http://www.scientificamerican.com/article.cfm?id=splitting-time-from-space

I never really did like the notion of inseparable spacetime, tbqh.

--
Tim Cook
http://empyrean.freesitespace.net

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Tim Cook wrote:
> http://www.scientificamerican.com/article.cfm?id=splitting-time-from-space

Very cool.  I recently saw another approach, in which the collapse of the 
quantum probability wave forms is caused by gravity waves, which are too 
weak at the sub-atomic level to actually have an effect.  It'll be 
fascinating to see how all this plays out.

-- 
Darren New, San Diego CA, USA (PST)
   You know the kamikaze monsters in Serious Sam
     with the bombs for hands, that go AAAAAHHHHHHHH!
   I want that for a ring tone.

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Why do I always get the feeling that quantum gravity reverses the normal
scientific process of discovery-theory? In other words, normally a new
unknown phenomenon is discovered, studied, measured and then theories are
developed to explain how it works and perhaps why.

  With quantum gravity the direction seems reversed: They have formed the
theory of a gravitational quantum *first*, and now they are really hard
trying to discover it somehow.

-- 
                                                          - Warp

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Warp wrote:
>   With quantum gravity the direction seems reversed: They have formed the
> theory of a gravitational quantum *first*, and now they are really hard
> trying to discover it somehow.

The problem is that both relativity and QED (quantum electrodynamics - 
quantum mechanics for non-nuclear interactions) seem to be very accurate in 
their appropriate timescales. But QED assumes absolute time (AFAIK), and 
relativity assumes continuously differentiable space (and hence energy 
levels), so we know we can't resolve those two into one theory without 
changing one or the other. (At least, that's my understanding of the problem.)

The approach that QED uses has been successfully applied to nuclear 
interactions with the strong and weak nuclear forces, as well as 
interactions between quarks (quantum chromodynamics). In other words, it 
looks like every force *except* gravity behaves like 
two-dimensional-probability "waves" traveling at the speed of light on average.

Hence the assumption that gravity is likely to also play by that rule, with 
gravitons mediating the effects of gravity on the small scale with 
statistical properties making it look smooth and consistent and "not 
quantum" over larger scales.

tl;dr - relativity and quantum are mathematically incompatible, and quantum 
accurately describes everything *except* gravity, so the assumption is 
gravity is wrong.

-- 
Darren New, San Diego CA, USA (PST)
   You know the kamikaze monsters in Serious Sam
     with the bombs for hands, that go AAAAAHHHHHHHH!
   I want that for a ring tone.

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Warp wrote:
>   Why do I always get the feeling that quantum gravity reverses the normal
> scientific process of discovery-theory? In other words, normally a new
> unknown phenomenon is discovered, studied, measured and then theories are
> developed to explain how it works and perhaps why.
> 
>   With quantum gravity the direction seems reversed: They have formed the
> theory of a gravitational quantum *first*, and now they are really hard
> trying to discover it somehow.

Had a look at String Theory lately? ;-)

http://www.xkcd.com/171/

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"Warp" <war### [at] tagpovrayorg> wrote in message
news:4b0cf846@news.povray.org...

> In other words, normally a new
> unknown phenomenon is discovered, studied, measured and then theories are
> developed to explain how it works and perhaps why.

This is a very neat and tidy, but ultimately wrong synopsis of how science,
or at least physics, has been working for over the last century, during
which time theories have often ventured far beyond what needs to be
explained. Of course they have simultaneously been falling far short of
explaining what needs to be explained, so it's a really complex picture.

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somebody <x### [at] ycom> wrote:
> "Warp" <war### [at] tagpovrayorg> wrote in message
> news:4b0cf846@news.povray.org...

> > In other words, normally a new
> > unknown phenomenon is discovered, studied, measured and then theories are
> > developed to explain how it works and perhaps why.

> This is a very neat and tidy, but ultimately wrong synopsis of how science,
> or at least physics, has been working for over the last century, during
> which time theories have often ventured far beyond what needs to be
> explained. Of course they have simultaneously been falling far short of
> explaining what needs to be explained, so it's a really complex picture.

  Well, *usually* science goes through the cycle:

1) We observe some phenomenon,
2) We study and measure the phenomenon.
3) We formulate hypotheses, and if these hypotheses can make enough accurate
   predictions which match new observations, they are made into theories.
4) If new observations and measurements contradict the existing theories,
   they are revised, or entirely new hypotheses are formulated, so we go
   back to step 1.

  In this particular case, however, I have the feeling that an observed
phenomenon (gravity) is tried to forcefully be fit into an existing theory
(quantum mechanics) even though it's contradicting it. In other words,
the theory is that "everything must be quantized", and they are observing
that "gravity doesn't seem to be quantized", and rather than revising the
theory they are trying to forcefully make gravity quantized to fit the
theory.

  Somehow I get the feeling that it's a bit the same as saying "the Newtonian
gravity laws are the truth" and then trying really hard to make the mechanics
of Mercury fit into the Newtonian laws of gravity, rather than accepting that
it doesn't fit, and devising a new theory which does fit observed phenomena.

-- 
                                                          - Warp

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>  Well, *usually* science goes through the cycle:
>
> 1) We observe some phenomenon,
> 2) We study and measure the phenomenon.
> 3) We formulate hypotheses, and if these hypotheses can make enough 
> accurate
>   predictions which match new observations, they are made into theories.
> 4) If new observations and measurements contradict the existing theories,
>   they are revised, or entirely new hypotheses are formulated, so we go
>   back to step 1.

Didn't Einstein predict black holes before we found any?

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scott wrote:
>>  Well, *usually* science goes through the cycle:
>>
>> 1) We observe some phenomenon,
>> 2) We study and measure the phenomenon.
>> 3) We formulate hypotheses, and if these hypotheses can make enough 
>> accurate
>>   predictions which match new observations, they are made into theories.
>> 4) If new observations and measurements contradict the existing theories,
>>   they are revised, or entirely new hypotheses are formulated, so we go
>>   back to step 1.
> 
> Didn't Einstein predict black holes before we found any?

It's not uncommon for a new theory to explain observed phenomina but 
also predict something that nobody has seen before. The interesting 
question is whether the thing is seen later.

(Isn't there some theory that predicts that Weakly Interacting Massive 
Particles exist, yet nobody has ever seen one?)

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"Warp" <war### [at] tagpovrayorg> wrote in message
news:4b0e5f8a@news.povray.org...

>   In this particular case, however, I have the feeling that an observed
> phenomenon (gravity) is tried to forcefully be fit into an existing theory
> (quantum mechanics) even though it's contradicting it. In other words,
> the theory is that "everything must be quantized", and they are observing
> that "gravity doesn't seem to be quantized", and rather than revising the
> theory they are trying to forcefully make gravity quantized to fit the
> theory.

In an ideal world, QM should be dead wrong. Unfortunately, it's been
verified beyond any reasonable (and unreasonable) doubt. So what are
physicists to do? If one could revise QM+QED+QCD+SM to fit GR in gracefully,
it would have been done.

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scott <sco### [at] scottcom> wrote:
> >  Well, *usually* science goes through the cycle:
> >
> > 1) We observe some phenomenon,
> > 2) We study and measure the phenomenon.
> > 3) We formulate hypotheses, and if these hypotheses can make enough 
> > accurate
> >   predictions which match new observations, they are made into theories.
> > 4) If new observations and measurements contradict the existing theories,
> >   they are revised, or entirely new hypotheses are formulated, so we go
> >   back to step 1.

> Didn't Einstein predict black holes before we found any?

  That would be step #3 above.

  What Einstein did not do is to observe a black hole, notice that it did
not conform to his theory, but tried to make it conform anyways.

  That's what I feel QM is doing.

-- 
                                                          - Warp

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Invisible <voi### [at] devnull> wrote:
> It's not uncommon for a new theory to explain observed phenomina but 
> also predict something that nobody has seen before.

  Actually that's one of the requisites in order to change a hypothesis into
a theory. (Ok, not a requisite per se, but if it the hypothesis does predict
something and later it results that the prediction was correct, that's a
strong incentive into making the hypothesis a theory.)

-- 
                                                          - Warp

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somebody <x### [at] ycom> wrote:
> In an ideal world, QM should be dead wrong. Unfortunately, it's been
> verified beyond any reasonable (and unreasonable) doubt.

  *Part* of it has been verified. As we have seen, it's currently unsuitable
to explain everything.

-- 
                                                          - Warp

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>  What Einstein did not do is to observe a black hole, notice that it did
> not conform to his theory, but tried to make it conform anyways.
>
>  That's what I feel QM is doing.

Maybe I missed something, but has anything been observed with regard to 
gravity that doesn't conform to QM?  I thought the issue is with gravity 
that they just haven't been able to come up with a way to prove or disprove 
the predictions that QM makes.

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scott wrote:
> Maybe I missed something, but has anything been observed with regard to 
> gravity that doesn't conform to QM?  I thought the issue is with gravity 
> that they just haven't been able to come up with a way to prove or 
> disprove the predictions that QM makes.

I thought that QM simply doesn't describe gravity *at all*, and that was 
the problem.

Then again, I know nothing about QM, so.....

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Warp wrote:
>   In this particular case, however, I have the feeling that an observed
> phenomenon (gravity) is tried to forcefully be fit into an existing theory
> (quantum mechanics) even though it's contradicting it.

The basic "faith" of science is that physical laws are consistent 
everywhere, everywhen, etc.  (Except perhaps for singularities like black 
holes or the big bang or whatever.)  The assumption, in other words, that 
the *true* theory of gravity is consistent with the *true* theory of QM is 
taken on faith.

Since QM is much, much easier to measure, we have much, much better evidence 
that it's correct at the energies well below LHC levels. Since QM seems very 
correct, the assumption is that at levels where we can't currently measure 
gravity, it's likely to act like QM does.

> the theory is that "everything must be quantized", and they are observing
> that "gravity doesn't seem to be quantized", and rather than revising the
> theory they are trying to forcefully make gravity quantized to fit the
> theory.

They *are* revising the theory. It's the theory of gravity they're revising.

I think there are also constant revisions of QM being proposed that 
harmonize it with gravity. I've seen people suggest that gravity is caused 
by the nearness of QM "multi-worlds", or that string theory predictions that 
relate the two, etc.

> and devising a new theory which does fit observed phenomena.

In what way is quantum gravity not devising a new theory? The problem you're 
seeing, I think, is that it's easier to measure QM effects than gravity 
effects, since gravity is many orders of magnitude weaker than the weakest 
QM interaction.

-- 
Darren New, San Diego CA, USA (PST)
   Human nature dictates that toothpaste tubes spend
   much longer being almost empty than almost full.

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Invisible wrote:
> I thought that QM simply doesn't describe gravity *at all*, and that was 
> the problem.

There are a number of different theories of "QM", depending on what you're 
looking at.

QM of photons interacting with electrons is QED, Quantum Electrodynamics. 
That covers everything but nuclear reactions and gravity. I.e., all of 
chemistry and everything that's based on chemistry, as well as why electrons 
"orbit" the nucleus, *why* the periodic table of elements is how it is, 
electricity, friction, lasers, pauli exclusion, partial and total 
reflections, diffraction gratings, polarization, etc.

There's a kind of QM (whose name I don't know) that accounts for the strong 
and weak nuclear forces. It has muons an mesons and stuff like that acting 
like photons, with neutrons and protons acting like electrons, and etc. (I'm 
probably messing all that up, but...) It's essentially the same formula with 
different numbers plugged in. This theory is not so well confirmed, because 
the numbers are a couple orders of magnitude bigger - i.e., the same 
difference between a chemical bomb and a nuclear bomb.

QCD is quantum chromodynamics, which I think accounts for all the different 
subatomic particles based on quarks. Again, it's essentially the same 
process, with a few extra kinds of numbers thrown in (but which behave the 
same way). Kind of like having polarization in other directions.

So given that every other "action at a distance" seems to follow the same 
basic formulas and seems to move at the speed of light, and that gravity 
itself seems to move at the speed of light, it's not surprising that gravity 
is thought to maybe follow the same basic formulas.

Just like people thought photons were waves because they followed the same 
basic formulas as waves do, but it turns out they're 100% always particles, 
it's sort of like gravity perhaps follows the same math as curved space 
time, but maybe is exchange particles after all.  I have never heard of us 
actually measuring actual curved space-time unambiguously. I'd be interested 
in hearing if we did.

Or, it's possible that gravity works in a way that's just incompatible with 
QM and the two physically cannot be unified regardless of theory chosen. :)

-- 
Darren New, San Diego CA, USA (PST)
   Human nature dictates that toothpaste tubes spend
   much longer being almost empty than almost full.

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Warp wrote:
> somebody <x### [at] ycom> wrote:
>> In an ideal world, QM should be dead wrong. Unfortunately, it's been
>> verified beyond any reasonable (and unreasonable) doubt.
> 
>   *Part* of it has been verified. As we have seen, it's currently unsuitable
> to explain everything.

What's missing in QM? Or, rather, what has QM predicted that it's unsuitable 
to explain?

That QM doesn't explain relativity doesn't mean QM is wrong. It just means 
it doesn't explain QM, any more than relativity explains nuclear reactions.

-- 
Darren New, San Diego CA, USA (PST)
   Human nature dictates that toothpaste tubes spend
   much longer being almost empty than almost full.

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Darren New wrote:

> QM of photons interacting with electrons is QED, Quantum 
> Electrodynamics. That covers everything but nuclear reactions and 
> gravity. I.e., all of chemistry and everything that's based on 
> chemistry, as well as why electrons "orbit" the nucleus, *why* the 
> periodic table of elements is how it is, electricity, friction, lasers, 
> pauli exclusion, partial and total reflections, diffraction gratings, 
> polarization, etc.

Wait, back up a sec - you mean there's a *reason* why the transition 
metals exist? And people actually know WTF this reason is??

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Orchid XP v8 wrote:
> Wait, back up a sec - you mean there's a *reason* why the transition 
> metals exist? And people actually know WTF this reason is??

Yes.

-- 
Darren New, San Diego CA, USA (PST)
   Human nature dictates that toothpaste tubes spend
   much longer being almost empty than almost full.

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>> Wait, back up a sec - you mean there's a *reason* why the transition 
>> metals exist? And people actually know WTF this reason is??
> 
> Yes.

OK, that's quite impressive.

Last time I heard, an atomic nucleous has a cloud of electrons floating 
around it. (Seems reasonable - they're negatively charged, while the 
nucleous is positively charged. Why wouldn't they orbit it?) Except that 
rather than just floating around, they all stay 100% rigidly confined to 
a discrete set of orbit shells. (Um, WTF? Why?) And the inner-most shell 
can only hold 2 electrons (OK), the next shell can only hold 8 (um... 
OK), and next one out also holds 8 (er... why?), and the next shell can 
contain up to 18 electrons but when you start filling that shell you can 
only fill it up to a certain point, and then you have to go back and 
fill the shell below and then you can finish filling this shell (WTF?!) 
And the shell numbers are apparently just plucked out of the air, and 
the shell filling orders are completely arbitrary. And this is all 
assuming an atom with zero energy; apparently real atoms have more 
energy than that, which causes electrons to migrate between different 
shells, and when one falls back to a lower shell it emits energy 
(usually in the form of EMR). And don't even get me started on chemical 
bonding...

It all seems wildly complicated and completely random.

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Invisible wrote:
>>> Wait, back up a sec - you mean there's a *reason* why the transition
>>> metals exist? And people actually know WTF this reason is??
>>
>> Yes.
> 
> OK, that's quite impressive.
> 
> Last time I heard, an atomic nucleous has a cloud of electrons floating
> around it. (Seems reasonable - they're negatively charged, while the
> nucleous is positively charged. Why wouldn't they orbit it?) Except that
> rather than just floating around, they all stay 100% rigidly confined to
> a discrete set of orbit shells. (Um, WTF? Why?) And the inner-most shell
> can only hold 2 electrons (OK), the next shell can only hold 8 (um...
> OK), and next one out also holds 8 (er... why?), and the next shell can
> contain up to 18 electrons but when you start filling that shell you can
> only fill it up to a certain point, and then you have to go back and
> fill the shell below and then you can finish filling this shell (WTF?!)
> And the shell numbers are apparently just plucked out of the air, and
> the shell filling orders are completely arbitrary. And this is all
> assuming an atom with zero energy; apparently real atoms have more
> energy than that, which causes electrons to migrate between different
> shells, and when one falls back to a lower shell it emits energy
> (usually in the form of EMR). And don't even get me started on chemical
> bonding...
> 
> It all seems wildly complicated and completely random.

And now you can see that the electrons are actually in those fields.
http://insidescience.org/research/first_detailed_photos_of_atoms

I had done the math in chem class, I could understand that this model
worked and predicted everything we knew, but seeing these images is
still a stunner.

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Invisible wrote:
> Last time I heard, an atomic nucleous has a cloud of electrons floating 
> around it. (Seems reasonable - they're negatively charged, while the 
> nucleous is positively charged. Why wouldn't they orbit it?) 

Because they're oppositely charged, and therefore would be attracted far too 
hard towards the nucleus for centripital force to hold them out.

> Except that 
> rather than just floating around, they all stay 100% rigidly confined to 
> a discrete set of orbit shells. (Um, WTF? Why?) 

Because of the fermi exclusion principle, and the fact that they *are* 
quantum particles, and there's only so much "room" that close to the 
nucleus. (Where "room" is measured in terms of possible quantum states.)

 > And the inner-most shell
> can only hold 2 electrons (OK), the next shell can only hold 8 (um... 
> OK), and next one out also holds 8 (er... why?), and the next shell can 
> contain up to 18 electrons but when you start filling that shell you can 
> only fill it up to a certain point, and then you have to go back and 
> fill the shell below and then you can finish filling this shell (WTF?!) 

Yep.

> And the shell numbers are apparently just plucked out of the air, and 
> the shell filling orders are completely arbitrary. 

No. It's just relatively complicated math.

> It all seems wildly complicated and completely random.

Well, somewhat random and fairly complicated when you look at the results of 
the arithmetic, yes. It's all based on sums of infinite series of complex 
numbers, where the values of the individual complex numbers are based on 
what particles are interacting and where (in 4-D space) they are.

But you're looking at stuff like "A handful of the dots move relative to the 
background, and sometimes even go backwards (WTF?) but most don't, except 
some show up every 76 years and they aren't even round, and then there's 
this big one that changes shape over the course of a month. It all seems 
wildly complicated and completely random."  And you're missing orbital 
mechanics, which is a small handful of simple math.

-- 
Darren New, San Diego CA, USA (PST)
   Human nature dictates that toothpaste tubes spend
   much longer being almost empty than almost full.

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Invisible wrote:
> And the inner-most shell
> can only hold 2 electrons (OK), the next shell can only hold 8 (um...
> OK), and next one out also holds 8 (er... why?), and the next shell can
> contain up to 18 electrons but when you start filling that shell you can
> only fill it up to a certain point, and then you have to go back and
> fill the shell below and then you can finish filling this shell (WTF?!)
> And the shell numbers are apparently just plucked out of the air, and
> the shell filling orders are completely arbitrary.

I recall it's 2 * n^2

2, 8, 18, 32...

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