Early Earth stayed warm because its ocean absorbed more sunlight; greenhouse gases were not involved, Stanford researchers say. See more about the Faint sun paradox here. A video clip follows.
From a Stanford University News press release.
Researchers have long wondered why water on Earth was not frozen during the early days of the planet, when the sun emanated only 70 to 75 percent as much energy as it does today. Some theorize that high levels of greenhouse gases in the atmosphere, the same mechanism cited in global warming today, were key. But new research involving Stanford scientists has a different explanation: The oceans, much larger than today, absorbed enough heat from the sun to avoid turning into ice.
BY LOUIS BERGERON
Four billion years ago, our then stripling sun radiated only 70 to 75 percent as much energy as it does today. Other things on Earth being equal, with so little energy reaching the planet’s surface, all water on the planet should been have frozen. But ancient rocks hold ample evidence that the early Earth was awash in liquid water – a planetary ocean of it. So something must have compensated for the reduced solar output and kept Earth’s water wet.
To explain this apparent paradox, a popular theory holds there must have been higher concentrations of greenhouse gases in the atmosphere, most likely carbon dioxide, which would have helped retain a greater proportion of the solar energy that arrived.
But a team of earth scientists including researchers from Stanford have analyzed the mineral content of 3.8-billion-year-old marine rocks from Greenland and concluded otherwise.
“There is no geologic evidence in these rocks for really high concentrations of a greenhouse gas like carbon dioxide,” said Dennis Bird, professor of geological and environmental sciences.
Instead, the team proposes that the vast global ocean of early Earth absorbed a greater percentage of the incoming solar energy than today’s oceans, enough to ward off a frozen planet. Because the first landmasses that formed on Earth were small – mere islands in the planetary sea – a far greater proportion of the surface of was covered with water than today.
The study is detailed in a paper published in the April 1 issue of Nature. Bird and Norman Sleep, a professor of geophysics, are among the four authors. The lead author is Minik Rosing, a geology professor at the Natural History Museum of Denmark, University of Copenhagen, and a former Allan Cox Visiting Professor at Stanford’s School of Earth Sciences.
The crux of the theory is that because oceans are darker than continents, particularly before plants and soils covered landmasses, seas absorb more sunlight.
“It’s the same phenomenon you will experience if you drive to Wal-Mart on a hot day and step out of your car onto the asphalt,” Bird said. “It’s really hot walking across the blacktop until you get onto the white concrete sidewalk.”
Another key component of the theory is in the clouds. “Not all clouds are the same,” Bird said.
Clouds reflect sunlight back into space to a degree, cooling Earth, but how effective they are depends on the number of tiny particles available to serve as nuclei around which the water droplets can condense. An abundance of nuclei means more droplets of a smaller size, which makes for a denser cloud and a greater reflectivity, or albedo, on the part of the cloud.
Most nuclei today are generated by plants or algae and promote the formation of numerous small droplets. But plants and algae didn’t flourish until much later in Earth’s history, so their contribution of potential nuclei to the early atmosphere circa 4 billion years ago would have been minimal. The few nuclei that might have been available would likely have come from erosion of rock on the small, rare landmasses of the day and would have caused larger droplets that were essentially transparent to the solar energy that came in to Earth, according to Bird.
“We put together some models that demonstrate, with the slow continental growth and with a limited amount of clouds, you could keep water above freezing throughout geologic history,” Bird said.
“What this shows is that there is no faint early sun paradox,” said Sleep.
The modeling work was done with climate modeler Christian Bjerrum, a professor in the Department of Geography and Geology, University of Copenhagen, also a co-author of the Nature paper.
The rocks that the team analyzed are a type of marine sedimentary rock called a banded iron formation.
Video: These rocks, billions of years old, tell a new story about the evolution of early Earth, Stanford researchers say.
“Any rock carries a memory of the environment in which it formed,” Rosing said. “These ancient rocks that are about 3.8 billion years old, they actually carry a memory of the composition of the ocean and atmosphere at the time when they were deposited.”
Another constraint on early carbon dioxide levels came from life itself.
In the days before photosynthetic organisms spread across the globe, most life forms were methanogens, single-celled organisms that consumed hydrogen and carbon dioxide and produced methane as a digestive byproduct.
But to thrive, methanogens need a balanced diet. If the concentration of either of their foodstuffs veers too far below their preferred proportions, methanogens won’t survive. Their dietary restrictions, specifically the minimum concentration of hydrogen, provided another constraint on the concentration of carbon dioxide in the atmosphere, and it falls well below the level needed for a greenhouse effect sufficient to compensate for a weak early sun.
“The conclusion from all this is that we can’t solve a faint sun paradox and also satisfy the geologic and metabolic constraints by having high carbon dioxide values,” Bird said.
But the theory of a lower Earthly albedo meets those constraints.
“The lower albedo counterbalanced the fainter sun and provided Earth with clement conditions without the need for dramatically higher concentrations of greenhouse gasses in the atmosphere,” Rosing said.
Beautiful science
It’s easier for mankind to lower albedo, e.g. with soot. I’m of the belief that cooling is certainly in the future, and perhaps we can do something about it. Maybe even AGW will be beneficial in that regard.
In South East Alaska and Iceland, cloudy weather is warmer than clear weather (all else equal). Where does the heat come from, if clouds are supposed to keep it from reaching the ground?
Please note that back in June 2009 I proposed this very solution to the faint early sun paradox here on WUWT, in The Thermostat Hypothesis. As usual, WUWT is way ahead of the news, you read it here first … many thanks, Anthony.
The oceans, much larger than today
Twice, three or more, times as large? 🙂
a far greater proportion of the surface of was covered with water than today
Same deal.
The existence of 4+ Gyr old Zircon grains indicates presence of continental crust early in the Earth’s history, and there is good evidence that the Earth lost its atmosphere and hydrosphere early on and that they have been gradually added since, so the situation is not that simple.
Has any credible science come out in the last several years that actually supports AGW?
The 2010 Sophie Prize is awarded to James E. Hansen for his clear communication of the threat posed by climate change and for his genuine commitment to future generation (Photo: Greenpeace).
The Sophie Prize is an annual environment and sustainable development prize (US$ 100.000). This is the thirteenth time it has been awarded. The prize was established in 1997 by the author Jostein Gaarder and Siri Dannevig.
http://www.sofieprisen.no/Prize_Winners/2010/index.html
“The oceans, much larger than today, absorbed enough heat from the sun to avoid turning into ice.”
“with a limited amount of clouds.”
“lower Earthly albedo.”
Entirely consistent with my suggestion that since then the Earth’s tropospheric temperatures have remained largely stable (subject to continental changes) due to the hydrological cycle now being faster than then.
Just extend Willis Eschenbach’s Thermostat Hypothesis to include the entire hydro cycle globally rather than just the tropics and there you have it.
‘Paradox’. That is one of the most misused words in academia.
Who are all these people who wrongly use ‘paradox’ to mean ‘problem’ or ‘contradiction’? What word do you use to mean the correct definition of ‘paradox’? bullblop?
Insane. As bad as those who at every opportunity replace ‘change’ with ‘evolve’.
Willis covered this. Since cold heavier air falls because it is higher density, we know clouds offer an insulation effect.
It is very sad that the “hot shot ” models of warming for the most part demand the total amount of cloud cover is constant.
Nope, I do not buy it: like the greenhouse gas hypothesis, this “albedo” hypothesis demand that an opposing effects happen to quite precisely counterbalance the increasing solar output, and this just by chance because both the greenhouse and albedo are independent from solar output (at least, the authors do not explain what mecanism would increase albedo (or decrease greenhouse gas for the greenhouser) in proportion of solar radiation – on the contrary both are considered positive feedback mecanism – at least among the warmist).
This is too much chance for me…
Something like the thermostat hypothesis sounds more likely, the fact that a lot of liquid water exist on earth ad allow to move quite a lot of energy by phase-changing and convection is likely the key…Also, Venus should be studied more, because obviously it did not turn out the same way for our planet sister…Why? At what point did it diverge? Is the moon (another very special thing about the earth) the main difference?
Those are the line along which I would base my research for trying to explain faint sun paradox, if I was at the start of my PhD or on a new grant…but hey, I am just a dilettante, neither geology nor astronomy, nor climatology are my specialities 😉
The earth’s rotation was faster in the past. Would shorter nights tend to reduce the total amount of outgoing long wave radiation somewhat?
Is it possible that the earth’s orbit was closer to the sun? That would make up for lower insolation.
gkai (12:28:22) :
just by chance because both the greenhouse and albedo are independent from solar output
For the Svensmark enthusiasts: the early solar wind was 100-1000 times a vigorous back then so few galactic cosmic rays would have made it to the Earth, so no low clouds [and higher albedo] due to them…
What about the amount of cosmic rays reaching the Earth back then? If the sun was so faint, a whole lot of cosmic rays must have been reaching the inner solar system. There must have been a lot of clouds creating a major greenhouse effect keeping the Earth warm and cozy… or is it that water vapour did not exist back then?
Give me a solar shield and i’ll freeze the earth solid in one day, amused God.
Phillep Harding (12:02:13) :
“In South East Alaska and Iceland, cloudy weather is warmer than clear weather (all else equal). Where does the heat come from, if clouds are supposed to keep it from reaching the ground?”
Here are two possibilities:
(1) If this is happening at nighttime, then it is simply the case of the cloud cover preventing ground infrared radiation escaping completely into the night sky (back-radiation effect).
(2) Otherwise, if the clouds are forming or precipitating, they are condensing liquid water from water vapor, which releases approximately 1400 joules/kilogram. Air has a specific heat capacity of about 1 joule per gram-kelvin, which means that the condensation of 1 kg of water can raise the temperature of 14 kg of air by 0.1 kelvin (if I did my math correctly). I live in the Puget Sound area of the Pacific Northwest, where our rainfall is quite steady through the year. As long as the weather is rainy, we can rely on it not being freezing.
“In South East Alaska and Iceland, cloudy weather is warmer than clear weather (all else equal). Where does the heat come from, if clouds are supposed to keep it from reaching the ground?”
The simple answer is that the clouds act like an insulating blanket, keeping heat from radiating back into space at night. That’s why deserts are hot during the day and cold at night, no clouds.
Willis’s thermostat hypothesis explains part of it. So does Ferenc Miskolczi’s theory.
There are at least three major factors equilibrating the earth’s temperature (i.e., providing negative feedback).
1) The tropics heat up and winds and ocean currents carry this heat toward the poles. More heat results in stronger currents, carrying more heat away.
2) When the tropics heat up, more water evaporates, which rises and eventually condenses. The heat of evaporation has been lifted from the surface to somewhere high in the atmosphere where it can more easily escape the atmosphere to space. Rain falls and the cycle continues.
3) Miskolczi says that water vapor will equilibrate the greenhouse effect. We don’t need CO2 for the greenhouse effect. Add more CO2, and the earth will reduce the equilibrium amount of water vapor. Less CO2 and there’ll be more water vapor.
The early earth just had to be warm enough to start this process. Assuming there was any liquid water, then there was water vapor, and with water vapor comes the greenhouse effect. The three effects above start doing their things and, bingo, temperature equillibrates.
BTW, the earth is 70% water. It couldn’t have been that “a far greater proportion of the surface of was covered with water than today.” At most, it was 30/70 = 43% if the entire surface was water.
Because the first landmasses that formed on Earth were small – mere islands in the planetary sea – a far greater proportion of the surface of was covered with water than today.Because the first landmasses that formed on Earth were small – mere islands in the planetary sea – a far greater proportion of the surface of was covered with water than today.
An expanding earth too could explain that, assuming the amount of water was the same then.
Prof. Svalgaard, could you give some context of your Zircon argument? What is the evidence that the earth lost its hydrosphere? And by what mechanism the earth regained it’s hydrosphere? I remember a certain radio-astronomer who was afraid to be declared crazy when he realised that radar data suggested that our earth is still receiving large daily amounts of ice meteorites, many of them as big as a bus.
Dan (Norway) (12:16:41) :Is that a prize for SOPHISTS? Then, he deserves it.
Are we assuming that the solar nebula (as currently seen via the zodiacal light and the gegenschein) was much thinner due to the higher solar winds billions of years ago?
Thunderstorms and Cumulus clouds tend to form when the air is warmer. These are negative feedbacks which help regulate the Earth’s temperature.
The reason why cloudy nights tend to be warmer is because clouds emit LW radiation towards the surface. A larger percentage of the radiation arriving at the surface originates from the atmosphere and clouds, than from the Sun.
So many things is the past are different from today. The composition of the atmosphere and the rotation time of the Earth, much faster then. The distance of the Moon to the Earth, this causes extreme tides and many have put more water vapor in the air, also being closer the tides on the crust would have been greater. There was less land mass and a different configuration of land masses changing ocean circulation patterns. The ocean itself was made up of different compounds than today along with a different color. The Earth was also still cooling and may have had significant heat coming from the crust.
“An abundance of nuclei means more droplets of a smaller size, which makes for a denser cloud and a greater reflectivity”
Does Svendsmark take this density/reflectivity component into account, or does his theory just assume greater coverage by clouds?
Also the atmospheric pressure counts.
Leif Svalgaard (12:36:52) :
gkai (12:28:22) :
just by chance because both the greenhouse and albedo are independent from solar output
For the Svensmark enthusiasts: the early solar wind was 100-1000 times a vigorous back then so few galactic cosmic rays would have made it to the Earth, so no low clouds [and higher albedo] due to them…
~
And what kind of interstellar medium would the sun have been embedded in then. Very hot, hot, medium, cool or cold would you say..?
Like somehow ah this should matter somewhere in the history of this planet. Well, maybe not in this particular instance. Yeah right, doesn’t make a difference. Can anyone tell me exactly what proportions of what were in the interstellar medium at the time?
It’s madness I tell you, madness. hahahhahahhahahhahaha
There had to be lower Albedo (as well as more greenhouse gases).
The chart at the beginning from Kastings shows that solar irradiance reaching the Earth has increased since the Sun reached main sequence maturity by about 30% (in close to a straight line) over time.
That means solar irradiance at the top of the atmosphere was just 1186 watt/m2 about 2 billion years ago (versus 1366 watts/m2 today).
The equilibrium temperature would have been about 10C lower than today and, in that situation, the mid-latitudes would be frozen over permanently and the ice-albedo feedback would leave the Earth as a frozen snowball. There would not be enough greenhouse gases to overcome this.
Now if the cloudiness of the early Earth was about half what it is now and there was more ocean versus land then, the lower solar irradiance would have been completely offset and the average temperature would be about the same as today.
It is the only answer that works.
Or the Earth was created as it is today and scientists can’t deal with that.
Leif Svalgaard (12:36:52) :
better, but still a little bit far fetched: I am still thinking a more direct regulation should be responsible, Svensmark theory is interresting too but it has a feel of second-order effect, just like the CO2 in fact.
Thermostat hypothesis is my current favorite one, with the strongly related “heat engine” apporach. Intuitively it feel powerfull enough to be a first-order regulator…
I also like it a lot because it emphasize the timing and spatial distribution of the cloud cover, something I do not have encountered in other theories…and to emphasize this is strongly needed: often the distinction is made between lower and higher clouds, always discussing the average cloud cover, with a lot of uncertainties regarding feedback: do more clouds warm or cool the surface? Well, imho, the incertitude just comes from the fact that average cloud cover is a really really bad metric: at night or near the poles, it is a warming effect, in the day closer to the equator, a cooling. Like any insulator, the net effect is cooling when it is “warmer outside”, warming when it is “cooler inside”.
So just mentioning average cloud cover without discerning by latitude or time or the day looks like utter nonsense, like asking what will be the effect on temperature of increasing the insulation without knowing if you insulate near a hot spot or a cold spot: Either a lot is lost in the simplified versions of many theories, or climate modelers never have used the same thermos to keep their ice tea cold and their coffee hot 😉
oups – warming when it is “cooler outside” of course….
Wasn’t the Earth, like, much smaller back then? (ducks) 😉
Phillep Harding (12:02:13) : “In South East Alaska and Iceland, cloudy weather is warmer than clear weather (all else equal). Where does the heat come from, if clouds are supposed to keep it from reaching the ground?”
Easy. Clouds also retain heat, preventing heat at ground level from radiating off at night-time.
gkai (13:41:28) :
Radiative Transfer Models used by GCMs are reasonably good at modeling both incoming and outgoing radiation, based on a given set of parameters.
“In South East Alaska and Iceland, cloudy weather is warmer than clear weather (all else equal). Where does the heat come from, if clouds are supposed to keep it from reaching the ground?”
When it is cloudy in South-Iceland (say Reykjavik where I live) the wind is usually blowing from the south and is mild. At the same time it is usually sunny in North-Iceland (say Akureyri) and the weather there often very warm.
When it is sunny in Reykjavik the (cold) wind is often blowing from the north. Then the weather can be beautiful but not very warm. At the same time it is cloudy, rainy and cold in Akureyri, with the cold and wet wind blowing from the sea.
gkai (12:28:22) : “Nope, I do not buy it: like the greenhouse gas hypothesis, this “albedo” hypothesis demand that an opposing effects happen to quite precisely counterbalance the increasing solar output, and this just by chance because both the greenhouse and albedo are independent from solar output (at least, the authors do not explain what mecanism would increase albedo (or decrease greenhouse gas for the greenhouser) in proportion of solar radiation – on the contrary both are considered positive feedback mecanism – at least among the warmist).
This is too much chance for me”
Perhaps chance is what happened and the only reason that we are here today is because that chance just happened to be right enough for Earth to become a place where plants and animals could evolve and a species such as humans could wonder about these things.
Hugo M (13:05:13) :
An expanding earth too could explain that, assuming the amount of water was the same then.
The Earth has not been expanding [rather contracting a bit when cooling]
some context of your Zircon argument?
Oxygen isotope studies indicate that the magma from which the zircons originated was recycled rock that had interacted with surface waters, showing that continental crust existed and was eroded by water [like today], and that tectonic processes like subduction were also operating.
What is the evidence that the earth lost its hydrosphere? And by what mechanism the earth regained it’s hydrosphere?
The ‘heavy bombardment’ that stopped about 3.9 Gyr ago would have evaporated the hydrosphere intermittently with new water being added by the very impacts that scour away the old, indicating a very dynamic, chaotic, and changing environment. Bottom line: we don’;t know and can’t just assume that everything was quiet.
rbateman (13:09:06) :
Are we assuming that the solar nebula (as currently seen via the zodiacal light and the gegenschein) was much thinner due to the higher solar winds billions of years ago?
No, there was also generation of new dust from incessant collisions.
Carla (13:19:52) :
And what kind of interstellar medium would the sun have been embedded in then. Very hot, hot, medium, cool or cold would you say..?
Probably didn’t matter because of the strong solar wind blowing everything away.
Rob (13:37:21) :
Or the Earth was created as it is today and scientists can’t deal with that.
Or it was created last Tuesday [with everything – including we and our memories – included]. 🙂
What’s that they looked at the rocks to find out if there was more CO2 billions of years ago? Don’t they know you aren’t suppose to look at data, you are suppose to make computer models, and the computer models will tell you that there was more CO2 back then.
Hugo M: Prof. Svalgaard, could you give some context of your Zircon argument? What is the evidence that the earth lost its hydrosphere?
He’s probably using the old assumption that the early Earth grew so hot that all the volatiles, including water, had outgassed and been lost to space. It was suspected that all the water came from comets/meteors, but that also ignores the water which exists in molten rock. There is evidence that full outgassing did not happen, including very old material inside zircons which required temperatures which imply an ocean was present. When the Moon was formed, we may have had a rock atmosphere but it apparently only lasted a thousand years or so, and there was an ocean immediately afterward.
Rob (13:37:21) :
Or the Earth was created as it is today and scientists can’t deal with that.
According to the scriptures it wasn’t created as it is today. There was no rain, for one thing. And there’s that whole fall from perfection thing.
So… 🙂
Since all the oxygen was locked up in CO2 there would not have been an ozone layer and hence UV would have been absorbed at the surface. The lack of an ozone layer would also mean completely different atmosphere dynamics since there would have been no stratospheric zone. Of course we are in an ice age so earth is normally a lot warmer than now to.
Leif Svalgaard (12:05:26) :
The existence of 4+ Gyr old Zircon grains indicates presence of continental crust early in the Earth’s history…
No, the existence of 4+ Gyr old zircon grains indicates the presence of partial melting of oceanic crust resulting in the formation of felsic (or granitoid) rocks at depth. These rocks may have not made it to the surface for 100’s of millions of years. There is evidence of crust at 2.8 Gya, island arc volcanics. The presence of the zircons does say that plate tectonics was active early in earth’s history.
I would suggest that the mechanism is convection versus conduction that increases the absorption of heat in a fluid compared to a solid.
So just how did they manage to keep the water from becoming a greenhouse gas and form clouds ?
To me, this “faint sun” hypothesis, is no paradox.
It is simple demonstrative proof (here I go way out on a limb and accept their assertion that there was such a faint sun) that the temperature comfort range here on earth, is feedback controlled almost entirely by the Physical and chemical properties of the H2O moloecule. And I should add, that probably biological processes (eventually) became part of the total chemistry of H2O.
If that simple concept is in fact true, that cloud cover modulation is the negative feedback regulation mechanism, that defeats any attempt by CO2 or any other GHG (including H2O) to overheat th planet; then it must be equally obvious, that the same feedback loop is also capable of filtering out real actual changes in solar output; either increases or decreases.
So there is no faint sun paradox; a variable sun is just another driving signal that is regulated by the cloud feedback.
No I don’t plan to ask for grants to spend the rest of my life proving this simple and quite obvious regulatory mechanism; but long after AGW rots on the trash heap of history along with ancient astrology; I’m sure it will be standard educational fair for new generations of young mush heads.
Paul Hildebrandt (15:01:27) :
These rocks may have not made it to the surface for 100’s of millions of years.
The amount of 18Oxygen in the zircons indicate that they were formed interacting with surface water.
It is strange that no-one discusses the concentration of Methane in the early atmosphere. In the “greenhouse warming” stakes, Methane leaves Carbon Dioxide streets behind.
The paper described actually talks about Methanogens – bacteria which produce Methane – as being part of the early earth system. With a low level of Oxygen in the early atmosphere, the Methane would have been relatively long-lived and so would surely have built up to a relatively high concentration. If that was the case, who needs Carbon Dioxide to produce warming – the Methane will do it all on its own…
The crux of the theory is that because oceans are darker than continents, particularly before plants and soils covered landmasses, seas absorb more sunlight.
“It’s the same phenomenon you will experience if you drive to Wal-Mart on a hot day and step out of your car onto the asphalt,” Bird said. “It’s really hot walking across the blacktop until you get onto the white concrete sidewalk.”
Water is not black. Oceans appear black because there is not much or no light coming back out. As you descend in water it gets darker and darker until it is pitch black. I have always experienced the warmest sea water in the shallows perhaps because the sun can warm sea floor particularly if it is sand. And, unlike a black top oceans are also highly reflective. I have never seen a photo of tarmac with the sun reflected in it’s surface.
If there was a greater surface area of oceans in the past then perhaps there were significantly more shallows also.
I have to recall 1976 again as my benchmark. The sea in Bournemouth that summer became warmer and warmer until it was possible to walk in without any of the usual acclimatisation. Bournmeouth bay is a large sheltered and shallow bay with a sandy bottom. The same summer I also visited a place called Dancing Ledge, just along the coast. There is no beach here, just a vertical rock face into 3 or 4 metres of water. It was disappointingly cold.
Leif Svalgaard (15:17:05) :
Paul Hildebrandt (15:01:27) :
These rocks may have not made it to the surface for 100’s of millions of years.
The amount of 18Oxygen in the zircons indicate that they were formed interacting with surface water.
——
I should clarify this: the zircons formed at depth, but the magma they formed in was recycled from surface rocks that had interacted [retained] with water, hence the 18 O ratio.
Negative feedback is a very powerful regulation mechanism.
Back when I was working on my Master’s Thesis (on electronically discriminating between Gamma rays, alphas, betas, and neutrons) using high counting efficiency Scintillation Crystal detectors such as stilbene or anthracene, I had to use a standard rack mounted vaccuum tube pulse amplifier, to amplify the output from a photomultiplier.
This pulse amplifier was of a fairly standard architecture for that day and age. Two nearly identical “ring of three” vaccuum tube feedback amplifiers in series.
The input to each stage contained both a high pass, and low pass adjustable cutoff frequency filter, and in between the two stages was a wide band attenuator to com=ntrol the input to the second stage.
Each “ring of three” amplifer, contained two cascaded common cathode gain stages, plus a final cathode follower output to drive output loads. Then overall feedback around the amplifier set the Voltage gain at a fixed Gain of +100, so the total gain could be 10,000, if no interstage attenuation was used. The outprut ring differend from the input one only in that the input stage employed a very low noise input tube, while the final stage, included a high power output tube to drive heavy loads.
The maximum bandwidth was from about DC to 20 MHz, relatively fast for that day and age, and the output stage was supposed to be able to deliver 100 Volt peak output pulses, with a certain noise performanbce.
Well when I got this amplifier, which had been around the place for eons, it worked very well, but fell short of its specs in two ways. First off, it was a good bit noisier than I had expected from the spec; and I couldn’t get more than a 90 Volt peak pulse out of it, although the spec claimed 100.
It also had a faint blue glow, which wasn’t mentionewd in the specs, but I used it any way. I asked my thesis supervisor if he thought the spec shortfalls were a problem, or whether I should just get the best results I could and not worry about it.
He offerend that since the amplifier had been in the department for years, it might have a bad tube in it. A bad output tube certainly would limit the output drive, and a bad input tube would make it noisier. So he suggested I test all the valves on a tester we had that measured the Gm of tubes, and other parameters; so I could find the bad tube.
So I pulled out all six of the tubes, and labelled them so they would go back in the same places, and went off to the tube tester, to see whether any of the tubes had less Gm than the data sheet said in the RCA handbook.
Well Glory be; lookey here ! To my utter astonishment; there wasn’t a single one of those six vaccum tubes that showed any measurable Gm when tested in the tube tester with the standard setting for that tube type.
All six of them were stone cold dead; they just hadn’t burned out their cathode heaters yet; but the cathodes had long since vaporized off most of the thermionic emission material from the cathode.
So a quick trip to the local valve emporium for what were relatively standfard radio type RCA tubes, and a new set of tubes was purchased.
When I fired up the amplifier, with new living vaccuum tubes, I found I could easily get 120 Volt output pulses, and the amplifier was as quiet as a church mouse.
Now the former dead amplifier, had still exhibited a stage gain of about 100 in each stage, since that was set by two precision wire wound resistors; and the gain really didn’t change perceptibly with the new tubes.
The ring of three architecture was a common feedback amp type, that was developed back in the “Rad Lab” days of MIT for Radar, and other purposes, and it permitted the use of an enormous amount of negative feedback to control its properties, which my experience showed were damn near entirely independent of the properties of the active gain elements; the tubes; which were dead on their feet and still kicking A***.
Well you see; old sol out there which Leif Svalgaard watches, and keeps tabs on its Gm, and its blue glows if any, is like one of those ring of three feedback amplifiers driving my system.
Yes it wanders around and doesn’t change a lot as regards its TSI, sso its Gm isn’t changing much; despite all the other skullduggery that that place may get up to; which will affect us indirectly; But I doubt that one can find mcuh solid linkage between the sun’s TSI and earth’s climate.
Sure it is the driving energy source, and as Leif constantly reminds us, plays other games besides TSI; but I believe that it is those two precision wire wound resistors that Gaia made and put into the cloud system; by her choice of physical properties for H2O; including that 104.5 deg bend; that is what is defeating all our efforst and all of geology’s efforts to screw things up royally.
So no I don’t beleive in any “weak sun” paradox. Weak sun maybe; but H2O takes care of that too.
Everyone reading this should realize that this is just one more THEORY explaining how the so-called young-sun paradox could be explained.
There are several others, some of which seem to still indicate the presence of much larger amounts of methane during this early time period. See for example:
http://www.nature.com/nature/journal/v440/n7083/pdf/nature04584.pdf
There is no proof of anything here, and even if this theory is correct, which it could be, it does not in any way affect or negate the dynamics of our current time period, as we have a completely different set of atmospheric dynamics, solar dynamics, ocean dynamics, etc…i.e. CO2 is still a greenhouse gas as is methane, and this study wasn’t meant to refute the basic physical properties of these compounds…rather, it is ONLY meant to provide one possible theory for the so-called young sun paradox. For AGW sceptics or believers to attach any importance to this particular theory related to the AGW debate is unwarranted.
The early proto-continents were quite dense and subducted back into the mantle much more readily. It took some time for these processes to distill out the lighter silicates which became our current lighter density and far more enduring continental plates. This more rapid overturning of the earlier and denser proto-continents promoted the burial and formation of the zircons.
Arigato gozaimasu Leif Svalgaard San for sparing your time.
I still think it is a combination of things.
I hope Svensmark’s theory will be validated ( again? ) by CLOUD.
The crux of the paper quoted above does not seem to explain the conundrum.
So much to learn/discover. So little time meh?
But that’s just my uneducated dolt’s opinion.
Michael J. Dunn (12:45:14) :
Phillep Harding (12:02:13) :
Michael, your point to Phillip will be greatly magnified with the correct factors:
~580 Cal/g or ~2425 kJ/kg, not 1400 J/kg
~1 Cal/g/K or ~4.2 J/g/K, not 1 J/g/K
“”” Michael J. Dunn (12:45:14) :
Phillep Harding (12:02:13) :
“In South East Alaska and Iceland, cloudy weather is warmer than clear weather (all else equal). Where does the heat come from, if clouds are supposed to keep it from reaching the ground?” “””
Correct observation; but wrong question.
Why didn’t you ask; “Where do those clouds come from?”
I’ll rephrase your observation.
“In South East Alaska and Iceland, warmer weather is cloudier than colder weather (all else equal). Where does the cloud come from, if warmer surface temperatures are supposed to cause more water vapor in the atmosphere?”
Maybe the clouds are a direct result of the warmer (and more humid) surface conditions; rather than being the cause of those conditions.
I see the phenomenon on an almost daily basis (in California) dewey lawn and dew all over my parked car, but clear sky before sunup. As the sun rises and the day warms up, the mositure on my car and lawn all evaporates, and eventually clouds start to form at higher altitudes, and the hotter it seems to get at the surface during the day, the higher that newly forming cloud layer will be by sunset.
Another tail wagging the dog phenomenon.
There is weather, then there is climate, and then there is Geology!
OT. The DMI polar temperature shows a very large jump in temperature in the last few days and also a large discontinuity. Watts up with that?
“”” David Segesta (16:59:25) : “””
David these wild gyrations freaked me out last year.
Let me suggest that you go down the page a little and bring up some of the past year complete year plots, and all of a sudden it will become clear to you what a normal year looks like.
Which doesn’t mean the answer to you question isn’t of interest; but at least you will see that it isn’t too differnt from previous years.
My guess is this is the result of totally wild Nyquist sampling violations; and isn’t really what the arctic is doing at all. Also suggests it is weather rather than climate.
George
Leif Svalgaard (15:17:05) :
The amount of 18Oxygen in the zircons indicate that they were formed interacting with surface water.
The heavy oxygen isotope signature is a sign that the zircons formed in a cool wet sedimentary environment according the reference I read from NASA. However, zircons don’t crystallize in cool, wet sedimentary environments. They crystallize at depth in cooling magmas, not near the surface in sedimentary environments. What this means is that the zircons incorporated oxygen into their structures from sediments that had been subducted and melted at depth. This means that weathering of rock was occurring near or at the surface (turbidites) and being subducted. It does not mean that their were continental land masses present at this early stage of earth’s history. What it also means is that plate tectonics was working at a very early time. Much earlier than once thought.
As for the heavy oxygen isotopes, I’m not sure about that at the moment as I always thought that the early earth atmosphere didn’t have much in the way of oxygen. Must have come from the weathering of any existing rock.
I’m not so sure about this. I know that Lindzen and Rondanelli argued that the FYSP was resolvable by the Iris Effect:
http://www.agu.org/pubs/crossref/2010/2009JD012050.shtml
“”” Stephen Skinner (15:29:22) :
The crux of the theory is that because oceans are darker than continents, particularly before plants and soils covered landmasses, seas absorb more sunlight.
“It’s the same phenomenon you will experience if you drive to Wal-Mart on a hot day and step out of your car onto the asphalt,” Bird said. “It’s really hot walking across the blacktop until you get onto the white concrete sidewalk.”
Water is not black. Oceans appear black because there is not much or no light coming back out. “””
Funny thing that; oceans appear black because there is not much or no light coming back out.
That is exactly the same argument that is offered as to why coal of tar, or flat black paint’s look black. Maybe they aren’t black either; it’s just that they look black, because not much or no light comes back out.
HP once made a very sensitive thermoplie sensor for broadband LWIR radiation. The achieved a surface which “wasn’t black” but “looked black”; it was actually gold; metallic ordinary gold. Well the surface was made up of zillions of tiny gold nano-partilcles; long before the term nano-technology ever was thought of.
And that labyrinthine nano surface looked as black as the ace of spades over the entire spectrum from UV out to 100 micorns and more; an almost perfect black absorbing surface. You might even be able to google up on an HP or maybe Agilent Technologies site; the original HP journal description of that sensor.
I really don’t have a good idea what Black means; other than some things “look black”, because not much or no light comes back from them.
The deep oceans are like that, because about 97% of at least solar spectrum radiation propagates into the water, and not much comes back out if the water is deep enough and clean enough.
In an early pre biological ocean; the water, might have been much more transparent than it is today. Phyto and zoo planktons do a lot of light absorption; and maybe there are also microbial critters that do too.
Without the atmospheric blue light scattering, I’m quite sure that from outer space, we might regard earth as the black planet, rather than the blue planet.
Leif Svalgaard (14:36:05) :
Carla (13:19:52) :
And what kind of interstellar medium would the sun have been embedded in then. Very hot, hot, medium, cool or cold would you say..?
Probably didn’t matter because of the strong solar wind blowing everything away.
~
So you say.
I’m picturing a hotter interstellar medium, very possibly flowing in the same direction of travel as the solar system. Maybe even shorter solar cycles here there Leif.
Unlike today where the interstellar cloud the solar system is embedded in, is traveling in the “opposite direction.” (we have a head wind)
Not to mention again, (but I like it) that indications are we are in the transition zone between the LIC local interstellar cloud and G cloud.
And lest we forget, haha the G cloud is faster, cooler and denser than the previous LIC cloud.
If the interstellar medium is hot, it would affect the entire system. Direction of travel changes in either or all also would.
Way too many missing pieces.
They said one of their assumptions was that the condensations nuclei sources were inadequate to provide large rain drops.
So when did some one invent the first volcano? Seems like todays volcanos are know to generate at least some nuclei that would be associated with rain.
The continental drift shows there has been no loss or gain of water on this planet since back to when water was finally settled.
This planet was also rotating much faster then today and orbited closer to the sun.
gkai (12:28:22) :
Also, Venus should be studied more, because obviously it did not turn out the same way for our planet sister…Why? At what point did it diverge?
—-
REPLY: Good topic to mention! I’ve repeatedly heard breathless climatologists compare Venus’s “runaway greenhouse effect” to what might happen on Earth.
However, Venus’ atmosphere is totally different from Earth. It is about 96% carbon dioxide, and the clouds are sulfuric acid, not water vapor! I believe Dr. Lindzen has spoken about the misuse of the comparison of the two planetary systems in lectures.
Talk about comparing apples to oranges….if Earth ever did encounter a runaway greenhouse effect resembling that of Venus, all life would be reduced to molecules.
Oceans also have a much denser density then land and is more dense the deeper you go. This effects heat exchange.
Leif Svalgaard (12:36:52) :
gkai (12:28:22) :
just by chance because both the greenhouse and albedo are independent from solar output
For the Svensmark enthusiasts: the early solar wind was 100-1000 times a vigorous back then so few galactic cosmic rays would have made it to the Earth, so no low clouds [and higher albedo] due to them…
Yes I had noticed that Svensmark cosmic ray theory works well very early in Earth’s history. Of course, it is still speculative as you are right to point out. Nevertheless Svensmark’s theories are currently being tested at CERN and, at least on this front, we should get some confirmation of the validity or otherwise of this cosmic ray hypothesis.
On the contrary, it does indicate the presence of a continental crust and plate tectonics.
Paul Hildebrandt (17:27:02) :
As for the heavy oxygen isotopes, I’m not sure about that at the moment as I always thought that the early earth atmosphere didn’t have much in the way of oxygen.
The 18O enrichment comes from evaporation of water where the lighter 16O preferentially evaporates leaving water with more 18O.
Carla (17:39:40) :
Way too many missing pieces.
Which means that you cannot just jump to the conclusion you like since there is no specific evidence for it.
This is interesting stuff. Obviously, at some early point, the Earth’s surface was predominantly water-covered. Thus the oceans of that time would have occupied something like 1.43 times as much area as today’s oceans (the Earth is not expanding or contracting. Maybe it has contracted a little since, say, 5 BY ago, when the interior was hotter than today; see below).
It is likely that plate tectonics initiated somewhere in the vicinity of 4.5 to 4.0 billion years ago. At that time the interior of the earth was hot compared to today, as a result of core formation and radioactivity (half or more the initial complement of U238 is now gone, only about a tenth the U235 remains, and technetium and much thorium is completely gone). Volcanism would have been prolific, and the mantle must have been relatively active probably resulting in spreading rifts galore. At some point, numerous little island arcs must have formed over subducting slabs of crustal material.
Still this had to have been a chaotic affair. Large meteorites were still smashing the Earth’s surface, affecting earth, sea and atmosphere. A lot of energy was being imparted into the Earth’s oceans by the Earth and by cosmological effects.
Still, in today’s Earth, chunks of terrane dating 4.0+ BY might amount to 1 percent of the 43% that is dry land (mainly in Greenland and Northwest Territories; can’t recall any others that age offhand). By 3.5 BY there are more significant chunks – parts of South Africa and Zimbabwe, maybe some Australia. By 2.7 BY there are substantial areas – much of Ontario, Quebec, Northwest Territories, Western Australia, Western Africa and Congo, Fenno-Scandia, Siberia, and India (and these are metamorphic ages; the absolute ages of these rocks could be older). And so forth. The Earth incrementally adds continental crust, and manages to aggregate all the little chunks formed here and there into bigger and bigger cratons as time goes on.
We can map to some extent the Earth’s crustal changes. Information in the rocks themselves sheds some light on other systems, like atmospheric composition, temperatures and so forth. But we’ll never concretely know much about the early evolution of the hydrosphere and the atmosphere, or of life itself, although we should increasingly be able to make good guesses.
It’s fun stuff, subject to much arm waving. But the key thing is, regardless how much chaos and radioactivity and kinetic energy and so on, the Earth has supported the proliferation of life of a certain kind from early on (the first algal mats preserved are something like 3.5 BY). From about 600 MY ago, no matter what Nature threw at the Earth, life has survived and further proliferated. Earth has maintained – regardless of the state of the Sun, whether or not massive bodies are slamming into us, volcanism on scales we’ve never witnessed, ice ages galore, etc. – a haven for life. The great “global warming” scare is purely bullshit in the face of this history.
But science that helps us understand the evolution of this magnificent world and universe is good. Thank you Stanford and thank you Anthony for bringing it to our attention.
One other aspect that should be considered is that the oceans were not, in fact, blue in the early Earth. They were likely a slight red color until all the iron and other metals were dissipated out by the rise of oxygen.
The atmosphere would also have had more combustible gases like methane until oxygen became more prevalent. The Ozone layer did not develop until oxygen levels were high enough so more UV and X-ray radiation reached the surface (and the Sun was more active at these wavelengths in its early history).
The first snowball earth episodes that we know about did not occur until after the rise of oxygen 2.8 billion years ago.
Uh oh! Dr. Richard Alley isn’t going to like this…see
http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml
“There is no geologic evidence in these rocks for really high concentrations of a greenhouse gas like carbon dioxide”
I thought it was well established that there was (very) large amounts of methane in the atmosphere until photosynthetic organisms built up oxygen levels about 2000 million years ago. Given the potent effect of methane as a greenhouse gas, would this not go a long way explaining faint sun problem?
Jim F (19:15:35) :
By 3.5 BY there are more significant chunks – parts of South Africa and Zimbabwe, maybe some Australia. By 2.7 BY there are substantial areas – much of Ontario, Quebec, Northwest Territories, Western Australia, Western Africa and Congo, Fenno-Scandia, Siberia, and India (and these are metamorphic ages; the absolute ages of these rocks could be older).
And the Sun was still faint then. Not 35%, but 25-15%, so the problem is still there.
Bill Illis (19:28:52) :
(and the Sun was more active at these wavelengths in its early history).
Today. Mars is losing its atmosphere to the solar wind. With a 100-1000 times stronger solar wind, even the Earth would have been scoured.
And they call us “deniers”
From the paper.
=> There is little consensus on when the first continents emerged, or the rate of growth since continental nucleation.
=> There is no simple relationship between the mass of continental material extracted from the mantle and the surface area of exposed land….
=> We have chosen to use the present-day area/volume relationship (Fig. 2a), which probably overestimates the continental area, and in consequence, the albedo for the early Earth.
=> Because the timing and rate of growth of the Earth’s continents is a matter of debate, we have included a scenario in which the surface area occupied by continents is constant over geologic time as one end-member in our model
So, a fairly ad hoc solution to the young faint sun paradox, and so there is still a lot more work to be done to have any real confidence that this describes historical reality.
D. Patterson (18:54:19) :
Paul Hildebrandt (17:27:02) :
It does not mean that their were continental land masses present at this early stage of earth’s history.
On the contrary, it does indicate the presence of a continental crust and plate tectonics.
I never said that plate tectonics were not occurring at that later date (read my post at 17:27:02), in fact, I said in that post that the presence of zircons that old with a heavy oxygen isotope signature indicates plate tectonic activity. However, there is still no evidence of any continental crust, just sedimentary processes which could be tidal action on near surface granites brought there by tectonic activity or by zircons caught up in volcanic activity in which the rock was pulverized explosively during contact with ocean water. The latter process would provide the necessary interaction with “surface” water.
Leif Svalgaard (18:55:14) :
Paul Hildebrandt (17:27:02) :
As for the heavy oxygen isotopes, I’m not sure about that at the moment as I always thought that the early earth atmosphere didn’t have much in the way of oxygen.
The 18O enrichment comes from evaporation of water where the lighter 16O preferentially evaporates leaving water with more 18O.
Thanks, that makes sense.
Need to add to the previous post that some continental land masses may have been present at 4.4 Gya. However, if they existed, they were probably scattered microcontinents and islands.
Not convinced. More water (as stand-alone explanation) sounds highly implausible to me. Perhaps a combination of more atmospheric water plus more internally produced heat. I don’t even have a back-of-the-envelope calculation to cite but it strikes me as wilfully blind to formulate theories to explain an early warm earth without openly considering the possibility of dissipation of heat from a recently-accreted planet with massive internal dynamics.
Even today most of the earth (in terms of volume) is red-hot (though not quite as hot as Al Gore appears to think it is). In early geological times it was SO hot this kept spilling out of the core/mantle onto the surface through tectonic and volcanic activities. It strikes me as quite plausible that Earth’s INTERNAL heat sources were significant enough at the time to compensate for a lower solar energy output. It is also plausible (to me) that geothermal energy declined in its effect on the surface, through stabilization of the Earth’s crust, more-or-less in step with the increase in the sun’s heat-releasing dynamics.
Paradox … begone!
@Leif Svalgaard (20:09:54) :
“…And the Sun was still faint then. Not 35%, but 25-15%, so the problem is still there….”
I guess I’m missing something. What is “the problem”? My post was merely setting a context on the earth’s geological development. None of that was affected by the Sun’s luminosity.
You must be more specific about which of Earth’s multiple atmosphere’s you are discussing. The Earth has had multiple atmospheres with radically different compositions and characteristics.
Earth’s first atmosphere was derived from the same matter as the nebula from which the planet and the Sun were formed. Different sources have estimated this first atmosphere to be 105 or up to 250 atmospheres in mass. Hydrogen was the overwhelmingly dominant atmospheric gas, until the Sun’s solar wind and a likely collison with a planetary mass the size of Mars, sometimes called Theia, stripped away about five Lunar masses of Earth’s hydrogen, helium, methane, ammonia, and more.
After about the first 500 million years following the proposed impact event with Theia, forming the Moon, the much smaller remnant atmosphere became augmented by outgassing from vulcanism and by a relatively high rate of further cometary and asteroidal impacts. This became Earth’s second atmosphere. Some sources are in substantial disagreement about the composition of this second atmosphere.
The earlier view described the second atmosphere as being dominated by water vapor, carbon dioxide, nitrogen, and sulfates. In this view, after the water vapor condensed out of the atmosphere to create the hydrosphere, the composition of the atmosphere was 80% or 800,000ppm carbon dioxide, water vapor, and much smaller percentages of nitrogen, sulfates, and trace gas.
The Early Cool Earth view presented recently proposes a second atmosphere which is far cooler at much earlier time periods with only small concentrations of carbon dioxide.
Earth’s third atmosphere came into being when it became possible for oxygen to remain fre in the atmosphere. Previously, any small amounts of oxygen liberated into the atmosphere immediately reacted with iron and other substances in the rocks and oceans to form oxygen rich compounds. Eventually, these oxygen reactive substances in the environment became saturated with oxygen, so free oxygen began to accumulate in the atmosphere. This free atmospheric oxygen was poisonous to the anaerobic lifeforms inhabiting this increasingly oxygen enriched atmospheric environment. Taking advantage of the new opportunities, aerobic lifeforms developed and radically changed the composition of the atmosphere by increasing the oxygen in the atmosphere while removing carbon dioxide from the atmosphere and sequestering the carbon as carbonates in the lithosphere.
That statement appears to be arguable.
Jim F (21:23:36) :
I guess I’m missing something. What is “the problem”? My post was merely setting a context on the earth’s geological development. None of that was affected by the Sun’s luminosity.
I was just referring back to the original topic [Faint sun paradox etc]. No problem with your comment. You pointed out that substantial land existed 3.5-2.7 Gyr ago, and during that time the Sun was still more luminous than today, so the Faint Sun was still a problem if we have to assume all water to explain away the paradox.
It is good news that the ancient CO2 level proved not high. This fact will be able to change the narrow view on the relation between CO2 and temperture.
As for the mechanism to change the albedo, I like the idea of H.-W. Ou (“Possible Bounds on the Earth’s Surface Temperature: From the Perspective of a Conceptual Global-Mean Model,” J. Climate, 14, 2976-2988 (2001)). He demonstrated that changes in the amount of high clouds and low clouds can explain the faint sun paradox. His theory is based on the maximum entropy production theory (or non-equilibrium thermodynamics), which is not established well enough yet.
Anyway, the albedo appears essentially important in the global climate.
@frank (19:39:20) :
Thanks for posting that link. A very interesting and animated talk. It seems like a good update on a lot of work in the field of geology/geochemistry.
I have some doubts however about some of the conclusions. I was particularly intrigued by his segue of the lag in CO2 versus temperature in ice cores into credit card debt and interest payments. There it seems somehow that the chicken morphed into the egg, or vice versa. Not a very edifying answer.
However, he seems to pin a rise in T to ~3 degrees C to a “doubling” of CO2, as opposed to 4-12 degrees C supposed by some of his warmist compatriots. He should look at his t vs. co2 charts that he showed several times early in the talk; to get those temperatures it would take something like 2000 ppm CO2.
Overall, it seems from his comments that CO2 acts at the margin. Orbital issues, albedo changes and other things come first; CO2 can add to or subtract a bit from those changes.
I would welcome others’ comments on the video (which incidentally was flawless in its presentation on my computer).
If I had to venture a guess, Dennis Bird has the belt buckle?
Where did they get T subscript s?
What is the importance of the increasing gap between T subscript s and T subscript e?
Is that because of water vapor?
WOW! Thanx Anthony. It is easy to understand why this IS the best SCIENCE blog in the world. It’s the only place that I know of where I can get a university grade edumacation for free!
🙂
No, using the word “proved” is incorrect. It is a competing hypothesis, which has not yet undergone the trials required to become adopted as a theory. The prevailing viewof the evidence has heretofore found an atmosphere with an 80% or 800,000ppm composition of carbon dioxide. The early Cool Earth hypotheses dispute the earlier findings, and their cited evidence conflicts with the eralier evidence. It remains to be seen how this irreconcilable views and evidence can become reconciled or supplanted.
Supportive of high carbon dioxide:
Supportive of low carbon dioxide:
It remains to be seen which hypothesis will withstand further research and scrutiny.
You’re confusing the differences between the geographer’s definition of a continent as a major body of dry land or terrain surrounded by the oceans versus the geological and geomorphological definition of a continent as a continental crust or crustal plate.
At “4.4 Gya” sial continental plates such as those existing today did not yet exist. The process of refining the basalts to produce the first granitic crustal plates had not yet progressed far enough to create sial continental crust or crustal plates. That would occur during the next 800 million years and become ecognizable at about 3.8Gya. The proto-crust and proto-continental crust was much more mafic in its composition. The proto- continental crust was slightly less dense, being composed of an anorthositic like rock similar to those found in the Lunar highlands, than the subducting non-continental crust. Since the density differences were so much less, it was much easier to progressively subduct the sima proto-continental crust along with the sima non-continental crust, resulting in further refinement and separation of the silicon and aluminum compounds which would become the sial continental crust 800 million years later.
Note, it is not necessary for a hydrosphere to be present to create a sima or sial continental crust. Continental crust in this geological context only represents the differences in density substantial enough for the lighterweight crustal plate to override a heavierweight crustal plate. The lighterweight crustal plate then persists so long as it is not eroded away by a subducting plate at the prism, and it is not itself subducted by collision with another lighterweight continental crustal plate.
Add water and you can then describe the heavierweight sima crustal plate as oceanic crust versus the lighteweight sima or sial continental crustal plate. It’s the relative compositions of the crustal plates, their densities, and their tectonics which defines a continent in geological terms, not the geographer’s view of a dry land amidst the oceans.
Leif Svalgaard (21:42:13) :
The sun’s core held more energy and rotated faster. This in turn made the suns carona smaller.
For some farout reason, science believe suns and planets rotate forever while still using and loosing energy. Even Atomics need a material to be repentished to continue.
How about the Earth ıtself. The early Earth was a ball of fıre and nuclear fıssıon. Surely that early state was stıll ın the process of coolıng down, and radıtıng lots of energy.
.
Hmmm, I wonder if Newton’s law of motion is incorrect?
“In the absence of a net external force, a body either is at rest or moves with constant velocity. Newton ”
Rotation has density that is compressible and can hold energy that is slowly released. The object, planet, sun, etc. slows down naturally through the “unwinding of compressed mass” Being gases or material.
In space, a body will still slow over time due to frictional forces such as specks of gases or mass. There is a great deal of dust debris in space.
The “paradox” might be explained by the fact that in the far past the Earth’s orbit was closer to the Sun. The Sun is loosing mass because, by ‘burning’ hydrogen, helium is formed + energy (whence mass loss). If the Sun’s mass is decreasing, the planets are slowly spiralling outward. The greater distance to the Sun might (almost exactly?) counterbalance the hotter Sun.
But don’t ask me details. I am not an astrophysicist.
“I thought it was well established that there was (very) large amounts of methane in the atmosphere until photosynthetic organisms built up oxygen levels about 2000 million years ago. ”
You can’t even trust scientists to count tree rings accurately but you expect to believe in the science of the planet billions of years ago from people more interested in their own ego than the truth?
Scientists find errors in hypothesis linking solar flares to global temperature
http://www.physorg.com/news189845962.html
Greenhouse? What Greenhouse?
When I was learning physics I was taught the usual theory about how a
greenhouse warmed. As a physics teacher in the 1970s, I also taught
my students the same theory. But despite it being in all the text
books the theory is wrong and has been known to be so for a hundred
years! 100 years ago, a simple experiment showed beyond doubt that
the greenhouse effect‘ has little to do with secondary IR radiation.
Yet no physics text books have ever bothered to correct the wrong
theory!
Note on the Theory of the Greenhouse
by Professor R. W. Wood, 1909.
THERE appears to be a widespread belief that the comparatively
high temperature produced within a closed space covered with glass,
and exposed to solar radiation, results from a transformation of
wave-length, that is, that the heat waves from the sun, which
are able to penetrate the glass, fall upon the walls of the
enclosure and raise its temperature: the heat energy is
re-emitted by the walls in the form of much longer waves,
which are unable to penetrate the glass, the greenhouse acting
as a radiation trap.
I have always felt some doubt as to whether this action played
any very large part in the elevation of temperature. It appeared
much more probable that the part played by the glass was the
prevention of the escape of the warm air heated by the ground
within the enclosure. If we open the doors of a greenhouse on
a cold and windy day, the trapping of radiation appears to lose
much of its efficacy. As a matter of fact I am of the opinion
that a greenhouse made of a glass transparent to waves of every
possible length would show a temperature nearly, if not quite,
as high as that observed in a glass house. The transparent
screen allows the solar radiation to warm the ground, and the
ground in turn warms the air, but only the limited amount
within the enclosure. In the ”open,• the ground is continually
brought into contact with cold air by convection currents.
To test the matter I constructed two enclosures of dead black
cardboard, one covered with a glass plate, the other with a
plate of rock-salt of equal thickness. The bulb of a thermometer
was inserted in each enclosure and the whole packed in cotton,
with the exception of the transparent plates which were exposed.
When exposed to sunlight the temperature rose gradually to 65°C,
the enclosure covered with the salt plate keeping a little
ahead of the other, owing to the fact that it transmitted the
longer waves from the sun, which were stopped by the glass.
In order to eliminate this action the sunlight was first
passed through a glass plate.
There was now scarcely a difference of one degree between the
temperatures of the two enclosures. The maximum temperature
reached was about 55°C. From what we know about the
distribution of energy in the spectrum of the radiation emitted
by a body at 55°C, it is clear that the rock-salt plate is
capable of transmitting practically all of it, while the glass
plate stops it entirely. This shows us that the loss of
temperature of the ground by radiation is very small in
comparison to the loss by convection, in other words that
we gain very little from the circumstance that the
radiation is trapped.
Is it therefore necessary to pay attention to trapped radiation
in deducing the temperature of a planet as affected by its
atmosphere? The solar rays penetrate the atmosphere, warm
the ground which in turn warms the atmosphere by contact
and by convection currents. The heat received is thus
stored up in the atmosphere, remaining there on account
of the very low radiating power of a gas. It seems to me
very doubtful if the atmosphere is warmed to any great extent
by absorbing the radiation from the ground, even under the
most favourable conditions.
I do not pretend to have gone very deeply into the matter,
and publish this note merely to draw attention to the fact
that trapped radiation appears to play but a very small part
in the actual cases with which we are familiar.
further comment by Philip Foster on the above:
This is why CO2 and H2O (along with O3, N2O and CH4) in
the atmosphere cannot cause warming. If they did we would
have access to unlimited energy for no cost! The very small
amount of radiated infrared from H2O and CO2 reaching the
ground cannot warm the ground as the temperature of these
gases is lower than the temperature of the ground – just
as hot coffee in a Vacuum flask does not start boiling!
By suggesting that it can is to break one of the laws of
thermodynamics (Kevin Trenberth seems to have have done this:
http://www.cgd.ucar.edu/cas/abstracts/files/kevin1997_1.html
The only role they can play is like that of a glass plate
as opposed to a rock-salt plate as described by
Prof. Wood above: namely to slightly inhibit the
warming of the ground. But as they cannot trap
the convecting air (unlike solid glass in a greenhouse)
all comparisons with a greenhouse effect‘ are invalid.
Leif Svalgaard (18:55:14) :
Carla (17:39:40) :
Way too many missing pieces.
Which means that you cannot just jump to the conclusion you like since there is no specific evidence for it.
~
Women, go figure, it always has and always will be, LOCATION, LOCATION, LOCATION. Our variable star is variable because of LOCATION within the galaxy it resides, orbits. Anytime the LOCATION CHANGES, so does the star.
Men, go figure, always dancing around LOCATION, some even think CO2 is everything. lol
And if at the time (young star) was nearer a star forming region, it would be hotter, with much faster winds, and varying densities surrounding said young star..
IMHO you can’t separate the star from its environment and expect to..
D. Patterson (00:22:00) :
Paul Hildebrandt (20:42:32) :
Need to add to the previous post that some continental land masses may have been present at 4.4 Gya. However, if they existed, they were probably scattered microcontinents and islands.
You’re confusing the differences between the geographer’s definition of a continent as a major body of dry land or terrain surrounded by the oceans versus the geological and geomorphological definition of a continent as a continental crust or crustal plate.
I’m not confusing anything. Hawaii is an island, yet it is not sialic. As I stated above, if they existed, they were probably scattered and few in number. The fact that zircons of that age have not been found in their native environment argues against microcontinents. However, that does not mean that they did not exist. We just haven’t found any or they haven’t surfaced due to the stable nature of the Archean cratons.
At “4.4 Gya” sial continental plates such as those existing today did not yet exist. The process of refining the basalts to produce the first granitic crustal plates had not yet progressed far enough to create sial continental crust or crustal plates.
If plate tectonic processes were ongoing at 4.4 Gya, would not partial melting of basaltic crust create calc-alkaline (sialic) melts? Furthermore, because the geothermal gradient at this early time in earth’s history was so steep, the basaltic crustal rocks would not have fully dehydrated before melting. Therefore, melting would occur at much shallower depths than present day melting. The time for these calc-alkaline magmas to reach the surface can take as little as 100,000 years. So, yes; 100 million years is more than enough time for calc-alkaline magmas to be formed and migrate to the surface.
D. Patterson (21:29:51) : Thanks for the info. I was of course referring to the atmosphere between ~4.5 to 2 billion years before present. Seems that there is still a lot of different opinions about. I have seen some comparisons to Titan, and some like your suggestion of lots of CO2 (and above with little). Looks like there is still a lot to be discovered/researched in this area, even if the oxygen history is much better understood.
The Group W think that without taking in to account the VARIABLEs of the sun’s orbital parameters..that most of what they read here is conjecture, including jumping to conclusion. So much time spent on the orbital parameters of planets and yet when it comes to the suns, ah oh well???
The Who, “Eminence Front.”
Jim F,
You’re most welcome for the link, and thank you for your analysis, which I agree with entirely. As an engineer, I don’t “respect” science that has to be contorted to explain similar phenomena over varying time scales, which I see a lot of in Dr. Alley’s presentation. Case in point is that while he attributes orbital cycles as the primary cause of the periodic glaciation, he invokes CO2 as a main driver between cycle endpoints. In my mind, this ignores basic physical effects like the inverse relationship between CO2’s solubility in water with temperature (Henry’s Law), and also appears to disregard the logical principals of Occam’s razor.
Carla (05:46:25) :
Our variable star is variable because of LOCATION within the galaxy it resides, orbits.
No, the LOCATION has nothing to do with it.
Carla (07:07:16) :
The Group W think that without taking in to account the VARIABLEs of the sun’s orbital parameters.
What you think does not make it so. The easiest to delude is oneself.
Leif Svalgaard (08:01:54) :
Carla (07:07:16) :
The Group W think that without taking in to account the VARIABLEs of the sun’s orbital parameters.
What you think does not make it so. The easiest to delude is oneself.
~
Geesh Leif, “Pour Some Sugar..” one lump or twooooo?
Maybe now that I’m delusional I should go back on my meds.
Whoaa here Group W says, “But your not on meds, Carla.”
Well now that I’m having some delusion maybe I should start? lol
wayne (16:26:04) :
Michael J. Dunn (12:45:14) :
Phillep Harding (12:02:13) :
“Michael, your point to Phillip will be greatly magnified with the correct factors:
~580 Cal/g or ~2425 kJ/kg, not 1400 J/kg
~1 Cal/g/K or ~4.2 J/g/K, not 1 J/g/K”
Dear Wayne,
My deepest apologies about the value for the heat of vaporization of water; I misread a table not only by a factor of “kilo” (k) by also by referencing the value for 300 C instead of 300 K. I’ve been in a rocky patch lately.
But you have misfired on the second number. I was giving the specific heat capacity of air, which would be warmed by any water condensation (where does the heat go?). You have given the specific heat capacity of water, which plays no role in condensation, since the water temperature does not change during the process.
Since air has about 1/1000th the density of water, this means that even a small mass of condensing water can greatly heat large volumes of air. This is known to anyone who has lived in a steam-heated dwelling. But the same effect still works in the realm of specific heat content, as can be experienced by walking through fog. Even at an equable temperature, the heat loss to the aerosol water droplets can be large, which is why fog is so chilly. (I know. I used to do a lot of horseback riding through the fog.)
This is all a footnote to the main thread of discussion, I suppose, but it does support the idea that local conditions can plausibly be the result of atmospheric heat transport processes.
@Paul Hildebrandt (06:10:47) :
“…I’m not confusing anything. Hawaii is an island, yet it is not sialic. As I stated above, if they existed, they were probably scattered and few in number. The fact that zircons of that age have not been found in their native environment argues against microcontinents. However, that does not mean that they did not exist. We just haven’t found any or they haven’t surfaced due to the stable nature of the Archean cratons….”
This is a fun topic – lots of room to wave one’s arms. I suggest Hawaii is a bad example; maybe an intraocean island arc would suit to form the calcalkaline partial melts you refer to. As to finding the pieces of microcontinents, recall that much of the Archaean in the Northern Hemisphere is covered, and we’ll probably never know what’s hidden (the SA is not all that well exposed either, and is mostly deeply weathered).
The Slave Province, where those ~4BY zircons originate, is an interesting place. It seems to be stitched together of several disparate terranes, and then this mishmash was crammed into other chunks to form the North American craton.
Here are some interesting references for those who care about such things:
http://www.mnh.si.edu/earth/text/4_1_3_1.html
2 Billion Years Ago – A Continent Is Born
Six microcontinents — some formed from Earth’s earliest continental crust — collided and stuck together to build the North American craton. The craton later became a part of three supercontinents: Laurussia, Pangaea, and Laurasia. Now it underlies 70 percent of North America. Parts of the craton contain rocks that range in age from 2.5 to 4 billion years, including Earth’s oldest-known rock. Most were highly deformed and metamorphosed as the craton was assembled.
http://geology.geoscienceworld.org/cgi/content/abstract/17/1/63
Accretion of the Archean Slave province -T. M. Kusky1
It is proposed that the high-strain zones separate four distinct terranes that have been juxtaposed during collisional orogenesis. From west to east, these include the Anton terrane, interpreted as an Archean microcontinent; the Sleepy Dragon terrane, possibly an exhumed more eastern part of the Anton terrane; the Contwoyto terrane, a westward-verging fold and thrust belt containing tectonic slivers of greenstone volcanics; and the Hackett River volcanic terrane, interpreted as an Archean island arc. The Contwoyto and Hackett River terranes represent a paired accretionary prism and island-arc system that formed above an east-dipping subduction zone. These collided with the Anton microcontinent, producing a basement nappe, expressed as the Sleepy Dragon terrane, during the main accretion event within the Slave province. The whole tectonic assemblage was intruded by late-kinematic to postkinematic granitoids.
http://geology.geoscienceworld.org/cgi/content/abstract/17/11/971
3.96 Ga gneisses from the Slave province, Northwest Territories, Canada
S. A. Bowring1, I. S. Williams2 and W. Compston2
Ion microprobe U-Pb analyses of zircons have identified the Acasta gneisses, from the westernmost Slave province, Canada, as the oldest known intact terrestrial rocks. Zircons from two samples indicate that the tonalitic to granitic protoliths of the gneisses crystallized at 3962 ±3 Ma, confirming earlier indications, from conventional zircon and Nd analyses, of the rock’s antiquity. The U-Pb analyses indicate that in addition to recent Pb loss, the zircons underwent an early episode of Pb loss and that new zircons crystallized ca. 3.6 Ga. The gneisses were derived from a source that had a long-lived enrichment in light REE, possibly from even older rocks that may be present in the Slave province.
and finally:
http://sp.lyellcollection.org/cgi/content/abstract/199/1/151
Archaean tectonics: a review, with illustrations from the Slave craton -Wouter Bleeker
The extensional and subsequent contractional evolution of granite-greenstone terrains may have occurred in the overall context of a plate tectonic regime (e.g. volcanic rifted margins, back-arc basins) but highly extended, intraplate, rift-like settings seem equally plausible. Explaining the evolution of the latter in terms of Wilson cycles is misguided. Periods of intense rifting and flood volcanism (e.g. 2.73–2.70 Ga) may have been related to increased mantle plume activity or perhaps catastrophic mantle overturn events. Although there is evidence for plate-like lateral movement in late Archaean time (e.g. lateral heterogeneity of cratons, arc-like volcanism, cratonscale deformation patterns, strike-slip faults, etc.), the details of how these plate-like crustal blocks interacted and how they responded to rifting and collision appear to have differed significantly from those in Phanerozoic time. The most productive approach for Archaean research is probably to more fully understand and quantify these differences rather than the common emphasis on the superficial similarities with modern plate tectonics.
Enjoy!
Carla (08:38:22) :
Whoaa here Group W says, “But your not on meds, Carla.”
It seems Group W runs your life. Perhaps try to get some control back and be boss over yourself.
Jim F (09:59:18) :
This is a fun topic – lots of room to wave one’s arms.
Indeed. It is also plausible that the continents have broken up and reassembled something lime 7 or 8 times over the life of the Earth.
I suggest Hawaii is a bad example; maybe an intraocean island arc would suit to form the calcalkaline partial melts you refer to.
Actually, I was using Hawaii as an example of mafic rocks forming islands. We’ve got plenty of continents to illustrate calc-alkaline rocks.
Thanks for the info. My thesis was in the Tetons working on Archean rocks. The layered gneiss there appears to be of island arc origin (for the most part), underwent granulite facies metamorphism, probably during accretion to the North American craton. It is definitely an accreted terrane.
Some very interesting comments thank you all.
I was wondering if anyone has examined Dan Bar-Zohar’s paper:
http://www.astronomy.net/forums/bigbang/messages/882.shtml
He asserts the sun in not powered by nuclear reactions, but by magnetism. It would solve the problem of a weak sun vis-a-vis the time-frame in question.
I have no opinion on this matter, just asking.
Looks like C. Karoff & H. Svensmark have been having similar thoughts…
How did the Sun affect the climate when life evolved on the Earth?
Authors: C. Karoff, H. Svensmark – Submitted on 31 Mar 2010
Abstract: “Using kappa Ceti as a proxy for the young Sun we show that not only was the young Sun much more effective in protecting the Earth environment from galactic cosmic rays than the present day Sun; it also had flare and corona mass ejection rates up to three orders of magnitude larger than the present day Sun. The reduction in the galactic cosmic ray influx caused by the young Sun’s enhanced shielding capability has been suggested as a solution to what is known as the faint young Sun paradox, i.e. the fact that the luminosity of the young Sun was only around 75% of its present value when life started to evolve on our planet around four billion years ago [and yet, paradoxically, the Earth didn’t freeze over]. This suggestion relies on the hypothesis that the changing solar activity results in a changing influx of galactic cosmic rays to the Earth, which results in a changing low-altitude cloud coverage and thus a changing climate. Here we show how the larger corona mass ejection rates of the young Sun would have had an effect on the climate with a magnitude similar to the enhanced shielding capability of the young Sun.”
Full paper here:-
http://arxiv.org/pdf/1003.6043v1
R. Gates (15:57:33) :
Everyone reading this should realize that this is just one more THEORY explaining how the so-called young-sun paradox could be explained…..
REPLY:
As far as I can see the gang here at WUWT is doing their usual job of dissecting the information and examining it. I don’t see much evidence of anyone saying . “thank you, thank you, for finally delivering the absolute truth to us, the brain dead masses.”
Frank,
Thanks for posting this video:
http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml
This was an excellent, and most illuminating presentation. Essentially gave a complete thumbnail overview of exactly why I am a 75% “warmist” and 25% sceptic.
When you deny the likeliehood of the existence of “continental land masses” and “continental crust” “at this early stage of earth’s history” except “some continental land masses may have been present at 4.4 Gya, can you describe for us exactly how you define your usage of the terms: “continental land masses” and “continental crust”?
Never forget, fence sitting is an imPALINg experience.
D. Patterson (14:12:28),
Those are the “adjusted” numbers.
The correct figures are .025% skeptic, and 99.975% true believer.
That’s my theory.
WilliMc (12:05:34) :
If the suns core is super compacted and compressed, how can nuclear reaction occur when they have to have room to “SLAM” into each other?
Being that compacted and rotating, it is possible to pop a molecule like a grape with massive pressure and friction.
Both the magnetic field on our planet and the sun would have been greater in the past then now as they were rotating faster.
Completely wrong. Land absorbs more sunlight than ocean and is thus warmer. Also, four billion years ago, the oceans barely existed. Earth’s oceans have grown through time.
In one sense it’s not that simple.
But in another sense it’s all too simple:
Attempting to go back 4+ billion years, or however old the planet is (dating is problematic), and reconstruct what was happening is…speculation…not much better than complete guess work.
Fun to do, but not very imformative…too many variables that can’t be quantified.
There is some question if Man really has any kind of handle on what the Earth was like…”in the beginning”.
Also, the desire to answer “in the beginning” type questions can lead to answers that end up sending Science in a wrong direction, which then hardens into dogmatism which can then retard scientific understanding about what is happening, now.
Understanding what the Earth’s physical relationships and dynamics are now is the most important set of questions to answer.
James F. Evans (18:03:46) :
Attempting to go back 4+ billion years, or however old the planet is (dating is problematic),
About the only thing that is not problematic about this is the dating.
If you look at the equation for methanogenesis you get:
CO2 + 4 H2 → CH4 + 2H2O
Writing out the thermodynamics you have:
delta_G_rxn = delta_G0 + RT ln Q, where in the case of methanogenesis you have:
Q = {CH4}/({CO2}{H2}^4).
Thus the energy derived from methanogensis is linearly related to the activity (concentration) of methane seen by the methanogen. As the concentration of methane increases the delta_G of the reaction increases until it is > 0, meaning the reaction is thermodynamically unfavorable.
This is what the authors mean when they are talking about the balanced diet. Since CO2 is in the denominator, an increase in CO2 also decreases the energy available from the reaction. The power of 4 on the hydrogen means also that the reaction is most sensitive to the hydrogen concentration.
Meh, I mean as the CO2 increases the energy available increases.
D. Patterson (13:40:35) :
When you deny the likeliehood of the existence of “continental land masses” and “continental crust” “at this early stage of earth’s history” except “some continental land masses may have been present at 4.4 Gya, can you describe for us exactly how you define your usage of the terms: “continental land masses” and “continental crust”?
What? That’s the best you can do? I refer you back to this post by Dr. Svalgaard in which he first brings up the term “continental.
Leif Svalgaard (12:05:26) :
The existence of 4+ Gyr old Zircon grains indicates presence of continental crust early in the Earth’s history, and there is good evidence that the Earth lost its atmosphere and hydrosphere early on and that they have been gradually added since, so the situation is not that simple.
I’m not condemning the good Doctor on the use of the word “continental”. I’m trying to keep the discussion in context. I could have used “sima” or “sial” like you to confuse the issue; However, I decided to remain in context and continue to use “continental”. I’m not quite sure why you are hung up on the semantics, but it seems rather puerile of you to get so worked up over one word. Try staying with the meat of the discussion, instead. Chill!
Leif Svalgaard (18:30:54) wrote: “About the only thing that is not problematic about this is the dating.”
It has been scientifically established that electromagnetic radiation effects radio-carbon dating, so that radiation decay rates are not necessarily linear and constant if an object has been subject to strong electromagnetic radiation, then radio-carbon dating is unreliable.
I’ll say this, however, Science has a better handle on how old the Earth is, compared to how old the Universe is — arrogant scientists not withstanding 🙂
James F. Evans (19:50:02) :
It has been scientifically established that electromagnetic radiation effects radio-carbon dating
Nonsense
I’ll say this, however, Science has a better handle on how old the Earth is, compared to how old the Universe is
More nonsense. The universe is 13.73 billion years old. The age of the Earth is estimated at 4.54 billion years, but is somewhat uncertain because there is no precise definition of what the age means. We have gone over this several times, so no need to hijack a thread again.
@David Deming (17:23:03) :
“…Also, four billion years ago, the oceans barely existed. Earth’s oceans have grown through time….”
Sez who?
.73 …ya, right. That’s the nonsense here.
James F. Evans (19:50:02) :
I’ll say this, however, Science has a better handle on how old the Earth is, compared to how old the Universe is arrogant scientists not withstanding 🙂
The 10 billion dollar collider is looking at a single big bang event. If that were the case, then all the solar systems would be of the same age and same region.
Would it not?
What about an athmosphere that was more dense earlier(warmer earth) and a warming sun that since has been depleting the athmosphere on earth and made the climate colder even if the sun has got warmer?
The albedo of mafic rock is really low…
IANAS, but let me get this straight.
The greenhouse theory of early Earth warmth assumed that there must have been high levels of CO2 in spite of a lack of evidence of said gas. Bird and Rosing have explained how early Earth warmth happened within the evidence.
Is that right?
“”” James F. Evans (19:50:02) :
Leif Svalgaard (18:30:54) wrote: “About the only thing that is not problematic about this is the dating.”
It has been scientifically established that electromagnetic radiation effects radio-carbon dating, so that radiation decay rates are not necessarily linear and constant if an object has been subject to strong electromagnetic radiation, then radio-carbon dating is unreliable. “””
I’m having some difficulty with this statement James. Arguably it is true that electromagnetic radiation (a)ffects radio-carbon dating; so one wouldn’t then quibble that it has been scientifically established.
But in what manner does that happen; and how was that established ?
The earliest radio-carbon dating was based on the premise that 14C was created at a constant rate out of Nitrogen, by Cosmic rays; which may or may not be “electro-magnetic” radiation. The radio-carbon is assumed to be taken up by living things, till they die, and then the 14C decays by ordinary beta decay (emits an electron) with a half life of 5770 years.
So ten half lives, or 57,700 years would reduce the 14C in the sample by a factor of 1024. Twenty half lives, or 115,400 years reduces it by over amillion. I somehow doubt that even a mass spec can reliably recover 14c that is diminished over one million times from any normal sample.
So radio-carbon dating is hardly a useful tool for anything more than 100,000 years; and I suspect that it is more like 50,000 years. That is hardly a useful measure of earth versus universe ages.
The original assumption of constant manufacture rate, of course was proven wrong, by RC dating each ring of old Bristle-cone pines, from the White Mountains near the California/Nevada border. One of the very few things that tree-rings analysis is good for.
The result of that study did enable a correction table to be derived for the RC age of samples.
But you talk of the samples themselves, being subjected to “”” strong electromagnetic radiation “””, and that implies that you believe that somehow, such radiation can affect the existing sample.
How would that work; and in what physical sense to you refer to the radiation as “strong”? Is that high intensity radiation; or do you mean high photon energy radiation (short wavelength)
Photons of a wide range of energies could temporarily place a 14C atom in some excited (electron) state; but somehow, I don’t think the carbon nucleus, would even know that was going on; so I don’t see how that migth either induce or prevent a beta decay from the nucleus. I’ve never heard of stimulated radioactive emissions; but you may be on to something.
You could have higher energy photons/particles actually hitting the nucleus, and soemhow transmuting the 14C prematurely into something else.
So I have no knowledge of electro-magnetic radiation of a sample, somehow affecting it RC dating result.; and in any case that is only a very short time dating system, in geological terms; ok for human history time scales; but otherwise not too useful.
George E. Smith (11:14:45) :
I accept your point that radio-carbon dating isn’t viable beyond 100,000 years.
Then we move into radio-metrics like uranium or thorium radioactive decay.
All dating techniques have assumptions. Whether those assumptions allow for the accuracy that proponents typically boast of — I apply reasonable skepticism.
Yes, the Earth’s age is immense, of that I’m sure, but trying to pin it down to the hundred thousand year place is hubris and arrogance.
If there is one thing I’ve learned in my recent study of Science…there is much folly in Science due to human arrogance.
James F. Evans (16:38:27) :
All dating techniques have assumptions. Whether those assumptions allow for the accuracy that proponents typically boast of — I apply reasonable skepticism.
Ignorance is a heavy shield and will shield you well from the truth. Skepticism must be based on facts, not just on refusing to know. The main assumption is that the laws of physics in the past were the same as today. All our evidence points to that they were.
Dr. Svalgaard:
In Science, ignorance typically results from a refusal to consider evidence because that evidence contradicts strongly held opinions and assumptions. People (scientists are people, too, you know) would rather ignore evidence than have their world-view subject to revision.
But getting back to the specifics of the assumptions of radio-metric dating:
Radioactive isotopes, Uranium, Thorium, Potasium, and strontium, are used to date rocks. These radioactive isotopes have a constant rate of decay which can be used to measure time passage. In example: Uranium has a constant radioactive rate of decay into Lead.
(Parenthetically, carbon-14 dating can’t be used on rocks as the rocks were never living tissue.)
So, with a rock embedded with Uranium one can tell how old the rock is by how much Lead is also embedded in the rock as the Uranium decays at a constant rate into Lead…sounds good.
But hold on, there are a number of assumptions.
First, one must assume that all the Lead in the rock is a product of the Uranium’s decay into Lead, but there is natural Lead that isn’t a product of Uranium decay and so the question becomes, what was the percentage content of ‘natural’ Lead in the rock to begin with — hard to tell, maybe impossible to determine. So any radio-metric dating has to decide what percentage of Lead is naturally occuring in the rock to begin with (an assumption) and what is the product of Uranium isotope’s radioactive decay into Lead.
So, there is a need for an assumption which clouds the ability to use radio-metric dating to determine how old a particular rock is.
Also, second, most metals don’t exist as pure elements in rocks, they exist as salts bound up with other elements. Of course, salts are soluble in water and so salts will disolve out of the rock when exposed to water, including radioactive salts. Most rocks have been exposed to water.
Consequently, a rock with Uranium salts exposed to water will have a percentage of Uranium salts leached out of the rock. This will effect the appearance of age for the rock derived from radio-metric dating because there is an assumption of what percentage of the Uranium salts are in the rock to start with (another assumption).
Finally, rate of decay of radioactive isotopes can be effected by things like bombardment with nutrinos or an increase in cosmic rays the result of supernova (also, I suggest intense bombard of electromagnetic particles will effect rates of radioactive decay, likely speeding the decay rate) these events are acknowledged as happening periodically in the past, and, so, thus, have a potential effect on the assumed constant rate of radioactive decay of these isotopes (so there is another assumption that the rock hasn’t been exposed to these physical forces).
So, again, “All dating techniques have assumptions. Whether those assumptions allow for the accuracy that proponents typically boast of — I apply reasonable skepticism.”
Yes, Dr. Svalgaard, ignorance is a heavy shield and it will shield you from the truth, but the first place to look for that ignorance is in ourselves, and not in others.
It is much easier to throw out sweeping statements than to back them up with evidence and reasoning.
And, yes, I subscribe to the idea that the laws of physics in the past were the same as today. What gave the idea that I didn’t — might I suggest there was an assumption made — how very typical for those so sure of themselves that they feel free to ignore evidence at their own capricious whim… because they know better than the rest of us.
Well, the rest of us mortals will continue to consider ALL observations & measurements as they are made available to us.
James F. Evans (05:47:45) : The other problem is the plurality of laws, everyone expaining reality as they “correlate” with local aspects of it and they have a technical and abosolutely valid application. It is the rejection to universal laws which could apply to every aspect of reality, wonderfully represented by Pitagoras Monochord.
James F. Evans (05:47:45) :
First, one must assume that all the Lead in the rock is a product of the Uranium’s decay into Lead, but there is natural Lead that isn’t a product of Uranium decay and so the question becomes, what was the percentage content of ‘natural’ Lead in the rock to begin with — hard to tell, maybe impossible to determine.
This is where your willful ignorance shows. Lead has many isotopes, and only 206Pb [decay product from 238U] and 207Pb [decay product from 235U] result from radioactive decays, while e.g 204Pb does not, so the ratios of the Lead isotopes shows what the natural content of Lead was. So, no assumption here.
is an assumption of what percentage of the Uranium salts are in the rock to start with (another assumption).
It is not the amount of Uranium that matters but the ratio of the two isotopes U238 and U235, so no assumption here either, apart from the fact that the interior or Zircon crystals [often used for dating] has not been leached.
Finally, rate of decay of radioactive isotopes can be effected by things like bombardment with nutrinos or an increase in cosmic rays the result of supernova>/i>
None of these things have any effect on the decay rate. This is an [unwarranted] assumption on your part.
because they know better than the rest of us.
In your case that is not hard, but you could learn, if willing.
Well, the rest of us mortals will continue to consider ALL observations & measurements as they are made available to us.
Well, you can begin now. Read up on Uranium-Lead dating. E.g. here http://geology.about.com/od/geotime_dating/a/uraniumlead.htm or
http://planetearth.nerc.ac.uk/features/story.aspx?id=121
And why, given all of the assumption involved, was Mars warm and wet at the time, as well?
Dr. Svalgaard:
I welcome your response.
I didn’t know you were an expert on geologic radio-metric dating…I’ll assume you aren’t, unless you provide some personal professional background that says otherwise.
(What I do know is that you are an arch defender of the scientific status quo — even in the face of overwhelming contervailing scientific evidence. Perhaps that explains your assertions that the Sun’s variance of irradiance and variance of total energy ouput makes no difference to Earth’s climate, and, thus, reinforces the arguments of AGW proponents — I’ve read your comments to this effect many times, here, on this website.)
So, since you aren’t an expert on geologic radio-metric dating, I’ll assume we are on a more equal scientific footing than normal.
And, so, I’ll assume the information you have given is principly from the links you have provided, unless you provide further evidences.
That said, let’s consider the evidence you provided from your first link, about.com: geology – Uranium-Lead Dating:
http://geology.about.com/od/geotime_dating/a/uraniumlead.htm
From the lead paragraph: “…[Uranium-Lead Dating] when done carefully, the most reliable. Unlike any other method, uranium-lead has a natural cross-check built into it that shows when nature has tampered with the evidence.”
So, the second thing we learn (the first is that Uranium-Lead Dating is reliable) is that, one, it must be “done carefully”, and, two, nature can tamper with the evidence, and, therefore, make it unreliable.
Further down in the article, we learn that, “If nothing disturbs the grain to release any of this radiogenic lead, dating it is straightforward in concept.”
What does this tell the reader?
Obviously, there are natural causes that disturb the grain (or the author wouldn’t have mentioned it), and, therefore, make the radio-metric dating unreliable.
Dr. Svalgaard (09:23:27) wrote: “Lead has many isotopes, and only 206Pb [decay product from 238U] and 207Pb [decay product from 235U] result from radioactive decays, while e.g 204Pb does not, so the ratios of the Lead isotopes shows what the natural content of Lead was. So, no assumption here.”
The article doesn’t say that 206Pb is ONLY caused by radioactive decay from 238U, unless you provide scientific evidence to the contrary, one can conclude there is natural 206Pb as well. The same can be said about 207Pb being a radioactive decay product from 235U; the article doesn’t say that 207Pb is ONLY caused by radioactive decay from 235U.
You have made an unwarranted assumption.
“There are four stable isotopes of primordial lead, namely
204Pb, 206Pb, 207Pb and 208Pb. The last three isotopes, however,
are also radiogenic, formed by radioactive decay in the 238U
(half-life 4.56109 years), 235U (half-life 0.76109 years) and
232Th (half-life 14.16109 years) decay series, respectively.” — “The changing nature of the 206Pb/207Pb isotopic ratio of lead in
rainwater, atmospheric particulates, pine needles and leaded petrol in
Scotland, 1982±1998”
I take it that “primordial lead” means the lead has four isotopes which are ‘natural’ and is not necessarily a product of 238U radioactive decay, although, the last three can be a product of radioactive decay, but it is not exclusive.
The same would hold true about 235U as well.
Dr. Svalgaard, your argument is dismissed as an erroneous assumption.
Dr. Svalgaard wrote: “It is not the amount of Uranium that matters but the ratio of the two isotopes U238 and U235, so no assumption here either, apart from the fact that the interior or Zircon crystals [often used for dating] has not been leached.”
Again, your assumption only holds true if nature has not tampered with the Uranium.
The About.com geology article goes on:
“First, its chemical structure likes uranium and hates lead. Uranium easily substitutes for zirconium while lead is strongly excluded. This means the clock is truly set at zero when zircon forms.
Second, zircon has a high trapping temperature of 900°C. Its clock is not easily disturbed by geologic events—not erosion or consolidation into sedimentary rocks, not even moderate metamorphism.”
This says nothing about whether Uranium not being able to be leached out of zirconium. Also, pay special attention to the phases, “This means the clock is truly set at zero when zircon forms.”, and, “Its clock is not easily disturbed by geologic events…”
So, apparently, the clock can be re-set to zero for any of a number of natural causes, principly being heated to a certain temperature. Also, this, here, discussion is about using radio-metric dating for determining the age of the Earth to a high level of accuracy — within one hundred thousand years. So, it becomes apparent from the About.com article that any number of natural physical events could intervene and “reset the clock to zero”.
Here’s the money quote from the About.com article”
“But even the best geologic methods are imperfect. Dating a rock involves uranium-lead measurements on many zircons, then assessing the quality of the data. Some zircons are obviously disturbed and can be ignored, while other cases are harder to judge.”
Dr. Svalgaard presents Evans’ statement (05:47:45): “Finally, rate of decay of radioactive isotopes can be effected by things like bombardment with nutrinos or an increase in cosmic rays the result of supernova>/i>”
And, Dr. Svalgaard responds: “None of these things have any effect on the decay rate. This is an [unwarranted] assumption on your part.”
This is false or misleading.
During the time of bombardment or ‘event’, the rate of radioactive decay is increased. It is true that after the bombardment or ‘event’ the rate wil return to its normal rate of decay, but for the time during the ‘event’ it is effected, and thus will “chop-off” an amount of decay, thus, leading to erroneous assessment of age using radio-metric dating.
As to the second link provided, it does what you attempted to do: Claim an exactitude beyond what the scientific evidence allows Science to know, which is a common occurance — as you typically comment when a NASA press release announces a new set of observations & measurements that assets a new scientific understanding — it’s “hype”. In your case, you put down evidence that upsets the status quo applecart — your modus operandi.
So, what do we have here?
Dr. Svalgaard posed as somebody who “know[s] better than the rest of us.”
And has been exposed as “the emperor without clothes.”
What no one, researchers included, seem to consider here, though I haven’t read all the posts, is that the atmospheric pressure 3.8E9 yrs ago was somewhere in the range of 200 – 300 bar, yes – ca. 3700 psi!!. What huge effect would only a few percent methane have on the earths temperature, let alone the massive quantity of water vapor in the dense atmosphere?
@Steve Schaper – the same goes for Mars too.
A higher atmospheric pressure of 1.5 to 2 bar, and possibly slightly higher O2 conc. in the Carboniferous explains how the huge insects of the time could get O2 into their bodies and how they could fly.
No, methane and ammonia were always a trace gas in the atmosphere.
Yes, there is “geologic evidence in these rocks for really high concentrations of a greenhouse gas like carbon dioxide.” Calcium carbonate rocks of the time are composed of low ratios of aragonite. Aragonite forms in an atmosphere with low concentrations of carbon dioxide, and it dissolves in an atmosphere with high concentrations of carbon dioxide. Any hypothesis claiming low atmospheric concentrations of carbon dioxide must reconcile those claims with the high and low ratios of aragonite in those calcium carbonate rocks.
James F. Evans (12:03:12) :
I welcome your response.
But you didn’t learn much.
I didn’t know you were an expert on geologic radio-metric dating…I’ll assume you aren’t, unless you provide some personal professional background that says otherwise.
My major was Geophysics, but every natural scientist knows these things, just like they know that the Earth is the 3rd rock from the sun.
I’ll assume we are on a more equal scientific footing than normal.
It is hard to stoop to your level.
one, it must be “done carefully”, and, two, nature can tamper with the evidence, and, therefore, make it unreliable.
Every scientist in that that field works carefully and any tampering shows itself in the data, so tampered-with data can be excluded, i.e. the method itself shows you when it is reliable.
The article doesn’t say that 206Pb is ONLY caused by radioactive decay from 238U, unless you provide scientific evidence to the contrary, one can conclude there is natural 206Pb as well. The same can be said about 207Pb being a radioactive decay product from 235U; the article doesn’t say that 207Pb is ONLY caused by radioactive decay from 235U.
You have not understood that the 206Pb and 207Pb amounts result by two different processes and that from this one can determine how much is caused by what. No assumption.
Again, your assumption only holds true if nature has not tampered with the Uranium.
Nature itself shows us if tampering occurred.
This says nothing about whether Uranium not being able to be leached out of zirconium.
You have not understood that no matter how much Uranium leaks out, the only thing that matters is the relative proportions of 238U to U235.
any number of natural physical events could intervene and “reset the clock to zero”.
Again you misunderstand what ‘reset’ the clock means. It means that the age is now determined as the time time the last rest, e.g. melting. This is the only definition that makes sense. The Uranium atoms themselves may be anywhere from 13 to 5 billion years old.
“None of these things have any effect on the decay rate. This is an [unwarranted] assumption on your part.”
This is false or misleading.
During the time of bombardment or ‘event’, the rate of radioactive decay is increased. It is true that after the bombardment or ‘event’ the rate will return to its normal rate of decay
No, that is simply not true. I don’t know where you get that erroneous idea from, but Nature doesn’t work like that.
As to the second link provided, it does what you attempted to do: Claim an exactitude beyond what the scientific evidence allows Science to know, which is a common occurrence
The second link explains the efforts underway to drive the precision even higher, from 1% to 0.1% or better.
Dr. Svalgaard posed as somebody who “know[s] better than the rest of us.”
Just than you, judging from your response.
Jim F (09:59:18) :
Continents, not the present continents, must have come into existence as the Earth’s crust cooled enough to solidify.
Nobody has mentioned the formation of the moon-earth pair as a source of considerable heating via tidal friction, when the moon was orbiting the earth much closer in the past. Solar radiation and nuclear fission are not the only sources of heat on earth.
Squarebob Spongepants (10:17:58) :
Nobody has mentioned the formation of the moon-earth pair as a source of considerable heating via tidal friction, when the moon was orbiting the earth much closer in the past.
There is good evidence that the Moon was formed by a gigantic collision with a Mars-sized proto planet. That probably melted or even vaporized much of the Earth and flung the Moon rather far out, meaning that tidal friction [although higher] may not have been very important.
Squarebob Spongepants (10:17:58) :
Tidal heating is negligible relative to the other processes underway. The Sun was in its T-Tauri phase typical for a young Main Sequence star. The Earth’s iron core had not yet established or re-established itself as a dynamo, so there was no significant magnetosphere to shield the first atmosphere from scouring by the itense T-Tauri solar winds. Presumably, the first atmosphere was something like 105 to 250 atmospheres in mass, depending on the source/s consulted, and was composed primarily of the same hydrogen and helium as the nebular cloud from which it condensed. The massive atmospheric pressures combined with the intense solar winds and cooling from the collisional formations would have been a tremendous source of heating. The Late Heavy Bombardment (LHB) would then have renewed heating of the lithosphere to something on the order of perhaps 900C as the highly frequent impacts occurred. By the time the LHB was coming to an end, probably something like 90% or more of the first atmosphere would have been lost to the intense T-Tauri solar winds, lack of a magnetosphere, and ejections by asteroidal and cometary impactors. Remnants of the first atmosphere consisting of the heavier elements and compounds such as water vapor, carbon dioxide, sulfur dioxide, and nitrogen would have been augmented by cometary impactors and vulcanism with water vapor, carbond dioxide, nitrogen, and traces of methane, ammonia, sulfates, and more. This second atmosphere would still have been many times more massive than the present atmosphere with all of the consequences of higher atmospheric pressures in a reducing atmosphere.
In addition to the radical changes in the solar environment, atmospheric composition, and atmospheric pressures; you also had a much faster and shorter diurnal rotation, the greater tidal effects you mentioned, the effects of an atmosphere lacking oxygen and its effects, and a emergent biosphere.
Walter Munk of Scripps did some of the calculations based on the then known rate of the Moon’s recession from the Earth in this 1968 paper: http://adsabs.harvard.edu/full/1968QJRAS…9..352M
(Once again-Tidal Friction. Quarterly Journal of the Royal Astronomical Society, Vol. 9, p.352)
Leif, what evidence is there that the moon was “flung…rather far out”, rather than an initial close orbit and then a gradual recession over several billion years?
I am told that for temperatures above the curie point for iron, 1043K, it ceases to be ferromagnetic.
As such, the core of the earth being supposed to be largely made up of this metal is irrelevant since the supposed core temperature for any estimate is above 2000K. Any dynamo activity is within fluid ionised portions of the globe – mantle, ocean or ionosphere.
meemoe_uk (12:18:47) :
‘Paradox’. That is one of the most misused words in academia.
_______
Two orthodontists walk into a bar. One says to the other “Are we othodox?”
Reply “No we are a paradox.”
Squarebob Spongepants (12:14:13) :
Leif, what evidence is there that the moon was “flung…rather far out”, rather than an initial close orbit and then a gradual recession over several billion years?
Scant, but some. If the Moon was formed by fission of the Earth [i.e. not collision] it would have been VERY close by definition. Put the angular momentum the Moon now has back into the Earth and the rotational period would be VERY short. The rotational period of the new Earth is unknown, but many asteroids have periods near six hours, so if we go by that and assume that the angular momentum [between that and now 24 hours] has been transferred to the Moon we can estimate the early angular momentum of the Moon and hence its distance [assuming the mass did not change much]. I’m writing this from memory so don’t have the actual figures handy, but remember from somewhere that the Moon was flung out to a respectable distance. Since tidal forces go with the inverse cube of the distance there is a very steep falloff. PS: you might want to play the numbers and see what distance you can come up with, based on the method I outlined.
Squarebob Spongepants (12:31:33) :
Any dynamo activity is within fluid ionised portions of the globe – mantle, ocean or ionosphere.
The Curie point is irrelevant. It is enough that the matter is a conductor, and Iron is [at any temperature].
The temperature in the Atmosphere falls on average 2 deg C pr 1000 ft.(305 M).
Above the seasurface 1 hpa per 8m = 1hpa per 27 ft.
So lets say that the standard atmosphere historically has not been standard, 1013.2 hpa, and in order to increase today’s global temperature 2 deg C from 15 deg C to 17 deg C we just have to add more atmosphere so that it gets 1000 ft. thicker or the standard seasurface pressure increases from 1013.2 hpa to 1050 hpa!
If we dont know what the historic “standard” thickness of the atmosphere has been we are “lost” if we try to solve this “paradox”?
Jon-Anders Grannes (14:44:14) :
Increased temperatures increases atmospheric volume. Atmospheric volume increases atmospheric altitudes and drags down LEO (low Earth ordit) satellites. Increased atmospheric volume and altitude places more atmospheric mass at higher altitudes, where the decreased gravity exerts less gravitational energy upon the atmospheric pressure, while the increased thermal pressure increases atmospheric pressure?!?!? Then there is the magnetosphere……..and all of those new fangled windmills swatting around the air…..
Parameterizations anyone?
D. Patterson (17:14:49) :
A steady hotter Sun will in the future remove all water and I guess atmosphere, 500-1000 million years time?
The global average temperature has mostly been around 23 Deg C.
The last 27 million years it has become steadily more colder (15 Deg C in warm periods and much colder during iceages) and more unstable.
My point is that a global thicker atmosphere, in mass and volume, from todays 1013.2 hpa too 1050 hpa will make the global temperature in theory 2 deg C warmer than it is today?
Are there any studies on historic possible changes in the thickness of the atmosphere ?
My hypothesis is that the atmosphere was much thicker when the Sun was on 70% intensity and still made the global temperature 23 Deg C.
And that a gradual more intense Sun the last 4 billion years is increasingly depleting the Earths atmosphere and thus making it colder .
Ozon O3 means that there is Hydrogen lost in space?
“”” Squarebob Spongepants (12:31:33) :
I am told that for temperatures above the curie point for iron, 1043K, it ceases to be ferromagnetic.
As such, the core of the earth being supposed to be largely made up of this metal is irrelevant since the supposed core temperature for any estimate is above 2000K. Any dynamo activity is within fluid ionised portions of the globe – mantle, ocean or ionosphere. “””
Well you can make a very strong magnetic field; without ANY iron core at all.
Marcus Oliphant at the University of Canberra (I think) set out to build a proton synchrotron that was more compact and powerful than the “Bevatron”.
Since the saturation of the iron core was the limiting factor in how strong a magnetic field he could generate; he solved that problem by getting rid of the iron altogether, and now he had a linear air cored magnet coils that had no upper limit to the magnetic field set by the iron.
The coil consisted of two turns of copper wire, each about one foot in diameter (the wire; not the coil). The two turns intersected each other, since they overlapped, and the current went in opposite direction in each turn.
Since the net current in the overlap section of the two turns was zero; you didn’t need any copper there, so that air space, was where the vaccuum chamber was placed.
With no iron, and only two turns, it took 6 million amps to drive the coil to get a large enough magnetic field; thatw as several times what could be achieved in the iron cored Bevatron magnet.
The 6 million Amps was generated with a Faraday disk generator having four disks in tow counter-rotating pairs, hooked in series to produce something like 800 Volts at 6 million amps.
Connection to the axis, and periphery of the disks, was made with brushes consisting of streams of molten sodium.
Quite a machine it was; they dubbed it the white Oliphant.
So you don’t need magnetic iron to get a magnetic field; as Leif points out just enough plasma current will do it; so conduction is all that is required.
“”” James F. Evans (05:47:45) :
Dr. Svalgaard:
In Science, ignorance typically results from a refusal to consider evidence because that evidence contradicts strongly held opinions and assumptions. People (scientists are people, too, you know) would rather ignore evidence than have their world-view subject to revision.
But getting back to the specifics of the assumptions of radio-metric dating:
Radioactive isotopes, Uranium, Thorium, Potasium, and strontium, are used to date rocks. These radioactive isotopes have a constant rate of decay which can be used to measure time passage. In example: Uranium has a constant radioactive rate of decay into Lead. “””
James, a problem with the Uranium/lead dating process, is that all of the radio-nulei heavier than lead, that don’t fission tned to eventually end up as lead of one atomic wieght or another; and exactly which lead isotopes you end up with depends a lot on what you assume as a primordial mix of heavy radio-active species.
Then even a fixed species, like 238U has several decay paths; that happen with different frequencies, and those different paths then lead to a whole gamut of daughter species; some of which also have multiple decay paths.
So although it is a useful tool; there are a lot of variable, and diffrent deposits of radio-active materials or elad, all have differing isotopic abundances.
So it’s a big mess, and not surprisingly, there is a lot of uncertainty in the numbers for ages; but it is a hell of a lot betetr than not knowing anything.
George E. Smith (17:45:43) :
a problem with the Uranium/lead dating process, is that all of the radio-nulei heavier than lead, that don’t fission tned to eventually end up as lead of one atomic wieght or another; and exactly which lead isotopes you end up with depends a lot on what you assume as a primordial mix of heavy radio-active species.
George, I think you are wrong on this. 204Pb is not a decay product and thus sets the original composition of the Lead. The method is actually self-correcting. There is no big mess. We do know these ages to better than 1%, pushing 0.1%.
Some info indicating that the historic atmosphere had more mass and thickness.
Strange that it is a “paradox” when many claim that the historic atmosphere was denser, more mass, thicker, more airpressure and therfore would make things warmer than todays atmosphere?
Since temperature falls on average 2 deg C pr 1000 ft.(305 M). It means that it also increases with 2 deg C pr 1000 ft.
So if want warmer climate just add more atmosphere!
http://pubs.acs.org/subscribe/archive/ci/30/i12/html/12learn.html
http://cseligman.com/text/planets/retention.htm
http://www.google.no/url?sa=t&source=web&ct=res&cd=17&ved=0CCEQFjAGOAo&url=http%3A%2F%2Fwww.pearsonlongman.com%2Fadult%2Fdownloads%2FLife-On-Mars-Worksheet.doc&rct=j&q=%2Bmillion+%2Byears+%2Batmosphere+%2Bthicker&ei=MBzES-3lIqeTOLOy1dsP&mk=0&mb=2&usg=AFQjCNEfZHOYLYXrAmeK3W8KtPwR81Tdaw
http://www.palaeos.com/Mesozoic/Mesozoic.htm
http://www.dinosaurtheory.com/thick_atmosphere.html