he’s a victim of over-thinking….
You guys don’t appear to know what is really going on here! Hawking was sought out and, in his condition, exploited by the BBC/Champagne sосналisтs. He didn’t trundle over to them. These ugly characters are using up whatever stature he still posesses.
–The idea that we can simply colonize another planet is ridiculous – especially ones without protective magnetic fields.–
Create lakes on Mars. Use waste heat from electrical power generation, to warm lakes.
Live under the lakes.
Each 10 meter of water depth on Earth, create 1 atm of pressure. Mars gravity is 1/3rd of Earth’s
so need about 30 meters. But many people live in 1/2 atm of pressure on Earth- so 15 meters or less is enough. The lower gravity of Mars means one travel deeper without getting the bends, and the force of buoyancy is 1/3 of Earth.
[A boat or balloon on Mars can lift same mass as Earth, but the force is less. Or holding a party balloon under water takes 1/3rd the force.]
gbaiki:
Yeah, good luck with that.
We would have an easier time, be safer and have more surface area colonizing the bottom of the abyssal plain.
czechlist,
The answers to these questions are simple…we do not destroy the earth…we fix it up, like we have done here in the US…but that takes money and that takes cheap energy. Lots of it.
We can hollow it out if need be.
But need will not be…populations will likely level off and decrease on their own once everyone is educated and comfortable…and that takes energy and wealth too.
At some point it seems likely a pandemic may take a huge toll, and there may not be much that can be done about it, so there is that.
There will be disasters, and eventually one or more will be unlike anything ever seen before… a mega tsunami that kills a few tens of millions or more, or who knows what…there are dozens of possibilities.
But super volcanoes?
Those do not occur very often.
Space rocks big enough to wipe out a continent?
Very long interval events…I am not going to lose any sleep over it, or predict that we have 100 years or we are all gonna die without a new planet…it will not happen on that time frame. Even a thousand years will be soon for such, IMO.
Our machines will need to be about a million times (okay maybe a few hundred thousand) cheaper and more reliable to leave Earth for keeps, and it will never be more than a tiny amount of people compared to the whole human population.
Putting a single live person on Mars will be very difficult and incredibly expensive and will almost certainly be a suicide mission…albeit one many would volunteer for …I would. Hell, I never wanted to live forever anyway (oh, wait…yes I did. Maybe living forever in history books, as the first person to die visiting another planet, may be the next best thing to actually living forever).
But the real jackassery of all that he has said…we need to deindustrialize…and we need to leave Earth.
One thing is for sure…the former precludes the latter.
“We would have an easier time, be safer and have more surface area colonizing the bottom of the abyssal plain.”
Well there is more surface area with abyssal plain but it’s at 300 atm [4410 psi] and pitch black.
Underwater on Mars could have more sunlight than England, and water depth wouldn’t be much more the 120 meters [about 4 atm]. One could have greenhouse below say 10 meters below surface. 10 meter being 4.9 psi, and greenhouse air pressure about 6 psi. So top at 10 meter and floor at 12 meter underwater- 5.88 psi. So less than 1 psi above water pressure at the “floor” of it. This allows plants to grow and anyone in it doesn’t need pressure suit to breath. They swim to it, with holding their breath, or using scuba gear. Plants don’t freeze, and have constant temperature and get sunlight during the day.
Being under water allows one to have less structural strength for a building. Or making 1 atm or 1/2 atm pressure on land surface, requires a lot of structural strength.
But it wouldn’t actually have floor, it would be bubble of air- so don’t need doors either.
Yeah, but…um…it’s on Mars.
–Yeah, but…um…it’s on Mars.–
Meaning it’s expensive to get there and/or expensive to stay there?
The cost of getting to Earth orbit has been lowering for decades, and would say it’s as
been lowering because we currently have 200 billion global satellite market which should be
1/2 trillion dollar market in couple of decades with a continued lowering of launch cost.
But there could even faster lowering of launch costs. There are few billionaires who are focused
on attempting to get dramatic lowering of launch cost. The most obvious is Elon Musk and his SpaceX company- who has saying he going to launch his Falcon Heavy for few years, now- and hasn’t, but maybe it happen this year. So this would be heavy launch vehicle which has not received any government money to develop, and will be largest launch vehicle since the Saturn V moon rocket- largest in terms launch able payload, which is planned to be 53 tons to LEO.
And it will be a reusable first stage rocket. It’s a variant of Falcon-9 rocket [which one could say did get government development dollars in terms of awarding launch contracts], and Falcon-9 is currently safely landing it’s used first stages and reusing them [which has never done before by anyone].. But there are other billionaires, doing stuff, like Amazon owner, who been launching
the New Shepard sub-orbital rocket- who plans to make a large orbital rocket- without government money. The suborbital New Shepard has also re-landed it’s rocket successful a number of times [using same rocket and doing test launches to space and landing- who actually did this before just before SpaceX first did it, but it’s sub-orbital rocket rather than orbital rocket.
Anyways such rocket develop could [and already has] significantly lowered launch costs, but there are other things which could cause an even more significant lowering of launch costs- which would involve increasing the size of current satellite launch market. Create new and different markets in space.
Another strange topic he has been talking about is micro space probes going to stars. While the concept is cool, how on earth could a micro space probe send a signal back to earth? What is the point in sending out a space probe if we can’t know what it encounters?
“Another strange topic he has been talking about is micro space probes going to stars. While the concept is cool, how on earth could a micro space probe send a signal back to earth? What is the point in sending out a space probe if we can’t know what it encounters?”
Funded by Russian entrepreneur Yuri Milner and with the blessing of Stephen Hawking, Breakthrough Starshot aims to send probes to Alpha Centauri in a generation
“The probes will also need to transmit observations back to Earth using onboard lasers with just a few watts of power—a problem potentially solvable by using the giant Earthbound laser array as a receiver.”
https://www.scientificamerican.com/article/100-million-plan-will-send-probes-to-the-nearest-star1/
as it should … I’d guess that without the wheelchair nobody would have ever heard of him …
Hate to have to educate more than one of us on gravity and light. First off, the sun is not moving in its gravitational field. It established that field long before any of us, even Willis, were born. The field does not depend on constant reinforcement from gravity beams radiating from the sun. It the sun does something different, then the field will adjust to it, but that hasn’t happened recently.
We travel thru this static field, adding our own little bit of gravity, but that hasn’t changed recently either. The question here is whether our centripetal acceleration is aimed at where the sun is now, or where the sun was 8 minutes ago. A steady orbit requires the former.
A centripetal acceleration toward the 8 minute old spot, something over a 9 thousand miles offset, would produce a small offset component that would, over time trash our orbit. I can’t say right offhand whether it would drag us in, or toss us out. I’d suspect out.
Gravity waves and light waves travel the same speed, so where we See the sun should be the same place we Feel gravity emanating from, n’est ce pas? Well, we see the sun where it Is now, although we see What it was doing 8 minutes ago. Basic astronomy, that part.
How did I end up here? This should be up above clarifying confusion on the Gabro
July 9, 2017 at 5:23 pm thread.
Why would it cause the orbit to fail? You are talking about very small adjustments in acceleration that would average out over the course of a cycle. That same description can also be applied to the elliptical shape of our orbit. If one doesn’t mess up the orbit, I see no reason to think that the other would.
As for your other argument, you are essentially saying that two different effects almost cancel out. That’s a completely different situation that what you are describing. It certainly doesn’t support the idea that gravity travels instantaneously.
Okay, folks. Education, this time involving only arithmetic.
We see the sun Doing what it was doing 8 minutes ago. Consensus. No problemo.
We see the sun Where it is Now, not where it was 8 minutes ago.
What?! Impossible!! Crazy, absolutely off his rocker.
I said simple astronomy. It’s an effect called stellar aberration, discovered by James Bradley in 1727. Since we’re moving around the sun, the sun will appear swept ahead of the position we’d see it if we were not moving.
All stars located normal to the direction of our orbit will appear swept ahead 20.2 seconds of arc. Six months later, when we’re headed the opposite direction in our orbit, they will appear swept 20.2 seconds the other way. Indeed, if you watch a star normal to the plane of our entire orbit, you will see it trace out a donut in the sky, always leading our present path.
Here’s where the arithmetic comes in.
At our speed, we will move something over 9,000 miles in those 8 minutes, and relatively to us, the sun will have moved that distance. So we’d need something over 9,000 miles of stellar aberration to move our view of the sun to where it actually is.
60 sec times 60 minutes times 360 degrees gives 129600 seconds per circle. Store in calculator memory.
93000000 miles to the sun times 2 radiuses times Pi gives 584336233 miles per circle.
Divide by 129600 seconds gives 450.8767 miles per second, times 20.2 seconds gives 9,107.7 miles of stellar aberration, just about enough to put the sun back in its rightful place in the sky.
So we see it When it was Where it is.
Great. another misplaced post. Good thing I’m not running the Super Collider.
Because where would we be without all that super collider knowledge?
Two effects mostly cancel out. Interesting point, but completely irrelevant to the discussion at hand. How is this related to your claim that gravity travels instantaneously?
To gbaikie,thahkyou for your reply .i took the figure of 100x’ denser ‘ from paragraph 9, line 3,of the article above ,starting with ” While earth &venus may look like siblings”……….&c
If it is even Hawking running the voice synthesizer. . .
Russians ….
obviously….notice he said “Trump’s action could push the Earth over the brink,”
Funny, I wouldn’t have taken Hawking for a flat-earther.
It’s turtles all the way down.
His voice synthesizer lacks a sarc tag, and Steve does not know it.
“Hawkthing” please. See my earlier contributions!
Poor old Stephen. Despite having a debilitating neurological condition, at least he realises it’s not all a chinese internet scam.
Your comment would have had at least a scintilla of rational thought had you correctly identified what “it” was actually called.
Hawking was diagnosed with ALS when he was 21, and he was not expected to see his 25th birthday. Generally ALS victims die within 5 years of onset. He is now 75 years old.
Eyebrow raising at the very least, no?
How is this possible?
Except for him, only one person ever lived even ten years after being diagnosed.
I wish him no ill on his health, and am glad for him, but it is very strange all by itself.
‘Generally ALS victims die within 5 years of onset’. I knew it, Hawking is a faker. 🙂
Actually, if you google longest lived survivors of ALS, there are those who have lives 15 and even 20 or more years after diagnoses. It’s rare, but not unheard of. Survival rates are just statistics that always have a number of outliers. Hawking is obviously one such individual.
“… internet scam”?
What is your excuse for saying such things?
Just joining the dots CW.
You know… Trump on Twitter: “The concept of global warming was created by and for the Chinese in order to make U.S. manufacturing non-competitive.”
That would be funny if um…never mind.
With all the leftist nutcases pushing the notion that harmless (and actually beneficial) CO2 is going to cause the oceans to boil and the planet to go poof .. we need to take the opposite tack: that CO2 is not only harmless but it’s good:
Tom Nelson @tan123 1d1 day ago
“The flaw in Trump’s energy plans; Continuing to view carbon dioxide as toxic is a mistake” https://twitter.com/tan123/status/883758375842000897
http://www.ncpa.org/images/1484.gif
I think you are correct. Counter the absurd with a talking point both opposite and true.
” At most, if we tried really hard, we could perhaps quintuple the CO2 concentration in the air –”
What they miss here is that CO2 partitions 50 to 1 into water, which means that to double the CO2 in the air, you would have to generate 50 times that much CO2 as the oceans would be fighting the effort. To quintuple CO2, we would have to generate 250 times the CO2 that is in the atmosphere.
Available carbon would only get us to raising atmospheric CO2 by about 20%. That’s it.
We can’t. Probably the best we can do is a mere 600 ppm, given current ice age conditions.
We will likely see greening accelerate, and deserts dwindle as plants and trees and grasslands encroach on them, holding moisture in soil, creating more soil moisture and low level humidity, leading to even more rain…we could see a very pleasantly surprising explosion of plant growth, and large areas be transformed from arid to not so arid to moist and fertile.
Picture the difference between a person with kwashiorkor malnutrition vs a well few and muscular athlete…and how much more than athlete can accomplish.
Oh the Humanity! All of those endangered deserts! And all the strange desert animals that will surely go extinct (because we all know that animals have no ability to adapt).
https://giphy.com/gifs/stupid-david-byrne-talking-heads-ocH91hYgkPe6I?utm_source=media-link&utm_medium=landing&utm_campaign=Media%20Links&utm_term=https://www.google.com.au/
Where’s the Principle of “Intellectual Honesty” in all this?
Hawking knows full-well that Gaia has survived successive so-called “tipping-points” (by today’s’ reckoning), that it — and we — should have been fried to crisps and evaporated in a Venusian chemical furnace many times over in the intervening Geological era. If he doesn’t know, he’s illiterate and /or tendentious in evidentiary pursuit of one-sided promotion of HIS CAUSE!
The guy is yet another shill for any movement that still gives his so-called “Wisdom” any credibility. Perish the thought that our Stephen should fail to have a pathetic line-up of gullible MSM-types tapping at his door, ready to hang-on to every heart-tugging, painful, Salvation-seeking, syllable-by-syllable piece of junk-science that ….. via his other orifice, his speech-synthesizer ….. keeps funding his diapers …. or whatever ….
In his case he is so enamoured of his alt. orifice, that he is reduced to searching therein for yet more junk-science pronouncements. The MSM morons keep buying it; so keep promoting it!!!
I suspect the deference and fame he has, has affected his sense of intellectual humility. I concluded a long time ago that he is basically a lightweight. It’s a shame because he is a pretty inspiring story but I don’t see any major contributions in his work. The prediction of Hawking radiation is probably correct but it doesn’t mean much in terms of understanding the origins or fate of the universe or the underlying structure of spacetime. His physics is very conventional and dogmatic, much like the petriphied climate orthodoxy. No original insights can come of it!
Move along, everybody. Nap time at the physicists retirement home.
I agree John.
He is the most celebrated scientific nothingburger ever.
There is something like the Dunning-Kruger effect except it is experts who overestimate their knowledge. link This is called expert overclaiming.
Then there is Nobel Disease.
The above link proves that “truth” is often in the eye of the beholder. In its list of Nobel Disease sufferers, it makes at least one, possibly two, errors.
Al Gore-
A Barrel of Incoherent B.S.
Or whatever the incomparably wrong book was called!
the article is completely unreadable. please fix the HTML/XML until it displays as its author presumably intended.
Agreed!
I am NOT convinced that those ridiculous words originated from any original line of thinking by Hawking on this matter. I wonder whether his attempt to respond to relevant questions posed to him got so synthesized by intermediaries that the result is nothing like he would say.
I just don’t believe those were Hawking’s words alone. If they were, then he is to be pitied rather than be condemned, because, obviously these words from that mind would indicate failing mental faculties.
“We are close to the tipping point where global warming becomes irreversible. Trump’s action could push the Earth over the brink, to become like Venus, with a temperature of two hundred and fifty degrees, and raining sulphuric acid,”
Both Hawking and Carl Sagan have been associated with this fantasy, Sagan since the beginning. Hawking went right along with the idea—there are discussions from several years back showing Hawking was a full supporter of the idea then (this just reappeared in the news—it’s really a rehash of statements made before, hoping for more exposure). Unless you believe Sagan somehow used Hawking to advance his theory. I see no evidence that Hawking was anything but a true believer.
Look – Venus’ 95% CO2 atmospheric concentration is only 5.96 percentzes away from Earth’s 0.04, so there’s real danger. It’s basic math, people!!!
please explain–I do not understand your “basic math” My basic math tells me that if earth”s atmosphere was 1% (.01) CO2, then Venus’s 95% would be 95 times greater, and since Earth’s atmosphere CO2 content is not even close to that 1%, , your math doesn’t compute
I eschewed criticism because I don’t know what a “percentzes” is.
Buffer overflow error.
I detect sarcasm.
PiperPaul is shrewd one.
Did Motl do the math right on his calculation of the temps of venus compared to earth (because of distance)? 1.17 times that of earth seems awfully close. If venus were at 50% of the distance of earth, it would be 4 times hotter (correct?). At 73%, what would that come to? (thanx to any and all in advance)…
You are correct, a planet at half the Earth’s distance would receive 4 times the radiation energy. Motl is also wrong when he writes,
“So Venus whose distance from the Sun is 0.73 times greater than the Earth’s…”
It is much more correct and understandable to say “So Venus whose distance from the Sun is 0.73 that of the Earth.”
Also since the radiation received is an inverse function of the square of the distance as you state, an object twice as far away receiving 1/4 the radiation, an object 1/3 the distance away receiving 9 times the radiation, Venus at .73 the distance of the Earth receives 1/(.73*.73) or about 1,88 times the radiation.
1.88 not 1,88. Going back and forth from the American way to the Spanish way sometimes gets me confused…
(gracias)…
As Lubos Motl pointed out, Luminosity is proportional to the 4th power of radiation/ temperature.
Venus receives 1.88 times earth’s radiation, so the temperature, assuming Venus’ atmosphere were the exact same as earth’s, would be proportional to the fourth root of 1.88, or 1.17 times that of earth, – Just what Lubos Motl said. Of course that situation would be unstable, with additional evaporation of oceans and disassociation of water molecules high in the atmosphere.
Thank You, Alan. That makes sense to me now. (it was all greek to me) So, 1.17×1.17×1.17×1.17=1.88.
Amazing how close the two planets would be, i’d have never guessed. i’ll have to try the numbers for mercury and see what i come up with…
i’m getting mercury being 1.62 times that of earth. (who’d have thunk!)…
Indeed all things being equal Venus is on the margins of the planetary habitable zone. However all things are not equal. Venus has an atmosphere that is 100x denser than Earth’s, and almost 200,000x the total CO2 molecules contained within that atmosphere.
Some say our oversized moon stripped away enough of our atmosphere to make the difference.
I have no idea…just sayin’ what someone else sez.
I think it was from a Larry Niven story.
By chance, last night I watched a BBC Horizon program about volcanoes in the solar system (unusually, it didn’t contain any climate change propaganda).
It gave the conventional explanation (which is probably true) to explain the stark differences between Venus, Earth and Mars: Earth is the only one to have active plate techtonics / continental drift. Although Earth’s volcanoes emit huge amounts of CO2 and other gases, much of it is re-absorbed into the crust by plate techtonics – I think it’s referred to as subduction. So, there was no uncontrolled build-up of these gases on Earth. It’s probably also why CO2 has been steadily falling over past millions of years.
Hawking really is an idiot to make that statement about Venus. The sad thing is that many people will assume it’s true. Fortunately, Earth will escape the fate of Venus and Mars as long as we have active plate techtonics and a magnetic field. But it’s probably just a matter of time before the true believers tell us plate techtonics and our magnetic field are threatened by that evil CO2!
Chris
Just a question…, If the atmosphere of venus is 96-98 percent co2. how can the atmosphere of venus be100x’ denser ‘than earth.If it i.e.Venus’ atmoshere is 96-98 per cent co2.the ‘density (do we mean specific gravity?)of co2’is given as 1.997kg/cu metre …On earth the ‘density of air is given as1.225kg/cu .metre@15deg c…..co2 is 1.67xdenser than that of earth air .Gravity on venus is reckoned to be 0.9of earth g.are we confusingthis with ‘thickness,’or’ depth’ from surface to top of atmosphere
@kendo
You are mixing percentages and densities (or specific gravities).
Check Nasa´s Venus Fact sheet:
https://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html
The atmospheric pressure at the surface of Venus is 92 bar, and at the surface of Earth is 1.01 bar. The atmosphere on Venus is 90 times more compressed than on Earth (at the surface)
The composition of the atmospheres is also different. Venus is 96.5% CO2 (molecular mass = 44 g/mol), The Earth is 78% N2 and 21% O2. (molecular mass = 28*0.78 + 32*0.21 = 28.56 g/mol of air) A mole of Venus air weights 1,53 times more than a mole of Earth air.
As you said, the density of air is about 1.22 Kg per cubic meter. (at 20 C) But the density of venus atmosphere at the surface is 65 Kg per cubic meter. (NASA fact sheet) So, Venus atmosphere is 53 times more dense than Earth´s. Apparently, calculations do not add up, but you have to take into account a couple of things. First, the temperature at the surface of Venus is 460 C. And second, at these pressures and temperatures CO2 is not really a gas, but a supercritical fluid.
In reply to Menicholas : I recall the same thing from reaing Larry Niven’s stories.. I think that assumption regarding the moon is wrong. Mars is much smaller than earth, has no significant moon, and has little atmosphere. Obviously, assuming continuity, there should be a mass size somewhere between Mars and Earth that has an Earth sized atmosphere.
We DO need the moon for stability of the polar declination. Our moon keeps our inclination between 22 and 24 degrees. Without the moon, Jupiter’s nudges would cause drastic changes in the inclination, at least an additional 24 degree, for a total tilt of between zero degrees and up to 40 or 50 degrees over a few million years. . Currently Mars has an inclination similar to Earth,, about 25 degrees, but past deviations due to Jupiter have changed that by close to 90 degrees,
https://en.wikipedia.org/wiki/Axial_tilt
A solar day on Venus lasts 116 Earth days long. Energy slowly accumulates on the sunny side over those 2,784 hours so that the surface temperature rises to 450C. All the water, all the volatiles that can turn into a gas, do indeed turn into a gas and Venus has a hot thick atmosphere. Simple physics that can actually be calculated in terms of joules per second energy accumulation rates.
Then you have a very thick atmosphere that spreads the heat around to the dark-side at a faster rate than the rotation rate. No greenhouse gases need to be involved in this process at all.
What happens to tidally-locked planets that are big enough to hold onto gaseous atmospheres. The scientists that are now studying extra-solar planets recently calculated that one tidally-locked planet has a surface temperature hotter than most stars, 4,600K.
What is the difference between this planet and Venus? The difference is that the extra-solar planetary scientists do not have to abide by the greenhouse gas law. Speaking of that, it is even a law? No, the other physicists know physics and planetary atmospheres.
I commented on Motl’s blog , http://motls.blogspot.com/2017/07/venus-and-hawkings-scientific-illiteracy.html#comment-3411639208 , that the very first computation I did when I got diverted into this brouhaha was to graphically confirm the square-root law of temperature with distance .
http://cosy.com/Science/PlanetTempPlotTa.gif
I comment that even this most basic quantitative ( settled ) law is far too little appreciated among “climate scientists” and lament the failure of the field to approach the issue of planetary temperature as one of applied theory based physics rather than a measurement and statistics soft science .
While chasing something else, I was reminded of http://wattsupwiththat.com/2011/08/18/bizarre-craptastic-theory-from-the-guardian-penn-state-and-nasa-et-will-kill-us-because-global-warming-will-tip-them-off-that-we-are-a-bad-species/
Things could be dumber….
And then the ET will commit suicide realizing that they are no better, having killed us off.
Yeah, if they are the ice creatures from Hoth…they hate warm planets.
Humans and plants and earth life in general…we loves it!
Surface temperature on Venus is a combination of solar distance, atmospheric composition, and atmospheric density. Mostly distance and density, though.
Going from memory here, that file is somewhere still after two computer changes this year. I did once calculate what the temperature should be on Venus – where the atmosphere is at the one bar level (Earth sea level mean pressure). Comparing that to the measurements available from the few surface probes, it is about 20 degrees Celsius higher than “expected.”
At one bar, the Venusian atmosphere is still virtually all CO2 – but that is highly unlikely to explain the higher than “expected” temperature. Why? At one bar, you are just barely into the aerosol layer – where the part of the atmosphere that is not CO2 is a witches brew of sulfur compounds (H2S, SO2, SO3, etc.). Compounds that have a completely different absorption spectrum than CO2 – and thus increase the temperature well above what a pure CO2 atmosphere there would be. (Plus re-radiating part of the absorption towards the surface like CO2 and H2O do here – as noted, there is still a very thick layer of CO2 and sulfur compounds above the one bar level.)
it is not even 20 degC above what we would expect. The temperature, at 1000mb (ie., Earth’s pressure at sea level), is only about +0.5K above what we would expect if Venus has no GHE, and this is probably within inherent margins of error in measurements. The maximum difference is about -5 K at 300 mb pressure.
For further details, you need to check the pressure temperature table for Earth and Venus on Huffman’s site:
http://theendofthemystery.blogspot.com.es/2010/11/venus-no-greenhouse-effect.html
This is my understanding of the physics as well. Yes, My heresy is complete! I’m a denier!
And I’m not a physicist so my opinion can be disparaged or ignored, but apparently my knowledge of physics in some areas exceeds that of Steven Hawking
Strikes me that that classic piece of sky-dragon slaying “science” omits the albedo of Venus.
The bond albedo of Venus is 0.75, so the planet is absorbing just 25% of Solar radiation at TOA.
Redoing the calculation to take account of that then….
E received at TOA = 2,636 W/m2
E absorbed at TOA = (1-0.76) / 4 = 158 W/m²
Earth is absorbing 340 W/m2
Which equates to an “effective radiating temperature” of 230K (-43°C).
The same calculation for the earth gives 255K (-18°C)
Reckon y’all best recalculate then, huh Toneb?
I have done ta.
Of course the BBC dutifully reported Hawking’s ludicrous claims without allowing any comments on the article. The only thing they seemed to think might be disputable was rhetorically stating if Hawking was the worlds most famous scientist or not.
They also got a political ‘bonus’ in that Hawking then went on to say that he thought Brexit would be bad for UK science. Whether Hawking volunteered his political opinions on Brexit is a moot point because we know that the BBC would have prompted him with such questions anyway, and probably not reported those opinions if he gave the ‘wrong’ answer. If the UK spent less on global warming pseudo-science alarmist twaddle then there might be more resources to spend on Motor Neurone Disease, but I don’t expect they put that question to him.
I thought that very little sunlight reached the surface of Venus, and so NO sun-produced “greenhouse effect” is even possible there. Venus is hot for other reasons. Hawking seemingly would know this, but those people speaking for Hawking or manipulating Hawking’s words seemingly might not know this.
I think he was pulling their leg, though not literally, more like voice synthesizer in cheek.
Robert: I thought that very little sunlight reached the surface of Venus
…
Pictures from the Venera 13 lander show otherwise: https://www.space.com/18551-venera-13.html
Depends upon your definition of “little”. Less reaches the surface of Venus than on average Earth, but still, obviously, enough for photography.
Despite the practically oceanic density of the Venutian atmosphere, photons get through. Think of a cloudy day in a high latitude on earth.
“Think of a cloudy day in a high latitude on earth.”
Very cloudy.
https://en.wikipedia.org/wiki/Lux
LuX
“1000 Overcast day;typical TV studio lighting”
One should able to take picture with TV studio lighting
“50 Family living room lights (Australia, 1998)”
If don’t need fast shutter speed, one should be able take picture in lighted living room
With the tiny camera built into my phone, I can take excellent pictures at night outside.
Whodathunkit?
There’s another theory for why Venus is so hot and it has nothing to do with the composition of the atmosphere, and the theory seems to apply to all solar system bodies tested so far, including the Earth.
Stephen Hawking should look into this area of physics.
https://www.omicsonline.org/open-access/new-insights-on-the-physical-nature-of-the-atmospheric-greenhouse-effect-deduced-from-an-empirical-planetary-temperature-model.php?aid=88574
This is a view long held by Harry Dale Huffman, who used to post on this site. See:
http://theendofthemystery.blogspot.com.es/2015/05/venus-no-greenhouse-effect-comments.html
The Nikolov & Zeller paper is very similar to the view expressed by the sl@yers. This site sought to close down discussions on that view.
The link I intended to cite is:
http://theendofthemystery.blogspot.com.es/2010/11/venus-no-greenhouse-effect.html
I just thought of it, but, Earth has ozone, which filters out most all the uv at a great altitude.
Does Venus have anything like that?
Or do those high energy photons sail right through the dense clouds and go right to the surface?
“The Nikolov & Zeller paper is very similar to the view expressed by the sl@yers. This site sought to close down discussions on that view.”
I’m not familiar with the “Slayer” discussions, that was before I got to WUWT, so I’m not sure why discussions were closed down. I have to assume the Slayers did not have sufficient evidence for whatever they were arguing. That’s the only way I can see that a discussion can be shut down. Otherwise, you have people like me asking why.
I don’t see how one can ignore this new research by Nikolov & Zeller. I can see disagreeing with the findings, but I can’t see how ignoring them is in any way scientific. It’s more like putting blinders on.
When you have a formula that applies to multiple planets and moons, then you have to think there is something significant here.
[here is why Nikolov and Zeller are not worth discussing: https://wattsupwiththat.com/2016/09/14/climate-skeptics-behaving-badly/ -mod]
Menicholas July 10, 2017 at 12:08 am
I just thought of it, but, Earth has ozone, which filters out most all the uv at a great altitude.
Does Venus have anything like that?
Or do those high energy photons sail right through the dense clouds and go right to the surface?
CO2 absorbs UV and undergoes photodissociation to CO and O in a similar range of wavelengths to O2 in the earth’s stratosphere. CO also absorbs UV as do SO2 and SO3 and H2S so I expect the UV is also filtered out high in the atmosphere.
Here is an excellent article at WND that explains all aspects of this issue.
http://www.wnd.com/2017/07/study-blows-greenhouse-theory-out-of-the-water/?cat_orig=education
To my surprise, if you can get past the breathless headline and first few paragraphs, that article (about the latest paper from Nikolov & Zeller) is actually worth reading.
(I almost didn’t bother to click, because Joseph Farah’s WND is the last place you would expect to find an article which explains climate change. WND [like NewsMax] pretends to be conservative, but it is not trustworthy [which, by my lights, means they are not conservative]. It contains a mixture of solid reporting and nonsense.)
Of course the article doesn’t actually explain climate change or “blow GHG theory out of the water.” Yet, the author, one Alex Newman, clearly spent a lot of time on it. He contacted and quoted both Nikolov & Zeller, plus no fewer than nine other climate skeptics and lukewarmers, and he reported that he also attempted to get responses from Michael Mann, Gavin Schmidt, and James Hansen (but they did not reply). I’m kind of impressed.
It has the same fundamental flaws as their earlier paper, which interestingly they refer to using the fake names they used to publish it which was a reason why it was withdrawn by the publisher. The discussion here about the previous paper produced the following remarkable comment by Anthony:
Anthony Watts September 15, 2016 at 1:33 pm
I find myself in agreement with Willis, Nick, and Phil.
Mark this rare moment in time. It may never come again
“A recent study has revealed that the Earth’s natural atmospheric greenhouse effect is around 90 K or about 2.7 times stronger than assumed for the past 40 years. A thermal enhancement of such a magnitude cannot be explained with the observed amount of outgoing infrared long-wave radiation absorbed by the atmosphere (i.e. ≈ 158 W m-2), thus requiring a re-examination of the
underlying Greenhouse theory. We present here a new investigation into the physical nature of the atmospheric thermal effect using a novel empirical approach toward predicting the Global Mean Annual near-surface equilibrium Temperature (GMAT) of rocky planets with diverse atmospheres.”
I don’t think atmosphere adds 90 K.
I think the variable of having an ocean, makes Earth warmer than it would
be without an ocean.
One could say one needs an atmosphere in order to have an ocean- therefore
any warming related to ocean is caused by atmosphere.
I think that is wrong way to look at it, but I still don’t think atmosphere and
ocean causes 90 K warming.
There are factors which cause a planet to be cooler. So if had or designed a
planet to be the coolest, from such baseline one could have such a 90 K
increase [maybe].
What you call a warm or cool planet can be subjective.
Broadly one could be concerned about the hottest surface temperature, or what
is the hottest average surface temperature.
One could also be focused on temperature of the surface air temperature [obviously
removing planets without air from consideration].
But there lot’s of things one could “count” roughly in this regard.
Another metric is how much does a planet absorb sunlight and then emit it.
Earth absorbs about 240 watts and emits 240 watts.
And no other planet we have, absorbs this much of the sun’s light..
And Earth absorbs this much energy, because it has global ocean of water.
Or if lacked an ocean of water, Earth would not absorb as much sunlight [and emits
this amount of IR].
Venus is highly reflective, and though closer to sun, it absorbs and emits less
sunlight per square meter.
But one would get vast agreement that Venus is hotter than Earth.
But in the category of atmosphere and ocean, Earth has more heat
[joules of energy] than Venus in terms category of Atmosphere and ocean [Venus
doesn’t have ocean- but I would rather separate ocean and the atmosphere, but
currently following some apparently stupid rule of combining them. Or let’s
call it the liquids and gases above the rocky surface [Venus has liquids above
it’s rocky surface- it’s dense acid clouds].
Gases tend to be transparent, anything transparent reflects that radiation it’s
transparent to, large atmospheres of gases will reflect sunlight.
The cloud and atmosphere of Venus reflect a lot of sunlight, and Earth reflects
about 400 watt of the 1360 watts which reaches it above atmosphere.
Earth has thick atmosphere but it’s quite insignificant to the Venus’
atmosphere.
Roughly, large atmospheres inhibit the sunlight being absorbed.
So one might think planets without atmosphere would absorb more of the sun’s
energy- but they don’t. They would if they have a surface which could absorb
a lot of solar radiation. Rock doesn’t absorb much energy, and planets
without atmosphere, don’t even have much solid rock at the surface- they
have dust which is much better insulation than solid rock.
{[anyone heard of impactors]]
But lunar surface certainly gets a hotter surface than Earth doing the day, but does
not absorb much heat, and it’s got slow rotation.
Anyways idea that Earth atmosphere warms by 90 K, begs the question in comparison
to what exactly.
And 90 K warmer is repeating the error of the “greenhouse effect theory”.
One could say one forced to follow stupid rules established by this pseudo
science of “global warming”.
But I prefer not continue with this error.
In fact, 90K (90°C) is, indeed, the approximate average temperature difference between the surface of the Earth and the Moon — despite the fact that the two bodies receive essentially identical amounts of radiation from the Sun, and despite the fact that the Moon’s albedo is lower than the Earth’s.
However days & nights are 29.5x longer on the Moon than on the Earth, which presumably accounts for a lot of the temperature difference: radiative emissions are proportional to the 4th power of the absolute temperature, so a body with wider day/night temperature swings will lose heat faster than another body with the same average temperature but smaller temperature swings.
— daveburton
July 11, 2017 at 7:00 pm
In fact, 90K (90°C) is, indeed, the approximate average temperature difference between the surface of the Earth and the Moon — despite the fact that the two bodies receive essentially identical amounts of radiation from the Sun, and despite the fact that the Moon’s albedo is lower than the Earth’s.–
I would say the Moon’s low albedo, has little to do with a amount of sunlight absorbed by the Moon- though albedo has some affect of it’s surface temperature.
Or if dump white sand in lunar surface, the white sand might absorb more energy as compared to the dusty regolith. And since white sand on Earth can become quite hot, the white dumped on lunar surface could also get fairly hot. But amount of sunlight absorbed has little to do with whether it’s white or dark sand or how hot the surface gets.
Or a huge block of copper, could not bevery warm in the Moon, despite days of sunlight shining on it- and it’s coolness would inform me of it’s mass- say it looked half buried and I didn’t know how massive it was.
Because copper is a good conductor of heat- or quite the opposite of lunar regolith.
So regolith surface could be 120 C and huge chuck of solid copper could be say, 40 C.
Though painted with something which absorbed the sunlight best, maybe it’s 70 C, and coating which absorbs less might 30 C. In either case of it’s coating, it could or would have absorbed more energy from sunlight than compared to the lunar regolith
Now some small space rocks are solid rock;
“The discovery also is the first evidence for an asteroid lacking the typical dust blanket—called regolith—of most larger asteroids. Instead, 2015 TC25 consists essentially of bare rock. It’s also one of the fastest-spinning near-Earth asteroids ever observed, completing a rotation every two minutes.”
http://www.futurity.org/tiniest-asteroid-ever-6-feet-across/
Now though suppose to very bright, I would interested to know what it’s temperature was, but
I could not find any explanation of how hot it got, nor it’s average temperature.
And always wondered what a round iron cannon’s temperature would be in high earth orbit, with similar luck finding an answer.
I did find this abstract, but I didn’t want to buy the article to see if had something useful to say.
“The effects of emissivity, absorptivity, and thermal inertia are taken into account in the calculation of meteoroid temperatures at the earth’s distance from the sun. Iron meteoroids at 1 AU with equivalent sphere radii in excess of about 1.5 meters may have temperatures departing substantially from radiative equilibrium temperatures as they move toward or away from the sun in highly eccentric orbits. The radiative equilibrium temperature of stone meteoroids is less than 0°C, whereas for iron meteoroids, it is substantially greater than 0°C. These results are consistent with observed temperatures of newly fallen meteorites.”
http://iopscience.iop.org/article/10.3847/0004-6256/152/6/162/meta;jsessionid=BB049F47A117656DFD77C3AB309ADB0F.c1.iopscience.cld.iop.org
Of course ideal thermally conductive blackbody sphere is suppose to have a uniform surface temperature of about 5 C [or 5.3 C]. Or 340 watts per square radiated from blackbody in vacuum,
in theory, has temperature of about 5 C.
Oops last link should have been:
http://onlinelibrary.wiley.com/doi/10.1029/JZ071i023p05681/abstract
and this:
always wondered what a round iron cannon’s temperature..
Should be:
always wondered what a round iron cannon ball’s temperature..
Whups! Dag nab memory… Just found that file. Ten degrees higher at the one bar level than “expected”; i.e., you would expect ~338K (OP has ~336K) – actual measurement is ~348K. (Note, the temperature reference I used is actually temperature vs. altitude vs. pressure – and the primary variable is altitude. Per my reference, the temperature of ~348K is at the 50km point, where my reference says 1.066 bar. I ignore the ~7% higher pressure for the temperature – so am actually on the conservative side here, the difference due to composition is probably somewhat less – my WAG, as I have to head out the door in less than five minutes, is that it is closer to seven or eight degrees C.)
SH states:
I guess that he does not know that the (contiguous) US has not warmed from the highs of the 1930s, and may even have slightly cooled since then.
I guess he does not know that the number of days over 90degF, 95 degF and over 100degF have reduced in number significantly since the dust bowl era of the 1930s.
perhaps if he checked the facts, he might be a little more sceptical.
“Facts? We ain’t got no facts. We don’t need no facts. I don’t have to show you any stinkin’ facts!”
Hawking tries to throw out a “scare” statement about not being accepted into U.S. Trump has already been banned from London. So much for tolerance.
The Progs want to abort not-yet-born babies if a disease or defect can be detected prenatally. They also want to euthanize older, ill humans rather than support them with custodial and medical care.
Hawking should watch his step in UK. He may be “welcome” straight into the Groningen Protocol unit of the local nationalized hospital, where a panel of cost-effectiveness-calculating bureaucrats will decide his fate.
Airport metal detectors and/or X-ray scanners pose a significant exposure risk to the Hawkthing which may reveal to the whole world the non biological substances which comprise 100% of the device.
Hawking has uttered rubbish about things relating to his own field too.
Venus likely originally acquired about as much water as Earth. The very high deuterium to normal hydrogen ratio in its atmosphere and Venus’ lack of a magnetic field to protect its atmosphere both indicate this water was destroyed (and partly removed) over time. Thus, early Venus, as it heated, likely had abundant water vapor in its atmosphere to enhance the greenhouse effect.
Did Venus ever actually cool enough from formation and the bombardments to have liquid water?
Let us assume that our water world planet Earth has just 100 ppm of CO2 in its atmosphere but it is situated where Venus is. It would then receive a lot more solar irradiance making the oceans far warmer.
If there is a positive water feedback loop as warmists postulate, what would stop run away global warming?
If that is the case, then the Goldilock zone, may be much narrower for planets which are water worlds.
IMO the same feedback loops which make Earth a (usually) self-regulating planet would stop runaway warming even at Venus’ distance from the sun. We might possibly have been spared the runaway cooling Snowball Earth events, however.
Thanks your comment.
Then you do not accept that there is a positive water feedback loop.
My point is that IF there is a positive water feedback loop (as per cAGW conjecture), it follows that the Goldilock zone is likely to be far narrower than astronomers presently assume to be the case.
Richard,
There are both positive and negative feedbacks from water. It’s possible that increased H2O in the air has an effect on temperature, but at the same time, evaporative cooling and clouds work to offset that radiative effect by cooling.
Water seems to be the dominant regulator of global temperatures. The Earth has had fairly stable, life friendly climate for nearly all of the last 3 billion years or more, while CO2 levels have varied greatly and the sun has steadily strenghthened. The only constant in maintaining the habitability of the planet is good old phase changing water.
A better understanding of waters negative feedback functions would fix the stupid models and
kill off the whole ridiculous idea.
See above – I don’t think that is a factor, at all. Temperatures during the Eocene optimum were comparable to the current temperature of Venus at the one bar level.
An inconvenient truth.
This blog belongs to its creator, our generous and hard-working host. However IMO its value as a scientific forum would be increased by permitting Sl@yer hypotheses to be discussed. Rather, the imbecilic lies and drivel of creationist ignoramuses is what ought to be banned. Permitting such blatant anti-scientific twaddle to be repeated here can only give ammunition to CACA advocates.
I agree. This is a site for discussion of climate science and other related scientific rational topics. Allowing any religious dogma and/or proselytizing just ruins any sane discussion of normal scientific enquiring minds, which is why most of us are here. Especially the ones advocating the world was created just 6000 years ago.
And yet you can’t swing a cat without hitting a creationist on this site. Even the Wiki article correctly tars WUWT with the creationist brush.
There is no shortage of lying blogs for antiscientific, antihuman creationists to peddle their phony wares. IMO this esteemed blog should let them know just how unwelcome their lies are.
I would appreciate your starting a different discussion on your own thread, not mine.
Not that I saw any of the creationists or ID’rs on this post – and, honestly, I don’t see the number of them that you apparently think infest WUWT.
Me neither.
Addenda – I did bit more research – and now I see where you are coming from. Thank you so much – and right back at you! Idiots.
I had never heard of this Huffman party, until I poked into the comments just now on the one article that Richard linked. Whee! Well, he is at least somewhat more creative than the standard Creationist!
Completely in la-la land, so far as planetary and/or biological evolution goes (from my perspective). But – standard physics knowledge, a minuscule bit of research, some very simple arithmetic – and even an off-the-wall religious fruitcake can get the same answer as this agnostic realist. AGNOSTIC, in case you are only getting the shouts. Agnostic, because while I have seen no convincing evidence, I do not fall into the trap of FAITH that the lack is evidence of absence. Absence of evidence proves only that there is no evidence – at the moment, and within the limitations of our current ability to probe the universe around us.
Isaac Newton was absolutely fascinated with the occult – didn’t make him wrong on certain other subjects such as gravitation, motion, the nature of light, etc. (Slightly inaccurate on some of these, true – but it took a quarter of a millennium for anyone to figure out why.)
Considered for a bit before hitting “Post” here, and decided to do so anyway. By Anthony’s design – as stated in his own words – this is NOT a “Creationist” blog. NOR is it an “Atheist” blog. It is a SCIENCE blog – where anyone who wishes to discuss SCIENCE is welcome. Even science dogmatists, although this being a SCIENCE blog, they can expect their dogmas to be challenged.
(BTW – I have not the slightest idea what “Slayer hypotheses” are, other than fans of a certain thrash metal band?)
Never mind on that last question. I had seen the reference once or twice, but hadn’t connected it.
Nope, sorry, I agree with Anthony on that one. Atmosphere, and its various properties (density, composition, etc.), have a definite effect on the surface temperature of a planetary body. Period. Claiming no effect from CO2 is just as unscientific as claiming it is the only thing with an effect. Although I do detest the completely inaccurate terminology of “Greenhouse Effect.”
“And yet you can’t swing a cat without hitting a creationist on this site.”
If you don’t want to see creationists commenting on this site, don’t swing your cat at them. I don’t generally see creationists commenting here (on the subject of creation) unless there is first some anti-creationist statement introduced, usually where there was no call for it.
SR
Well said. There are undoubtedly creationists all over the place – it is a “popular” belief. Ignore them on cosmology. Same with Dr. Hawking – he is a “whack job” on climatology.
Being a creationist does not prevent one from being, say, a good electrical engineer. Being a whack job on climatology does not prevent one from being, say, a good theoretical astrophysicist.
There is no need to exclude anyone who has a rational grasp of one thing – here, it is climate science – just because they are seemingly far around the bend on something else.
Well, there is that small matter of the moon and sun being roughly the same apparent size!
😉
Well…what are the odds?
Anyone?
Anyone?
Bueller?
–richard verney
July 9, 2017 at 7:08 pm
Let us assume that our water world planet Earth has just 100 ppm of CO2 in its atmosphere but it is situated where Venus is. It would then receive a lot more solar irradiance making the oceans far warmer.–
Let’s give it 1000 ppm of CO2. It still wouldn’t get very warm.
Earth distance is 1360. Venus distance is 2600 watts per square meter.
Earth now reflects about 400 watts of the 1360 watts- 960 / 4 = 240 watts
Earth at Venus [without warming up and making more clouds] should reflect about
same percentage of sunlight- .3. So 2600 would reflect 780 watts.
2600 – 780 = 1820 watts. Divide by 4 is 455 watts per square meter average
455 watts from BB in vacuum is 299.3 K [26.15 C].
–If there is a positive water feedback loop as warmists postulate, what would stop run away global warming?–
Earth greenhouse effect is suppose to add 33 C.
Co2 is suppose to be forcing “agent”. We don’t need a forcing agent because the sunlight at venus distance is doing lot’s of “forcing”. Or say CO2 adds 1 C from doubling plus it’s warming effect of 1-6 C
the sunlight at venus distance is already doing this vague number of 1- 6 C. Or doubling of Co2
causes at most 1 C of warming.
Or not going matter much if CO2 is 100 or 1000 ppm.
So if crazies are right, one have less than 33 C added. But let’s add it anyhow:
26.15 + 33 is a global average temperature of 59.15 C.
That pretty warm. We can assume it melt the ice caps, evenually- so within hundred
years or so, no ice cap and + 50 meters to sea level.
Now important thing is how hot is the tropics. With earth over half of the sunlight falls in the tropics
and the tropics is 40% of entire earth surface. And there is no reason that if Earth were at venus distance that it too should have more than 1/2 of sunlight reaching the tropics- or other 1/2 [or less] going to the rest of planet with 60% of surface area.
On earth at earth distance we get on clear sky, sun at zenith, 1050 watts of direct sunlight and 1170 watts of direct and indirect sunlight.
How much of that sunlight heats the skin surface of the ocean- somewhere around zero- maybe 5 watts per square meter, the rest goes beneath the skin surface and a large amount is absorbed within top 1 meter of the water.
So when a zenith about 300 watts of direct sunlight is diffused//re-radiated/scattered/reflected/whatever. And 2600 watts we assume about 22% of direct sunlight also prevented from reaching
the surface:2600 – 572 = 2028 watts of direct sunlight. And direct and indirect of about 2150 watts.
So on earth our land surface is warmed to 70 C, from 1000 watts of direct sunlight.
What temperature does 2028 watts of direct sunlight do. With blackbody in vacuum it’s 435 K [161.85 C].. Earth has atmosphere so there is some amount of temperature [heat] loss depending on the air temperature.
To know air temperature one must know ocean temperature, as oceans cover 70% of the planet.
So 2150 watts per square meter of direct and indirect sunlight is not going to boil water, but certainly going to increase the amount of evaporation.
Earth present ocean reaches a surface temperature of 35 C, and the sunlight of 2150 watts might make around 50 C with enormous amount evaporation.
So with tropical water can reach 35 C and average air temperature of tropics is 26 C.
So one could ocean temperature reaching 50 C and have average tropical air temp of about 40 C.
And in desert air temperature might reach about 60 C [assuming there are deserts with all the water being evaporated by the oceans- though blazing sun could cause more deserts].
So 60 C air and and surface which could heat to 162 C [if no convectional losses]. So I would think there would a lot convectional heat loss and though land surface could reach or exceed boiling temperatures.
As general note probably life as evolved on Earth, would have hard time living in tropics- or anywhere land surface reaches boiling temperature, hard imagine plants surviving it. Basically one probably need land surface temperature to be below 80 C.
And if 2028 watts of direct sunlight is at 30 degree above horizon or less, then level surface get 1/2 of sunlight plus must travel thru twice as much atmosphere. Or probably 40% of land area could survivable for earth evolved plants, And ocean would less affected, perhaps as much as 20- 30% could death zones.for creatures near surface [probably varying depending on weather].
In terms of entire ocean, Earth is about 3 C, and at Venus distant could as high as 30 C- though polar ocean could much cooler, and one still get snow in winter at high elevations [but ice caps and polar ice, completely gone], And it take our present icebox climate Earth thousands of years to get such a warm ocean if “drop” our Earth into Venus distant from the sun. But seems ocean life could survive at that distant, and life on land could evolve to survive in larger area of land surfaces- compared to earth life- mainly in regards to the plant life.
richard verney asked, “If there is a positive water feedback loop as warmists postulate, what would stop run away global warming?”
That’s not how positive feedback works, Richard. It is a common misconception, so I wrote up an explanation here:
http://www.sealevel.info/feedbacks.html
Dave Burton – learn some ‘control theory’
Learn about amplifiers. Any ‘system’ where anything happens and something then happens can be thought of as a system/network of amplifiers.
First and most important thing to grasp is that an amplifier need not amplify as ‘the man in the street’ thinks.
There are inverting amplifiers (output goes opposite in sign to input)
There are non-inverting amplifiers (output moves in phase with input)
Of these 2 basic types, there are 3 variations on each.
1. Amplifier with unity gain.
Output is same amplitude as input and may or may not be inverted.
Commonly called a ‘buffer’
2. Amplifier with over-unity gain.
Output magnitude is larger than input and may or may not be inverted.
What is commonly regarded as an ‘amplifier’
3. Amplifier with less-than-unity gain.
Output magnitude is smaller than input and may or may not be inverted.
On your blog, you say non-inverting amplifiers have ‘positive feedback’ and inverting amplifiers are ‘negative feedback’
Innocent. Naive. Wrong.
In your example of a positive 10% feedback amp you describe a classic negative feedback amplifier because you are negating (removing) 90% of the output before you send it to the input..
In a true positive feedback system, the entire output is fed back to the input.
So, input of 1 becomes 1.1 output becomes 1.1 input becomes 1.21 becomes 1.331 etc etc
It is the classic compound interest calculation – you borrow one dollar at 10% interest and after 25 years you owe 13 dollars.
That is positive feedback.
That is a runaway system.
Peta from Cumbria, now Newark wrote, “Dave Burton – learn some ‘control theory’ / Learn about amplifiers.”
Been there, done that, got the T-shirt. Got a degree in it, in fact. Well, in Systems Science, which is the field that studies such things. (It’s really mostly a subset of EE.)
Peta continued, “On your blog, you say non-inverting amplifiers have ‘positive feedback’ and inverting amplifiers are ‘negative feedback’ / Innocent. Naive. Wrong.”
No, my site does not say that. It’s only “feedback” if it is actually “fed back” and added to the input.
Peta continued, “In your example of a positive 10% feedback amp you describe a classic negative feedback amplifier because you are negating (removing) 90% of the output before you send it to the input.”
Wrong. The “fed-back” output is added to the original input.
Peta continued, “In a true positive feedback system, the entire output is fed back to the input.”
No, if any part of the output is “fed back” and added to the input, it is a feedback system. (If inverted it is negative feedback, if not then it is positive.)
Peta continued, “So, input of 1 becomes 1.1 output becomes 1.1 input becomes 1.21 becomes 1.331 etc etc / It is the classic compound interest calculation – you borrow one dollar at 10% interest and after 25 years you owe 13 dollars. / That is positive feedback. / That is a runaway system.”
That’s wrong, but it is a common point of confusion. What you imagine to be a feedback system is actually an iterative device in which the output is substituted for the input, rather than added to it, after a defined delay (in your example one year). If the output is larger than the input then such a system is inherently unstable, and only the loop delay makes it not immediately so. The shorter the delay the more wild and immediate the instability, and with zero delay it is instantly unstable.
That’s the opposite of a classic feedback system. In a feedback control system, zero delay is the (impossible) ideal, but the closer you can get to it the better.
In a classic feedback system, (a portion of, or a signal derived from) the output is “fed back” and added to the input. The original input (or “forcing” as a climatologist would call it) is not replaced, it is merely augmented. As long as the loop gain is less than unity, such a system will be stable, even with zero loop delay. Positive feedback less than unity causes calculable, well-bounded amplification, not a “runaway” explosion.
With negative feedback, the effect of input changes is attenuated (reduced), rather than amplified (increased). With strongly negative feedback, you can get a great reduction in the effect of an input change, though high gain negative proportional feedback combined with a substantial loop delay can cause “overshoot” or oscillation (“ringing”), and the longer the loop delay the worse the problem.
the surface temperature of Venus is the result of the atmospheric lapse rate. the average temperature of the atmosphere is set by solar radiation, however due to the lapse rate the surface is warmer than average and the atmosphere towards the top of the lapse rate is cooler than average. Because the atmosphere on Venus is much denser than on earth, the lapse rate extends over a much greater distance, resulting in a much greater range of temperature.
The dry air lapse rate on both Venus and Earth are exactly equal to the force of gravity for the planet. It is equal to the exchange between potential energy and kinetic energy with altitude during convection. While the total energy of the atmosphere does not change with convection, the form does. And since only kinetic energy affect temperature, the lapse rate result in increased temperature with decreased height.
I believe the 90+ atmospheres of pressure along with the proximity to the sun pretty much explain the temperatures on Venus, irrespective of the atmospheric composition.
exactly. at approximately 50km altitude the atmospheric pressure of Venus matches that of Earth’s surface. the atmospheric temperature at that altitude is slightly greater than Earth, as would be expected since Venus is closer to the Sun. There is no runaway greenhouse effect, because it is the lapse rate, not back-radiation that is enhancing surface temperatures. And the lapse rate on Venus is HUGE as compared to Earth, even though gravity is slightly weaker, because it extends over a much greater vertical distance.
Well said, ferd despite some slight quibbles witrh the terminology.
I’ve been pointing that out for years.
ferdberple wrote, “The dry air lapse rate on both Venus and Earth are exactly equal to the force of gravity for the planet.”
No. 9.8 °C/km is not equal to 9.8 m/sec². That’s just a coincidence of numbers.
ferdberple wrote, “It is equal to the exchange between potential energy and kinetic energy with altitude during convection.”
That sounds like it makes sense, until you try doing the arithmetic, as I did here:
https://wattsupwiththat.com/2016/09/14/climate-skeptics-behaving-badly/comment-page-1/#comment-2300871
No. 9.8 °C/km is not equal to 9.8 m/sec². That’s just a coincidence of numbers.
=========
Metric system at work. Lapse rate = gravity/specific heat. Specific heat of air = 1 (approx).
So, no back radiation. Lapse rate determined by gravity. N2/CO2 will have slightly different specific heat but not enough to make much difference.
No. 9.8 °C/km is not equal to 9.8 m/sec². That’s just a coincidence of numbers.
=========
Metric system at work. Lapse rate = gravity/specific heat. Specific heat of air = 1 (approx).
So, no back radiation. Lapse rate determined by gravity. N2/CO2 will have slightly different specific heat but not enough to make much difference.
I stand corrected. Thank you!
ferdberple July 9, 2017 at 7:24 pm
the surface temperature of Venus is the result of the atmospheric lapse rate. the average temperature of the atmosphere is set by solar radiation, however due to the lapse rate the surface is warmer than average and the atmosphere towards the top of the lapse rate is cooler than average. Because the atmosphere on Venus is much denser than on earth, the lapse rate extends over a much greater distance, resulting in a much greater range of temperature.
The dry air lapse rate on both Venus and Earth are exactly equal to the force of gravity for the planet.
Not true, the lapse rate is equal to g/Cp. (ge=9.8, gv=8.9)
A further problem is that that equation is derived for an ideal gas, the Venusian atmosphere is far from Ideal, in fact the lower atmosphere is a supercritical fluid!
I would say that lapse rate depends on where the air it heated.
On earth the air is heated at sea level [mostly].
And one Venus the air is heated at around 50 Km or around 1 atm as earth atmosphere is
heated.
Or simple rule, if sunlight warms the planet, where is most sunlight is “blocked” in some manner, is where the heating occurs.
So with Venus one has clouds starting at elevation 30 km up to about 60 km, and these clouds block the sunlight from going lower in the atmosphere.
So it’s commonly said the Venus clouds reflect about 75% of sunlight.
The Venus cloud coverage is suppose to be global [covering entire planet].
And some sunlight gets thru the clouds to the surface [we know, because we photographs of the Venus being lit by sunlight]. And the sunlight at Venus surface is diffused and is like sunlight on Earth going thru clouds.
Now, it seems if Venus atmosphere is warmed at the level of the clouds, the amount of warming should depend on what elevation the clouds are which are blocking the sunlight. Or cloud elevation vary by as much as 30 km distance.
So looking in simple way, if clouds are the same at 30 and at 60 km, there should be different amount of heating depending what elevation they are at. Also if cloud were somehow the same, there should an optimal elevation which causes the most heating. Of course the clouds are probably not the same.
Now Earth also has clouds and do they also warm atmosphere as I am saying clouds do on Venus?.
I would think they do to some extent, but there is a lot difference regarding Venus as compared to Earth.
On earth there is lots different types of clouds [though maybe there even more different types of clouds on Venus]. and the different clouds on Earth would have different warming effect by being heated by sunlight, And any lapse rate effect would depend upon their elevation. And also high elevation clouds,even in warm tropics, have frozen ice particle rather than droplets of liquid water
at high enough elevation- though heating of ice particles in the cold air, doesn’t require the ice to melt in order to warm the air,rather instead they need to be warmer than the air. But sunlight would also melt and evaporate cloud droplets and ice particles. With Venus if droplets are undiluted acid,
they have very high boiling point- “337 °C (639 °F; 610 K) When sulfuric acid is above 300 °C (572 °F), it will decompose slowly”- wiki, Sulfuric acid.
Also clouds on Earth and probably on Venus can radiantly cool to space- or clouds would both be warming effect and also be cooling effect, in terms net planetary gain or loss.
So the bloody thing is complicated.
Hausfather is modestly above the others for venturing out on this instance but he took it mostly back by tarring honorable sceptic Nobel Laureates with his remark about Nobel disease. I’m compassionate about the remarkable Hawking because he may, as the longest survivor (70yr old) of the degenerative ALS disease, actually not be half his former self.
Hawkings’s not rushing over to BBC to tell them of his outrage over Trump. He may not even have heard of Trump until they grilled him (the reason: he’s still got stature with ordinary folk ) He’s being badgered for comment because immoral neomarxbrothers want to milk this poor fellow into the grave for their ideology which is under siege and soon to collapse.
Hausfather is basically part of the set who will rue the day when this egregious thing falls apart and their names are on the list of its promoters as indelible history – something that will follow them into retirement and old age – no memoirs to be written, at least by these folks themselves. Terms such as Karlization, Mannian statistics, Trenberth travesties, Death train Hansen, Algoreithms, Pachoochoo Voodoo science, and many more.
Some of them may be useful idiots that know not what they-ve done . Ironically, some who delude themselves into thinking they have a Nobel Prize are the ones with real Nobel Disease.
I notice the worst of them have suddenly agreed there was a pause. Santer who was the chief деиуя of the pause has just published that their was one after all! (a sort of get outa jail free card,? ) And this just after Hausfather published a paper proving Santer’s earlier abandoned belief and Karl of the Karlization who took one for the team and retired has just been thrown under the bus, too! Maybe no memoirs, but a Gilbert and Sullivan type operetta might do justice to the story.
I respect your opinion, but I think Hawking slipped on a banana peel while taking his final bow.
Other than that…yes, history will not be kind to the High Priests of the Warmista Brotherhood.
As well it should not.
I personally think the justice system should not be kind to them either.
Lubos,
The Venus Syndrome may have originated with Dr. James Hansen. Certainly it is trumpeted in Chapter 10 of ” Storms of my Grandchildren”.
Hansen says there that in December 2008 he gave the Bjerknes lecture at the annual meeting of the American Geophysical Union in San Francisco titled “Climate Threat to the Planet”.
He says,” I began my lecture with a discussion of the Venus Syndrome showing the ‘Goldilocks’ chart ( figure 29) I had used in my Iowa talk in 2004.”
With regard to Venus, he continues ” …So the early Venus atmosphere contained lots of water vapour. The sun was 30% dimmer at the time, so Venus was probably cool enough to have oceans on its surface.But they did not last long.As the sun brightened, the surface of Venus became hotter, water evaporated and the strong greenhouse effect of water vapour amplified the warming.Eventually a ” runaway ” greenhouse effect occurred, with the ocean boiling or evaporating into the atmosphere….
So Venus had a runaway greenhouse effect.Could earth? Of course we know that it could….”
Hansen has never recanted this material.
Hansen says the Bjerknes lecture was” taken from the “Efficacy of Climate Forcings” paper I published with several co-authors in 2005″.
The only good news here is that Hansen’s and Hawkings are now largely disowned and refuted even by Alarmist blogs. See ” Hawking is Wrong”: Andthentheresphysics,July 7,2005.
Stoat ” On Hawking Radiation ” etc.
Will Hansen or the AGU refute this nonsense?
In my http://cosy.com/Science/HeartlandBasicBasics.html on the impossibility of Venus being explained as a spectral GHG effect I include a clip of Hansen making his claim which should have been laughed out of an undergraduate heat transfer class ( full clip ) : http://cosy.com/Science/JamesHansenRunawayVenusGreenhouseEffect.avi .