Search found 96 matches

by Mettra
Sat May 24, 2008 12:34 am UTC
Forum: Science
Topic: chem and physics books
Replies: 6
Views: 1376

Re: chem and physics books

You may want to try the Feynman Lectures on Physics. My school has recently seen the light and started using Griffith's for 3rd and 4th year quantum and EM. For Stat Mech I think they use Reif. The Feynman lecture series are good to learn but are not a good reference and not terribly math-oriented ...
by Mettra
Fri May 23, 2008 11:55 pm UTC
Forum: Science
Topic: Nuclear Power (merged threads)
Replies: 325
Views: 53416

Re: Nuclear Power, what's your issue with it?

Solar power will one day be the main replacement for grid power, at least in my opinion. It is no where near able to do that. Right now the environmental cost alone for making that many solar panels (and of course disposing of them when they break down, and replacing damaged parts, etc), and taking...
by Mettra
Fri May 23, 2008 11:52 am UTC
Forum: Mathematics
Topic: A Matter of Steam-Powered Math
Replies: 29
Views: 3169

Re: A Matter of Steam-Powered Math

Just thought I'd make an additional comment to back up some things touched on above. The reason a program will crash if it divides by zero is basically because the programmer made a special case for it, or the programming language/module has a built-in case-specific fix. A programmer could program 0...
by Mettra
Fri May 23, 2008 11:32 am UTC
Forum: Science
Topic: Destructive interference and the conservation of energy
Replies: 12
Views: 4037

Re: Destructive interference and the conservation of energy

For an interesting related topic (fermions instead of bosons), see:

http://en.wikipedia.org/wiki/Pauli_exclusion_principle
by Mettra
Thu May 22, 2008 7:51 pm UTC
Forum: Science
Topic: Wheeler-deWitt Equation and the nature of time
Replies: 38
Views: 3171

Re: Wheeler-deWitt Equation and the nature of time

I've been thinking about several points in your essay (smithjcn) that have been niggling at me. The first one is the Feynman reference. "The late Nobel Laureate Richard Feynman was fond of using what he called the "trick" of substituting units of length in place of units of time as a ...
by Mettra
Thu May 22, 2008 5:38 pm UTC
Forum: Science
Topic: How many ways can you empty a glass of water?
Replies: 129
Views: 13125

Re: How many ways can you empty a glass of water?

To state that a glass has been emptied requires certainty that the water has left the glass... But if you don't know where the water is, how can you be sure it's not in the glass? Now you're worse off than when you started... Then the solution is obvious. Measure the POSITION of the water very very...
by Mettra
Thu May 22, 2008 5:29 pm UTC
Forum: Science
Topic: Feasibility of Hamster-Ball Drive
Replies: 19
Views: 1818

Re: Feasibility of Hamster-Ball Drive

Well, the drive wheels to which they are attached. Those forces have to be there to satisfy the moment condition. When you break a moment into its constituent forces, you have to have a force couple otherwise it is not equivalent. If there is a force exerted on the bottom of the wheel as a result o...
by Mettra
Thu May 22, 2008 12:44 am UTC
Forum: Science
Topic: Feasibility of Hamster-Ball Drive
Replies: 19
Views: 1818

Re: Feasibility of Hamster-Ball Drive

once the center of gravity (which is presumably around halfway between the center and the bottom of the ball) gets rotated to a height such that the upward acceleration of this point by the wheels = 9.8 m/s 2 , then the horizontal force component of the carriage at that angle will be converted enti...
by Mettra
Wed May 21, 2008 10:09 pm UTC
Forum: Science
Topic: Capabilities of Human Genomics
Replies: 25
Views: 2271

Re: Capabilities of Human Genomics

If you really want to solve the mayhem of human existence: become a physicist and teach us how to understand and wield the energies of the universe. If we had as much energy as we do oxygen or ocean water, all the problems of the world would solve themselves.
by Mettra
Wed May 21, 2008 9:03 pm UTC
Forum: Science
Topic: Feasibility of Hamster-Ball Drive
Replies: 19
Views: 1818

Re: Feasibility of Hamster-Ball Drive

The forces you have circled don't seem to exist. You could just as well have drawn them north or south. If some THING touched the wheels at that point, it would experience a force. But nothing is touching it as far as I can imagine. Consider a wheel spinning in deep space. It has rotational kinetic ...
by Mettra
Wed May 21, 2008 8:33 pm UTC
Forum: Mathematics
Topic: so maths is useful for what now?
Replies: 31
Views: 3666

Re: so maths is useful for what now?

mathematicians often blatantly disregard "proper" mathematics in favor of "this should work out, so I'm going to do it." It then takes other mathematicians a while to catch up to providing proper justification for why the mathematician can (or can't) do that. same happens in all...
by Mettra
Wed May 21, 2008 5:08 am UTC
Forum: Mathematics
Topic: so maths is useful for what now?
Replies: 31
Views: 3666

Re: so maths is useful for what now?

I'm doing maths because it is ment to help me get a job. I have no idea why though, I want to be a Jeweller. My question is why do we put so much strain on maths? The reason math is stressed so much in general is that humans don't understand it easily, but it's the most powerful tool we have availa...
by Mettra
Wed May 21, 2008 4:00 am UTC
Forum: Science
Topic: Feasibility of Hamster-Ball Drive
Replies: 19
Views: 1818

Re: Feasibility of Hamster-Ball Drive

I should point out that with your setup, the CG will *always* be in the center, no matter the orientation. [1] Other than that... I can't think about it right now heh. Hopefully a third party will weigh in. I completely understand the setup and how it should work, I'm just not convinced it will. [2...
by Mettra
Wed May 21, 2008 3:00 am UTC
Forum: Science
Topic: Feasibility of Hamster-Ball Drive
Replies: 19
Views: 1818

Re: Feasibility of Hamster-Ball Drive

Ok, I thought of a similar setup without remembering that you had written about it. Why wouldn't the device just spin around the inner surface of the sphere, without causing it to move? If there was a sufficiently high force on the north side and a sufficiently high force on the south side, pushing...
by Mettra
Wed May 21, 2008 1:22 am UTC
Forum: Science
Topic: Feasibility of Hamster-Ball Drive
Replies: 19
Views: 1818

Re: Feasibility of Hamster-Ball Drive

...You need wheels placed opposite each other and pressing into the sphere. This way, when the wheels spin, they will drag the sphere around with them... By opposite what I meant was if one wheel makes contact at a point on the inside of the sphere, the other wheel of that 'pair' makes contact at a...
by Mettra
Tue May 20, 2008 7:49 pm UTC
Forum: Science
Topic: Terraforming
Replies: 38
Views: 4494

Re: Terraforming

Why start from scratch when we have a perfectly good template to work ontop of? And along that same line of thinking, how much total energy would it take to do one vs. the other? I'd imagine planet-building would take an order of magnitude more, although one might do that anyway for different reaso...
by Mettra
Tue May 20, 2008 4:50 pm UTC
Forum: Science
Topic: Feasibility of Hamster-Ball Drive
Replies: 19
Views: 1818

Re: Feasibility of Hamster-Ball Drive

FBD Disclaimer: I'm an engineer but I'm not particularly talented at dynamics. I don't think your description is correct. From what I gather, you are imagining that the drive wheel will directly induce rotation in the ball. I'm not sure this would work. If the friction coefficient between the ball ...
by Mettra
Tue May 20, 2008 4:48 pm UTC
Forum: Science
Topic: SI Units
Replies: 22
Views: 2311

Re: SI Units

All the SI units are arbitrary though. Is there any set of 7 base units that are ... less arbitrary? You could use the mass of one proton for the mass unit, instead of a mole (6E23 atoms/molecules/whatever) set new_avogadro = 1, etc. 0K is a good base point for temperature, but the size of the unit...
by Mettra
Tue May 20, 2008 3:27 pm UTC
Forum: Science
Topic: is anything actually random?
Replies: 26
Views: 2928

Re: is anything actually random?

I'd say your teacher was extrapolating his interpretation of QM a bit too far. However, I'd assert that the question of free will is a silly one. Free from what? Once you try to define the question, you find it is meaningless. Free from relationships or interaction? -There lies a path to non-existe...
by Mettra
Tue May 20, 2008 3:18 pm UTC
Forum: Science
Topic: Feasibility of Hamster-Ball Drive
Replies: 19
Views: 1818

Re: Feasibility of Hamster-Ball Drive

Disclaimer: I'm not an engineer, I'm a physicist. It all really depends. A huge factor will be the friction on the outside of the sphere. If that is arbitrarily large, then your big limiter will be the power of the motor turning the wheels. Gravity can be overcome with powerful enough wheels, howeve...
by Mettra
Tue May 20, 2008 2:11 pm UTC
Forum: Science
Topic: SI Units
Replies: 22
Views: 2311

Re: SI Units

much like base vectors you can pick any orthogonal vectors as a base, but the point of SI is to stick to one in particular. But I don't really like how they've defined some units in terms of other units. 1 m = distance travelled by light in 1/3^10 seconds. Shouldn't there be some other independent ...
by Mettra
Mon May 19, 2008 3:20 pm UTC
Forum: Science
Topic: How many ways can you empty a glass of water?
Replies: 129
Views: 13125

Re: How many ways can you empty a glass of water?

seladore wrote:Measure its momentum really, really accurately.

Repeat if necessary.


I'm pretty sure you can all stop now. This is the winner.
by Mettra
Sun May 18, 2008 10:57 pm UTC
Forum: Science
Topic: Wheeler-deWitt Equation and the nature of time
Replies: 38
Views: 3171

Re: Wheeler-deWitt Equation and the nature of time

I meant no offense. Since most of the jabbering in this thread is mine, it was a joke meant to be at my expense.

All of your arguments (including in your essay) are at least as reasonable and valid as mine or any others' here. Sorry for the confusion.
by Mettra
Sun May 18, 2008 9:54 pm UTC
Forum: Science
Topic: Wheeler-deWitt Equation and the nature of time
Replies: 38
Views: 3171

Re: Wheeler-deWitt Equation and the nature of time

Apologies for misunderstanding anything you said. [1] Well, since such a theoretical "strongest" system can never exist, I'm afraid I don't quite understand what you're trying to say. If maths isn't the whole picture, then what else is there? [2] I'm not sure about this. Any universal Tur...
by Mettra
Sun May 18, 2008 6:59 pm UTC
Forum: Science
Topic: Wheeler-deWitt Equation and the nature of time
Replies: 38
Views: 3171

Re: Wheeler-deWitt Equation and the nature of time

This is not my understanding of the incompleteness theorems or of the halting problem. The incompleteness theorem talks about sufficiently strong consistent formal systems being incomplete and unable to prove their own consistency. That doesn't mean that a stronger formal system can't prove its con...
by Mettra
Sun May 18, 2008 6:06 pm UTC
Forum: Science
Topic: Wheeler-deWitt Equation and the nature of time
Replies: 38
Views: 3171

Re: Wheeler-deWitt Equation and the nature of time

Thank you for a thoughtful post. I find that I have similar issues with the arbitrariness of human perception. Time has one dimension and always moves forward because that is how we interpret it (maybe). I can appreciate your faith in the mathematics. However, don't Godel's incompleteness theorems ...
by Mettra
Sun May 18, 2008 2:50 pm UTC
Forum: Mathematics
Topic: new theory on numbers
Replies: 29
Views: 3531

Re: new theory on numbers

What I was really asking was: how the hell do you draw that, and is there extra information when you draw it using these areas? For example, if you drew a solution for something very much like this: http://en.wikipedia.org/wiki/Isocline a very simple sort of problem without any 3D information - when...
by Mettra
Sun May 18, 2008 2:44 pm UTC
Forum: Science
Topic: is anything actually random?
Replies: 26
Views: 2928

Re: is anything actually random?

Not being able to predict does not equal random. It just means we don't know. These two things are not even remotely connected. [1] Restatement: Things aren't random just because we don't know something. [2] Things that are "random" usually are not random. In fact, I can't think of a sing...
by Mettra
Sun May 18, 2008 4:32 am UTC
Forum: Mathematics
Topic: new theory on numbers
Replies: 29
Views: 3531

Re: new theory on numbers

My question would be: how do you resolve this with the already fairly complicated and already existing topology of stuff like solutions of differential equations (forgive my unimaginativeness, I'm a physicist in the maths forum).
by Mettra
Fri May 16, 2008 11:10 pm UTC
Forum: Science
Topic: Terraforming
Replies: 38
Views: 4494

Re: Terraforming

Perhaps the traditional flaw in terraforming is that humans are so weak in terms of what we require to survive. Maybe what we need is genetic modification to make it easier on ourselves to live on other planets, perhaps a special lung for breathing a different type of gas? Blood and other fluids wi...
by Mettra
Fri May 16, 2008 10:42 pm UTC
Forum: Science
Topic: Wheeler-deWitt Equation and the nature of time
Replies: 38
Views: 3171

Re: Wheeler-deWitt Equation and the nature of time

Aye, there's the rub! If our circles were meeting up where they should I'd wager we wouldn't be facing the current glaring disconnect between general relativity and quantum mechanics. And I believe our traditional concept of "time" is the most likely culprit. The absence of a time variabl...
by Mettra
Fri May 16, 2008 5:02 pm UTC
Forum: Serious Business
Topic: Argument vs. Discussion
Replies: 19
Views: 3892

Re: Argument vs. Discussion

I too take issue with the thread title and the inferred meaning of the two words. An argument is a tool that one uses to reach a conclusion about a debated topic. Propositions are put forth until all sides agree on an outcome (or agree to disagree). A discussion is not necessarily an argument but ca...
by Mettra
Fri May 16, 2008 4:50 pm UTC
Forum: Serious Business
Topic: Predicting the Future
Replies: 70
Views: 6119

Re: Predicting the Future

personally... yes, the universe is deterministic. deterministic being a fancy term for 'only one thing can happen at a time.' which is true. I can't roll a single die and get both a two and a six. so if i knew every vector, every constant, every degree, every minute force, and every position/veloci...
by Mettra
Thu May 15, 2008 12:05 am UTC
Forum: Science
Topic: is anything actually random?
Replies: 26
Views: 2928

Re: is anything actually random?

Yeah, it really is random, at least in an interpretation consistent with quantum mechanics (one of the better-tested theories ever). To make things like virtual particles be determined by something would require lots of of work (by particles or alternate dimensions or aliens), and why would such a ...
by Mettra
Wed May 14, 2008 11:51 pm UTC
Forum: Science
Topic: Wheeler-deWitt Equation and the nature of time
Replies: 38
Views: 3171

Re: Wheeler-deWitt Equation and the nature of time

I'm convinced that there is a serious logical flaw in what is euphemistically known as the "operational" definition of time, i.e., "time is that which is measured by clocks." This so-called "operational" definition currently serves as a fundamental underpinning of phys...
by Mettra
Tue May 13, 2008 5:30 pm UTC
Forum: Science
Topic: Living on a (roughly) flat plain
Replies: 12
Views: 2434

Re: Living on a (roughly) flat plain

* Is there a tutorial anywhere on how to use this <math> stuff? It doesn't seem to do anything for me except change the font. I found the LaTeX wikipedia page, but nothing seemed to work correctly. Just put the LaTeX in math blocks. For instance, [math]a \in B \rightarrow a \in C[/math] becomes: a ...
by Mettra
Tue May 13, 2008 5:06 pm UTC
Forum: Science
Topic: [Physics] Time Travel
Replies: 70
Views: 8006

Re: [Physics] Time Travel

One problem that always comes up with time travel (into the past, of course) is the need for some kind of time-recursive mechanism. In other words, the mechanism that allows you to travel into the past needs to travel into the past itself (and therefore needs another mechanism to travel into the pas...
by Mettra
Sat May 10, 2008 3:12 pm UTC
Forum: Science
Topic: A giant comet is headed towards Earth (hypothetically)
Replies: 86
Views: 7270

Re: A giant comet is headed towards Earth (hypothetically)

Doesn't make any sense. Assuming that people actually survive, and don't all get hit on the head or something and forget everything they will still know everything they knew. Plus, it isn't hard to store *huge* collections of information into a fairly small space, that is much more durable than peo...
by Mettra
Sat May 10, 2008 1:45 pm UTC
Forum: Science
Topic: relativity and co-ordinate systems
Replies: 11
Views: 1488

Re: relativity and co-ordinate systems

You can slap your coordinate system anywhere in the universe. It will expand in every direction. The location of the coordinate system doesn't matter. There is no 'center' of the universe for us to call the origin. This may not be the most kosher answer, but someone with more GR background could giv...
by Mettra
Sat May 10, 2008 1:39 pm UTC
Forum: Science
Topic: How far will the divisibility go?
Replies: 23
Views: 3443

Re: How far will the divisibility go?

Of course, we don't "know" that QED, QCD, relativity etc. are "real" - just that they work very well. About 2/3 of my point was that the question is too philosophical to answer with science. In science we deal with things that we currently 'know' and we accept them as real as lo...

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