Andrew said - >If anyone is serious about perpetual motion then you should be >looking at converting heat (atomic kinetic energy) to motion, so some sort >of nano-machines turning a generator or a very sensitive infra-red >solar-cell. Then you can get power *out* of your fridge :) and Russell (with more time than sense, after having finally produced the crucial customer demo he has been working on forever) sez - Nope. This ain't perpetual and is even allowable as long as the heat keeps flowing downhill. Maximum theoretical energy percent extractable is related to the temperatures involved and is given by the Carnot efficiency of (Tin-Tout)/Tin x 100% Tin = room temperature Tout = fridge temperature T in absolute units (typically kelvins) For a fridge at 0 degrees C (273 kelvins) and a room remperature of 20 degrees C (293 kelvins) the theoretical efficiency is (293-273)/293 = 6.8% Achievable efficiency is lower than theoretical by typically a factor of 4 to 10 for real devices - YMMV. You've still gotta make the cold first though and guess what ... (Yep, I know Andrew knows this :-)) > only over way is tapping zero-point field energy (if it can be tapped), >since it seems that the volume of 'empty' space occupied by a cup is enough >to boil all the oceans, this option is likely to a) not work, b) blow us all >to bits. Zero Point energy (Casmir effect (spelling?) and its friends) sounds much more promising but nobody knows exactly how big it really is or if there is really any energy there at all. If it DOES work its NOT perpetual motion - just more energy hanging around ready to use than we can find anywhere else. Also its tied to the Hubble constant (believe it or no) AND the cosmological constant (which Einstein said was his biggest mistake ever and doesn't exist)(but it may) and you tend to be trying to push things around at atomic distances more or less so we may not be getting amything from this area for a while yet. See both Arthur C Clarke novel (???) for a reasonable sounding drive based on this and a (believe it not) Buzz Aldrin SciFi novel drive which described the drive in some detail and which depends on its characteristics for a major plot turning point. It all hinges on quantum mechanics which NOBODY knows anything about (all we do is describe what we see happen) which says that as space can't be empty (coz Heisenberg would get upset) so it must have some energy in it .. >we could always make a small black hole, feed it charged particles and give >it a good spin. So long as we kept feeding it to keep the spin up we could >extract power. Sooner or later though it may get a little hard to handle! Feeding it is cheating we want perpetual motion here. Anyway, you don't need to feed it to get energy out! Once we learn how to make small black holes (which seems "impossible" at this stage in the state of things we find they have some very intertesting properties. Big ones which have been there since the beginning of time (ie for at leat 6000 years :-))(but that's another story :-)) are very big and radiate energy as if they were a very very very cold black body. Thus we have the standard aphorism Black holes suck. This aint true folks. Its just that our universe has a basic temperature of about 2.7 kelvins and big black hole are colder BBR (black body radiators) than this so they suck up the background radiation plus nay matter that comes along. Stand clear. BUT Small black holes which have a BB (black body) temperature above 2.7 kelvins are net energy radiators. Turns out temperature is inversely proportional to mass. Smaller they get the hotter they get. At the size of the moon in mass the BB temp is 2.7K and we get net radiation. balance. Smaller and we radiate to background space. Size is about 0.1mm diameter. Could fit in your pocket with ease but you may have trouble carrying it. Now lets make it smaller. Lifetime is inversely proportional to cube of mass. Get down to the size of a modest mountain and it will last 15 billion years and is as big as a proton. This is at about 1 trillion degrees so we should be able to detect its radiation :-) Ebergy output rate is still surprisingly low Shrink it on down and it gets hotter ! and faster energy out. In the last second of its life you get 1,000,000 megatonnes of energy out - warm enough yet? Yes, this looks promising. >PS: Since we are getting tones of sunlight, why not use that? Anyone made >a solar powered PIC grass eating robot? More practicla but its not in the same class as a black hole powered lawnmower. At about 1300 watts/m^2 on a very clear tropical day or a realistic 100watt or so of shaft power on a typical hot & clear Oz or Arizona day (do they have grass in Arizona?) it would need around 20 square metres of solar cells to get even moderately enough power to cut a nice dry Arizona lawn. But, very importantly, at least this design would be more on topic because it, at least, does incorporate a PIC:-) . I wonder how many people have got this far :-)? If you have you are probably not the sort who complain about a little OT stuff :-) Have a look at www.easttimor.com - still fairly disturbing stuff. What makes you think that the 200,000 people who were force deported are now safe just coz the UN are slowly taking over where they USED to live? Send someone useful an email or something (they helpfully supply a list of useful people and their addresses) . regards, RM (and someone will still flame me re the East Timor comment, go figure) PS - if you did read this far let me know (just say "read it" or something - it would be interesting to know how many read this sort of thing :-) _____________________________ What can one black hole-less man do? Help the hungry at no cost to yourself! at http://www.thehungersite.com/ Hi Jeanette :-)