jayphailey on May 08, 2010, 05:18:32 am
Hey folks,

Sorry.  Nerdy nit pick, here.

The current story arc features tall towers built on the Lunar surface.

Any such towers would be blasted by solar radiation - specifically ionizing radiation.  Residents would suffer brain and nerve damage after long exposure.  I am not sure how long it would take to show effects.

A solar flare would wipe out anyone living in the towers.

You'd need something like 6 feet or more of dirt or rock to absorb the radiation and prevent damage. -  burying lunar ihabitations would also make sealing and temperature control easier.

-*-

There was an experimental dealy called the M2P2 -
http://www.ess.washington.edu/Space/M2P2/
http://en.wikipedia.org/wiki/Magnetic_sail#Mini-magnetospheric_plasma_propulsion


The accounts I read said that these magnetic sail blocks ionzing radiation.  however I have heard nothing further about that... Not that I have looked really.

Jay ~Meow!~

Brugle on May 08, 2010, 10:13:08 am
I'd guess that the walls and windows would be thick enough (and made of appropriate material) to block harmful EM radiation and most ions.  In the rare case of dangerous ion emission (perhaps from a coronal mass ejection headed this way), a few minutes warning should be sufficient for everyone to get to a place with better shielding (probably the core of the tower).

Of course, there may be better technology available in EFT's time.  Sandy?

SandySandfort on May 08, 2010, 10:36:23 am
I'd guess that the walls and windows would be thick enough (and made of appropriate material) to block harmful EM radiation and most ions.  In the rare case of dangerous ion emission (perhaps from a coronal mass ejection headed this way), a few minutes warning should be sufficient for everyone to get to a place with better shielding (probably the core of the tower).

Of course, there may be better technology available in EFT's time.  Sandy?

Like you said. Thick shielding and safe rooms in the core* plus maybe new technology such as ultra-powerful electromagnetic fields or the like.

* Last night on Discovery or NatGeo or wherever, I saw a show about the Burj Dubai, the tallest building ever erected. In addition to internal firefighting equipment, there are fire resistant refuges areas every 30 floors or so. Residents will not leave the building in the even of fire (impossible). They will go to the fire resistant rooms, each of which has its own air supply, and await rescue after the fire is put out.

ZeissIkon on May 13, 2010, 04:01:52 pm
The radiation problem in the Lunar towers is exactly the same one present in all interplanetary spacecraft (albeit, given constant boost, for much longer time on the Moon), and to all dwellers in either surface domes or ships (or Ghetti) in the asteroid belt (though the Belt gets some 1/16 the radiation level compared to the Lunar surface, over time it still adds up).

An earlier story arc has already suggested nanobots exist to prevent long-term adaptation to low- or microgravity (bone density loss and muscle atrophy, for instance) that would make return to a full 1 G field impossible for life; nanobots complex enough to do those things could probably be programmed to excise radiation damaged cells.  Brain damage is the only issue that simplistic approach won't solve; the radiation level at Earth orbit would likely have an effect, over time, similar to staying drunk for years on end.  Better nanobots, capable of repairing damaged cells, would prevent all damage below some threshold level that exceeds their ability to cope.

Magnetic shielding deflects charged particles to the magnetic poles, just as does the Earth's magnetic field; those (solar protons and electrons, also the primary risk from coronal mass ejections and flare events) are the most serious risk, and using magnetic shields to avoid the need for heavy mass shields keeps the risk from cosmic rays manageable (say, by nanobots).

SandySandfort on May 13, 2010, 05:17:41 pm
The radiation problem in the Lunar towers is exactly the same one present in all interplanetary spacecraft (albeit, given constant boost, for much longer time on the Moon), and to all dwellers in either surface domes or ships (or Ghetti) in the asteroid belt (though the Belt gets some 1/16 the radiation level compared to the Lunar surface, over time it still adds up).

Do they? That is the orthodox belief, "any radiation is dangerous." The problem is there there is absolutely no experimental evidence to support that assertion. It is only extrapolated backwards from high radiation dosages. "Well, if a lot is bad for you, then a little is bad for you too, only less so."

To the extent that there has been any research on the subject, the opposite has been shown to be true. That is, a little radiation (up to about 100 times natural background radiation on the surface of the earth) is beneficial to your health, resistance to disease, mental functions, resistance to cancer, etc. See:

     http://en.wikipedia.org/wiki/Radiation_hormesis


quadibloc on May 15, 2010, 01:20:21 pm
The problem is there there is absolutely no experimental evidence to support that assertion. It is only extrapolated backwards from high radiation dosages. "Well, if a lot is bad for you, then a little is bad for you too, only less so."
That makes sense not as something to assume as fact, but simply as a basis on which to set safety standards. We want to avoid adding even a slight chance of getting cancer, but there is no practical way to set up a study to measure the bad effects, if any, of very small amounts of radiation. So we work from what we know is the most pessimistic assumption.

Now I am surprised to hear that up to 100 times background is still in the area of hormesis (which word I first heard of, I think, from Heinlein - probably in Starship Troopers, or at least in a discussion somewhere of that story).

sams on May 15, 2010, 03:02:28 pm
Now I am surprised to hear that up to 100 times background is still in the area of hormesis (which word I first heard of, I think, from Heinlein - probably in Starship Troopers, or at least in a discussion somewhere of that story).

When Rico is stationed at the Sanctuary, the Federation Fleet Fortress, he have a discussion with a Pin head about the lack of enough radiation that might affect the primogeniture of the colonist. The idea is that radiation is driver force of evolution ... but like Rico say : I don't get the whole stuff and it would be easier if a trigger was involved

Brugle on May 15, 2010, 06:03:48 pm
The problem is there there is absolutely no experimental evidence to support that assertion. It is only extrapolated backwards from high radiation dosages. "Well, if a lot is bad for you, then a little is bad for you too, only less so."
That makes sense not as something to assume as fact, but simply as a basis on which to set safety standards.
If we didn't know better, it might make sense to set safety standards using the linear no-threshold hypothesis.  But we do know better.

We want to avoid adding even a slight chance of getting cancer,
I'd gladly accept a slightly higher chance of getting cancer in exchange for something of greater value (for example, a larger reduction in other risks).  If you have an extreme fear of cancer then take whatever steps you think appropriate to ensure that you die from something else, but don't enlist the state to make us pay for your phobias.  (Since low levels of radiation may protect against cancer, the policies you appear to support may actually increase your (and our) cancer risk.)

but there is no practical way to set up a study to measure the bad effects, if any, of very small amounts of radiation.
As Sandy said in another context, think about how you'd solve the problem.  I know of at least 2 fundamentally different ways of studying the effects of low-level radiation on health, with several variations on each way.  Give your brain a chance--it may work better than you think.

SF author James P. Hogan has occasionally written about radiation hormesis:
http://jamesphogan.com/siteindex/keyword.php?key=687
« Last Edit: May 15, 2010, 06:32:08 pm by Brugle »

SandySandfort on May 15, 2010, 10:38:20 pm
... but there is no practical way to set up a study to measure the bad effects, if any, of very small amounts of radiation...

Actually, there are any number of ways. Two that have actually been studied are cancer rates among shipyard workers who work on nuclear ships vs non-nuclear ships and the incidence of cancer around ground zero for the two bombs dropped on Japan.

My recollection is that the ship workers who were around radiation that was significantly higher than background had fewer incidents of cancer and other health problems than did their equivalent workers on non-nuclear ships.

In Japan, cancer was very high out to a certain distance from ground zero, then dropped off to extremely low levels in a sort of "sweet spot." Further out, the incidence of cancer increased again to national norms.

You know, people drown if they get too much water. Just to be on the safe side, we should outlaw water, because any level might be dangerous.

terry_freeman on May 16, 2010, 05:32:23 am
Aye! We should totally ban dihydrogen monoxide

http://www.lhup.edu/~dsimanek/dhmo.htm

 ... or perhaps not.

NemoUtopia on May 16, 2010, 09:49:23 am
As pointed out with water, consider too the 'trace elements' our body NEEDS for healthy function. The real issue with radiation is the type/mixture, and consider too the official definition of radiation is ANY process where energy travels through a medium or space to be absorbed by another body. What most people assosciate the word radiation with is Ionizing Radiation, which generally is harmful in even small amounts. Other types can be thought of like water and trace elements: we have a 'sweet spot' that is good for us, and then there's an absence that harms us and an abundance that harms us. The simplest example here is heat...you need heat, but too much causes varying degrees of injury. Others simply do not harm us below a certain threshold, but high exposure is lethal. Think X-rays and microwave radiation. It's yet another case where laymen get a small amount of information and draw incorrect all/nothing conclusions from them.

In the case of the lunar towers, I would expect there to be quite a few options at the given tech level. I would actually be surprised if the towers are not constructed to generate their own magnetic field...exact mechanism unknown, but the basic idea is the same as how Earth's magnetic field brings ionizing radiation to the poles. An absorbing or dispersing mechanism at the peak of the tower makes the most sense in this context. Advanced composite material glass with nanobots to absorb radiation and good old fashioned lead-lined walls with their own composite structures. With the presumed ability to handle anything short of a solar flare, the secured room scenario would cover that. All presumption, but reasonable considering what we know.

Brugle on May 16, 2010, 11:37:09 am
Ionizing Radiation, which generally is harmful in even small amounts.
Almost all of the evidence suggests that ionizing radiation is not harmful in small amounts, and much of the evidence suggests that ionizing radiation is beneficial in small amounts.  Of course, no amount of evidence will guarantee that a theory is true, but it is usually more reasonable to accept the evidence than to claim that the evidence is wrong.

Follow the link in reply #4 or follow some of the links from the page linked in reply #7.

NemoUtopia on May 16, 2010, 01:54:33 pm
Ionizing Radiation, which generally is harmful in even small amounts.
Almost all of the evidence suggests that ionizing radiation is not harmful in small amounts, and much of the evidence suggests that ionizing radiation is beneficial in small amounts.  Of course, no amount of evidence will guarantee that a theory is true, but it is usually more reasonable to accept the evidence than to claim that the evidence is wrong.

Follow the link in reply #4 or follow some of the links from the page linked in reply #7.


I did, and they both contain qualifiers that the effect has not been (sufficiently) studied in humans. Additionally, what studies have been done show age variation. Ionizing radiation in humans is known to disrupt our biology, and there is conflicting evidence and debate concerning this. This isn't to say that we can't cope with certain harmful levels, or that the idea of building radioresistance through exposure is implausible. In fact I'd bet that it varies by the type of ionizing radiation, since they are very different...pulled off the top of my head [i.e. out my ass] I wouldn't be surprised controlled dosages of alpha radiation have little appreciable effect one way or the other, beta radiation in controlled exposure provides benefits, and gamma rays remain the big bad wolf. More evidence is needed to support any conclusion about low doses of radiation now that existing evidence has called assumptions into question...but suffice to say I won't be volunteering as a test subject.

SandySandfort on May 16, 2010, 04:18:27 pm
I did, and they both contain qualifiers that the effect has not been (sufficiently) studied in humans. Additionally, what studies have been done show age variation. Ionizing radiation in humans is known to disrupt our biology, and there is conflicting evidence and debate concerning this. This isn't to say that we can't cope with certain harmful levels, or that the idea of building radioresistance through exposure is implausible. In fact I'd bet that it varies by the type of ionizing radiation, since they are very different...pulled off the top of my head [i.e. out my ass] I wouldn't be surprised controlled dosages of alpha radiation have little appreciable effect one way or the other, beta radiation in controlled exposure provides benefits, and gamma rays remain the big bad wolf. More evidence is needed to support any conclusion about low doses of radiation now that existing evidence has called assumptions into question...but suffice to say I won't be volunteering as a test subject.

Let me see if I have the right. For the sake of argument, let us say there are some qualifiers with regard to the beneficial effects of low-level ionizing radiation (more on this below). So are you saying that in a situation where no research has shown detrimental effects of radiation vs. some research that shows some benefit, you think it is prudent to avoid radiation? One would think the smart money would bet on the benefits.

At any rate, see this:

   http://www.radpro.com/641luckey.pdf

This paper includes citations of numerous studies including those of Japanese exposed to atomic bomb radiation and shipyard workers including 7 million person-years of exposed and control workers in nuclear shipyard and atomic bomb plants in Canada!

All the evidence points toward low-level ionizing radiation being good for you. No evidence suggest otherwise. As one of my friends said, "Americans are chronically gamma ray deficient." By the way, the same friend has Fiestaware dishes placed around where he works at his computer. He sits on it. FYI, Fietsaware used to be made with uranium paint to give it its red-orange color. The old stuff definitely puts out low-level gamma radiation.

Frankly, I do not understand why anyone would be resistent to the proponderence--make that, unanimity--of the scientific evidence.

NemoUtopia on May 16, 2010, 07:17:14 pm
Let me see if I have the right. For the sake of argument, let us say there are some qualifiers with regard to the beneficial effects of low-level ionizing radiation (more on this below). So are you saying that in a situation where no research has shown detrimental effects of radiation vs. some research that shows some benefit, you think it is prudent to avoid radiation? One would think the smart money would bet on the benefits.

At any rate, see this:

   http://www.radpro.com/641luckey.pdf

This paper includes citations of numerous studies including those of Japanese exposed to atomic bomb radiation and shipyard workers including 7 million person-years of exposed and control workers in nuclear shipyard and atomic bomb plants in Canada!

All the evidence points toward low-level ionizing radiation being good for you. No evidence suggest otherwise. As one of my friends said, "Americans are chronically gamma ray deficient." By the way, the same friend has Fiestaware dishes placed around where he works at his computer. He sits on it. FYI, Fietsaware used to be made with uranium paint to give it its red-orange color. The old stuff definitely puts out low-level gamma radiation.

Frankly, I do not understand why anyone would be resistent to the proponderence--make that, unanimity--of the scientific evidence.

No, the unanimity and preponderance do not. I did read the Japanese study, and it does provide compelling evidence that there are tolerance limits. But the human radiation studies are large-scale without accounting for any (and I do mean any) other variable. I'm among the first people to tell you that these studies appear validatable and viable as well as that the FDA has set unreasonable limits and also to tell you that the LNT model is based on bad assumptions and terrible statistics. I'm also among the first people to tell you that this doesn't mean the new studies and considerations have done anything more than start off on a good foot. So let's start with "Oh, stewardess, I speak Statistician"

First factor: Deaths from radiation sickness appear to have to been treated as non-cancer deaths and therefore ignored by the study. This is a SERIOUS flaw in a study based on the idea of proving 'no-harm', even if it proves to indeed be like innoculation where the cost of saving X^(10Y) is a relatively minor Z. This also precludes the ability to determine risk factors for such a reaction. Additionally, the idea of surviving radiation sickness with proper medical care does not account for the level of said care.

Second factor: Cancer related death is treated as a static variable and does not appear to have been actually controlled for age and the actual type of death, despite the token chart on Page 11. The age of the victim at the time of exposure and the age at their time of death, as well as the cause of death itself, must be controlled for. It also assumes that cancer is the only risk-of-death situation with radiation (see above) and that all cause-of-deaths were accurately determined. Cells damaged by radiation or that decay prematurely because of damage to genetic structures have a variety of effects beyond cancer, most degeneration related as opposed to growth related. To their credit, their life-span figures seem to be solid evidence and account for variations in populations, and evidence DOES suggest that radiation damage tends to focus in what is referred to as 'junk DNA', reducing the risk of exposure having negative effects even within generations of future offspring.

Thirdly:
Quote from:  Page 10, Plutonium, third paragraph
Although the small number of subjects allows no statistical significance, the data suggest plutonium exposures are beneficial.
Without statistical significance (and their apparant lack of ability to run an alternate statistical test for small sample sizes, because they do exist) the data can suggest nothing, no matter how much you wish it do. Oh, do I know this pain personally.

Fourthly: The studies are based on source of radiation, not type of radiation. This is extremely significant, because isotope decay and other sources of ionizing radiation have very different effects on organisms, particularly humans, wearing a lead-rich safety apron and welding helment and one wearing no such protection. Nothing in the study suggests that this has been accounted for in estimates of exposure.

Fifth: The chain of study they refer to only begins at radiation at 1919. Before this time point, it only establishes concepts important to the understanding of the study in the use of mathematical models and assumptions. Radiation very likely does follow a check/v/U curve in terms of effect, but the effect it has is vastly different to mamalian biology than in plant life (we 'photosynthesize' vitamin D through a much different mechanism than plant photosynthesis). Similarly, the effect of ingested and induced toxins is very different than that of our body handling ionization.

Sixth: Factors that can cause spurrious correlation are varied and numerous. Earlier or later undocumented sources of radiation exposure, exposure to or existence of risk factors for other causes of death, availability of and quality of medical care, significant variations in diet between the control group and the study group...if you think any of these sound ridiculous (particularly the last), consider the following: fishers and port-city populations eat a different diet than inland farming and animal raising communities, which also varies from large inland cities. We already know how the difference between primary sources of meat and general level of ingestion affect health concerns.

So for clarity: these studies look promising, and I look forward to the results they yield. But it's going to take considerably more studies to convince me to enter that chamber, take that pill, get that shot, or let you get near me with that radiation gun. Since I plan on world travel [by airplane!] on top of that, including radiation study, I'll be sure to account for accurate estimates of self exposure when the time comes.
« Last Edit: May 16, 2010, 07:21:57 pm by NemoUtopia »