Darren New wrote:
> Mueen Nawaz wrote:
>> Darren New wrote:
>>> You say this, but it's not actually true.  You cannot distinguish two 
>>> hydrogen atoms as long as you ignore the stuff that lets you 
>>> distinguish them.  Like, say, their positions.
>>
>>     Have to agree with andrel here.
> 
> Hmmmmm.... OK.  I can see that.  How does space-like separation affect 
> that, tho?
> 
space- like is from relativistic physics, the point we are discussing is 
  quantum mechanics. As you know the two are incompatible. So, being a 
formally trained physicist with a 20 year old education, I don't know. ;)

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Alain wrote:
> The data will, of course, include the precise speed and direction of
> every atoms, along with it's mass, magnetic momentum and spin, and how
> it can interact with other atoms and any photons. With that information,
> you can predict where it will be at any time of your choosing within a
> Km radius.
> 

Which leads to the question: Is our universe the real one, or the one
modeled by this giant database existing outside of our perceived space-time?

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Darren New wrote:
> Alain wrote:
>> The data will, of course, include the precise speed and direction of
>> every atoms, along with it's mass, magnetic momentum and spin, and how
>> it can interact with other atoms and any photons. With that
>> information, you can predict where it will be at any time of your
>> choosing within a Km radius.
> 
> You're joking, right? :-)
> 
Why joke? We are already considering a giant computer outside of
space-time. Why not assume it has enough processing power to model all
of the physical forces that the universe requires?

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Darren New nous apporta ses lumieres en ce 2007/11/12 23:52:
> Alain wrote:
>> The data will, of course, include the precise speed and direction of 
>> every atoms, along with it's mass, magnetic momentum and spin, and how 
>> it can interact with other atoms and any photons. With that 
>> information, you can predict where it will be at any time of your 
>> choosing within a Km radius.
> 
> You're joking, right? :-)
> 
Not at all! If you could realy have all of that information for every atoms in 
the univers, you could conceivably be able to predict when a star will apears, 
how long it will live, how it will finish, if it will have planets and how many, 
the exact description of every single one, if it will host any life, and if 
inteligent life will apears. All that for a future star for whitch most of it's 
constituant matter is still contained in several other stars. Star that will 
only start to form in a billion years.

The joke is that: You can't have all of that information, and even if you could 
have it, there is no way that you could possibly process it.

-- 
Alain
-------------------------------------------------
'I had to hit him -- he was starting to make sense.'

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Sabrina Kilian nous apporta ses lumieres en ce 2007/11/13 18:03:
> Alain wrote:
>> The data will, of course, include the precise speed and direction of
>> every atoms, along with it's mass, magnetic momentum and spin, and how
>> it can interact with other atoms and any photons. With that information,
>> you can predict where it will be at any time of your choosing within a
>> Km radius.
>>
> 
> Which leads to the question: Is our universe the real one, or the one
> modeled by this giant database existing outside of our perceived space-time?
Very good question.

-- 
Alain
-------------------------------------------------
"If you see me running, try to keep up."
       ...Back of bomb technician's shirt

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Sabrina Kilian wrote:
> Which leads to the question: Is our universe the real one, or the one
> modeled by this giant database existing outside of our perceived space-time?

Permutation City, by Greg Egan.

Buy it, read it, love it. :-)

-- 
   Darren New / San Diego, CA, USA (PST)
     Remember the good old days, when we
     used to complain about cryptography
     being export-restricted?

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andrel wrote:
> Darren New wrote:
>> Mueen Nawaz wrote:
>>> Darren New wrote:
>>>> You say this, but it's not actually true.  You cannot distinguish 
>>>> two hydrogen atoms as long as you ignore the stuff that lets you 
>>>> distinguish them.  Like, say, their positions.
>>>
>>>     Have to agree with andrel here.
>>
>> Hmmmmm.... OK.  I can see that.  How does space-like separation affect 
>> that, tho?
>>
> space- like is from relativistic physics, the point we are discussing is 
>  quantum mechanics. As you know the two are incompatible. So, being a 
> formally trained physicist with a 20 year old education, I don't know. ;)

Heh. OK, fair enough.

And thank you. I think I've had that misconception for a while. Thanks 
for clearing it up.

-- 
   Darren New / San Diego, CA, USA (PST)
     Remember the good old days, when we
     used to complain about cryptography
     being export-restricted?

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> Not at all! If you could realy have all of that information for every 
> atoms in the univers, you could conceivably be able to predict when a star 
> will apears, how long it will live, how it will finish, if it will have 
> planets and how many, the exact description of every single one, if it 
> will host any life, and if inteligent life will apears. All that for a 
> future star for whitch most of it's constituant matter is still contained 
> in several other stars. Star that will only start to form in a billion 
> years.

Could the machine also tell you exactly what happened in the past?

The key question is if it is possible to predict the exact behaviour of 
every particle based on its current state.  Are there not some things that 
exhibit truly random behaviour?

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scott nous apporta ses lumieres en ce 2007/11/14 03:01:
>> Not at all! If you could realy have all of that information for every 
>> atoms in the univers, you could conceivably be able to predict when a 
>> star will apears, how long it will live, how it will finish, if it 
>> will have planets and how many, the exact description of every single 
>> one, if it will host any life, and if inteligent life will apears. All 
>> that for a future star for whitch most of it's constituant matter is 
>> still contained in several other stars. Star that will only start to 
>> form in a billion years.
> 
> Could the machine also tell you exactly what happened in the past?
Absolutely!
> 
> The key question is if it is possible to predict the exact behaviour of 
> every particle based on its current state.  Are there not some things 
> that exhibit truly random behaviour?
> 
> 
Quantum fluctuations, with it's probability coud, is purely random. But, the 
random range is prety tight, even if it extend almost to infinity.
Take any given electron at rest. You can know it's location within an amstrong 
radius, and you have more than a 99.999999% chance to effectively find it within 
that radius, BUT, there is a non-zero chance to find it at over 1 light-year away.

-- 
Alain
-------------------------------------------------
'Power corrupts. Absolute power is kind of neat, though.'

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