Credit where credit is due: that idea didn’t originate with Sagan, but with Freeman Dyson.
Hence its name - the Dyson sphere.
Quoth m3:
Actually, Three Mile Island is often cited as an illustration of just how safe nuclear power really is. The key point is that what happened there was an absolute worst-case scenario for that type of plant-- And there were still zero deaths and no confirmed injuries or sicknesses as a result of it. Chernobyl did, in fact, cause a chilling amount of damage, but what happened there absolutely could not possibly occur at any nuclear power plant in the first world countries. What happened at Chernobyl, was the graphite used to moderate the neutrons in the core caught fire-- A plain, ordinary fire just like the fire in your grill when you’re barbequeing. Strictly speaking, it wasn’t even a nuclear accident at all. The reason that this could never happen in America or most of Europe is that our plants use water to moderate neutrons, which is not only not flammable, but it’s a lot better at conducting heat away so as t prevent anything else in there that might be flammable from igniting.
As to coal: If coal is not of biological origin, then how does one explain the intermediate steps in its production, such as peat?
WRT solar energy, I just finished reading an article in
?Scientific American? (the magazine is at work but I think that’s what I was reading) which postulates that 10,000 square miles of photo-voltaic cells would power the entire US. That sounds like a lot, I know, but if the cells were put on top of commercial buildings all over the country it sounds feasible. The same article mentioned that landfills must be “capped” for a certain amount of time after they’re filled before they can be used for other purposes, and would make and excellent placement points.
I would like to know who has “disproven” the theory that coal deposits are made from living things (plants). From the pretty extensive research I’ve done over the last 8 years I would have to say that that would be a view of a very small minority of scientists at best, and thus I would like to see what the reasoning behind this theory is. On a related note, it is entirely true that it does not form from “dead dinosaurs” as most popular culture tells us.
The origin of coal and the coalification process has been pretty well understood for a long time. There are really only two large unknowns in the process:
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Whether coal beds are depositied primarily in situ, or are a function of drift from massive floods and enormous flood debris.
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Whether it forms from swamp debris or forest debris, and whether this is from aerobic or anaerobic action.
And yes, you can always find people saying the flood theory proves the existance of the great deluge which Noah survived, etc., etc. I won’t comment on that.
Coal has the imprints of leaves and vegetable matter because that’s exactly what it is. Due to particular very local phenomemna, these are sometimes clearly identifiable as plants, roots, stems, etc. It’s a similar, but not the same reason, as is used to explain why we don’t have millions of times more fossils than we currently do - conditions have to be right to preserve these. Specific species of plants and trees have been identified from these fossils, and this has been noted since the early 1800’s. This is not that unusual or unexpected.
Una,
The Coal Goddess
[QUOTE]
*Originally posted by scr4 *
**
<AheM> Isn’t that a Jiggawatt? And where’s your Flux-capacitor? 
-Sa,
I would put the theory of inorganic coal right up there with the debunking of evolution.
To suggest that Chernobyl was “technically” not a nuclear accident is semantics. It was an accident that resulted in contamination of a wide area with radioactive materials. If a guy falls asleep at the wheel and hits another car, is that not a car accident (it wasn’t the car’s fault)?
I’ve worked with engineers and have a great deal of respect for them, but no technology is accident-proof. To suggest that Three Mile Island is a worst-case scenario for that type of plant is short-sighted. Hell, we’ve got to plants in California that sit right on large faults. Of course, if one of the reactors at San Onofre is cracked open by a major earthquake, it won’t “technically” be a nuclear accident…
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I’m not necessarily opposed to the use of nuclear energy, I just think we need to be honest with ourselves about the nature of risks, even though they are quite small. The biggest one is the generation of high-level waste; it’s a problem 'cuz no one (not even the biggest nuclear power advocates) wants it stored near them, but the biggest risk is that it has to be transported over highways and rails to get to the storage facility (which will be located in the least politically powerful region in the country, as opposed to the safest scientifically chosen site).
There are some graphite reactors in the first world. While all of the commercial plants are light water reactors, I believe that the plutonium breeders used by the DOE are still graphite based, at least the first ones used for the Manhattan Project were, and I believe that they are still using that design today.
Hmm, I think that it sounded too much like I was splitting hairs in that last post there… The reason that the Chernoble accident occured had nothing to do with the fact that it was nuclear. However, the reason that the accident was such a big problem was, of course, nuclear. My point was that risks of that sort were not inherant to all nuclear plants. As for nuclear plants sitting on major fault lines, you’re right, jrepka, I hadn’t even considered the implications of that. Even in that event, I suspect that the damage wouldn’t be as bad as Chernobyl, but it’d still be pretty bad… Unless, of course, it happened in Los Angeles-- Anything that renders LA a radioactive wasteland can’t be all bad 
Uhhhh…you realize this makes no sense?
The guy is saying that coal couldn’t be from decomposed plants, because then the plant parts would be destroyed. So it must be mineral in origin. BUT THERE ARE PLANT PARTS IN COAL!!!
So his theory that decomposition will destroy all identifiable plant parts is wrong. If coal is of mineral origin, then how did all the carbonized plant parts get into it? The other big problem with the mineral theory is that you’d have to explain why all the carbon wasn’t oxidized as the earth formed. That’s why coal burns, it hasn’t been combined with oxygen yet.