exchemist

It seems to me St. Paul is to blame for -ve Christian attitudes towards sex. There's practically nothing in the OT or the gospels about it being "bad". It's a misconception, (hahaha), to think that the Fall or Original Sin had anything to do with sex. That's just been read into it, by puritanical-minded people, later.) Unfortunately St Paul has had almost as much influence as Jesus on the way the religion has developed. Having said all that, it is natural that sexual activity should have been the subject of control by society, because the human baby is very demanding to take care of, for a very long time indeed. So creating babies is something that should be done responsibly, in a stable environment in which they can be reared satisfactorily. Sometimes I think that we, living as we do nowadays in an era of easy access to contraception, don't recognise why there had to be social means of controlling sexual activity in the past.

Yes but the overall genital area with body hair won’t have such a low pH. And, if it comes to that, I am not aware that men produce a body odour smell from the groin either. Only from the armpit. So I’m wondering if there a different secretion there , or if there is another reason why Staph. hominis can only thrive in the armpit? Actually, thinking a bit more, one obviously unique feature of the armpit is the huge amount of sweat secreted. There must be a lot of eccrine glands there. Although, as I understand it, it is the apocrine glands, in the hair follicles, that secrete the smell precursors, the sheer amount of sweat and almost continual dampness of the armpit may be what provides the environment for Staph. hominis to do its thing there, rather than elsewhere on the body. But I'd still love to know what the bacterial population of the man who didn't wash ended up being.

You don’t want to use a material that is within 100C deg of its melting point. It will have lost all its strength. And steel, being a metal, is a conductor of heat, which would be catastrophic. Anyway, have a read. There’s quite some discussion of the options for various materials and the challenges involved.

According to the attached NASA slideshow, temperatures reach 1700C for slower, "flying" type re-entry, but hotter for capsules that make a "ballistic" re-entry. It's quite interesting for you to read. They have, not surprisingly, given quite a bit of thought to this topic. daryabeigi-NMS talk-2c.pdf

This prompts two further reflexions: 1) My experience is the genital area does not become smelly like armpits, even though no woman I've been to bed with (sample size 13) used any deodorant on that area of the body. Why is that, if both armpits and genital areas have these apocrine glands? Or does Staph. hominis for some reason only inhabit the armpit, and if so why would this be? 2) I read a year or two ago about a man who conducted an experiment by not washing as modern people do but simply allowing nature to take its course. He claimed that after a couple of weeks of being smelly, the smelly gradually reduced until it was no longer noticeable. When I heard of this originally I assumed he had just got used to his own smell, but now I wonder if there might have been competition among skin bacteria that eventually resulted in the Staph hominis population stabilising at a low level, due to being checked by rival groups of bacteria that can't grow when one washes daily in the usual way.

Graphite is often used, as it conducts heat well only along the plane of the structure and has a very high sublimation point (it doesn't melt), over 3,000C. Something that melts at 660C will lose mechanical strength well before then and will just disappear. I really think you need to work harder on this aspect.

Al will be a hopeless choice: it melts at 660C. Also, being a metal it conducts heat! You will need something far more refractory that is also a good insulator (e.g. even tungsten won't do). I know nothing about 3D printing but I fear your idea may come to grief on this point, if you can't find a high melting point insulator that can be worked by your 3D printer.

So 3D printing is the key feature. I see. What material would it be made of then, that can be 3D printed (I assume ceramic tiles cannot be)?

Why would it be less laborious to replace this proposed ablative surface than to replace thermal tiles?

Actually, this is quite interesting. There was a paper in Nature in 2020 about the bacterial enzyme responsible for generating these thioalcohols that are mainly responsible for the smell: https://www.nature.com/articles/s41598-020-68860-z They also did some work to project back in time to estimate the point at which this enzyme evolved in the unique bacterium responsible (Staphylococcus hominis), finding it may have been around the time the primate lineage first appeared, c.60m year ago. From this they suggest there may have been evolutionary selection pressure encouraging this enzymatic function, in the symbiotic relationship between this bacterium and the primates that were the ancestors of modern Man. So the suggestion is that smelly armpits were originally a reproductive advantage. Here is the relevant paragraph from the Discussion section of the paper: This discovery raises important questions about the role of odour production in the evolution of modern humans. The emergence of an enzyme present in bacteria found in the human underarm with unique activity to catalyse production of 3M3SH suggests selection pressure for the production of odours over an extended period of evolutionary time. This was presumably driven by an evolutionary advantage for both the host (primate, human), that actively produces the odour precursors for no other apparent physiological reason, and their microbiota, which converts them to volatile odorous molecules. Here, we have identified a definite substrate-product relationship, namely the conversion of specific thioalcohol precursors by malodour producing staphylococci. We show that S. epidermidis unequivocally does not metabolise these precursors, despite being the most abundant Staphylococcusspecies present in the axilla. Could these thioalcohol precursors secreted by the apocrine sweat glands be significant for the ecological success of S. hominis in the human axilla? This raises important and as yet unanswered questions regarding the mechanisms that govern the structure and composition of the axillary microbiome. Early man (and woman) may have found the smell a turn-on. To this day, perfume preparations commonly include "musky" elements. (One of these is ambergris, which is basically shit from constipated whales........)

OK thanks. To me, EVA means extravehicular activity, so I was a bit stumped. Mind you, to me, STD means subscriber trunk dialling................

Yes, nice point.

But Christians are not Jews. Christianity is defined by the New Testament, put together between 50 and 100AD or thereabouts.

Traditionally, in say the 1960s and 1970s, feminism meant support for the concept of treating women equally with men in society, without preconceptions as to what roles may be appropriate for women to fulfil. As a male student at university in the early 70s, I used to describe myself as a feminist. I am not sure what further nuances the term may have acquired today, but I still regard myself as a feminist. Having worked in the Arabian Gulf, I feel sure that feminists in those societies aspire to exactly the same ideal. They are just further from achieving it. I do not really see that having entered the "digital age" changes anything. (P.S. This is now I think the 4th thread you have started about the sexes.)

Where's the chemistry? You don't provide any details of the composition of these objects. What's an EVA sponge?

Well I suppose the Roman Empire at the time of Christ could be said to be an Iron Age civilisation, but I think the term is generally restricted to pre-history, i.e. before there were written records.

Well obviously I am talking about the teaching of Christ as the figure represented in the gospels. One can do that without getting sidetracked into the quite separate question of evidence for and against Jesus as a historical person. This thread is about a question of Christian teaching. Let's not hijack the discussion.

I did not say St. Paul was an ascetic. Read more carefully. I said he was an advocate of asceticism. I think that is pretty hard to dispute when you read his epistles. It's not just marriage.

In my view, St. Paul has a lot to answer for, when it comes to the historically twisted attitude of much of Christianity towards sexual relations. It is significant, I think, that Christ himself had practically nothing to say on the subject. But in the Old Testament you get a very different picture from that painted by St. Paul. , for example the rather beautiful story about Adam's rib in Genesis 2:23-14 :- "This one at last is bone of my bones and flesh of my flesh! She is to be called Woman, because she was taken from Man. This is why a man leaves his father and mother and becomes attached to his wife and they become one flesh." What a poetic and non-judgemental way to describe the primal urge for sex. To be fair to St. Paul, he was clearly an advocate of asceticism, which is by no means unique to Christianity. The practice of abstinence and the control of carnal appetites by the intellect, in order to achieve a higher state of spirituality, is practised in many religions. Even St. Paul acknowledges it is not for everyone. (By the way, some of your threads seem to betray a rather unhealthy attitude towards sexuality, for instance, besides this one, the one in which you are preoccupied with incels and the one about the roles of the sexes in society. I confess I am starting to find this a bit creepy.)

Oh indeed. I suspect the point here is that religion offers a way to appeal to the better nature of these youths, guiding them towards prosocial attitudes and behaviour, in a way they probably find fairly natural and acceptable, culturally. Some people think religious teaching is all about forbidding things and retribution, but of course it isn't at all like that really.

OK but then I'm not sure what you are now arguing. If you accept there are "universal principles" that Mankind tends to observe regardless of religion then they would also tend to be observed by those, such as Buddhists or atheists, who do not believe in a God or gods. To your second point, a drug cartel is not really a "social group". However there is indeed evidence that religion has a role to play in reducing crime. This 2014 study for instance, showed a significant beneficial effect of religion on youth crime: https://academic.oup.com/edited-volume/41333/chapter/352355230?login=false I quote the 1st para of the Conclusion: This chapter provides evidence that religious influences are consequential in crime reduction. The vast majority of studies reviewed document the importance of religious influences in protecting youth from harmful outcomes as well as promoting beneficial and prosocial outcomes. The beneficial relationship between religion and crime reduction is not simply a function of religion’s constraining function or what it discourages (e.g., opposing drug use or delinquent behavior) but also a matter of what it encourages (e.g., promoting prosocial behaviors).

I think it is important to read these Genesis stories as allegorical. If you try to take them literally you end up looking a prize idiot, seeing as they are contradictory in so many ways. The main Christian (and, I believe, Jewish) denominations have always seen them as allegorical, with a message behind them, rather than literal fact. It seems to me the story of the Fall is basically a way to explain why there is hardship in life, in spite of the apparently contradictory belief in a loving God who takes care of His creation. The ancient Greeks, for instance, had no such concept of a loving God. So for them the vicissitudes of life could be attributed to the gods fooling with humanity arbitrarily, for their own amusement. But Christianity and Judaism have this idea of a benign, personal God, which is a bit hard to reconcile with all the unpleasant aspects of life. Coming to the specifics, there is no suggestion in the bible, so far as I am aware, that childbirth would be a source of sorrow. It would be painful, sure, but the arrival of a child is assumed, generally in the bible, to be a source of delight and celebration.

I think it's a misconception to think that natural selection will necessarily eliminate all inherited traits that do not promote reproductive success. Furthermore I'm not sure it is at all clear that that sexual orientation is inherited in the first place. With that in mind one should be able to see why homosexual behaviour might continue to be found in nature, natural selection notwithstanding. Even if homosexuality is to some degree inherited, considering that Man is a social creature, success for the group would be expected to be driven by factors that help the group to pass on its genes successfully to subsequent generations, rather than simply operating at the level of the individual. There are roles in human society for individuals that contribute to that, apart from procreating themselves. For instance one explanation for the longevity of human life, way past procreation age, is that the wisdom and skills of experience have value to the group, as does the help of grandparents with childcare. So individuals that don't actually procreate themselves may nonetheless serve an evolutionary purpose at group level.

This doesn't bear a moment's serious examination. While it is true that morality in western societies is strongly coloured by the pervasive heritage of Christianity, similar moral principles are found in numerous societies elsewhere that have a radically different idea of God or gods, or no idea of a god at all. (One obvious example of the last would be Buddhist societies.) Respect for life and for property seems to be a natural trait among human beings - and one can immediately see why it would be, for a social animal, simply to avoid conflict. Religions with a god or gods may present these natural principles as instructions from a God who judges humanity's compliance. This certainly provide societies with nice, explicit and easy to grasp reasons for morality, but it is idle to pretend that without belief in a god these moral principles would not be present.

The requirement for (reproducible) observational evidence is only axiomatic for applying the scientific method, the purpose of which is the study of nature. The scientific method is shown to "work", in the sense that we can understand and predict far more about nature than we could before the Renaissance. So I can't see there is anything circular about employing it. Secondly, you are wrong to characterise faith in science as faith in what you call "individuals". The whole nature of science is that it is a collective enterprise that does not rely on individuals. That's why observations need to be reproducible, i.e. capable of being agreed upon by different people, in different places and using different methods. The hypotheses and theories put forward by any one individual to account for observations are also subject to criticism by other people. Active areas of research are full of disputes and argument. You are obviously right that we all take on trust a great deal of what one can call "settled science", by reading books, attending lectures and so forth. The same is true in all other disciplines of study. If nobody did that we would all be constantly reinventing the wheel. But that obviously does not mean, in the case of science, that we have abandoned the requirement for reproducible evidence. We simply trust the observations reported and validated by others and well-tested theories associated with them.