CaptainPanic

First of all, can someone please press the green +1 on Santalum's post? I meant to do that, but clicked the red one instead. It's a good post though. Aren't there some areas of the brain that compete? How else can you get distracted when you are actually motivated to stay focussed? And there are many things that can distract you. Also, humans will definitely share, but only within their social circle. So, for a Global Brain, we would a larger social circle so we start caring for each other, and therefore also a way to connect that larger social circle. The internet solves the connections at least in a rudimentary way. But humans usually cannot deal with a social circle larger than a few hundred. And this is why I have to agree with you: it won't work.

Would you like to discuss anything in particular, or are you just a frustrated person who complains about his own lack of understanding by trolling about science in general? Science acknowledges it is not all-knowing. That doesn't give everybody the right to come up with some random story, and call that science too.

I would first experiment before installing a final version. I'm glad to see you start with an open system to avoid trouble with steam. Good. The heat transfer coefficient you want to know will be anything from 400 W/m2K to only 20 W/m2K. Multiply that value with the surface area of the pipe (in m2), and by the temperature difference (in Celsius or Kelvin), and you get a power (in Watts), which can be used to calculate how much your water will increase in temperature - depending on the flow rate. That heat transfer coefficient is gonna be influenced by practical things like: - The turbulence in your heating place. In other words: it changes as you change the fire itself. - The geometry of the coil. - How dirty the coil got from soot. The heat transfer will get worse as the coil gets dirty. Soot is an insulator. I cannot give a better estimate than 500 W/m2K to 20 W/m2K... although I would guess that it will be much closer to the low value than to the high value. Start with your water pump at maximum flow, and measure the temperature. Then reduce that flow as long as your water will not be too hot. Also, your fireplace will probably not produce a constant power (it can vary easily by a factor 2, if not more), so either install a feedback system (something that changes your water flow depending on the temperature), or go for a safe value and keep the water from boiling all the time. Your temperature control is probably gonna be your biggest nightmare, and for me that would be the reason not to try this myself. I'm sorry that I cannot be bothered to convert all your feet, inches and fahrenheits to some more modern units, like meters and kelvins. You'll have to do the calculations yourself, or convert them for me. My advice would be to see if there isn't a ready-made wood burning central heating system. It's a lot more costly, but a whole lot more efficient, and safer too.

The people can democratically choose not to be educated. For example, if Americans would vote Santorum for president, that would be a vote against education, and still completely democratic. The public can vote itself into oblivion, and still democracy would function as it is meant to do. It's a weird system, and far from perfect. I agree with the words of Churchill, who said: "Democracy is the worst form of government, except for all those other forms that have been tried from time to time." Economists also know little about economics. I agree with your point in general, but I think you chose a poor example, as nobody seems to understand the economy.

Good point: you want to place the pump near the water level, not at the upper end of the hose. You can push water up quite high, but you can only suck it up for about 10 meters. And sorry to carry on about the water... it's a minor detail, but I think it's interesting. I was thinking that probably you don't need a pump at all: your hovercity will hover on a bed of compressed air (the pressure below the city will be higher than the atmospheric pressure, which is the reason it can float. Assume that your city weighs 20 ton/m2 ground surface (you said you have skyscrapers, so that's not so much?), then your city will exert a pressure of, well, 20 ton/m2, or about 2 bar pressure. So, if you put a pipe through the road surface down into the water, the water would come up 20 meters (all by itself, due to the higher pressure below the city). 20 meters equals about 60 ft, so that might be enough.

I tried, and you're right, I couldn't. As stated in my previous post, a world with only plants and fire would be able to sustain life, which grows and has evolution, without any food chain. I maintain that you need a way to recycle the essential building blocks to have 'life' in a sustainable way, but fire would be able to do that too. Although, assuming that such a only-plants-world would still be governed by evolution, it stands to reason that some plants eventually become practically incombustible, either by chemical adaptation or sheer size (for example). When the circle of life is broken, either by a species which is an ultimate winner, or some other way, evolution would slow, and life would gradually slow down until it is pretty much stagnant. And irrelevant. So, I wonder how sustainable life would be without a food chain. The success of life on earth is the evolution of food chains, where multiple species co-evolve.

Just look at university restaurants, or company canteens. Restaurants are expensive if you get a menu, and it's freshly cooked... but if they can prepare hundreds of similar meals all at once, it becomes much cheaper. I guess this point is true in the USA (and Canada too?), but certainly not in the rest of the world. Generally, seasonal fresh vegetables and fruit, from your own country (not the ones imported from other continents!) are CHEAP. We're talking 1 to 2 euro per kg, where you typically eat about 200 grams per meal. In other words: fresh veggies cost 20 to 40 cents per person per meal over here.

We are human. Resistance is futile. We've colonized islands in the ocean that have a life expectancy of mere decades. I'd say a million years is plenty of time for the colonists to come up with a good plan.

I have cookies disabled, but I pressed that green button on the post. ... given the fact that the people are incredibly suicidal. It's like forever playing a combination of the game where you can't say "yes" or "no", and Russian roulette. You're not likely to be a winner... and the stranger who makes a remark about their eyes is probably the least of their worries. Sorry to drift so far off topic.

Here's a picture of how a bloody AIRPLANE can take water while FLYING. And that doesn't even have "hydrogen power" It's funny how keeping the city flying is not a problem, but taking the water is a problem. I would say it's the other way around. Taking water is easy. Keeping skyscrapers flying is difficult. To say the least. [edit] forgot the link

Let me start by saying: "Higgs". When I'm working, I pronounce a lot of words in my mind in the accents of (former) teachers, colleagues or other people I know through work. So, it is quite a mix of (mostly) European accents. I never say any of them out loud, of course...

LOL! Welcome to the forum, Antti. This is quite normal behavior for this place... you ask for new puzzles, and post your own favorite, and instead your favorite puzzle will get ripped apart and nobody posts a new one. You'll surely get enough brain exercises here, and we all mean to do well... we just don't always give the replies that somebody wants. Anyway, while I think I understand the examples with only 1 or 2 people with blue eyes, I do not see how you can extrapolate that to four. One person with blue eyes will think: "Ok, the newcomer said there are people with blue eyes. And I can see 3 of them. Those 3 individually will see only 2, and they have no way to realize that they themselves have blue eyes too." And all 4 will have the same response.

Here's a link to an article about seeing spots (not necessarily blue though). It can be as simple as low blood sugar. But it can also be more serious. Of course, getting professional advice is always a good idea. I certainly encourage you to see a doctor. But I would also take a critical look at your diet... and if you go to see a doctor be sure to mention your diet too - so you don't get diagnosed with something weird when you only should eat one more slice of bread at lunch, or occasionally take some fruit. I've experienced the low blood sugar spots myself a few times... and often when I was so engaged in something (mostly work or gaming) that I kinda forgot to eat or drink enough. It's nothing that some fruit, a decent lunch or even some soft drink can't help. It went away within (approx.) 30 minutes. Obviously, there is no instant remedy - it takes a little while before your blood sugar is up again... but fruit sugars seem to be the quickest in my limited experience.

Allow me to link to an earlier thread on the same topic. It's only of December 2011.

Hello and welcome to the forum. First of all, it would have been a lot easier with a picture. That's not criticism, because I know it's much harder to make a good picture with a computer than with a pen and paper. Still, I find that even for myself, I can solve problems easier with a picture. So, I understand the problem that we have a lake. At the bottom you want to add hot water. And at the top you get an overflow as a result of the additional water added. And you say that the top doesn't mix with the bottom. Is that last assumption correct? If the flow of water into the lake is negligible compared to the volume of the lake, you shouldn't worry about it heating up? So, I assume that the flow into the lake is significant. If the flow is quite large, then the bottom will slowly fill up with hot water, and the boundary between the heated water and the cool top water will move up... The boundary will move up because the volume of hot water keeps growing, but also because hot water is lighter than cold water, and it will have a buoyancy effect. Just like hot air goes up, hot water also rises. So, I would think that the hot and cold water will actually mix... and you should approach the problem as a non-stationary heat balance (which is btw something I only learned at university, engineering levels, so it's not a shame not to know this). In a heat balance, we are looking for an accumulation of energy, in this case in the lake. For a balance, you write down: Accumulation = IN - OUT The accumulation is the bit we're trying to find out. The IN - OUT is what's known. It will result in an equation looking like this: Accumulation = IN - OUT [math]\frac{d(C_P\cdot{V}\cdot{T})}{dt}=F\cdot{C_P\cdot{T_{in}}}-F\cdot{C_P\cdot{T}}[/math] Assume V, F, Cp, Tin constant, then you can rather easily solve the differential equation. Tin is the temperature of the water you feed into the lake. To will be the temperature of the lake at t=0. And T is a function of t (Temperature is a function of time). I got: [math]T=(T_0-T_{in})\cdot{e^{\frac{-F\cdot{t}}{V}}}+T_{in}[/math] Hope I didn't make a mistake, but a plot looks what I would expect. If you play with those numbers, then you find out soon that what matters is the ratio F/V. When the volume of the water that has flowed into the lake is equal to the volume of the lake itself, the temperature will be approximately 0.63*(Tin-T0). Please note that this equation assumes no evaporation... and that assumption will lead to quite large errors (compared to reality) when you do have evaporation.

Depends what color they are.

I think it is not a bad assumption... although I doubt there are many statistics of the statistics to back up the claim. We can however say that: 1. Most measured data points will (or at least should) be expressed with a margin of error. That in itself is already a statistical statement, which means that the vendor of a piece of equipment, or the scientists themselves say: "We expect that with XX% certainty the true value is within so-and-so many units from this data point". 2. And if you read a conclusion of a paper, very often the results will be summarized. Average values, or a fit will be presented. Many scientists enjoy using a statistical fit of a data set, which makes it easy to interpolate (or even extrapolate!) data. 3. The scientific method almost always will duplicate an experiment, but in practice the data points will not exactly overlap, so it is a common practice to use average values. I don't think anyone would dare to claim that all scientists apply statistics correctly. I have seen plenty of disasters in papers where statistics were used wrongly, or even abused, to fabricate some results. But it is used a LOT. Anyway, 56% of all statistics are wrong - including this one.

I'll use an example... What I mean is that life will at least be moving some electrons or molecules around. If it would be in a perfect chemical equilibrium, it would be as lifeless as a piece of rock. Something that is lifeless will not change over time. Life will always change in time. And change requires an input. In life, as seen on earth, that input is food. We need food to power our growth, our thoughts, our movements. In extraterrestrial life, they may do something else. But they will do something. And therefore, require "food" of some kind. Yes, actually it could be possible. Plants do that. They take CO2 and water, and by using light they will create complex molecules such as glucose. And then forest fires could burn the plants back into CO2 and water. Other nutrients only make the picture more complex, but do not change the principle. And I don't think it can be disproven that this could not be the only life to exist somewhere. Hmm... so yeah, if you have only plants, and recycle the building blocks by fire, then you could have a sustainable eco system without food chains.

In my world, the words "plausible" and "antigravity" do not occur in the same sentence a lot. But if antigravity/null gravity was known (whatever antigravity/null gravity may be), then I assume they would use it. Also, in your fantasy it wouldn't even have to cost any energy. Then the total power need would be about 1 GW for all other applications (a regular modern town of about 200,000 people, including some industry and transport, would use that much energy), unless all other applications are also from the realm of fantasies, in which case the number is quite different. A town of 3 miles diameter is just a speck in the mediterranean. If it is normal technology, then it would probably be buried. 6000 years is definitely enough to bury something, and the Nile delta is quite capable of (1) letting something sink into the mud and (2) depositing more sediments on top of it. But if it has antigravity/null gravity, wouldn't it be more likely that it just took off into space, away from Earth? Wouldn't antigravity engines crash upwards instead of downward? I'm asking you, since you know more about antigravity than me (since it doesn't exist, except in your game / story).

Life needs energy, and life needs building blocks of some kind. Extraterrestrial life will not be completely stagnant. We defined life and lifeless, and that means we know that extraterrestrial life will at least fit that definition, or we wouldn't call it life. There are only 2 cases where life could exist without a food chain: 1. If life does not require any matter. If only energy (directly from a star) would be sufficient. 2. In an unsustainable situation where some resources are being depleted. As soon as a particular resource can be depleted, but will still be available in life itself, life will attempt to optimize it. A foodchain will ensure a constant recycling. A foodchain is the logical result from a continuous lack of equilibrium in life.

I have no idea what's in it for the big pharma. It's not marketing, because their names aren't even mentioned in the article. Perhaps it's as you say, ewmon, that they just get government money to do this. I'm also always wondering if I am too critical (cynical?), but there simply aren't many companies in the world that aren't primarily about making money.

I shower 5-10 minutes. The benefit of showering to quickly is that I can sleep longer. I do not see a benefit of wasting so much time in the shower... but perhaps it's mentally relaxing. Depending a little on where you live, you are especially wasting energy (gas or electricity) to heat up the water. A shower is basically a 5 kW to 10 kW heater turned on. So, in terms of energy, a 1-hour shower costs 5 to 10 kWh. 10 kWh is the equivalent of about a liter of gasoline. In very dry places where water is very costly and it takes more energy to make clean water, the picture looks different.

Are you asking which is superior: nature or god? Did god create nature, or did nature create god? If god created nature, it is logical that god created foodchains. If nature created god, then nature evolved the foodchains. I think that life couldn't exist without food chains. Life means growth, reproduction, metabolism. You need to get some nutrients to do that. You also need to "remove" a body when it died, otherwise there would be corpses everywhere. In summary: you need to recycle. And that only works when you eat other living (now dead) things. Eating each other is a logical result of life itself.

Yes, the companies seem to thrive in a capitalist world. But I was talking about workers, and perhaps a country or society. A person also has an income, also has expenses. With a little fantasy, you can see yourself as a company too. And your production costs are too expensive, and Chinese and Indian employees simply out-compete you. They do the same job for less money. The question is then: why can they do that? Don't they have to eat, don't they have a roof over their heads? For a part, their basic needs are indeed cheaper. But not so much. The main reason is that in their society, they do not have much overhead. There are no large districts of financial institutions. No armies of businessmen who push money around without producing anything tangible. A single company will do a reorganization when it's in financial trouble, and it will definitely look at the overhead costs. A country or society as a whole never seems to do that. Many skyscrapers in Manhattan, or London or Paris belong to companies that do not even produce anything. They just move money around. It's true that in India and China there are financial institutions too, but the ratio between those and the 'real' industry is quite different than in the US and Europe. So, you can protect your American workers with a trade barrier. Or, you can make your economy lean again by removing some of its overhead.

As a first approximation I would just extrapolate an existing hovercraft to a giant size: Existing hovercraft Length: 29.3m long Width: 15m beam Weight: 70 tonne all up weight Power: Lift engines - 2 x air-cooled, turbo charged, MTU 12V2000-R1237K37 diesels - each producing 675kW + Propulsion engines - 2 x air-cooled, turbo charged, MTU 16V2000-R1637K37 diesels producing 899kW So, 3 mile (4.8 km) diameter is a surface of 18,000,000 m3 of surface, which is approximately 41,000 times as large. So: City-size hovercraft Diameter: 3 miles (4.8 km) Displacement 3 million tons Power: 129 GW (GigaWatt) The power consumption should benefit from the large scale though, so without any calculation, I would just divide that by 10. Power: 13 GW. Since that's a lot more than the city will use for all other things (like lights, heating), you can just take that as the total power requirement. It will displace its own volume. I would assume that the average density of the construction materials is 2000 kg/m3, so the displacement of water is half that of the weight of the hovercity: 1.5 million tons of water. Of course, this is all not much better than a wild guess... You can make a million assumptions to move the answers in any direction you like, so if you're not happy with it, feel free to change it.