Wednesday, 3 August 2011

Flat Earth

Courtesy of OrkneyLad


“Try this experiment. Ask an ordinary person what Christopher
Columbus wanted to prove when he set out to reach the Orient by way of 
the Occident and what it was that the learned men of Salamanca 
stubbornly denied, trying to prevent his voyage. The reply, in most 
cases, will be that Columbus believed the earth was round, whereas the 
Salamanca sages believed it was flat and hence thought that, after 
sailing a short distance, the three caravels would plunge into the 
cosmic abyss. 
So what was the big argument all about 
in the time of Columbus? The sages of Salamanca had, in fact, made 
calculations more precise than his, and they held that the earth, while 
assuredly round, was far more vast than the Genoese navigator believed, 
and therefore it was mad for him to attempt to circumnavigate it in 
order to reach the Orient by way of the Occident. Columbus, on the 
contrary, burning with a sacred fire, good navigator but bad astronomer, 
thought the earth smaller than it was. Naturally neither he nor the 
learned men of Salamanca suspected that between Europe and Asia there 
lay another continent. And so you see how complicated life is, and how 
fragile are the boundaries between truth and error, right and wrong. 
Though they were right, the sages of Salamanca were wrong; and Columbus,
while he was wrong, pursued faithfully his error and proved to be right
—thanks to serendipity.”

The Greeks had tried hard to find out how large the 
Earth is and managed to calculate many different figures depending on 
the methods and accuracy of their work. The most famous effort was that 
of Eratosthenes, Librarian of Alexandria, who wrote a treatise On the 
Measurement of the Earth, in which he gave a figure for the Earth’s 
circumference of 250,000 stadia. Depending on how long a stadia actually
was this is the equivalent of about 23,000 miles, pretty close to the 
true figure of 24,900 miles.

At the time Eratosthenes’s result did not demand 
universal assent and was widely seen as too big. A more popular figure 
is that given by Strabo and Ptolemy, two distinguished Greek geographers
of around the first century AD who both suggested 180,000 stadia. We 
are not sure where they got their figures from but they were repeated by
the Latin writer Seneca who transmitted them to the medieval West. By 
the time that it became a live issue for Columbus, Eratosthenes’ figure 
was back in vogue and the experts were wisely urging the Italian not to 
set sail. In particular a committee set up in Salamanca examined the 
plans and rejected them on the grounds that Columbus had underestimated 
the distance he would have to travel. Their concern is easy to 
understand – imagine how much trouble Columbus would have been in if the
Americas had not been there. He could not possibly have survived the 
trip all the way to the east coast of Asia and was very lucky that some 
land intervened before he and his crew had to pay for his mistake. In 
the end, however, Queen Isabella of Spain was won over and donated the 
resources required.

It is not difficult to see how the story of Columbus
was adapted so that he became the figure of progress rather than a 
lucky man who profited from his error. According to Jeffrey Burton 
Russell here,
the invention of the flat Earth myth can be laid at the feet of 
Washington Irving, (the author of Rip Van Winkle) who included it in his
historical novel on Columbus -its theme was the victory of a lone 
believer in a spherical Earth over a united front of Bible-quoting, 
superstitious ignoramuses, convinced the Earth was flat- and the wider 
idea that everyone in the Middle Ages was deluded has been widely 
accepted ever since.

Then later authors repeated this error:

“Nineteenth-century secular thought, irritated by the 
Church’s refusal to accept the heliocentric hypothesis, attributed to 
all Christian thought (patristic and scholastic) the idea that the earth
was flat.The nineteenth-century positivist and anticlerical made a meal 
of this cliché, which, as Jeffrey Burton Russell has demonstrated, was 
strengthened during the battle the supporters of Darwinian theory joined
against every form of fundamentalism. It was a matter of demonstrating 
that, as the churches had erred about the sphericity of the earth, so 
they could err also about the origin of species.”

The myth that Christians in the Middle Ages thought the world was flat was given a massive boost by Andrew Dickson White’s weighty tome The Warfare of Science with Theology.
This book has become something of a running joke among historians of 
science and it is dutifully mentioned as a prime example of 
misinformation in the preface of most modern works on science and 
religion. The Flat Earth is discussed in chapter 2 and one can almost 
sense White’s confusion that hardly any of the sources support his 
hypothesis that Christians widely believed in it. He finds himself 
grudgingly admitting that Clement, Origen, Ambrose, Augustine, Isodore, 
Albertus Magnus and Aquinas all accepted the Earth was a globe – in 
other words none of the great doctors of the church had considered the 
matter in doubt. Although an analysis of what White actually says 
suggests he was aware that the Flat Earth was largely a myth, he 
certainly gives an impression of ignorant Christians suppressing 
rational knowledge of its real shape.

What can be stated categorically was that a Flat 
Earth was at no time ever an element of Christian doctrine and that no 
one was ever persecuted or pressurised into believing it. This is 
interesting because the Bible itself implies the Earth is flat (for 
example at Daniel 4:11) and in [Isaiah 40:22] that it is spherical. 
Clearly, belief in the complete scientific accuracy of the scriptures 
against known facts was not upheld by the early or medieval church who 
were happy to accept figurative interpretations.

Anti-clerical ‘history of science’ writers have promulgated the myth so that even today, in his book The Discoverers,
Daniel Boorstin manages to produce a totally misleading account 
(although he eventually gets Columbus right). His bias shows badly when 
he castigates Christians for thinking the world was flat when they did 
not and then praises the erudition of Chinese geographers who actually 
did believe it. The myth is so prevalent that the blurb on the back 
cover of the UK version of Umberto Eco’s Serendipities, the editor repeats the myth even though within the book itself, Eco devotes a good deal of attention to debunking it!

The doyen of historians of Medieval Science, Edward Grant, covers the issue in his 2001 book, God and Reason in the Middle Ages
where he finds all educated people in the Middle Ages were well aware 
the Earth was a sphere. Perhaps today we can at last dispense with this 
patronising belief about the Christian Middle Ages.

Monday, 27 June 2011

The Myth of Peak Oil


Peak Oil is a myth that has been around at least since the 1950’s.
Every time there is a prediction that oil will run out, there are major new discoveries of reserves, or new technologies are introduced that improve recovery from existing fields.
A recent example of  new discoveries are the pre-salt oil reserves off the coast of Brazil in 2009. These are truly vast oil reservoirs below a layer of salt that is up to  6000 ft thick in places. The salt layer absorbs seismic energy so that traditional seismic surveys cannot “see” the oil below the salt layer. This oil was discovered by the very old fashioned method of drilling a wildcat well through the salt to have a look at what was underneath. Almost the entire deepwater area off the coast of Africa, and the whole of the Mediterranean Sea has a similar layer of salt, just waiting to be drilled. The Brazilian fields will come into production in the next couple of years. In 15 years time, Brazilian oil exports will eclipse Saudi exports.
An example of new technology is the discovery of how to release gas trapped in shallow layers of shale. The gas has been known to be in place for many years, but only recent has rock fracturing technology advanced to the point that the gas can be tapped economically. This has resulted in the USA now producing more gas domestically than Saudi Arabia, and this is just the start of the shale gas revolution. http://www.energyindustryphotos.com/shale_gas_map_shale_basins.htm
There is enough Shale gas resources in the USA to supply all their energy requirements, including transportation (LPG fuel) for 200 years at the present rate of consumption!
On top of this, recovery factors for oil have continuously increased from just being able to recover 20% of reserves back in the 1950’s to being able to recover about 55% at present- we haven’t worked it out yet, but there is no reason to suppose we cannot continue to improve recovery of known oil in place up to 80% or even more. Many North Sea platforms were due to be scrapped back in the 80’s, yet they are still economically producing oil due to enhanced recovery technology...

Wednesday, 30 March 2011

Tsunamis in the UK

I was interested to read in the MSM recently that the UK was fortunate in that it was "impossible" for us to be hit by a Tsunami like the one that recently devastated Japan.

between six to eight thousand years ago, Great Britain and the northern British Isles was inundated by a huge Tsunami which wiped out  the coast of the North Sea.

Whereas most tsunamis are caused by undersea earth quakes, some are caused by undersea "landslides".

The North Sea tsunami was caused by a huge submarine  landslide off the coast of Norway, and the area is now known geographically as the "Storegga Slide".

There were actually three major slides in the area, the first was around 50,000 years ago(BP), a second one around 22,000 BP, followed by one around 7300BP. This lasttsunami is estimated to have been between 19-25m high in the shetlands, and around 9m high along the coast of NE England.

Here is a computer simulated map of the extent of the slide, with the height of the average "run up" of the Tsunami- (as opposed to recorded peak heights due to wave focus, which were much higher in places such as river mouths etc)



references:
T. Bugge, R. H. Belderson, N. H. Kenyon “The Storegga Slide” Philosophical Transactions of the Royal Society of London 1988


Bernhard Weiniger et al The Castastrophic Final Flooding of Doggerland by the Storegga Tsunami Documenta Praehistorica 2008 ucl.academia.edu http://ucl.academia.edu/KevanEdinborough/Papers/419926/The_Catastrophic_Final_Flooding_of_Doggerland_by_the_Storegga_Slide_Tsunami

THE ENTIRE GLOBAL ECONOMY IS BUILT ON CREDIT.

The entire global economy is built on credit. if you want to see what the world looks like with out fractional reserve banking and extensive credit, just look to North Korea.

There is no way the western world would have prospered the way it has over the last 120 years  without the humongous credit market.

Thursday, 23 December 2010

Explaining the exponential growth in Technological change


In the 1950'sThe Nobel prize winning economist Solow discovered that about 90% of all economic growth in the USA between 1909 and 1949 was directly attributable to technological invention and innovation. http://nobelprize.org/nobel_prizes/economics/laureates/1987/press.html

There is a huge area of economic study related to this discovery and how best to finance R&D- For example, should it all be government funded or privately funded ?

Anyway, my own view is that the exponential growth of knowledge, technology and innovation is directly related to the number of human brains on the planet. As population increases, less communal brain power is dedicated to getting food, and more thinking time is dedicated to things such as how to improve a jet engine's fuel efficiency, or how to make a microprocessor smaller for example. So as population increases, the rate of change in technological innovation also increases. For this reason I am optimistic for the human race. The computing power of 9 billion brains by 2050 are sure to solve most of our pressing problems about environment, sustainable development and the improvement of the human condition.

Sunday, 28 November 2010

Gauge resolution and accuracy

If you have a thermometer with 1 degree centigrade divisions, it is reasonable to say that the thermometer has a resolution of 1c, or +/- 0.5c If the accuracy stated by the manufacturer is 0.5c, then the combined error margin is +/- 1.0c. In this case all temperatures recorded with this thermometer should be rounded up to the nearest 1c. It is impossible to measure 1.5c or 1.75c etc, even if it appears you can do so when you are looking at the thermometer. Even then, you should still remember that your observed recording is +/- 1c.
(need to expand on this at some point)

Wednesday, 13 October 2010

Metrology

This post is actually about the poor quality and processing of historical climatic temperature records rather than metrology.


My main points are that in climatology many important factors that are accounted for in other areas of science and engineering are completely ignored by many scientists:

  1. Human Errors in accuracy and resolution of historical data are ignored
  2. Mechanical thermometer resolution is ignored
  3. Electronic gauge calibration is ignored
  4. Mechanical and Electronic temperature gauge accuracy is ignored
  5. Hysteresis in modern data acquisition is ignored
  6. Conversion from Degrees F to Degrees C introduces false resolution into data.

Metrology is the science of measurement, embracing both experimental and theoretical determinations at any level of uncertainty in any field of science and technology. Believe it or not, the metrology of temperature measurement is complex.


It is actually quite difficult to measure things accurately, yet most people just assume that information they are given is "spot on".  A significant number of scientists and mathematicians also do not seem to realise how the data they are working with is often not very accurate. Over the years as part of my job I have read dozens of papers based on pressure and temperature records where no reference is made to the instruments used to acquire the data, or their calibration history. The result is that many scientists  frequently reach incorrect conclusions about their experiments and data because the do not take into account the accuracy and resolution of their data. (It seems this is especially true in the area of climatology.)


Do you have a thermometer stuck to your kitchen window so you can see how warm it is outside?


Let's say you glance at this thermometer and it indicates about 31 degrees centigrade. If it is a mercury or alcohol thermometer you may have to squint to read the scale. If the scale is marked in 1c steps (which is very common), then you probably cannot extrapolate between the scale markers. 
This means that this particular  thermometer's resolution is1c, which is normally stated as plus or minus 0.5c (+/- 0.5c)
This example of resolution is where observing the temperature is under perfect conditions, and you have been properly trained to read a thermometer. In reality you might glance at the thermometer or you might have to use a flash-light to look at it, or it may be covered in a dusting of snow, rain, etc. Mercury forms a pronounced meniscus in a thermometer that can exceed 1c  and many observers incorrectly observe the temperature as the base of the meniscus rather than it's peak: ( this picture shows an alcohol meniscus, a mercury meniscus bulges upward rather than down)
Another  major common error in reading a thermometer is the parallax error. 
Image courtesy of Surface meteorological instruments and measurement practices By G.P. Srivastava (with a mercury meniscus!) This is where refraction of light through the glass thermometer exaggerates any error caused by the eye not being level with the surface of the fluid in the thermometer.
(click on image to zoom)
If you are using data from 100's of thermometers scattered over a wide area, with data being recorded by hand, by dozens of different people, the observational resolution should be reduced. In the oil industry it is common to accept an error margin of 2-4% when using manually acquired data for example. 


As far as I am aware, historical raw multiple temperature data from weather stations has never attempted to account for observer error.


We should also consider the accuracy of the typical mercury and alcohol thermometers that have been in use for the last 120 years.  Glass thermometers are calibrated by immersing them in ice/water at 0c and a steam bath at 100c. The scale is then divided equally into 100 divisions between zero and 100. However, a glass thermometer at 100c is longer than a thermometer at 0c. This means that the scale on the thermometer gives a false high reading at low temperatures (between 0 and 25c) and a false low reading at high temperatures (between 70 and 100c) This process is also followed with weather thermometers with a range of -20 to +50c 


 25 years ago, very accurate mercury thermometers used in labs (0.01c resolution) had a calibration chart/graph with them to convert observed temperature on the thermometer scale to actual temperature. This would take into account all the inconsistencies inherent in manufacturing the thermometer. Here is an example of a 0-100c thermometer that indicates a correction  of -0.2c at zero, a -0.35C correction at 50C and +0.4C at 100C - this curve accounts for the change in length of the thermometer due to temperature changes, the increase in volume of mercury inside the capillary tube as opposed to the volume in the bulb, but most importantly it accounts for variations in the diameter of the capillary tube. (it is almost impossible to make a perfectly consistent glass capillary tube)



New Edit inserted here 12.feb.2011


Nowadays, precision "standard" thermometers used in weather stations have an accuracy of +/- 0.5c




What this means is that even with the best will in the world, using a modern thermometer manufactured in the last 25 years, the best accuracy achievable is +/- 0.5c, and the best resolution would be +/- 0.25c. Combining these tow potential errors, gives us a minimum error range of +/- 0.75c


Most weather station thermometers are a lot older than 25 years though. Thermometers made in the 19th century might have an error range of 3-5c...




Temperature cycles in the glass bulb of a thermometer harden the glass and shrink over time, a 10 yr old -20 to +50c thermometer will give a false high reading of around 0.7c


Over time, repeated high temperature cycles cause alcohol thermometers to evaporate  vapour into the vacuum at the top of the thermometer, creating false low temperature readings of up to 5c. (5.0c not 0.5 it's not a typo...)


Electronic temperature sensors have been used more and more in the last 20 years for measuring environmental temperature. These also have their own resolution and accuracy problems. Electronic sensors suffer from drift and hysteresis and must be calibrated annually to be accurate, yet most weather station temp sensors are NEVER calibrated after they have been installed. drift is where the recorder temp increases steadily or decreases steadily, even when the real temp is static and is a fundamental characteristic of all electronic devices.

Drift, is where a recording error gradually gets larger and larger over time- this is a quantum mechanics effect in the metal parts of the temperature sensor that cannot be compensated for typical drift of a -100c to+100c electronic thermometer is about 1c per year! and the sensor must be recalibrated annualy to fix this error.


Hysteresis is a common problem as well- this is where increasing temperature has a different mechanical affect on the thermometer compared to decreasing temperature, so for example if the ambient temperature increases by 1.05c, the thermometer reads an increase on 1c, but when the ambient temperature drops by 1.05c, the same thermometer records a drop of 1.1c. (this is a VERY common problem in metrology) 


Here is a typical food temperature sensor behaviour compared to a calibrated thermometer without even considering sensor drift: Thermometer Calibration depending on the measured temperature in this high accuracy gauge, the offset is from -.8 to +1c


But on top of these issues, the people who make these thermometers and weather stations state clearly the accuracy of their instruments, yet scientists ignore them!  a -20c to +50c mercury thermometer packaging will state the accuracy of the instrument is +/-0.75c for example, yet frequently this information is not incorporated into statistical calculations used in climatology.


Finally we get to the infamous conversion of Degrees Fahrenheit to Degrees Centigrade. Until the 1960's almost all global temperatures were measured in Fahrenheit. Nowadays all the proper scientists use Centigrade. So, all old data is routinely converted to Centigrade.  take the original temperature, minus 32 times 5 divided by 9.
C= ((F-32) x 5)/9


example- original reading from 1950 data file is 60F. This data was eyeballed by the local weatherman and written into his tallybook. 50 years later a scientist takes this figure and converts it to centigrade:
60-32 =28
28x5=140
140/9= 15.56
This is usually (incorrectly) rounded  to two decimal places =: 15.56c without any explanation as to why this level of resolution has been selected. 


The correct mathematical method of handling this issue of resolution is to look at the original resolution of the recorded data. Typically old Fahrenheit data was recorded in increments of 2 degrees F, eg 60, 62, 64, 66, 68,70. very rarely on old data sheets do you see 61, 63 etc (although 65 is slightly more common)


If the original resolution was 2 degrees F, the resolution used for the same data converted to  Centigrade should be 1.1c.


Therefore mathematically :
 60F=16C
61F17C
62F=17C
etc


In conclusion, when interpreting historical environmental temperature records one must account for errors of accuracy built into the thermometer and errors of resolution built into the instrument as well as errors of observation and recording of the temperature.


 In a high quality glass environmental  thermometer manufactured in 1960, the accuracy would be +/- 1.4F. (2% of range)


The resolution of an astute and dedicated observer would be around +/-1F.
Therefore the total error margin of all observed weather station temperatures would be a minimum of +/-2.5F, or +/-1.30c...


Any comments much appreciated