Edtharan

How strong a field would it have to be (out of curiosity - so just estimates is good enough). I know it would depend on the velocity of the particle pair and the distance between he plates. How much energy would it remove from the magnets to do this? From what I have been told, the magnets would only be weakened as the electron/positron were actually moving (do to the fact that they would set up an opposing magnetic field as they are moving electric charges). Once they were stopped in the plates, as I understood it, they would not be setting up that counter magnetic field. I take it that you could extract energy from this, only that it would be really innefficient. So they can be used to store energy, it is just difficult to get it back out.

Yes. In a fire there is a chemical reaction (and exothermic reaction - that is it produces heat). However, if you can take the heat away faster than the chemical reaction can generate it, then the fire will go out.

It's the Appeal to Authority logical fallacy. He is trying to set him/her self up as an authority by virtue of time spent, then using that "authority" claim that their argument is correct.

Fire is a gas that is so hot (due to chemical reactions) that it glows. This is the same as the filament in an incandescent light globe. If you cool it down, it is no longer hot enough to glow. So, if you were to "freeze fire", you would have to cool it down and it would then stop being "Fire". So no. It is therefore impossible to freeze fire as to do so would stop it being fire.

Ahh so the magnets would be weakened over time by this effect. Hmm, then would it be a good way of storing energy

The way I understand it is: As the liquid iron core cools, it becomes more dense, this causes it to move towards the centre. Now at the location where the iron is cool enough to crystallise out as a solid, it releases some of that heat energy to do so. This warms up the liquid iron just outside of that (as the heat has nowhere else to go), which becomes less dense and is pushed outwards by the incoming cooler iron. This sets up a convection current, and any motion of a conductive liquid (and liquid iron metal is conductive) in the presence of a small initial magnetic field will act as a dynamo and amplify that initial magnetic field. This is the source of the Earth's magnetic field. Because it comes from the planet Krypton . Seriously though, what Klaynos said is right. It is a fluid without friction. It is caused by the fluid being so cold that certain quantum mechanical effects that are usually swamped by the vibrations of all the atoms in the fluid (heat is really just atoms vibrating).

Here is my idea (I don't actually think this would work but I haven't been able to find an answer why it wouldn't). Most Perpetual Motion Machines tend to use classical mechanics, I suppose that it is easier for people to think in those terms. However, my machine is Quantum Mechanical in nature. According to QM and the uncertainty principle, there are virtual photons and even virtual matter forming and disappearing all the time. When, say, a virtual electron/positron pair form, they exist for a fraction of a second and then annihilate with each other. It is the fraction of a second that they exist that I found interesting. These virtual particles have an electric field, and they have momentum. This means that if they encounter a magnetic field, they should curve, and in opposite directions. However, if all there was was the magnetic field, then they could just curve around and collide with each other as they finish the circle. My ideas involves setting up such a magnetic field, but instead of allowing the particles to just circle around, there will instead be a pair of curved (1/4 circle arranged so that the nearest ends are in the magnetic field and the other ends are outside the magnetic field), conductive plates that the particles can collide with. The position and shape of the plates would be critical. You would actually have to have four devices arranged as below, with the centre of the magnetic field in the centre of the diagram (btw, instead of being straight, the plates would be curved). \\ // // \\ The virtual positron can collide and annihilate with an electron in one conductive plate. This then balances the "borrowed" energy of the virtual particles. It also (because of entanglement) promotes the virtual electron to a real electron which is now embedded in the other conductive plate. So one plate has lost an electron (and therefore has a net positive charge) and the other has gained an electron (and therefore has a net negative charge). We now have a potential difference and can use it to do work (by connecting the two conductive plates in an electrical circuit. This is sort of an effect like Tunnelling whereby an electron appears to tunnel between the two conductive plates. It is also a bit like Hawking radiation around a black hole, but instead of a gravitational field, we are using a magnetic field. It also relies on "quantum teleportation" using entanglement. Can we show how and why this won't work as expected.

But if you were also to then heat and cool the shafts, this would erase that information too. The only signal left would be the radiant heat travelling outwards. But then you would have to travel faster than light to "read" it. You would in effect have to travel backwards in time to get the information back. Yes, as photons. But again, you have the problem of having to travel faster than light to read it. If you are free to violate the laws of physics, then sure, you can construct a scenario to "recover" the information. As a pre-emptive response: If you were to set up a device that would intercept this out going "information" of radiation and record it, you are introducing a new element into the system. Namely that you are copying the information before it is erased. Of course, if you copy the information before you erase it you can get it back, but if you think about it, that ignores the point I was making. As far as any observer of the erasure event is concerned, the information is irretrievably lost to them. If you were to travel faster than light (travel backwards in time) you can then view the information. But after that erasure event, the information is lost to all future observers of the system.

If you build a RepRap, they ask that you produce the parts (at cost) for at least 2 other people who want to build one. At the moment, as there is only one that has successfully built a "Child" machine, there is not a lot of RepRaps out there that are producing pieces yet. From what I have read it takes about 5 days to replicate the plastic parts and then a day to assemble them. (about a week). As the first Child was made earlier this month, they haven't had time to make a lot of copies yet.

What you have fallen for her eis the Equivocation Logical Fallacy. It is an easy one to fall for, especially as humans are good at arbitrary associations and pattern seeking even when none exists. Just because something is like something else, it does not mean that they actually share the same attributes. Just because a tree has layers, it does not mean that because Earth has layers then they both must share the same property: "Alive". It is a bit like the scene from the movie: Shrek, where Shrek is trying to explain to Donkey that Ogres are complex. Shrek uses an onion to explain that Ogres have "Layers", but Donkey keeps misunderstanding and making the Equivocation Fallacy and keeps thinking that Shrek is talking about the other properties of onions (like if you leave them in the sun the grow little white hairs). So in Shrek, just because Onions and Ogres have layers, it does not mean that if you leave an Ogre in the Sun they will grow little white hairs. It is that same between the Earth and Trees. Both might have layers, but that does not mean that they both must be alive (or that if you leave them in the sun they grow little white hairs, or are big, green, bad tempered and and sound like Mike Myers ). Well cells have a dual layer of lipids around them, and the Earth doesn't for one. Also, there are fundamental size limitations for cells (as chemicals needed for their operation have to diffuse into them through pores in the lipid layers) and beyond a certain size the cell would cease to operate. Actually plants have many stimulus responses, this means that they do know what stimuli are. Many plants tilt their leaves to face the sun, this means they must have some way of detecting the angle of the sun and responding to it. Some plants even respond to touch and will close their leaves up to prevent themselves being eaten. So yes. Plants do know stimuli. Humans are part of Nature, so what we do is also part of nature (and just because something is natural does not mean it is good. See Naturalistic Fallacy). Also, if I was to go and pile up a lot of rocks and dirt into a hill, this would be part of the Earth. But it is also Man made and by your argument it couldn't be alive. But you are also saying that Earth is alive. So would that hill be alive or not, and as it is part of the Earth would the Earth be alive or not. What do all living things do: Reproduce/Growth: They take material from their environment and use it to build a new version of themselves. Excrete: They take in all sorts of things, not just the stuff they need, so they then eject those undesirable materials. Now it might be argued that a planet can grow because it pulls in material from its environment (in the form of asteroids and comets), but it doesn't get rid of anything, it keeps it all. Planets don't excrete. Life is an auto catalytic process. That is, living things make more living things and discard that which does not aid them in making more of themselves (its not a complete answer to what is alive, but it is a property that all living things share). There is no process that exists on planets that allows them to do this. As this property is common to all known living organisms, planets therefore are not alive.

Ok, Try this one: Get your self and Abacus. Set it so that the number it represents is your birthday. You now have some information on the abacus. Now tip it upside down and then back upright. This will "erase" the information (your birthday) from the abacus. Now, get it back. It leaves no trace that can be recovered, so no machine will be able to put it back together. Or: Set up a sequence of Atoms that have their spins aligned up or down. Use these to represent a binary value (lets use your birthday again). Now, rearrange their spins randomly. There is no way that you can recover that information it is destroyed completely. Information can be destroyed. It is not like Matter or energy, it is only a pattern of matter or energy. Change the pattern and you loose the information.

They are looking into conductive polymers and low temperature melting point metals for laying down "wires". They could then just build up the wires inside the plastic structure, they would be completely integrated within it. This I think will be the big stopper for a while, although they are talking about using a "Pick and Place" system of placing the electronic elements (essentially the pick and place is a robotic head that can pick up electronic components and place them onto the circuit board and soldered in with another component of the head - this method is used in some factories today).

Partially Self Replicating 3D Printer I read about this in New Scientist and was impressed by the progress they have made with this kind of technology. It can't self replicate completely... yet, but they are making good progress. It is still in the development stage, but it is to a point where hobbyists could easily build one. I like that they have made it Open Source so that anyone can (well those with a little bit of technical know how) can build one and experiment with it. At only around $650au, the outlay, especially compared to other 3D printers, is very affordable. It also looks like they are attempting to use easily obtainable feed materials for the system so that it is cheap to run too (they are looking at using PLA). I'd be interested in seeing what the SFN community thinks of it (and if any of you have one already).

But what if that Grand Unified Theory said that it was impossible? Current attempts at a GUT don't allow for antigravity, so it appears that it might not be something that comes out of GUT.

The problem with this is that speciation should occur faster, or the "less fit" organisms will die off quicker and the population size will crash. Think of it like this: Let's say that green colouring is better for hiding from predators, but a red colouring is better at attracting a mate (as an individual that could stand out to predators and still alive must be better at surviving, getting food, etc). But, each organism could produce offspring (and with a developing embryo the parent needs more food and is heavier so can't run as fast). There is now a strong evolutionary drive to develop the green colouring due to the fact that if a creature stands out they will not live long enough to give birth, or their offspring will not get enough nutrients to develop into healthy individuals. So standing out will not be strongly selected for, even if it is a sexual selection signal (that is the creatures prefer to mate with red individuals). It will be those that have to settle for the undemonstrative individuals that will end up with the best chance of producing healthy offspring. Sexual selection will then likely switch from the Red to the green as that is what gives the best chance of reproducing (or another aspect will become the sexual selection characteristic). Now, because the sexual selection will likely switch to the same as the environmental selection, this reduces the effect of sexual selection (it is the same, or similar to the environmental selection). Without that clear signal for sexual selection, the ability of one member to determine the fitness of another is therefore reduced too and beneficial alleles spread is slowed down. I am not saying that sexual selection is completely removed, just that it's effects will be damped down as the need for safe gestation/nesting/etc will over ride demonstrative sexual selection systems. Also there might be some sexual selection systems that could survive (displays that can be hidden, or through behaviours and so forth).

Not consciously . However, it is a commonly discussed situation whenever "Deep Time" is discussed in relation to archaeology (or even palaeontology).

I think this could be close to the mark. In Hermaphrodites, the pressure of sexual selection is reduced. If you can mate with any other of your species, the the drive that pushes one gender to compete against others of the same gender is greatly reduced. Sexual selection has many secondary effects that determine (or at least advertise) the fitness of the organism. For instance brightly coloured species are more easily spotted by predators, so only the most fit individuals would have the energy reserves to deal with this increased pressure. There is even a pressure on those that carry the children to not be brightly coloured so that they can more easily avoid predators. Since there is not as much information to determine which members are more fit, and any member can mate with another, this would in effect reduce the ability of the species to select the most fit individuals. So it would produce more diversity in the "gene pool" of the species, but the selection of the good alleles will be reduced.

So can the dates, 2011 and 2013 or any other number you care to like. No it is not when it ends, but when it complete it's full cycle. The Mayan calendar is a cyclic calendar and it has "ended" in this same way before without the Earth being destroyed (damn those pesky Vogons). Or neither....

You are wrong. Metal on Metal does produce friction. There have been many examples in this thread that you can do yourself that prove that metal on metal does produce friction. Here is a really simple one. Get two chunks of metal and rub them together. To make sure that it is not just the mechanical effort of using your own arms that creates a difference, place one on the floor and the other on top. Then stack weights on them to increase the amount of force pushing them together. If there was no friction then no matter how hard you push them together it would not get any harder to rub them together. However. If metal on metal does produce friction, then the harder you push them together the harder it will be to rub them together.

As a hypothetical exercise I find this interesting. Now, instead of developing on a planet, what if the organism developed in space (say like on the dust grains and small asteroids of Saturn's Rings)? Could such a creature exist (maybe just a bacteria like organism - nothing too complex)? It might start by getting it's energy from chemical reactions (breaking down iron/sulphur compounds). Later a form of Photo Synthesis might allow it to get energy from the nearby star. Movement among the dust grains would be a problem, but I think it might be possible with larger organisms or when collisions occur between them. If multicellular organisms develop, you might get something like the bombardier beetles defense as a kind of propulsion system. Thermal regulation would be a big problem. As would radiation. I think it could be possible, but highly unlikely (as compared to the chance of terrestrial abiogenisis - what ever that is).

No not all the information is stored on the hard drive (and by the way ROM stands for Read Only Memory - that is nothing can be written to it). What happens to a document that you are writing and that you don't save and you have a black out. Can you get that document back? No. It was stored in RAM (random access memory - you can read and write to that one). However, the information stored in the RAM can only exist as long as electricity is supplied to it. If you turn off the electricity, the data (information) can no longer be retained. Information can be destroyed, it is the result of what is called Entropy. What you are getting confused with the that Matter/Energy can't be destroyed. Actually, here is a really simple experiment that you can do to prove that Information can be destroyed: 1) Write down some information on a piece of paper. 2) Burn it... 3) Try and get that information back. You can't! The information was destroyed.

Actually if there were any species that had a technology as complex as our own that came before us, it is actually unlikely that we would ever find any evidence of them. In just a few thousand years, evidence of human activity is hard to come by. In a few hundred thousand years it would almost be wiped of the face of the Earth. In a few million years we wouldn't expect anything to remain. It the proverbial Needle in a Haystack, but where the Needle has a high chance that it has dropped out and fallen through the cracks in the floorboards.

Yes Bacteria do have a high mutation rate, but mutation isn't what drives Evolution. Mutation only drives variation. However, mutation is not the best driver of variation. Sex is the best driver (that we know of) of variation. Bacteria reproduce asexually, this only provides a slow rate of change. It is true that most mutations are bad (in that environment - they might be good in another environment though), as this is the case, it take a long time for good mutations to accumulate in the gene pool of the organism. Some bacteria can exchange genes (a sort of a sideways transfer which is different than sex). In Sexual reproduction there is more opportunity for variation and for good genes to accumulate as each set of genes in a sexually reproducing species comes from 2 parents, where as bacteria only have 1 parent. In sexual reproduction the 2 parents are the result of a string of successful mutations and they then provide the offspring with 2 different sets of genes (each successful and each providing different mutations). It effectively doubles the number of mutations in the organisms family history.

A Faraday cage is made of metal and charge on a conductor spreads it self out. Also, like charge repels. These together mean that any electric field creates a charge on the Faraday Cage and that this charge th4en covers the entire cage. As all this charge is the same polarity it repels all the charges elsewhere on the cage. Therefore net charge inside must be 0. It helps if you think of it as a sphere (other shapes are possible, it is just that the mathematics are more complicated but they still cancel to 0 inside the cage). Because of this, if you have a metal bodied car, it is quite protected during a lightning strike (from electricity, but the sound of the thunder would be quite loud and you might get shattered windscreens).

Have a look at what the brake disks in your car are made from... Metal And also have a look at what they clamp onto... Also Metal. Metal on metal clearly has enough friction to stop objects. With a train, it also has a lot of wheels, and braking is applied to all the wheels when a train needs to stop. This means that even though each wheel only provides a small surface area for braking, the total surface area because of all the wheels is quite large and provides a lot of friction used for braking.