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At Multiverse Impasse, a New Theory of Scale

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Re: At Multiverse Impasse, a New Theory of Scale

#21

Post by coldtea »

possibilistic wrote: post #6
lutusp wrote: post #4

Earlier quoted context omitted.

Entropy = the inverse of available energy to do anything at all. EDIT: Look -- if you don't understand physics, don't compound your ignorance by downvoting the posts of people who do. Instead, post a written objection, and I will explain why you're wrong.

I don't like that definition. I like to consider ∆S the result of a smoothing operation over energy differentials. You can put work into a system to reestablish an energy differential. It just necessitates obtaining that other energy differential with which to do the work.

>I don't like that definition.

Yeah, but physics aren't a la carte. Either prove it wrong (and get a nobel) or accept it.

Re: At Multiverse Impasse, a New Theory of Scale

#22

Post by coldtea »

notastartup wrote: post #17

Feels like I'm a kid and I've just been told Santa Claus is made up.

Actually it should feel more like a tall story from your uncle at a family dinner, that's not corroborated and doesn't even imply what he insists it implies.

That is, half of the article is trash and the other doesn't represent the science correctly.

Re: At Multiverse Impasse, a New Theory of Scale

#23

Post by coldtea »

itry wrote: post #9

"size differences are illusory" So two things standing next to each other are the same size as one thing alone? Damn hard to imagine. I would think "size" does not really "exist" but is a man made concept. And by its definition, two things next to each other form a "bigger" thing.

The article is badly written, but it doesn't really mean sizes are illusory (even if it says so at the beginning). It goes on to say that sizes and mass "spontaneously emerge" from lower interactions, which is to say, they become real for us.

But, to address your example: "So two things standing next to each other are the same size as one thing alone? Damn hard to imagine".

That might not hold for size, but a very similar thing does occur (and is proven) for speed.

If you are in a car that goes at 0.8 miles per minute, and you throw a dart that goes at 0.3 miles/minute, its speed is 1.1 miles/minute (the sum).

But if you travel at the 0.8x the speed of light and you throw something forward at 0.3x the speed of light, its speed is not 1.1x the speed of light, but c. That is, trying to add velocity doesn't get you faster than the speed of light.

http://curious.astro.cornell.edu/question.php?number=145

Re: At Multiverse Impasse, a New Theory of Scale

#24

Post by collyw »

givan wrote: post #20

I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.

Yes. Open minded comments like this, questioning the limits of science get down voted here on HN.

Re: At Multiverse Impasse, a New Theory of Scale

#25

Post by l33tbro »

trhway wrote: post #14

>With their field stuck at a nasty impasse of course. Natural thing when a field is dominated by orthodoxy that closes their eyes to everything that they don't want to see. Like yesterday "entangled photon imaging" where what really happens is that a beam modulated by an image heats/excites crystal (with that heating/excitement thus obviously modulated by the image) which generates another beam (thus that another bea…

I wouldn't say that the "field is dominated by orthodoxy that closes their eyes to everything that they don't want to see".

I'll admit most physicists I've met are suspicious of wild-eyed theory. But I wouldn't say they're overly orthodox. I think it's more a healthy skepticism of anything which involves humans projecting science-ficiton wish-fulfilment into science.

I'd go further and say that "entanglement" and "multiverse" are not at all en vogue. I think most seasoned physicists realize that these were trendy fields some years ago (for solipsistic reasons - ie, make us feel special).

So I think the return to a fundamental assessment of phenomena is pretty natural thing. Calling out assumptions like scale. What's more, I think the more discerning will also be suspicious of the "post-multiverse" dialectic. It's just the process really.

Re: At Multiverse Impasse, a New Theory of Scale

#26

Post by lutusp »

coldtea wrote: post #23
itry wrote: post #9

"size differences are illusory" So two things standing next to each other are the same size as one thing alone? Damn hard to imagine. I would think "size" does not really "exist" but is a man made concept. And by its definition, two things next to each other form a "bigger" thing.

The article is badly written, but it doesn't really mean sizes are illusory (even if it says so at the beginning). It goes on to say that sizes and mass "spontaneously emerge" from lower interactions, which is to say, they become real for us. But, to address your example: "So two things standing next to each other are the same size as one thing alone? Damn hard to imagine". That might not hold for size, but a very si…

> But if you travel at the 0.8x the speed of light and you throw something forward at 0.3x the speed of light, its speed is not 1.1x the speed of light, but c.

Not really. Velocities near c don't sum that way. And your reference doesn't support your claim.

Re: At Multiverse Impasse, a New Theory of Scale

#27

Post by sampo »

dspillett wrote: post #10
vecter wrote: post #3

Earlier quoted context omitted.

What does entropy have to do with anything?

If the available energy is dispersed and chaotic, we won't be able to concentrate enough to perform the experiments? Though I doubt that'll be the case at any time while the human race is in existence... (caveat: I know very little of real physics)

You should first worry about how we get out of this planet before the Sun turns into a red giant and swallows the Earth after 5–6 billion years from now.

Re: At Multiverse Impasse, a New Theory of Scale

#28

Post by trhway »

l33tbro wrote: post #25
trhway wrote: post #14

>With their field stuck at a nasty impasse of course. Natural thing when a field is dominated by orthodoxy that closes their eyes to everything that they don't want to see. Like yesterday "entangled photon imaging" where what really happens is that a beam modulated by an image heats/excites crystal (with that heating/excitement thus obviously modulated by the image) which generates another beam (thus that another bea…

I wouldn't say that the "field is dominated by orthodoxy that closes their eyes to everything that they don't want to see". I'll admit most physicists I've met are suspicious of wild-eyed theory. But I wouldn't say they're overly orthodox. I think it's more a healthy skepticism of anything which involves humans projecting science-ficiton wish-fulfilment into science. I'd go further and say that "entanglement" and "mu…

>I'll admit most physicists I've met are suspicious of wild-eyed theory.

...

>So I think the return to a fundamental assessment of phenomena is pretty natural thing. Calling out assumptions like scale.

i see big difference between "Calling out assumptions like scale" as a "return to a fundamental assessment of phenomena" and "Calling out assumptions like scale" in order to fit it into a wild-eyed theory like superstrings (basically to salvage the theory).

Re: At Multiverse Impasse, a New Theory of Scale

#29

Post by possibilistic »

lutusp wrote: post #7
possibilistic wrote: post #6

Earlier quoted context omitted.

I don't like that definition. I like to consider ∆S the result of a smoothing operation over energy differentials. You can put work into a system to reestablish an energy differential. It just necessitates obtaining that other energy differential with which to do the work.

>> Entropy = the inverse of available energy to do anything at all. > I don't like that definition. Physics isn't a popularity contest. http://en.wikipedia.org/wiki/Entropy > You can put work into a system to reestablish an energy differential. Yes, but that doesn't change the definition of entropy -- it just borrows energy from somewhere else.

I feel like you're being that guy. Forgive me if I come across the same way.

Why link me to the Wikipedia article or insinuate I'm pulling this out of--to put it more politely--ex culo? Given my use of notation, one might assume I am at least a little familiar with how the thermodynamic entropy functions are mathematically derived.

To be pedantic for a bit, Entropy is an abstract mathematical state function useful for the prediction of thermodynamic systems. Much like the Gibbs and Helmholtz terms, entropy has no direct qualitative basis; there are many open-ended interpretations seeking to justify what it means, which is not unlike looking for God or faeries or what have you.

Mathematically speaking, I think you got your equality / definition wrong. Which energy function do you refer to? If you are still convinced about an error on my part, you can demonstrate in classical thermodynamics that,

    S = "the inverse of available energy to do anything"
Or stats thermo, if that's how you roll. (Mine isn't that great anymore, sadly.)

Re: At Multiverse Impasse, a New Theory of Scale

#30

Post by gus_massa »

lutusp wrote: post #26
coldtea wrote: post #23

Earlier quoted context omitted.

The article is badly written, but it doesn't really mean sizes are illusory (even if it says so at the beginning). It goes on to say that sizes and mass "spontaneously emerge" from lower interactions, which is to say, they become real for us. But, to address your example: "So two things standing next to each other are the same size as one thing alone? Damn hard to imagine". That might not hold for size, but a very si…

> But if you travel at the 0.8x the speed of light and you throw something forward at 0.3x the speed of light, its speed is not 1.1x the speed of light, but c. Not really. Velocities near c don't sum that way. And your reference doesn't support your claim.

I agree. More details: http://en.wikipedia.org/wiki/Velocity-addition_formula

If you add two velocities that are less than c, you can never get c, you always get something smaller.

0.8c + 0.3 c ~= 0.887 c (It's smaller than c)

At low speeds the effect still exists, but it's negligible. There is an important difference between "it doesn't exist" and "it's so small that if we forget it we will be fine".

It's so small that you must use floating point numbers with too many digits to calculate it. It's more useful to calculate the difference between the "relativistic" sum and the "classical" sum. Another way is to aproximate the formula with a Taylor expansion

dif = (X+Y) / (1+(X * Y/c^2)) - (X+Y) ~= - (X + Y) (X * Y/c^2)

0.8mph + 0.3 mph = 11mph - 5.9 * 10^-39 mph

The correction is veeeeery small.

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