Radiation

[timfinch]

Do you understand the difference between a linear scale with an exponential axis and a logarithmic scale?

[timfinch]

Probably not or you wouldn't have made that asinine remark.

[Luke Pemberton]

Time for another recap:

• Tim brought a graph to the forum and claimed the average dose does not fall below 0.22 mGr/day.
• It was kindly pointed out to him that the data did not show this and he did no read the graph scale properly. 
• Tim argued that the graph was a exponential plot and not a log plot. 
• Not that the last point really matters as the data refutes Tim's claim. 
• It was explained to Tim that if one plots the graph in ExCel using a log scale the graph is faithfully reproduced. 
• Tim argued that the data, which fall below his criteria, should be averaged - surely.   
• We explained that if you average a bunch of numbers, all below 0.22 mGr/day, lo and behold the average is less than 0.22 mGr/day.   
• Tim was then asked about extrapolating data to a more active solar cycle.
• He then argued that in making this point we were saying the CRaTER data was not valid.
• No, he was confounding two points being made by 'us', his interpretation of the data and validly applying recent data to Apollo. 
• Tim then presented more data, this showed an average of 0.24 mGr/day.
• It was then presented to Tim that he was now using a different data set which did not account for fluctuations in  GCR.
• Tim asked if we were suggesting that GCR flux changed (he thought this was incredulous). 
• It was explained that the GCR flux did change and could fall below the average and rise above the average, he should know this from his graph.
• It was also explained that the dosimetry for Apollo and his data were made using different monitors so it is possible there could be a difference.
• Tim argued that moon dust is radioactive, but then presented evidence for dosimetry on the moon is of little biological concern for astronauts on short missions.

Sorry to use the royal 'we.'

Edit: Made a clarification of one bullet, and added more faces for effect.

[timfinch]

On a logarithmic scale a third is slightly more than half (.522). Why?  because the log of 3.3333 is .523.  It is basic stuff but it must be said.

[Luke Pemberton]

On a logarithmic scale a third is slightly more than half (.522). Why?  because the log of 3.3333 is .523.  It is basic stuff but it must be said.

This has been repeatedly explained to you. The scale on the graph is log, the data is not turned into logs and then plotted relative to the scale. That's the really basic part about it all.

[Luke Pemberton]

On a logarithmic scale a third is slightly more than half (.522). Why?  because the log of 3.3333 is .523.  It is basic stuff but it must be said.

None of this matters anyway, as if you look at the data it is clearly marked in the text file as cGr/day. Look at the data file and you'll find your criteria are fulfilled numerous times, bang in the middle of solar cycle where you would expect the GCR flux to be lower.

[Jason Thompson]

Do you understand the difference between a linear scale with an exponential axis and a logarithmic scale?

Do you understand that the graph you keep referring to is on a logarithmic scale? You are misinterpreting the dotted lines that correspond to the x-axis divisions as being a grid that applies to all of it.

But in any case, the numbers, the actual data, are all there for you to download and plot yourself. Why will you not do it? At least two people have done so.

[smartcooky]

Radiation is the transfer of energy by particle are photons and radioactive is the decay of unstable isotopes.

So, what are the decaying, unstable isotopes that are making  the lunar surface radioactive?

[Jason Thompson]

On a logarithmic scale a third is slightly more than half (.522). Why?  because the log of 3.3333 is .523.  It is basic stuff but it must be said.

On any scale 3.333 is not a third.

On a logarithmic scale 3.333 is 3.333. The only difference is how the axis is scaled. In a logarithmic conversion 3.333 is 0.522. However, there is no evidence that the numbers have been converted that way. When a graph uses manipulated data the axis is labelled accordingly. The label on the y-axis states it is the dose in cGy/day, and that is the same unit as the data provided with the graph. If it was a plot of the log of the data the y-axis would say that. Now, either you believe the graph is wrong or the data is misleading, because the data states quite clearly what the dose rates recorded are and huge swathes of them drop below 0.2mGy/day.

Tim, for the umpteenth time, why will you not take five minutes out of your day to download the data set and simply plot the graph on a log scale and see for yourself?

[Luke Pemberton]

On a logarithmic scale a third is slightly more than half (.522). Why?  because the log of 3.3333 is .523.  It is basic stuff but it must be said.

On any scale 3.333 is not a third. When a graph uses manipulated data the axis is labelled accordingly. The label on the y-axis states it is the dose in cGy/day, and that is the same unit as the data provided with the graph. If it was a plot of the log of the data the y-axis would say that. Now, either you believe the graph is wrong or the data is misleading, because the data states quite clearly what the dose rates recorded are and huge swathes of them drop below 0.2mGy/day.

Tim, for the umpteenth time, why will you not take five minutes out of your day to download the data set and simply plot the graph on a log scale and see for yourself?

... and to add to this, if you plot the log of a number there are no units, because a log is a dimensionless number - unless my physics teacher was wrong when he explained this to me at an early age. The ordinate scale in your precious graph clearly has units that correspond to the data. In other words, the scaling of the axis and the data in text file stack up.

Hence the axis is scaled on a log, and plot the true value of your data relative to the log scale.

[onebigmonkey]

India launched a lunar mission to the moon (Chandrayaan-1) in 2008 and the 5 day transit recorded a 1.2 millirem/hr transit.  Chandrayaan-1 was in 200 km lunar orbit, where the flux and dose rate measured ~2.8 particles cm-2 s-1 and ~11 µGy h-1 (2.645 mgy/day). .

Citation required.

Chandrayaan also took photographs showing evidence of human activity at Apollo 14, 16 and 17 landing sites. Someone isn't understanding the data properly. Maybe it's you.

[Jason Thompson]

Ok, I'll play along.  Accumulated dose = 30 over 15 days the average dose is 2 units/day.  So is that the tactic?  You want to pretend daily fluctuation occured and sometimes they got less and other times they got more?

That's not pretending, that's reality. As you can see from the CraTer data you brought to this very discussion.

Dosimeters measure accumulated dose.

Tim, literally your entire argument is based on average dose rates. The whole problem is you can't understand what an average is and why you can't point to an average value, then a specific value, and claim that the specific value being less than an average is a problem. That is mathematically guaranteed!

You remind me of Michael Gove when he was minster for education demanding more than 50% of schools should get an 'above average' grading during the Ofsted inspections. Mathematics wasn't his strong suit either...

[Luke Pemberton]

You remind me of Michael Gove when he was minster for education demanding more than 50% of schools should get an 'above average' grading during the Ofsted inspections. Mathematics wasn't his strong suit either...

Nor the OFSTED criteria, which are outstanding, good, requires improvement and inadequate. As you point out, quite amusingly, Mr Gove did not quite understand maths either.

In theory, 100% of schools could be outstanding, in which case more than 50% of schools are above the average criteria, but 0% of schools are above the average and 0% are below the average. That's what happens when one tries to combine continuous data and categorical data.

[onebigmonkey]

Chandrayaan data cited by timfinch:

https://arxiv.org/ftp/arxiv/papers/1012/1012.2014.pdf

If anyone cares to translate.

[Luke Pemberton]

Chandrayaan data cited by timfinch:

https://arxiv.org/ftp/arxiv/papers/1012/1012.2014.pdf

If anyone cares to translate.

That's brilliant. I've skimmed, but there's plenty to talk about.