Archive for the ‘science’ Category

>The moon and the age of the earth

2009 December 15 6 comments

> In my defence of a young earth I wanted to address the philosophical issues which I think are foundational to the argument. Discussions that fail to identify these issues end up with proponents of an old earth indirectly defending their presuppositions as if they are conclusions.

Consider 2 dating systems that give contradictory results. Which do we take as preferable? They both cannot be true. One or neither is true. Frequently the position is taken that dating system A gives the correct result and dating system B in in error because of incorrect assumptions X, Y, and Z. But it may be just as reasonable to take B as the correct result and explain why A is in error. Unfortunately proponents of A fail to see the philosophical validity of this. And even if they do, their subsequent arguments still frequently assume A.

I am not saying that all systems are equally convincing in their arguments. Rather that if B can be questioned then so can A.

I anticipated giving further specific arguments in favour of a young earth, or at least against a 4 billion year old earth. One argument is the maximum age of the moon.

The moon is known to be receding from earth. The rate is currently about 4 cm per year, though it is decreasing; the moon receded more quickly in the past. The recession is due to a transfer of angular momentum from the earth to the moon. The loss of angular momentum on earth is due to ocean tidal friction.

If we calculate how long it would take the moon to get to its current position if the moon was initially at the surface of the earth we get a figure of ~1 billion years. This is the maximum possible age for the earth-moon system. It can be much younger than this.

This maximum age is slightly, but negligibly, shorter if we consider the Roche limit. The earth’s gravity exerts a force on the moon dependant on the distance of the moon from the earth. At a certain distance the force exerted from the earth on the near-side of the moon compared to the lesser force on the far-side of the moon is greater than the gravitational force holding the moon together. This is called the Roche limit. This ignores added force from any internal tensile strength that holds the moon together.

The Roche limit for the moon is ~18,000 km from the centre of the earth. The moon is currently ~384,000 km from the (centre of the) earth. The earth’s radius is ~6,300 km.

Categories: creationism, moon, science

>Adjusting multi-site and single site temperature data

2009 December 8 2 comments

> NIWA offer as their explanation for the temperature adjustments the paper

  • Rhoades, D.A. and Salinger, M.J., 1993: Adjustment of temperature and rainfall measurements for site changes. International Journal of Climatology 13, 899–913.

Though they do not link to it nor give a digital object identifier (doi:10.1002/joc.3370130807).

The abstract states

Methods are presented for estimating the effect of known site changes on temperature and rainfall measurements. Parallel cumulative sums of seasonally adjusted series from neighbouring stations are a useful exploratory tool for recognizing site-change effects at a station that has a number of near neighbours. For temperature data, a site-change effect can be estimated by a difference between the target station and weighted mean of neighbouring stations, comparing equal periods before and after the site change. For rainfall the method is similar, except for a logarithmic transformation. Examples are given. In the case of isolated stations, the estimation is necessarily more subjective, but a variety of graphical and analytical techniques are useful aids for deciding how to adjust for a site change. (Emphasis added)

I did not fully follow all the maths in the paper. It was not particularly complex but I would need to spend some time doing examples to completely grasp it.

In the introduction they define “site change”,

We use the term site change to mean any sudden change of non-meteorological origin. Gradual changes can seldom be assigned with any certainty to non-meteorological causes. Where long-term homogeneous series are required, for example, for studies of climate change, it is best to choose stations that are unlikely to have been affected by gradual changes in shading or urbanization. This is no easy task. Karl et al. (1988) have concluded that urban effects on temperature are detectable even for small towns with a population under 10000.

…This paper is concerned with the estimation of site-change effects when the times of changes are known a priori, such as when the station was moved or the instrument replaced.

The paper predominantly discusses adjustments to data when there are site changes and there are surrounding overlapping data sets (nearby thermometers) that can be used to assess whether there needs to be adjustment.

Later in the paper when discussing sites that have no overlapping data the authors state,

Such an adjustment involves much greater uncertainty than the adjustment of a station with many neighbours. A greater degree of subjectivity is inevitable. In the absence of corroborating data there is no way of knowing whether an apparent shift that coincides with a site change is due to the site change or not. However, several statistical procedures can be used alongside information on station histories to assist in the estimation of the effect of a site change. These include graphical examination of the data, simple statistical tests for detecting shifts applied to intervals of different length before and after the site change, and identification of the most prominent change points in the series independently of known site changes. Finally, a subjective judgement must be made whether to adjust the data or not, taking into account the consistency of all the graphical and analytical evidence supporting the need for an adjustment and any other relevant information.

Moreover when they apply this adjustment to a station in Christchurch to demonstrate their method comparing with the more accurate method used earlier in the paper they significantly over estimate the difference,

The 1975 site change at Christchurch Airport is somewhat overestimated, when compared with the neighbouring stations analysis. The contrast between the estimates based on 2 years data before and after this site change is particularly marked. For the neighbouring stations analysis the estimate is 0.45°C (Table TI); for the isolated station analysis the estimate is 1.58°C (Table V). This is to be expected when a site change coincides with an actual shift in temperature, as occurred in this case. The isolated station analysis then estimates the sum of the site change effect and the actual shift.

In their conclusion they note,

Adjustments for site changes can probably never be done once and for all. For stations with several neighbours, the decision to adjust for a site change usually can be taken with some confidence. The same cannot be said for isolated stations. However, large shifts can be recognized and corrected, albeit with some uncertainty. Ideally, for isolated stations, tests for site change effects would be incorporated into the estimation of long-term trends and periodicities as suggested by Ansley and Kohn (1989). This is not practicable at present on a routine basis, but may be in the future.


Whatever adjustment procedures are used, the presence of site changes causes an accumulating uncertainty when comparing observation that are more distant in time. The cumulative uncertainties associated with site change effects, whether adjustments are made or not, are often large compared with effects appearing in studies of long-term climate change. For this reason it is a good idea to publish the standard errors of site change effects along with homogenized records, whether adjustments are made or not. This would help ensure that, in subsequent analyses, not too much reliance is placed on the record of any one station. (Emphasis added)

Ironically, the methods suggested in this paper do not include the method used by NIWA in defending their Wellington data.

>NIWA defends it adjustment of data

2009 November 27 Leave a comment

>NIWA have released a statement that the data that shows a warming trend in New Zealand over 100 years was adjusted.

NIWA’s analysis of measured temperatures uses internationally accepted techniques, including making adjustments for changes such as movement of measurement sites.

Though the paper (and my post yesterday) suggest adjustment was the likely explanation. However the graph and the surrounding paragraph fail to mention the data is adjusted. I read significant numbers of scientific papers and they are always referencing the raw and the adjusted data labelling both. There are statistical issues with some of these papers but this is not one of them.

NIWA go on to say,

Such site differences are significant and must be accounted for when analysing long-term changes in temperature. The Climate Science Coalition has not done this.

NIWA climate scientists have previously explained to members of the Coalition why such corrections must be made. NIWA’s Chief Climate Scientist, Dr David Wratt, says he’s very disappointed that the Coalition continue to ignore such advice and therefore to present misleading analyses.

Unfortunately this comment fails to identify and thus address the issue which is: “why” is not the question the Coaliltion is asking; it is “what” and “how”. What is the adjustment? and how have you done it? Treadgold (an author of the paper) writes,

We cannot account for adjustments, because we don’t know what they are. We ask only to know the adjustments that have been made, in detail, for all seven stations, and why.

Transparency demands that the specific reasons for data adjustment be given.

  • What stations have been adjusted?
  • When were they adjusted?
  • Is the adjustment stepwise or a trend?
  • Is there overlap of data when stations are shifted?
  • Does the overlapped data show good correlation?
  • Have adjustments been modified in subsequent years? Why?
  • What is the computer code that applies the adjustment?

This sort of information allows others to review the legitimacy of such decisions. And various groups can argue for and against these reasons and the weighing various reasons should be given.

Why the secrecy? The refusal to be open with data and theories is looked upon with suspicion, and rightly so.

Gareth Renowden writes a post explaining why adjustments are made to the data. The excessive rhetoric notwithstanding, the argument is plausible. But it still leaves questions unanswered. While the Wellington station may just be used an example, what of the other 6 stations? Wellington may show a rise after adjustment, but this will be diluted when averaged across all the station unless they all showed a rise. It they did what is the explanation for them.

Though I am not fully convinced with NIWA’s explanation. The Airport and Kelburn temperatures seem well correlated, with Kelburn cooler being at a higher altitude. And Thorndon and Airport are both at the same elevation (sea level). But there is no correlation established between Thorndon and the other 2 locations.

Elevation is not the sole determiner of temperature. There may be other considerations that make Thorndon and the Airport different temperatures. If so, then the adjustment down of the Thorndon data may be excessive. It should be easy to set up further measurements at Thorndon currently and see how they correlate to Kelburn and the Airport. If they all correlate well then we can establish a more accurate correction factor for the pre-1930 Thorndon data.

>New Zealand not warming?

2009 November 26 18 comments

>It seems to residents that the country has not being getting warmer over the last decade. Such that advocates of global warming prefer the term climate change so that any weather anomaly can be attributed to anthropomorphic global warming. And people are willing to parrot claims that some parts of the world will get colder (this may be a prediction of the theory but should encourage one to cautiously consider these claims).

The New Zealand National Institute of Atmosphere and Water Research (NIWA) do not show significant change since 2000 but they do show an increase over the last century as seen in this graph.

Graph. Mean annual temperature over New Zealand, from 1853 to 2008 inclusive, based on between 2 (from 1853) and 7 (from 1908) long-term station records. The blue and red bars show annual differences from the 1971 – 2000 average, the solid black line is a smoothed time series, and the dotted line is the linear trend over 1909 to 2008 (0.92°C/100 years).

Yesterday the New Zealand Climate Science Coalition released an article challenging this rise using NIWA’s own data. They plotted the temperatures from the NIWA source data and got this graph.

Whereas the first shows a rise of ~1°C per century, the second shows no discernable rise. The difference between the 2 graphs? The second uses raw data, the first (probably) has adjusted the data.

About half the adjustments actually created a warming trend where none existed; the other half greatly exaggerated existing warming.

There are legitimate reasons why data can and should be adjusted. Cities grow and hence warm so later temperatures may be warmer, especially overnight. Different thermometers may be used that show a consistent measurable difference. But there are 2 comments to make about adjusting data. Firstly adjusted data should be labelled as such with the unadjusted data displayed alongside it and the factors the data was adjusted for.

Secondly, it makes a difference whether adjusting data removes or produces an association. Frequently differences in data are seen because they attributes of the data sets are different. If we compare test scores between highschools to create a league table it may be reasonable to correct for number of children in different grades as some schools may have more students at higher levels, or one school may only let its brightest children sit the test. But we should be more cautious about accepting an association that only appears after adjustment. It is not that there can be no difference, rather it is that enough statistical manipulation can show a difference and the reasons for the adjusted variables are then argued after the fact.

If you do find a difference after adjustment you need to check your adjustment factors are not associated with the variable that is under consideration, in this case you cannot adjust for time as time changes are what is being looked for; and you must validate your adjustment with an independent data set.

On top of the release of emails and computer code from the now infamous Climate Research Unit at the University of East Anglia, UK; perhaps there might be some room for debate around the issues of climate change. Is it happening? Are humans responsible? Would it be detrimental? Should we pay attention to scientists who refuse to reveal their data and formulae?

>The illegitimacy of anti-supernatural causation

2009 September 28 7 comments

>My recent post led to some discussion, mainly in response to my opposition in defining science as methodological naturalism. I think the previous use of the term Natural Philosophy was adequate for the time. It made it clear that it was the study of natural phenomena without the baggage of additional metaphysics that are unnecessary to the practice of science. The subsequent addition of historical science to operational science to encompass all “science” makes short descriptions more difficult.

My contention is that forcing singular past events to be natural (that is not supernatural) is artificial (not genuine) and arbitrary (not determined by necessity); in that if God did make an object, methodological naturalism would prefer the false explanation that man made it over the true explanation that God did. david w states

The difference is artificial if there can be evidence for supernatural causation. How… [can] we know if God made a house?

This is putting the cart before the horse. One cannot argue philosophically that God does not exist thus he cannot make anything thus nothing is made by God. One can argue philosophically the case for and against God, but if there is empirical evidence otherwise, that must be taken into consideration.

To ask what such evidence is for God, but deny that evidence is even possible within one’s philosophy is disingenuous.

If God exists and he made man, and is at least as capable as man then he can make anything man can make. It does not matter whether or not we can identify a particular object is made by God, the fact is this is theoretically possible. And a definition that excludes God from producing something when it possible that he could, and thus God didn’t, even if he did, is fallacious.

I think there is reason to think that God made some objects. But definitive evidence, or even any evidence, that God made something is not necessary to allow that possibility. We allow for that possibility in other situations, such as an unknown culture, or the search for extra-terrestrial intelligence.

It must be recognised that we are looking at effects, thus inferring the source. Extensive knowledge, or any knowledge, about the source is not required beforehand. It is in studying the effect that we theorise about the source.

Categories: design, logic, philosophy, science

>Bypassing the argument thru definition

2009 September 21 54 comments

>Choosing one’s terms and labels may be an effective rhetorical technique; albeit frequently a dishonest one. Here are few examples that I find irritating.

Pro abortion as pro-choice

I have concerns with terms used on both sides of this debate, but this the more insidious. It is describing the issue in terms of freedom, but opponents to abortion are by no means anti-freedom. They see the issue as one of murder. I don’t hear “pro-choice” people advocating for the freedom of men to murder adults, or steal property. The pro-freedom position is reasonably described as libertarian. It is true many libertarians are “pro-choice” but this is not universal with some libertarians arguing against abortion. More relevant however is the position “pro-choice” people take otherwise, and this is commonly a socialist leaning position, hardly a paragon of choice or freedom. I would not be surprised to learn that opponents of abortion have a stronger commitment to choice outside the abortion debate.

I don’t particularly like the term “pro-life” either. The debate is about whether a fetus is living in a sense that confers the fetus natural rights. Although I hold this position, many abortion advocates disagree with it. As such they could argue they are pro-life and consistent by opposing capital punishment. I think it preferable to use accurate unloaded terms such as “pro-abortion” and “anti-abortion.”

Science as methodological naturalism

Science does not need to be defined this way and historically it was not. While it may seem somewhat reasonable on the surface, it fails on 2 counts. The meaning and reason for the term “methodological naturalism” is that one can not invoke the supernatural as an explanation, rather science seeks natural explanations for various phenomena. Given that operational science was invented by supernaturalists whose concept of God (immutable) gave them reason to think the world was orderly and thus amenable to repeated observation with an expectation of identical findings, it is uncertain why a definition using “naturalism” needs to be invoked centuries later.

It fails because it does not apply to historical science which has no such non-supernatural limitations yet historical science is considered part of the broader concept of science. And it fails because it contains a philosophical term: Naturalism has a range of claims which are not derived from science, nor does science intrinsically favour naturalism.

Such a term can lead to the claim that science has disproved God. But analysis of this claim will show it to be circular. God is excluded by definition, and any thesis sans God is deemed “scientifically” preferable, even if untrue.

Gender neutral as gender accurate translation

There is debate about how to best translate various Greek words into English in Bible translation. Does one translate masculine pronouns such as “he” inclusively or specifically? Does the Greek word anthropos mean “person” or “man” with generic connotations at times? I do not intend to discuss the merits of both arguments, just note that the inclusive school uses the term “gender accurate” to describe their theory. They argue that an inclusive view is intended by biblical authors, thus improved accuracy. One problem is that the term “accurate” is more synonymous with “precision” than “intention”. The other problem, of course, is that the debate is around which translation theory is the most accurate. Using a term as part of your definition, then claiming something is thus, by definition—often implicitly—resolves nothing.


The reason this annoys me is that the terms are deliberately chosen. Their inventors are not so much trying to frame the debate as circumvent it. I find it disingenuous.

This is not to suggest choosing various terms is intrinsically dishonest. If a different term brings clarity, or is neutral, or both, then it may be preferable.

Sometimes one should consider terms used by his opponents. While the adoption of labels from the opposition is not compulsory, they may sometimes be accurate. Another option is to use historical terms.

>The ropens of Papua New Guinea

2009 September 15 4 comments

>Mike T brings my attention to the incompletely documented creatures called ropens. Several eye-witness accounts describe featherless flying creatures that perch upright on trees on the islands of Papua New Guinea.

Around Manus Island, the wingspan is three to four feet, according to Jim Blume, a missionary in Wau, on the mainland. Blume’s investigations indicate that wingspans may reach ten to fifteen feet in other areas. Whitcomb’s book mentions a few ropens that are even larger, including the ones seen by Hodgkinson and the Australian couple.

I am familiar with a variety of sightings of reptiles that are otherwise thought to be extinct, such as the bunjip. But I had not heard about ropens.

The description seems to be of a pterosaur. What I found particularly interesting about these sightings was the mention of lights on the animals.

Two natives described a ropen holding itself upright on a tree trunk (fruit bats hang upside down from branches), and his book also describes an apparently bioluminescent glow that may help the nocturnal creatures catch fish.

I am not aware that palaeontologists propose bioluminescence in pterosaurs. However previous eye-witnesses have suggested something similar. In his book After the Flood, Bill Cooper quotes Marie Trevelyan’s book Folk-Lore and Folk Stories of Wales, published in 1909.

The woods around Penllin Castle, Glamorgan, had the reputation of being frequented by winged serpents, and these were the terror of old and young alike. An aged inhabitant of Penllyne, who died a few years ago, said that in his boyhood the winged serpents were described as very beautiful. They were coiled when in repose, and “looked as if they were covered with jewels of all sorts. Some of them had crests sparkling with all the colours of the rainbow“. When disturbed they glided swiftly, “sparkling all over,” to their hiding places. When angry, they “flew over people’s heads, with outspread wings, bright, and sometimes with eyes too, like the feathers in a peacock’s tail”. He said it was “no old story invented to frighten children”, but a real fact. His father and uncle had killed some of them, for they were as bad as foxes for poultry. The old man attributed the extinction of the winged serpents to the fact that they were “terrors in the farmyards and coverts” (emphasis mine).

The Welsh description may be iridescence rather than luminescence, but I think the parallel striking. While I know too little about the Papua New Guinea story to vouch for its veracity, the lack of communication between Welsh and New Guinean witnesses concerning a pterosaur trait not otherwise recognised does give one pause.

Categories: animals, creationism, science