mistermack

Disagree. It's mostly bollocks. As in this case. "This sculpture aims at denouncing the absurdity of war and at highlighting children's courage when faced with violent, catastrophic situations triggered by others," Colomina wrote. More bollocks.

I would pretty much disregard the last 6,000 years when considering our current genetic makeup. With a long-lived slow reproducing animal like humans, it's not really long enough to have produced much change. The only thing that has happened that might make a difference is the greater mobility of the current era, producing more rapid and widespread mixing of genes than was historically happening. Usually that's a good thing, avoiding inbreeding problems, but it can introduce problems if you are breeding with people like Neanderthals, who's genes are reckoned to produce some genetic problems in Europeans and Asians. I was wondering if breast feeding has been tested for an effect on allergies. I seem to remember some speculation or indications that breast-fed people suffered less from allergy problems. Maybe nuts and eggs etc eaten by a mother might prime the babies immune systems through the milk.

Yeh, but what happens today, and what happened in the past are two very different things. This thread is really concerned with evolution long ago in the past. What kind of direction evolution is taking today is really worth a thread on it's own. But the genes that we carry today were selected for long ago in very different circumstances. In times of famine in the past, having an allergy might cost you your life, whereas today, you are just told what to avoid. A lot of evolution happened under times of severe stress, when for example, a few birds eggs or nuts might make the difference between life and death.

It doesn't really work that way though. It might not prevent you from successfully having offspring, but if it prevents one in ten, then it's a factor in evolution. It's really a numbers game at population level, which is where evolution happens.

The OP question is interesting though. Why doesn't evolution weed out all disorders? Especially inherited ones. Take haemophilia as an example. What possible benefit can it bestow on sufferers, so that it survived the evolutionary process? Wikipedia has a whole page on the variations and ramifications of haemophilia. So evolution certainly doesn't produce perfection. The workings of animals is so incredibly complicated that it's likely that every disorder has a different root, so there's no overall answer. Evolution only needs one human to produce one successful offspring, to keep the numbers up. So even with our low reproduction rate, there's room for a lot of wastage. And it's the wastage that drives evolution. Sometimes it's just down to luck. Your parents had certain genes that when combined, gave problems. It could be a one in fifty thousand chance. Other times, it's exacerbated by a bit of inbreeding, maybe several generations ago. Like the way that the royal families of Europe inflicted many of it's members with haemophilia B. Or Ashkenazi jews have a high incidence of haemophilia C. From an evolutionary point of view, rare occurrences don't kill enough individuals to wipe out the tendency in the general population. I remember reading somewhere that the small percentage of Neanderthal dna that non-African people have are thought to cause quite a lot of inherited disorders, that Europeans and Asians get, that Sub-Saharan Africans don't. Other times, something that helps you fight one thing, can cause disorders of a different kind. Like sickle cell trait, in Africans, that helps fight malaria, but causes a debilitating illness in some. So in some areas it might be an overall benefit, because of high malaria, but in others, it's an evolutionary drag on the population. So it's really so complicated that one simple rule doesn't apply to all.

I'm amazed that scrap stainless is worth that much more. They must be able to accurately classify it for re-use, to pay that much more for it.

Allergies, like a lot of disorders, are thought in many quarters to be the result of the lifestyle of modern humans. Research indicates that stone-age people didn't suffer from a whole raft of problems that are common now, like obeisity, high blood pressure, allergies and heart disease. Some studies indicate that exposing babies to dirt etc actually primes their immune system in a healthy way, even if it intitially makes them a bit sick. Our ancestors evolved in Africa, living outdoors, and babies would be putting anything they picked up into their mouths, just as they do now. And the mother's wouldn't be stopping them, or taking much notice. It's a totally different start to life compared to today.

It's the other way around. Mining the moon or asteroids and manufacturing in space would be more profitable than sending up finished products that were made on Earth. Once living in space is mastered. It will take a long time, but it will happen. Unless our descendant kill each other.

Anyone can be a great painter these days. Talking about blades, I thought that stainless steel was second class, compared to carbon steel, when it comes to fine knives and swords? Or has that changed?

That's why size is important. Tests have shown that for 1g of artificial gravity, a diameter of 224 M or more will give an environment that doesn't cause problems of balance in humans. I posted this earlier, you must have skimmed over it. Anything over that size will be fine. And size and mass will even out any rotation wobbles. And in any case, that can be computer monitored, and easily corrected by movement of balance weights.

Seems like a medieval attitude to learning. Surely, in this age of information, research and study replaces trial, error, sweat and tears? Having said that, I agree that it can be theraputic doing it the hard way. And bladed articles seem to wake sleeping instincts in (mostly) men. It's hardly surprising, the quality of a weapon probably played a big part in the survival of our ancestors, ever since the first stone weapons. Maybe even long before that, as wooden weapons would have come long before stone ones. Personally, I LOVE stainless steel, I always did. When I was little, sixty five years ago, we had spoons that had to be regularly polished. I don't know what they were, it wouldn't have been silver. But there was one spoon in the drawer that alway looked clean, never needed a polish, and we kids would fight like cats over it. It was engraved with the letter N on the handle, we called it the "N spoon". We always felt great, if we won the argument, and managed to bag the "N spoon" at dinner time. We grew up thinking it was special, and only found out years and years later, that the N stood for NAAFI ! It was probably filched from the Air Force mess !! Wish I still had it.

To me, morality is something we are saddled with because of our evolution. There is no good or bad, except in our inherited common attitudes. Having said that, I'm saddle with it just like everyone else, and I generally like the way current attitudes are heading around the world, even if change is slow. For me, the true test of a society, is how we treat people who are different to us. It's easy to identify with people who look and sound like us and our families. In Germany in the thirties, people were very nice to other Germans. But people like Jews and Gypsies were that little bit different, and people didn't see them the same way. They found it easy to hate, because of the differences. Women look and sound different to men, and historically men found it easy to class them as inferior humans. Israeli Jews are strongly bonded to fellow Jews, but treat the non-jews like shit. It's the same everywhere, or nearly everywhere. And it's inside all of our heads, naturally inherited, but some people override the instinct because of their upbringing and peer pressure. I think if you want to avoid trouble, you have to limit the speed at which "different" people move into your society. Everything might be just dandy when people are relatively prosperous, but when things get really tough, the newcomers will get seriously picked on, depending on how different they still look and sound and behave. That's what Hitler exploited, and more people are struggling, the more Hitlers will come to the fore.

The economics don't seem to be there, even with today's high gas prices. Otherwise, as you point out, they could be putting hydrogen in with domestic gas supplies. If it doesn't make economic sense now, it's going to be way out of order when gas prices normalise. In some countries, like Australia, you have vast empty areas suitable for solar generation, and probably wind too. If the process of producing hydrogen was economically viable, there would be a huge industry there for the taking. Investment would be piling in. But the current high oil and gas prices are likely to fall substantially. The futures markets are well below current prices. Probably because much of the world is heading into recession, and demand is forecast to fall.

All this talk of hydrogen production relies on there being a huge surplus of renewable power some time in the future. If they use it to make hydrogen, they are likely to use that at night, or when the wind doesn't blow, for electrical generation. I don't think that it's likely there will be a big surplus, over and above that. There would need to be a sure-fire market for hydrogen, at a high price, before people would invest in renewable hardware to produce it. You could create that market, by banning marine diesel, but I can't see that happening.

When you kill all the beavers to make silly hats, you will get more floods, and a drop in the water table in dry periods. They are re-introducing beavers to a few isolated parts of the UK. The selling spiel is that it will regulate water. Probably more of a curiosity, we don't have that much of wilderness to support them, but the USA has lots. Kentucky does have beavers but they are trapped and shot legally as a pest, or for the fur. Without the beavers, the rainfall runs off faster, so you get flooding and rivers that dry up quicker.

I wouldn't want to work on a hydrogen powered ship. It would need very high pressure, to keep the fuel a reasonable volume. Any leak would be very dangerous. In any case, it would involve a lot of infrastructure to make and deliver the fuel. If there was loads of very cheap hydrogen going to waste, it might make some sort of sense, but I don't see where that's coming from. Maybe you could use the hydrogen to make hvo from waste vegetable sources, if you wanted to waste a fortune. That could be used without changing the engines or infra-structure.

Didn't you post elsewhere that energy is frame-dependent? How would that match up with net zero? Say you have a bank account with nothing in it, and you borrow £100, then you have £100 in your pocket, and the bank has minus £100, so the net amount is zero. But the bank has to have money from someone else to make the loan. Maybe the Universe has to have access to the total energy from somewhere else, for what we experience to exist.

Thanks, good post. (to me) But say you have a stretched rope, and you send a "wave-packet" along it with a single twitch, isn't that energy that you put into it the wave packet, and the rope just the medium? And likewise, the photon is the energy, and the field the medium? But if you compare a field with no photon, and a field with a photon passing through it, then the difference between the two is the photon, and isn't that difference the passing of an energetic phenomenon? So the photon is the energetic occurrence, and the field is the enabling condition? Does "orbital zone" not imply movement then? And I'm not arguing, I am interested in the facts. I pictured an indistinct cloud, of a moving electron, that couldn't be pinned down, from what I have read. I thought that movement was inherent in that picture, even if it can't be predicted or tracked.

It seems to be a weakness of moths and butterflies that they tend to specialise to exploit specific niches. Not a problem, till humans come along with our industial scale mono cultures in the fields. Evolution hasn't prepared them for that. The wiki article on the Oak Eggar is interesting. It looks like people must have been nicknaming acorns as "oak eggs" and the cocoons look like acorns, hence the name. I did wonder how it got such an odd name.

But you made the unwarranted snarky leap that I was "People who don't know what they are talking about" because I wrote orbit. In this case it was wrong, because I did know that electrons don't orbit in a planetary fashion. So it didn't naturally follow. If you want only physicists to post in speculations, maybe you should make that clear. I already made it clear earlier in this thread that I'm not one. Hence imprecise terminology. I'm interested, that's all. My OP was not pushing "my theory", I haven't got one. It was just to see what others thought, and there have been some interesting informative posts, yours included.

Well, ok, things might have moved on. But that's how Einstein described it. " In 1905, Albert Einstein published a paper in which he proposed that many light-related phenomena—including black-body radiation and the photoelectric effect—would be better explained by modelling electromagnetic waves as consisting of spatially localized, discrete wave-packets.[10] He called such a wave-packet the light quantum (German: das Lichtquant). https://en.wikipedia.org/wiki/Photon So is a wave "stuff" ? In any case, I thought that the e in E=MC² was the energy of a particle, and hence the energy of stuff.

I didn't say planetary orbit. This is the usual attempt at nit-picking. Wikpedia said "Thus, the planetary model of the atom was discarded in favor of one that described atomic orbital zones around the nucleus where a given electron is most likely to be observed ".[31][32] https://en.wikipedia.org/wiki/Atom#Energy_levels

What is a substance?

Doesn't vibration count as movement anyway? And don't particles also have wave properties, which involves movement of energy? Electrons are described as having an orbit, which implies movement, even when the lump of matter is at rest. Maybe so, but you can demonstrate the trajectory, by issuing a stream of photons, and intercepting them at various points.

That's why my OP was a question, an invitation to debate. A photon is decribed as a "packet of energy". And it moves at the speed of light in a vacuum. Surely that means moving energy? The ball is composed of energy, if E=MC2 , so you are tossing a lump of energy in the air.