Radiation

[Obviousman]

Is this an example of the Dunning-Kruger Effect?

I'm reluctant to say because this isn't really my area of specialty.  Dunning and Kruger studied competence and its effect on subjects' ability to judge their own competence and that of others.  It also briefly studied the mutability of this phenomenon.  My feeling is -- and this goes beyond just Tim -- that many fringe claimants exhibit behavior that Dunning and Kruger didn't study, but which might be related to or involved in some way with what they did uncover.  If I second-guess how psychologists tend to think through these problems, I would say that they would see a difference between simply misjudging competence and responding to it with hostility.

Keep in mind also that fringe argumentation often wants to invoke different modes of thinking.  A person may recognize that others are, say, "book smart" about something while he has a certain intuition or insight that provides expertise in a different way or via different means.  I don't think any such effect was made visible in "Unskilled and unaware of it," Dunning and Kruger's seminal paper.  They made no distinctions in different constructions of competence.  To borrow an example from the paper, someone who has objectively poor grammar skills would be said to lack the metacognition necessary to recognize that he was unskilled.  And he would be similarly ill equipped to judge the grammar skills of another person.  But in the paper, that subject would believe he is competent in the normal way, not in some alternative way he invented to make up for an acknowledged deficiency in the standard mode of knowledge.  My impression is that psychologists would see that as a significant departure from Dunning and Kruger's conclusions.

Thank you, Jay.

I thought some might misunderstand me, as when I posted that, I wasn't being insulting.... I was wondering if this were a genuine, real-world example where we can see the effect. I thought that we had an area where some greater technical knowledge of the subject matter is required to really understand the subtleties and this person seemed to be becoming more entrenched in their belief every time their misunderstanding of a facet of the matter was pointed out.

I agree with you and I think it is more complex; for example does 'pride' factor into the Effect? Someone has been proven wrong on critical points in their cherished debate, and so their pride will not allow them to admit error, to rethink their assumptions, etc (I can't help but think of Jack White in this regard!).

[Mag40]

I read through this whole thread and feel exhausted by the repetition from TF. I know nothing about space radiation, but I do know that two different space craft decades apart, with different collection machines, different solar activity, different distant stellar activity and most importantly of all, different effectiveness against stopping the radiation from penetrating, well that is going to provide a whole heap of variables that are going to produce different results.

I didn't see anyone address this question about the transit of the 'deadly' Van Allen belts by Apollo. This great video shows how the trajectories all flew through the weaker areas of both belts:

[Count Zero]

I read through this whole thread...
I didn't see anyone address this question about the transit of the 'deadly' Van Allen belts by Apollo. This great video shows how the trajectories all flew through the weaker areas of both belts:

*sigh* I posted that and two other videos in reply #327 on page 22.  That post was completely ignored by both sides in favor of continued discussion of that confusing and, IMO inferior pencil sketch.  Hell, Jay's photograph of a glazed doughnut with a card-stock parabola is more instructive to laymen than that damn sketch.   

[bknight]

I read through this whole thread...
I didn't see anyone address this question about the transit of the 'deadly' Van Allen belts by Apollo. This great video shows how the trajectories all flew through the weaker areas of both belts:

*sigh* I posted that and two other videos in reply #327 on page 22.  That post was completely ignored by both sides in favor of continued discussion of that confusing and, IMO inferior pencil sketch.  Hell, Jay's photograph of a glazed doughnut with a card-stock parabola is more instructive to laymen than that damn sketch.   

I only posted a 2-D image and didn't have a 3-D or video.  I didn't seem to overlook it, sorry if you felt I did.  BTW great video and visualization to you and Mag40, thanks. tf would have ignored it since it invalidated a portion of his belief., and he could not visualize the 2-D image for sure.

[benparry]

Thanks again jay for those 2 answers

[JayUtah]

Thanks again jay for those 2 answers

Glad to be of help.  Although re-reading it leads me to an erratum:  A flux of 10^-1 s^-1 would be one particle every 10 seconds, not every 100 seconds.

[Count Zero]

tim has tried on two different forums CosmoQuest and here to show his ineptitude and been handed his hat to him.

I've been looking for his thread and not finding it.  Link please?  T.I.A.

[Nowhere Man]

I've been looking for his thread and not finding it.  Link please?  T.I.A.

This looks like it.

https://forum.cosmoquest.org/showthread.php?166821-Moon-Landing-Question

Fred

[smartcooky]

A proton can interact with an aluminum shield in a number of ways.  Those result in different species of secondary radiation, ranging from none to significant.  The trick is simply to provide enough thickness of aluminum that the secondary radiation can be absorbed in the inner portion of the shield and attenuated to a sustainable level.  The goal is almost never to get to zero.  In all the different collision modes, the primary proton is an ejectile, but it leaves with considerably less energy than it came in with.  If that proton should wind up hitting your liver, you hope that it does so at low energy and thereby deposits only a very small amount of energy.  That's sort of the thumbnail sketch of shielding theory.

If the shielding is composed principally of hydrogen, there is a limit to what the worst-case proton collision (direct elastic hit on the nucleus) can produce by way of secondary ejectiles.  In higher-Z materials, significantly massive chunks of shattered nucleus may be recoiled.  The problem is that ideal materials like water pose handling problems in space.  Wanting to shield with water complicates the other parts of the engineering.  Similarly with high-density polyethylene, another "ideal" absorber.  Stopping power is a function purely of a material's mass density for a given energy dissipation rate.  It's not a function of shield chemistry.  Therefore to get enough polyethylene thickness to stop very high energy protons, you need many centimeters of it since it's less dense than metals.  Again that complicates other aspects of spacecraft design.

Aluminum is the material of choice because it has excellent properties for other requirements in spacecraft engineering.  But in terms of radiation attenuation it's a semi-optimal compromise.  It's low enough Z that the secondary radiation it produces is reasonably tolerable.  And it's dense enough to provide reasonable stopping power in thicknesses that don't become onerous for the rest of the design.  It's a great example of typical engineering tradeoff.

Back in 1986/87, on the Giotto Spacecraft that rendezvoused with Comet Halley, the designers used a shield to protect the spacecraft (during its approach) from particles of matter being shed by the comet as its ices sublimated. IIRC, it was essentially a double layered shield, the idea being that the outer layer would stop most of the smaller particles, slightly larger particles that might penetrate outer layer would either vaporise, or lose most of their energy, and would then not penetrate the inner shield.

I wonder if a similar arrangement would help (or hinder) in the the case of GCR? Would multi-level thinner shielding be any more or less effective than a thicker shield? Could it help with mitigation of secondary radiation, or would it potentially make it worse? 

[Count Zero]

I've been looking for his thread and not finding it.  Link please?  T.I.A.

This looks like it.

https://forum.cosmoquest.org/showthread.php?166821-Moon-Landing-Question

Fred

Oh!  It was 5 months ago.  No wonder I couldn't find it.  I thought it was in the last week or two.  My bad.  Thanks Fred!

[MBDK]

The dosimeter method just skips to the end.  It won't necessarily differentiate between kinds of radiation (although many do), or keep a detailed breakdown of whether it was a little bit over a long time, or a lot in a short time.  A health physicist's first question will be what the total absorbed dose is.  Imagine filling up a pitcher at the sink, where you vary the water flow by idly twisting the knob as it fills.  Sure, a physicist can get all over that and integrate the varying flow rate over time and predict with math how much water ended up in the pitcher.  But the quick and dirty method is just to measure the amount of water that got in there.  This is essentially what Tim's dosimeter data does.  It doesn't account for different sources of radiation.  It doesn't account for varying effects of shielding.  It doesn't account for natural fluctuations in the dose rate.  It just gives you total accumulated dose.  Of course in practice the Apollo crews read off their dosimeter readings at periodic intervals, so we at least have some time-varied data.

Just a little adjustment/clarification for your dosimeter reading portion. 
From: https://history.nasa.gov/SP-368/s2ch3.htm

"To allow accurate determination of overall radiation exposure of the crewmen, each carried a personal radiation dosimeter (PRD) (figure 4) and three passive dosimeters (figure 5). The PRD provided visual readout of accumulated radiation dose to each crewman as the mission progressed. It is approximately the size of a cigarette pack, and pockets were provided in the flight coveralls as well as in the space suit for storage. The passive dosimeters were placed in the garments worn throughout the mission. By placing these detectors at various locations (ankle, thigh, and chest) within the garments, accurate radiation doses for body portions were determined."

So, the PRD kept track of total dose (at the chest, where the pockets were) during the flight, as they provided a constant visible read-out.  However it was the passive dosimeters that were read out with separate machines on Earth (they heated the thermoluminescent materials in them and measured the amount of light they gave off which was proportional to the dose they received) that were used for the records, as they are far more accurate. 

So, probably way more than you all cared to know, but I am OCD that way.     

Note:  Edited to clarify the function of the PRD.

[nomuse]

One said volume might be a hardbound collection of papers from the late 50's that I happen to have in my bookshelf, where the neutron issue is theorized and calculated. You, like several hoax believers past, seem to want to characterize this as a surprising new fact NASA was too slow to cover up. It is not.

Overall, future lunar travelers face a radiation dose 30 percent to 40 percent higher than originally expected

It is interesting to note that the article says "originally expected" and not measured.  I could read volumes into that.

[JayUtah]

Back in 1986/87, on the Giotto Spacecraft that rendezvoused with Comet Halley, the designers used a shield to protect the spacecraft (during its approach) from particles of matter being shed by the comet as its ices sublimated. IIRC, it was essentially a double layered shield, the idea being that the outer layer would stop most of the smaller particles, slightly larger particles that might penetrate outer layer would either vaporise, or lose most of their energy, and would then not penetrate the inner shield.

I wonder if a similar arrangement would help (or hinder) in the the case of GCR? Would multi-level thinner shielding be any more or less effective than a thicker shield? Could it help with mitigation of secondary radiation, or would it potentially make it worse?

It wouldn't help.  You're thinking of laminated armor that uses alternate layers of dense and sparse material.  It's actually how the micrometeoroid shield on the Apollo LM was designed, and to a lesser extent the space suits.  It works for ballistic particles where "particle" here means dust, not some exotic thing ending in -on.  The theory behind laminated armor is that the collisions with the hard outer layers fragment (in a mechanical, not subatomic, way) both the injectile and the armor.  The soft inner layers (if they aren't just empty space) attenuate the velocity, but what they really do is provide distance for the collision products to fan out and vent their energy on the next hard layer across a broader surface area.  You don't really need that allowance to shield against ions.  So you fall back to the general rule that density is king:  you want collision products from GCR to encounter another atom within the shielding as soon as possible.  I recall the ANR reference for the LM had a good drawing of how the micrometeoroid shield worked.

[jfb]

Is this an example of the Dunning-Kruger Effect?

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In my (uneducated layman's) opinion, no.  Tim isn't simply overestimating his skills in a particular area - he's engaging in a pattern of thought (delusion of conspiracy) that's largely orthogonal to what D-K were studying. 

I mean, the nut of his argument was that because the dosimeter readings for Apollo were lower than those for MSL/RAD, then the Apollo numbers must be fake.  Or, if they're real, then no astronaut actually left LEO and the landings were faked. 

There was apparently no thought to investigate possible differences in the cislunar radiation environment between Apollo and MSL/RAD, or differences in equipment, procedures, or analysis, or any of a hundred other mundane scientific or engineering differences could account for the discrepancy.  For him, the immediate, obvious, go-to answer is fakery.

That's not D-K.  That's a different pathology. 

[onebigmonkey]

The CM hull had a dosimeter in it didn't it? Were the results from those ever published?