AlphaSheeppig

I love this one too. The version I know ends with "Can you guess the riddle?"...

Actually, in practice, the sound waves are distributed over a distance of around 10 μm... It is not a instantaneous change. The density is extremely large, but not infinite. This is not a field that I know much about, but in most cases like this, some other principle that was negligible in the original theory becomes significant. Quantities often diverge, but in every case I've seen, there's some other principle that comes into play to stop it reaching infinity...

If you could build a hypothetical tower that's perfectly strong and rigid from here to the point where you start encountering low earth orbit satellites, and you stood at the top of the tower, you'd feel only 5% less gravity, and you probably wouldn't even notice that... These changes are minute...

A thought experiment is bounded by the same rules as a physical experiment, it just happens in your head rather than in reality... To me, a speculation is more of a hypothesis or theory that does not have much support. You could use a thought experiment to disprove a speculation, or provide support for it. But then a thought experiment could also be used to disprove or provide support for a generally accepted theory that has gone far past the point of being considered a speculation.

My 82 year old grandfather had no problem learning Linux (it was Ubuntu as well. It's a very good starter), so you should be fine. It took him a few days to get used to it, but it's actually far easier to use than DOS is, and it's a bit more intuitive too. You managed to learn DOS, so there's no reason you wouldn't be able to use something else. I don't know why you think your age puts a limit on what you can do. Any DOS software you knew will work through the DOSbox in Linux, so you won't really have to learn to use new software. The thing is, DOS is very outdated technology, and there's not really any support for it with the newer technology, like USBs and decent internet browsers. You'll be much better off switching.

5,430 °C... And if the earth was just a ball of flames, that might rise to maybe 7,000 °C (at a guess) which is way short of the 15,000,000 °C that the sun's core has been estimated to be at. Don't forget that only about 0.05% of the earth can burn and release heat. The rest will just melt or boil and absorb heat.

Yes, that's right. The origin is (usually) the bottom left point on the graph, so the bottom line should be 1. Merged post follows: Consecutive posts merged OK... multiply the 1, 10, 100 and 1000 by a million to get the right scale. Then the 5505390 would be plotted two thirds of the way between the 5th and sixth lines above the 1 million. 13722390 would be plotted a bit above halfway between the 10 million line and the one above it and so on...

A little bit, yes, but not by more than a few hundred degrees... WW3, now that's a completely different story. Merged post follows: Consecutive posts merged Yes, exactly, it only became accepted as science because it could make predictions that could be tested and were experimentally verified. It just went against what science at the time said.

No, it would burn at pretty much the same temperature, but I'd have to base my reasoning on science...

For the record, 99% correct is more 99 times more reliable than 1% correct. And we can look at how things were a million years ago, apply science, and see how they should be today, and they turn out to be correct. And, no, he's not saying that humans need to start the fire. He's saying that the flames from burning oil aren't hot enough to be a star. I'm not sure what temperature oil burns at, but I'm pretty sure its somewhere around 1000°C or 1800°F, give or take a third. A star burns at a few million degrees at it's core, but oil can only burn on it's surface (there's no oxygen at the core). Even on it's surface (which we can see and measure), the sun is way hotter than that... Anyway, stars don't burn. They produce energy through a sustained fusion reaction which comes off as heat.

My personal opinion (as meaningless as it is) is that the contraction and dilation does not "physically happen", because I will never see myself contract or fell any time dilation. I will only ever see it happen to other objects as they move toward or away from me or I move away from or toward them or what ever. It is only noticed by an observer, so it's sort of like an illusion (but with measurable effects). Slightly flawed logic, I know, but it's what makes sense to me.

As you move away from the origin on the log axis, there's a big gap between the first line and the second, but the gaps get smaller and smaller... After the 10th grid line, the pattern repeats... Importantly, the origin does not represent zero sice log(0) is undefined, so starting with the origin, number the lines 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400 and so on... Make sure the major grid lines (the ones just before the biggest gaps) are numbered in increasing powers of 10, (i.e. 1, 10, 100, 1000, etc...) You can just scale it to fit your data if you need to (eg. if the lowest number in your data is 0.00035, you'd number the origin as 0.0001). After that, it's just like normal graph but with weird spacing...

Science is wrong anyway... It's all based on mathematics anyway, and you don't see the universe sitting there with its pocket calculator trying to work out what everything does... The reason scientists view science as "right", and pseudoscience as "wrong" is only because science has been used for a couple of hundred years to make predictions, and these predictions have come true. More than that, they've been used to design things, and these things work - extremely complicated things like aeroplanes and nuclear reactors... The reason science is accepted and pseudoscience is rejected is because science is made up of very few principles, but has been extremely successful at making accurate predictions in the past. Sure, pseudoscience has occasionally given correct results in the past, but most of the time, it's predictions have been wrong. Don't forget a little over a hundred years ago, there was a guy who said practically all of science was wrong, and that solid objects changed size and shape as they moved differently, and time flowed differently for different observers. Back then, that could have been considered pseudoscience...

I think in this case, the c, g, etc. should represent the amount of grass the cow, goat, etc. eat per day, so its a rate, rather than a simple quantity... so you can set up a matrix of the original equations as (sorry it looks horrible, I did try in this forum's latex thing but it didn't work...) [ 1 0 1 -1 ] [c] = [1/45] [ 1 1 0 -1 ] [d] = [1/60] [ 0 1 1 -1 ] [g] = [1/90] [ 1 -1 -1 0 ] [r] = [ 0 ] And you can invert it to get [ 1 1 -2 -1 ] [1/45] = [c] [ 0 1 -1 -1 ] [1/60] = [d] [ 1 0 -1 -1 ] [1/90] = [g] [ 1 1 -3 -2 ] [ 0 ] = [r] Which gives [c] = 1/60 [d] = 1/180 [g] = 1/90 [r] = 1/180 which is exactly the same as what Sisyphus got using logic. (Since it's pretty much the same argument just in algebraic form...)

Personally, I think wind is the future. At the moment practically all of Africa's power comes from coal. I know several people who are working on wind power as an alternative power source, but the biggest problem is that the winds inland are very slow, so the turbines have to be designed very efficiently to extract a decent energy from the air, which is not easy or cheap to do. I have seen a test turbine with a 2m diameter, which produces about 1kW... That's really not that much. It pretty much powers the tea room in that building. But in the Cape, there are much better winds, and wind power has been implemented and works beautifully there. It is also true that the sun here is extremely bright, so solar power works very well. The problem is that no one here really manufactures quality panels, so you have to import everything. It works out pretty expensive. I just wish someone with finances would see it as a business opportunity.

Well, pressure is a scalar because it acts equally in all directions. If you consider a tiny bit of fluid next to the wall, the fluid exerts some pressure against the wall, but it also pushes the rest of the fluid around it with exactly the same pressure... How would you define the direction for fluid that's in the middle of a container and not next to a wall? In the maths we deal with this problem by representing the area the pressure acts on as a vector perpendicular to and pointing away from the fluid to get the force out as a vector.

Think of it this way: both object A and B want to travel in straight lines, but both are prevented from doing so by a force from the other object. The force stopping object A from leaving the system comes from object B, and the force stopping object B from leaving the system comes from A, so it goes in a circle, and they balance out. The forces don't cancel from object A or B's perspective, only from some point outside the system. All object A feels is the force B exerts on it, and not the force it exerts on B (because technically speaking, they're the same thing, but don't worry about that)... If that makes any sense?

I've never dealt with liquid nitrogen, only liquid oxygen, which was stored in what I always assumed were pressurised tanks... I asked one of the lab technicians earlier and he said it was just a really well insulated tank... I guess I should know by now not to make assumptions.

A teaspoonful of it would weigh around 2.5e+12 kg... Although I have absolutely no idea what would happen to it. A neutron soup is my bet, but I can't back that up with anything...

Your logic is correct, but why would there be a perfectly uniform contraction of matter? It would imply some sort of change in the universal constants (like Planck's constant) and we're not observing any change in those. Thing's that are governed by these constants like electron energy levels are not changing, so we can assume that the universe is expanding and it is not matter that is contracting. Of course you could argue that all the constants are changing and that they only appear constant because our units we use to define them are changing too, but lol... Occam's razor...

Increased pressure will drop the freezing point of the water and raise the freezing point of the oil, as far as I know, which helps your case... I think the difficulty here comes in applying the liquid nitrogen to the gap underwater. Also, the temperature drop liquid nitrogen causes is because it absorbs a lot of energy because it cools down rapidly as it approaches room pressure and tries to expand to become a gas. It is actually not cold, which is a point a lot of people miss. When it is not being used, it is stored at high pressure and can be stored at room temperatures... The high pressure down there would cause a huge drop in the amount of energy the liquid nitrogen would absorb, and I'm not sure it would drop the temperature by much. Probably not by enough to cause the oil to freeze.

Remember that supposedly nothing could travel faster than the speed of light from the point in space where the big bang happened. This sets a size limit on the universe as a sphere with a radius of 13 or so billion light years. We should in theory be able to see at least some portion of the edge of the universe and the centre from where we are (or at least some past version of them). We are just limited by the sensitivity of our instruments, and we have reached the point where radiation from background noise is greater than the radiation from the objects we are trying to observe.

I know that. It's a rotational example of what I was trying to say, and I can think of millions of rotational examples. I can also think of dozens of translational examples, but they all oscillate... I can't think of any that don't oscillate. I guess if there really was an easy one, it would be used all over the place.

Haha... OK... I think I've got some serious thinking to do... Merged post follows: Consecutive posts mergedTo answer the original question, this is the initial misunderstanding: The force does not necessarily cause more movement. It cancels or alters the straight line motion of that component that would happen if the force wasn't there. Don't forget Newton III - something else in the system needs to exert the force, and the original component will exert a force on that. From a point of view outside the system, these two forces cancel each other out, so there is no energy leaving the system. Think of a simple solar system with one planet and a star. The planet wants to drift off into space in a straight line, but the gravity makes it move toward the star. This means that the planet's path curves toward the star, but the star also moves toward the planet (much less though, since it's so much heavier). If the planet is too slow, it will crash into the star, and if it is too fast, it will drift off into space, and matter will indeed leave the system like you say. But if the speed is right, the planet will do neither and just drift around the star in a stable orbit. No matter leaves the system, and no energy needs to be added or escapes because the force the pull the star exerts on the planet to keep it in orbit is cancelled exactly by the pull the planet exerts on the star. Does that make sense? In a mechanical system of cranks and levers, it is exactly the same. The force that linkage A exerts to keep linkage B in the system is cancelled exactly by the force linkage B exerts to keep linkage A in the system, so there is no energy loss. Friction and losses like that are irrelevant for this argument, since energy escapes in the form of heat, and this energy can be forced to remain in the system by defining the entire universe as the system.

Yeah, now that I think about it, you're right. Friction does play a role because without the friction, the box moves back at the same time... I can't think of any examples that give linear motion right now, but I can think of several that give rotational motion - helicopters for one.