CaptainPanic

The Great A'tuin, the Giant Star Turtle, has great thoughts, but he/she does not think very fast. It's possible that such life forms might be considered as "lifeless" by some lifeforms that live a faster life. Not a very scientific response, I admit, but equally useful/useless as other speculations about aliens.

Researchers are searching for amino acids and/or proteins in space to find life. That means they assume it's carbon based. SETI is searching for intelligence, and that SETI's type of search is technology focussed.That means they assume the technology is similar. who says that those two assumptions make any sense? Nobody looks for organized patterns in rocks (for example). I think that KtownChemist suggests that aliens might just misunderstand Earth's life, and overlook it. That would automatically mean that we're not able to see those aliens as well, despite the fact that they are here on earth. Similarly, we might be overlooking life as well in our searches.

Right now, I'm happily helping mankind to get sustainable energy (that's my job), and happily traveling around the world (that's my hobby). When I become really too old and when stuff becomes boring, I plan to start base jumping off steep cliffs, try heroine and cocaine, insult stupid politicians or do stuff that the bad guys in James Bond movies would be proud of... in short: do things one shouldn't do. Things that can kill you. But hey, when the end is so near, who cares? I certainly don't want to end up doing crosswords every day, telling my neighbours that it's a good life and that I am never bored.

Ok, let's see: 7.5 billion gallons = 28.4 billion liter = 22.7 billion kg, which is equivalent to 9.1E17 J (assuming biodiesel has a heat of combustion of 40 MJ/kg). Surface area: 200,000 ha, or 2.0E9 m2. So: the "NREL energy production" equals 9.1E17 / 2.0E9 = 4.55E8 J/m2 per year Now, let's compare that to my realistic (but still very high) numbers: Therefore, a more realistic number would be: 7.88E9 J/yr m2 total insolation 7.88E8 J/yr m2 converted to biomass (10% = high!) 3.94E8 J/yr m2 converted to oil (50% oil, 50% biomass = high!) 9.85 kg/yr m2 converted to oil I conclude that the number NREL calculated is incredibly high, because it is higher than my really optimistic estimate... but not as unrealistic as the other wikipedia value... In addition, NREL claim that they place their entire reactor in the desert, which may be more sunny than my assumption (which was southern Spain). Still, everything has to be absolutely perfect to achieve this number... I am sure however that none of the process energy requirements are included. And cooling will be a major issue in the desert too. Therefore, I don't believe that the NREL number is realistic.

What is your current container made of? What do you need from your container? Are you going to heat it up? Is the container allowed to influence the magnetic field in any way? Without any answer to those questions, it's hard to help you. I'd go for ceramics.

White dwarves remain after a star expanded to a red giant. This means that any planet close to the star will likely be destroyed by the expanding star. Most planets are discovered due to changes in the star's position, light intensity or wavelength. White dwarves simply aren't very bright, so possibly that makes detection difficult. In addition, as mentioned before, all planets will be at significant distance, and therefore changes observed in the star's position, light intensity or wavelength will be slow and may go undetected. But maybe an expert can add some useful information - I'm certainly not an expert

There's also a limited number of wikipedia pages online, but if you want to read them all, you still ... well... you just can't. At a rate of 600 words a minute, twenty-four hours a day, a person could read nearly 27,000,000 words in a month. In the month of July 2006, Wikipedia grew by over 30,000,000 words. Given this, it is impossible for any single reader to read all of Wikipedia's new content.

You're right about the hot and cold. Cold air IS more dense. Hot air IS less dense. Those density differences are in addition to the things I just described... the picture gets more complicated as we write more posts And to make things more complicated: air heats up and cools down all the time... and that, my dear Watson, is how wind is created. Wind and pressure differences (low pressure, high pressure zones) are caused mostly by heating / cooling (although water has a big hand in this: if it evaporates, the air cools, and if it condenses, it heats). It's quite complicated, which is why weather forecasts are reliable for only a few days ahead.

hehe, That's how I got used to gnuplot: I use Octave.

gnuplot?

See it like this: All the way at the edge of space, there are still a few molecules, but really few. However, these do have a little weight, and gravity pulls them down a bit. That means they push on the next couple of molecules below them. The molecules below them are therefore a little more compact. Same as when you sit on a ball, you will compress the air inside because you're so heavy. - the effect of air is less obvious, because air is very thin - but we have a few hundred kilometers of air above us, pushing down! So, those molecules a bit further down, together with the ones all the way at the edge of space, are attracted, and together push down on the ones below them. The molecules that they all push on are therefore compacted even a bit more. And those all push down on the ones below them, and therefore compact those even more. And therefore, the lower you go, the more molecules are pushing down on that particular layer of air.

It's easy: The air that's on top is pushing down (gravity is pulling it down). So, all the air in the upper atmosphere pushes down, and compacts the air below it.

Openly disrespect? Where did that come from? I hope you understand that all the arguments given here are objective. This means that you can read them, check them, counter them (with equally objective arguments). The point is: If you want to make the world a better place ("help the cause"), then you must do the most environmentally friendly and ecologic thing. Did it occur to you that 1 million turbines in the river bed might actually be a really bad idea? You have to place 1 million machines, with moving parts in a river. They will break and litter the river with broken parts. In addition, I have reason to assume that the construction will require more material than a single dam (because those turbines will need a serious foundation, if they are not to be washed away): Hoover dam: 6.6 million ton of concrete (link 1, link 2). this means that your 1 million turbines can use a maximum of 6 ton of concrete per turbine. That's 3 m3 / turbine. I believe that that would actually be realistic... because you'll need to drill poles into the soil. Therefore 1 million turbines might use the same amount of concrete as 1 dam. I am helping "the cause" here... and you're "openly ignoring" all arguments given here.

I fail to visualize this. A bucket of water, sugar and yeast. Two electrodes. High voltage? Water actually conducts, so where is the semiconductor?

Nope. In science everybody is constantly b*tching about each other's theories until they're convinced themselves that this theory is the best explanation. The only way to find out is to, as was said before, really try to pick it apart. If picking it apart doesn't work, there might be some truth in it!

Please don't think that I don't like this kind of news, just because I don't reply. It's just that I don't have any questions or comments!

A warm welcome to all new people. I hope you'll be able to find what you're looking for, and I hope that we can also learn something from you guys as well!

The Dutch, English, Danish, Swedish, Norwegians, Spanish (all functioning democracies) have a surpreme leader as well. We just call it head of state (king or queen). They call it different. Same deal though. Our constitution says that queen has the power to stop any law. And (although I am not sure) she can send away ministers and/or the entire government. Not sure about the power of the heads of state of the other countries I mentioned. The difference is that our system is slightly more stable and that we're friends of the USA. I bet that if any of the previously mentioned countries would ever annoy the USA, the democracy would be questioned and the position of the head of state would be called undemocratic. Right now, nobody complains. I don't see how this is any different from both the elections where Bush got "elected". Even if the outcome of the much debated recounts were different, the system in the USA is such that a minority can elect a president. The popular vote isn't the same as the actual vote because of the electoral college. All I try to say is: don't judge too hard... examples of all the things you say can be found in the modern Western society as well... on both sides of the Atlantic. Indeed - instead of shouting that the election isn't fair, applaud the fact that they even have an election where more than 30% of the votes go to the opposition! I think the democratic situation in Iran isn't half as bad as in many other countries. They're even going to recount the votes in some areas.

Don't-blink-or-it's-gonnium?

Microscope? I'm not sure... first thing that comes to mind that works with charged particles is the mass spectrometer... but maybe that's not what you're looking for. Did you do precipitation tests? XRD? We might require a bit more information, or a member who was in the same college as you.

No, the 10% is an overestimation of the realistic (big scale) value of the overall efficiency. Algae in a normal pond will do about 1-2% efficiency (overall, not per cell)... or less. Algae in super-mega-fancy-bling-lab-reactors can do 13% efficiency on light (which is specific LED-light I tihnk). That's the highest number I've heard. (Citation needed ) Since measurements on a single cell aren't possible, due to the fact that the really high efficiency requires incredibly turbulent mixing, the numbers are always the overall efficiency. You're partially right on the liquid pumps: the liquid pumps are relatively efficient. Obviously, inducing extra drag using vanes will cause problems: 1. You increase drag. You increase the pressure drop per m of pipe. Therefore either you use shorter pipes, or your pressure behind the pump is higher (meaning your pipe system must withstand higher pressures). We're talking about several bars of pressure here. 2. Algae and other stuff will get stuck behind the vanes, and you will spend all your income on cleaning and maintenance. However, O2/CO2 pumping systems are the real big one. These will consume a significant portion of the energy produced. Gas compression requires much more energy than liquid pumps... and we're dealing with incredible amounts of gas. The gas flow is likely to be several times higher than the product (algae) flow. To achieve the really high production rates, the algae need constant mixing. However, I don't see any future for the algae bioreactors. I think the best way is to simply have a racetrack pond, which does not require any input of energy other than a small amount for a rather insignificant liquid flow.

Let's assume the average water consumption of a household is about 100 m3/yr, so 100000 liters, 10x more than you said, or 100000 kg/yr. Let's assume that it falls 10 meters down. Let's assume we have a 100% efficient turbine. [math]Energy = m*g*h[/math] [math]Energy = 100000*9.81*10=9810000 J[/math] in 1 year. [math]Power = energy/time[/math] [math]Power = 9810000/(3600*24*365)=0.31 W[/math] 0.31 W isn't even enough for your phone charger. Please spend your time on something useful!

Funny thing, I have a master in Chemical process engineering, but I have never heard of a "operating convection coefficient". Google also gives zero hits for the term. Instead, it links to this book. I am sure that the "heat transfer coefficient" is meant here... but that is just because (1) heat transfer coefficients are largely determined by convection and (2) the book I just linked to also uses symbol h for the parameter, and h is the usual letter for the heat transfer coefficient and (3) the units (W/m2K) match. Sadly I have no time for this little exercise today.

I'll reply only to the wikipedia link about algae, which is crap. Unfortunately, they use several assumptions which aren't proven on big scale, or just wrong: 1. Efficiency on sunlight. Estimate is much higher than realistic. 2. Algae need constant mixing (they need light-dark-light-dark-light-dark etc), which requires a serious pump to keep the liquid turbulent. 3. Algae need CO2, and produce O2. These two gases need to be added to and removed from the water. This requires one enormous gas compressor for the CO2, and a complicated system for O2 removal (because oxygen is actually toxic to algae, believe it or not). Therefore, the yields described have been achieved on lab scale, where power input was neglected, and where artificial lights provided the energy for photosynthtesis. I absolutely disbelieve (and I'll prove you why) that algae can be that efficient. 1. Claim: "algae can produce 100,000 gallons of oil per acre". 100,000 gallons = 378,000 liter = 300,000 kg Heat of combustion of vegetable oil = 40 MJ/kg Total energy per acre / yr = 300,000*40E6 = 1.2E13 J/(yr acre) That is equal to 1.2E13 / 4,046.8564224 = 2.96E9 J/(yr m2) (finally, it's all in SI units!!) Total insolation on 1 m2 in a warm, sunny place is about 250 W/m2, or 250 J/(s m2). That's the 24 hrs average for a place in the south of Spain. Therefore in 1 yr, we get 250 * (3600*24*365) = 7.88E9 J/(yr m2) At this point, it's worth noticing that the total insolation (7.88E9 J/(yr m2) is only a bit larger than the total energy which is supposedly captured in the algae's oil (2.96E9 J/(yr m2), algae growth itself not even included!!). The very best algae on earth can convert 10% of the sun's energy into biomass (not: oil). Of that biomass, only a part is oil. Therefore, a more realistic number would be: 7.88E9 J/yr m2 total insolation 7.88E8 J/yr m2 converted to biomass 3.94E8 J/yr m2 converted to oil 9.85 kg/yr m2 converted to oil Total yield per acre = 40000 kg/acre, or 10500 gallons / acre (why did I convert it back to gallons / acre? dammit!) Note: this is the best case scenario!!!!!! 10 times lower than the myth that's found on wikipedia Points 2 and 3 only reduce the efficiency, because a gas compressor that will bubble CO2 through water needs serious power. The CO2 is likely not pure (it costs a lot of energy to purify CO2, and not many sources actually produce pure CO2 - perhaps ethanol factories?). Then you still need to recover the oil. The algae are wet, and you need to separate the oil from the rest (which needs to be recycled to recycle the nutrients)... probably you need to dry and burn the algae, which (because it's so wet) does not necessarily provide a lot of energy. Conclusion The estimate of 100000 gallon / acre is totally unrealistic, and probably won't even be reached if you place the whole algae reactor on the sunniest place of the galaxy: planet Mercury. In addition, the power requirements to make the whole thing run are huge. You need enormous pumps and compressors, and the investment is also significant.

It's only logical that sometimes a silly spider makes a mistake. I mean, they sometimes just float in using one thread of spider silk as a sail. I would reverse the question: what evidence is there that no spider ever gets eaten by people in their sleep? None. Therefore, it's likely that it does happen sometimes. It's just not true highly unlikely that it happens as in the myth: 2 or 8 per night.