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Warp wrote:
> Darren New <dne### [at] san rrcom> wrote:
>> Warp wrote:
>>> A theoretical question: Can mass be converted to other forms of energy?
Nuclear fission.
Nuclear fusion.
Matter-antimatter annihilation.
In each case the mass lost is accounted for by emitted photons.
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Warp a écrit :
>
> Well, you know what? Go fuck yourself. I'm tired of your condescending
> attitude.
Expert speaking...
Fabien.
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Warp wrote:
> Paul Fuller <pgf### [at] optusnetcomau> wrote:
>> Warp wrote:
>>> Paul Fuller <pgf### [at] optusnetcomau> wrote:
>>>>> Assuming yes, how does this conversion affect angular momentum?
>>>>>
>>>> Simple - a photon carries angular momentum.
>>> Is electromagnetic radiation the only possible form of energy?
>>>
>> No.
>
>> Are you being obtuse ?
>
>> Let me re-phrase that. You are being obtuse. Is it deliberate ?
>
> Why the hell are you constantly trying to turn this into a flamewar?
>
> I asked if mass can be converted to other forms of energy, and if this
> is so, what happens to the angular momentum. Your answer to this was that
> "a photon carries angular momentum". That seems to clearly imply that all
> forms of energy consist of photons. When I ask you if what you are trying
> to say is that all forms of energy consist of photons you call me obtuse.
>
> Well, you know what? Go fuck yourself. I'm tired of your condescending
> attitude.
>
I guess there is an equal and opposite reaction :)
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Darren New wrote:
> Paul Fuller wrote:
>> If 'No' then please provide an explanation or link explaining how any
>> form of energy can be turned into angular momentum in a closed system.
>
> Hold your cat upside down, then drop him. ;-)
>
...into a cardboard box (leather gloves recommended). Close the lid
flaps, overlapping them in such a way as to hold the box closed. Then
check the crisper drawer in your fridge. If any vegetables have
decayed, you should really clean out your fridge more often.
--Sherry Shaw
--
#macro T(E,N)sphere{x,.4rotate z*E*60translate y*N pigment{wrinkles scale
.3}finish{ambient 1}}#end#local I=0;#while(I<5)T(I,1)T(1-I,-1)#local I=I+
1;#end camera{location-5*z}plane{z,37 pigment{granite color_map{[.7rgb 0]
[1rgb 1]}}finish{ambient 2}}// TenMoons
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Warp wrote:
> Paul Fuller <pgf### [at] optusnetcomau> wrote:
>>> Assuming yes, how does this conversion affect angular momentum?
>>>
>> Simple - a photon carries angular momentum.
>
> Is electromagnetic radiation the only possible form of energy?
No. Mass is the only possible form of energy. :-)
--
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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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Warp wrote:
>>> A theoretical question: Can mass be converted to other forms of energy?
>
>> Mass *is* energy. That's where energy is stored. That's why things with
>> lots of kinetic energy are heavier. That's why a helium atom weighs
>> less than four hydrogen atoms. E=mc^2.
>
> That didn't really answer my question.
The answer is "mu". That is the answer that unasks the question.
There is no "other form" of energy. All energy and mass are the same
thing. To ask whether mass can be converted to other forms of energy is
meaningless. All forms of "energy" are sloppy ways of measuring the
change of mass. Kinetic energy is an increase in measured mass. Energy
of atomic fission comes from a decrease in rest mass of the atoms left
behind.
It's like asking if heat can be converted to kinetic energy. Heat *is*
kinetic energy, just going all different directions.
>>> Assuming yes, how does this conversion affect angular momentum?
>> It doesn't. It doesn't go anywhere. It's all the same stuff.
> Since angular momentum is dependent on mass, that means that eg. heat
> has mass?
Yes. As the atoms move faster, they gain mass due to relativistic
increases. Yeah, really.
--
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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Darren New <dne### [at] sanrrcom> wrote:
> There is no "other form" of energy. All energy and mass are the same
> thing. To ask whether mass can be converted to other forms of energy is
> meaningless.
Then wikipedia is horribly wrong, I suppose.
http://en.wikipedia.org/wiki/Energy_conversion
--
- Warp
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Warp nous apporta ses lumieres en ce 2007/10/29 09:32:
> Darren New <dne### [at] sanrrcom> wrote:
>> Warp wrote:
>>> A theoretical question: Can mass be converted to other forms of energy?
>
>> Mass *is* energy. That's where energy is stored. That's why things with
>> lots of kinetic energy are heavier. That's why a helium atom weighs
>> less than four hydrogen atoms. E=mc^2.
>
> That didn't really answer my question.
>
>>> Assuming yes, how does this conversion affect angular momentum?
>
>> It doesn't. It doesn't go anywhere. It's all the same stuff.
>
> Since angular momentum is dependent on mass, that means that eg. heat
> has mass?
>
Absolutely! It's just that in everydays terms, it's to small to be evaluated
using ordinary instruments. Heat is manifested by an increase in the average
motion of the atoms around a resting location. More heat = faster and longer
movements of the atoms. Faster movement = more kynetic energy.
--
Alain
-------------------------------------------------
For here we are not afraid to follow truth wherever it may lead.
Thomas Jefferson
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Darren New wrote:
> Yes. As the atoms move faster, they gain mass due to relativistic
> increases. Yeah, really.
They don't. While to the outside observer there's no visible/relevant
difference between an *apparent* change in mass and an *actual* change
in mass, it's still not the same thing. Even if it gives an identical
measurement at any precision. Why? Because I say so. :P Kind of like
how a rhombus with four equal angles isn't the same thing as a square,
even if it has all the same properties. ;)
--
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean
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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> There is no "other form" of energy. All energy and mass are the same
>> thing. To ask whether mass can be converted to other forms of energy is
>> meaningless.
>
> Then wikipedia is horribly wrong, I suppose.
E=mc^2
Energy and mass are the same thing. You can't take mass and turn it into
energy, because it's the same thing.
The difference between the energy in carbon bonds and the energy in
quickly moving water droplets is where the energy is stored and what
tools you use to measure it. But it's all ultimately mass.
You're asking whether the bits in a void* can be converted into the bits
in a float. The question is in one sense nonsensical: They're all bits,
ones or zeros. The question in another sense is about the
interpretation of the behavior of different patterns assigned arbitrary
meanings by human beings. I answered the former. Wiki answered the latter.
Energy *is* mass. Mass *is* energy. They're the same thing as seen from
different sides, measured with different tools. When Wiki says "you can
convert chemical energy to heat energy", they mean you can change the
tool you need to use to perceive as a human being the mass stored in
different places. They mean "energy that shows up as increased mass
because of a gravitational field can be distinguished from energy that
shows up as increased mass because of the velocity relative to the
observer." They're both increased mass. You can take bits of the mass
(like some of the mass that four hydrogen atoms have in excess of a
helium atom made from the same fundamental particals) and distribute it
into massy photons and massy relativistic increase in speed of air
molecules flying away from the explosion. But the mass is still there.
--
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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Darren New wrote:
> E=mc^2
>
> Energy and mass are the same thing. You can't take mass and turn it into
> energy, because it's the same thing.
Bzz bzzt. 'Equivalent' does not mean 'the same thing'. There is a
definite difference between mass and energy. At the very least, 'mass'
is a subset of 'energy'.
--
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean
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Alain <ele### [at] netscapenet> wrote:
> Absolutely! It's just that in everydays terms, it's to small to be evaluated
> using ordinary instruments. Heat is manifested by an increase in the average
> motion of the atoms around a resting location. More heat = faster and longer
> movements of the atoms. Faster movement = more kynetic energy.
That sounds a bit like saying that a combustion motor *is* a lightbulb
because the energy consumed by both can be measureds in watts.
Common properties don't necessarily make to things the same.
--
- Warp
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Tim Cook wrote:
> Darren New wrote:
>> Yes. As the atoms move faster, they gain mass due to relativistic
>> increases. Yeah, really.
>
> They don't. While to the outside observer there's no visible/relevant
> difference between an *apparent* change in mass and an *actual* change
> in mass, it's still not the same thing.
Err, sorry? Are you trying to make a joke or something?
--
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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Tim Cook wrote:
> Darren New wrote:
>> E=mc^2
>>
>> Energy and mass are the same thing. You can't take mass and turn it
>> into energy, because it's the same thing.
>
> Bzz bzzt. 'Equivalent' does not mean 'the same thing'. There is a
> definite difference between mass and energy. At the very least, 'mass'
> is a subset of 'energy'.
And what energy isn't mass, then, given that E=mc^2 and c is a constant?
--
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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Warp wrote:
> Alain <ele### [at] netscapenet> wrote:
>> Absolutely! It's just that in everydays terms, it's to small to be evaluated
>> using ordinary instruments. Heat is manifested by an increase in the average
>> motion of the atoms around a resting location. More heat = faster and longer
>> movements of the atoms. Faster movement = more kynetic energy.
>
> That sounds a bit like saying that a combustion motor *is* a lightbulb
> because the energy consumed by both can be measureds in watts.
>
> Common properties don't necessarily make to things the same.
They're not the same. But the difference between them isn't the mass.
It's the patterns the mass is moving in, and the interactions.
--
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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Darren New <dne### [at] sanrrcom> wrote:
> They're not the same. But the difference between them isn't the mass.
> It's the patterns the mass is moving in, and the interactions.
You have still refused to answer the question of whether mass can be
converted to other forms of energy.
Saying "no, because mass is energy" is like, when asked the question
"can water be converted into ice", answering "no, because water is ice".
--
- Warp
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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> They're not the same. But the difference between them isn't the mass.
>> It's the patterns the mass is moving in, and the interactions.
>
> You have still refused to answer the question of whether mass can be
> converted to other forms of energy.
>
> Saying "no, because mass is energy" is like, when asked the question
> "can water be converted into ice", answering "no, because water is ice".
All forms of energy are stored as mass. Thus, the only kind of energy is
mass. There are lots of different ways of storing energy in mass (as in,
kinetic energy, heat energy, potential energy, elastic energy, chemical
energy), but they all manifest as mass.
It's like saying "Can H2O be converted into different kinds of water?"
When I say "No, because H2O is water", you say "well, what about Wiki,
that talks about ice and steam and oceans and rain?" They're all H2O.
You can convert rain to steam and steam to ice, but you can't convert
H2O into different kinds of H2O. "Different kinds of energy" are like
"steam" and "rain" and "ice." It's all H2O, so you can't convert water
into different kinds of steam or different kinds of ice.
That's why I said the answer to your question is Mu. It's a category
error to even ask the question. Different kinds of energy are different
arrangements of mass. You can rearrange the mass, but you can't "convert
it to energy".
It's like asking "can you convert photons into different kinds of
electromagnetic radiation?" And then pointing to the Wiki which lists
gamma rays, visible light, and radio waves, and saying "See?"
--
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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Darren New wrote:
> It's like saying "Can H2O be converted into different kinds of water?"
> When I say "No, because H2O is water", you say "well, what about Wiki,
> that talks about ice and steam and oceans and rain?" They're all H2O.
> You can convert rain to steam and steam to ice, but you can't convert
> H2O into different kinds of H2O. "Different kinds of energy" are like
> "steam" and "rain" and "ice." It's all H2O, so you can't convert water
> into different kinds of steam or different kinds of ice.
Ah, but there ARE different kinds of Hâ‚‚O. 2 Deuterium + 1 Oxygen is
still water. XD
--
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean
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Darren New wrote:
> And what energy isn't mass, then, given that E=mc^2 and c is a constant?
Any energy that isn't in the *form* of mass isn't mass. The end.
You're basically saying that all mathematical figures are the same thing
because they're just different representations of sets of points.
--
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean
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Tim Cook wrote:
> Darren New wrote:
>> And what energy isn't mass, then, given that E=mc^2 and c is a constant?
>
> Any energy that isn't in the *form* of mass isn't mass.
Name energy that isn't in the form of mass?
Then explain what E=mc^2 means.
--
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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Darren New wrote:
> Name energy that isn't in the form of mass?
> Then explain what E=mc^2 means.
Light isn't in the form of mass. Sound isn't in the form of mass.
Electricity isn't in the form of mass. Magnetism isn't in the form of
mass. And so forth.
E=mc^2 means that the amount of energy stored in a given mass can be
determined by multiplying the mass by the speed of light squared. It's
like...a bank account. The number in the bank's computer that says how
much is in the bank account is not the same thing as however many
physical dollar bills and change, but they are treated as equivalent.
--
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean
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Tim Cook wrote:
> Darren New wrote:
>> Name energy that isn't in the form of mass?
>> Then explain what E=mc^2 means.
>
> Light isn't in the form of mass.
Yes it is. Photons have mass. Indeed, the reason they go the speed of
light is (sloppily speaking) that they are *all* energy, so they *have*
to go the speed of light just to have mass to hold the energy.
> Sound isn't in the form of mass.
The atoms move to make sound. Sound is kinetic energy, which is mass due
to relativistic movement.
> Electricity isn't in the form of mass.
Electrons move, hence kinetic energy, hence mass.
> Magnetism isn't in the form of mass.
Magnetism consists of photons. Photons have mass.
> E=mc^2 means that the amount of energy stored in a given mass can be
> determined by multiplying the mass by the speed of light squared.
Equally, it says that the amount of energy can be determined by
multiplying the amount of mass by the speed of light squared. That's an
equal sign there. That's how relativity works.
Where does the kinetic energy in a moving asteroid go if I accelerate my
spaceship up to the same speed? Does the stationary observer see more
energy than the observer moving at the same speed? Wouldn't that mean
that energy can be created and destroyed at will, just by moving the
observer without changing the experiment? Do you understand why leaving
a gravity well makes you heavier?
I know what you're trying to say. You're trying to say that there is
energy that's not the equivalent of mass, and that E=mc^2 only applies
to mass, not energy. That's incorrect. Intuitive, but incorrect. Really
and truly. That's why it took so long to be accepted.
--
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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Darren New wrote:
> Tim Cook wrote:
>> Darren New wrote:
>>> Name energy that isn't in the form of mass?
>>> Then explain what E=mc^2 means.
>>
>> Light isn't in the form of mass.
>
> Yes it is. Photons have mass. Indeed, the reason they go the speed of
> light is (sloppily speaking) that they are *all* energy, so they *have*
> to go the speed of light just to have mass to hold the energy.
>
>> Sound isn't in the form of mass.
>
> The atoms move to make sound. Sound is kinetic energy, which is mass due
> to relativistic movement.
>
>> Electricity isn't in the form of mass.
>
> Electrons move, hence kinetic energy, hence mass.
>
>> Magnetism isn't in the form of mass.
>
> Magnetism consists of photons. Photons have mass.
>
>> E=mc^2 means that the amount of energy stored in a given mass can be
>> determined by multiplying the mass by the speed of light squared.
>
> Equally, it says that the amount of energy can be determined by
> multiplying the amount of mass by the speed of light squared. That's an
> equal sign there. That's how relativity works.
>
> Where does the kinetic energy in a moving asteroid go if I accelerate my
> spaceship up to the same speed? Does the stationary observer see more
> energy than the observer moving at the same speed? Wouldn't that mean
> that energy can be created and destroyed at will, just by moving the
> observer without changing the experiment? Do you understand why leaving
> a gravity well makes you heavier?
>
> I know what you're trying to say. You're trying to say that there is
> energy that's not the equivalent of mass, and that E=mc^2 only applies
> to mass, not energy.
No, I'm trying to say that...mass is a specific form of energy, as are
all those other forms of energy, but they aren't each other. Sound is
not light, because it has defining properties that are different.
Otherwise we'd just call everything 'energy'. It's like...number sets.
Energy is the set of all numbers, mass is the set of all positive
integers, light is the set of all negative primes, and so forth. You
can convert one to another with a bit of fiddling, but they aren't
congruent subsets.
--
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean
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Tim Cook wrote:
> Otherwise we'd just call everything 'energy'.
Those who understand how it works *do* call everything "energy". Before
people understood what "energy" is, they called different aspects of the
same thing "energy". Like asking whether the elephant is a rope, or a
tree, or a wall.
People used to think width != height != length != duration, too, but
that isn't right either, and they're all aspects of the same thing.
That's why they call it "spacetime" instead of "space" and "time".
Asking "can mass be converted to different kinds of energy" is like
asking "can different kinds of distances be converted to other kinds of
distances?"
> Energy is the set of all numbers, mass is the set of all positive
> integers, light is the set of all negative primes, and so forth.
No. That's what the = sign means. Heat energy is stored as mass. Nuclear
energy is stored as mass. Kinetic energy is stored as mass. Energy is
mass, mass is energy. All mass is energy, all energy is mass. There
isn't some energy-that-is-mass and some energy-that-isn't-mass and you
can convert between them, because then energy wouldn't be conserved in a
closed system, and an experiment you do here would have different
results than an experiment you do there.
It's like saying "how do I convert my word-processor into a number
cruncher?" You rearrange the patterns of bits. But there's no separate
word processor or number cruncher. It's the same parts (i.e., electrons)
in different places.
Put it this way: Do you believe in the conservation of energy? That
energy cannot be created or destroyed in a closed system? If so, where
does the extra mass come from when you accelerate something close to
relativistic speeds? Where does the energy you used to lift a brick out
of a gravity field go? (I.e., what *is* "potential energy" beyond just
words?)
There's no such thing as "energy" beyond a mathematical concept. The
different kinds of energy are different ways of measuring the same
thing. They are ways of calculating patterns of mass.
In exactly the same way, infrared light is ultraviolet light is gamma
radiation is radio waves. Can you convert infrared light to ultraviolet
light? Sure. You don't even have to do anything to the light. Just start
moving real fast towards the source of the light. They are *identical*,
and asking whether it's possible to convert photons to light waves is
unanswerable, because they really are in every respect the same thing
looked at with two different mathematical mechanisms.
Can you explain what kinetic energy *is*? Can you explain why an object
gains mass as it leaves a gravitational field, or why it seems heavier
to an observer moving relative to it compared to an observer stationary
with respect to it? Can you explain where the kinetic energy of a
falling brick comes from if it started at rest in a gravity field?
--
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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Darren New wrote:
> Asking "can mass be converted to different kinds of energy" is like
> asking "can different kinds of distances be converted to other kinds of
> distances?"
The answer is, simply, 'yes'. Metric distances can be converted to
imperial distances. A few grams of Uranium can be converted to a
heaping mass of heat, light, smoke, radiation, et cetera, but is not
inherently those things.
> No. That's what the = sign means. Heat energy is stored as mass. Nuclear
> energy is stored as mass. Kinetic energy is stored as mass. Energy is
> mass, mass is energy. All mass is energy, all energy is mass.
The important bit of this paragraph is "is stored as". That's a vital
difference.
> It's like saying "how do I convert my word-processor into a number
> cruncher?" You rearrange the patterns of bits. But there's no separate
> word processor or number cruncher. It's the same parts (i.e., electrons)
> in different places.
But it has a different function and appearance. A number cruncher is
not a word processor, in terms of how it is used.
> Put it this way: Do you believe in the conservation of energy? That
> energy cannot be created or destroyed in a closed system? If so, where
> does the extra mass come from when you accelerate something close to
> relativistic speeds? Where does the energy you used to lift a brick out
> of a gravity field go? (I.e., what *is* "potential energy" beyond just
> words?)
I remember reading something along the lines of 'that's what time is'.
Put simply, an object at rest moves through the 'time' dimension at the
speed of light, which is why time appears to slow to nothing for the
object as it approaches c. So that's what potential energy is. Time.
> There's no such thing as "energy" beyond a mathematical concept. The
> different kinds of energy are different ways of measuring the same
> thing. They are ways of calculating patterns of mass.
But they're more than just a mathematical concept, because they are
tangible and can be perceived.
> Can you convert infrared light to ultraviolet
> light? Sure. You don't even have to do anything to the light. Just start
> moving real fast towards the source of the light.
But then you are doing something to the light there; you're changing
your point of reference. ;)
--
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------
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Tim Cook wrote:
> Darren New wrote:
>> Asking "can mass be converted to different kinds of energy" is like
>> asking "can different kinds of distances be converted to other kinds
>> of distances?"
>
> The answer is, simply, 'yes'. Metric distances can be converted to
> imperial distances.
But that's only changing what you call it. That's not changing what it
is. Changing the axis you use when measuring a vector doesn't change
where the vector is.
> A few grams of Uranium can be converted to a
> heaping mass of heat, light, smoke, radiation, et cetera, but is not
> inherently those things.
Uranium isn't radiation, no. But radiation is mass. Asking if uranium
can be turned into different kinds of radiation can be answered "yes".
>> No. That's what the = sign means. Heat energy is stored as mass.
>> Nuclear energy is stored as mass. Kinetic energy is stored as mass.
>> Energy is mass, mass is energy. All mass is energy, all energy is mass.
>
> The important bit of this paragraph is "is stored as". That's a vital
> difference.
No, it's not. It's the same thing, measured a different way. By "is
stored as" I meant it's the same thing - that all energy is in the mass,
that's where it *is*, that's where it *lives* so to speak. There's not a
pile of energy, and a pile of mass, that you convert between, any more
than a vector has an amount of high and an amount of wide that you
convert between by rotating your reference axis. The vector is what it
is (like the mass), and if you measure it in one direction, you get a
little height and a lot of width (like a little kinetic energy and a lot
of potential energy), and if you look at it a different way, you get a
lot of height and a little width. But asking whether the vector itself
can be converted into different kinds of heights and widths is a
category error, because the height and width are "stored as" the vector.
That's why people kept discovering new "forms" of energy, and then over
the years realized they're all the same sort of thing, with heat being
kinetic energy of atoms, and chemical energy being electrostatic energy
of their valence electrons, and so on.
>> It's like saying "how do I convert my word-processor into a number
>> cruncher?" You rearrange the patterns of bits. But there's no
>> separate word processor or number cruncher. It's the same parts (i.e.,
>> electrons) in different places.
>
> But it has a different function and appearance. A number cruncher is
> not a word processor, in terms of how it is used.
But that's how you look at it, not what it inherently is. It's how you
measure the functionality. They're both the same computer. Asking if
mass can be turned into different kinds of energy is asking if the
computer itself (while running both programs) can be turned into a word
processor or a number cruncher. It *is* both those things already,
depending on how you care to measure it. Exactly: Mass is energy,
depending on how it's used. Different forms of energy are different
depending on how they're used, not what they are. It's a mental
category, unrelated to reality. A plant in your garden is only a weed if
you don't want it there.
You can turn mass of one type into mass of a different type. You can
turn neutrons into photons. But it's all mass, and they'll all have the
same total mass when you're done. If you want to speak imprecisely, and
ignore the energy that is rest mass, then yes, you can turn *rest* mass
into energy. But that isn't how physics actually works, any more than
Newton had the laws of motion precisely right. That one is sloppy in
ones definition of "energy" doesn't mean the precise person is
incorrect. :-)
>> Put it this way: Do you believe in the conservation of energy? That
>> energy cannot be created or destroyed in a closed system? If so, where
>> does the extra mass come from when you accelerate something close to
>> relativistic speeds? Where does the energy you used to lift a brick
>> out of a gravity field go? (I.e., what *is* "potential energy" beyond
>> just words?)
>
> I remember reading something along the lines of 'that's what time is'.
> Put simply, an object at rest moves through the 'time' dimension at the
> speed of light, which is why time appears to slow to nothing for the
> object as it approaches c.
Uh, sort of. Not really. That's one way of looking at it,
mathematically speaking. Like changing the axes you use to look at a
vector, and saying "the reason it gets higher is it gets less wide."
> So that's what potential energy is. Time.
Errr, no. Quite the opposite.
Anyway, you didn't answer the question. Do you believe in the
conservation of energy. If so, where does the extra mass come from?
>> There's no such thing as "energy" beyond a mathematical concept. The
>> different kinds of energy are different ways of measuring the same
>> thing. They are ways of calculating patterns of mass.
>
> But they're more than just a mathematical concept, because they are
> tangible and can be perceived.
You're perceiving the interaction of the mass against other mass as
mediated primarily by photon exchange between electrons. They're no more
different than meauring heat in kelvins and heat in farenheit.
This is exactly my point: Energy *isn't* tangible and *can't* be
perceived. Tell me how you perceive potential energy? How you perceive
kinetic energy? Can you look at a lump of coal and perceive the
chemical bond energy in it? No, you have to turn them into some other
form of energy in some other piece of mass for which we have measuring
devices.
>> Can you convert infrared light to ultraviolet light? Sure. You don't
>> even have to do anything to the light. Just start moving real fast
>> towards the source of the light.
>
> But then you are doing something to the light there; you're changing
> your point of reference. ;)
That's my point. It's your point of reference that says mass is
different from energy. If you're moving fast relative to the rock, it
has lots of energy. If you're not, it doesn't. Did the rock change?
--
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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Darren New wrote:
> Warp wrote:
>> Darren New <dne### [at] sanrrcom> wrote:
[snip]
The trouble with this discussion is that it started off with Newtonian
mechanics, and now you're arguing over the finer wording of some of the
consequences of special relativity. And while you're technically right
about the equivalence, you can't really say that a photon has mass
without being more specific - it can have the mass associated with its
energy, but must have no *inertial* mass or relativity doesn't work at all.
Warp was trying to clarify his understanding of momentum (which can be a
tricky concept to separate from energy if you've not learned physics to
quite a high level) and this isn't likely to help him. :-)
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On Mon, 29 Oct 2007 15:17:18 -0500, Warp wrote:
> Then wikipedia is horribly wrong, I suppose.
Wikipedia isn't always right....
Jim
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Warp nous apporta ses lumieres en ce 2007/10/29 16:17:
> Darren New <dne### [at] sanrrcom> wrote:
>> There is no "other form" of energy. All energy and mass are the same
>> thing. To ask whether mass can be converted to other forms of energy is
>> meaningless.
>
> Then wikipedia is horribly wrong, I suppose.
>
> http://en.wikipedia.org/wiki/Energy_conversion
>
No.
Energy stays contant, it's only it's "manifestation" that change, or *how* we
perceive it that change.
--
Alain
-------------------------------------------------
My wife is such a bad cook, in my house we pray after the meal.
Rodney Dangerfield
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Tim Cook nous apporta ses lumieres en ce 2007/10/29 23:29:
> Darren New wrote:
>> Tim Cook wrote:
>>> Darren New wrote:
>>>> Name energy that isn't in the form of mass?
>>>> Then explain what E=mc^2 means.
>>>
>>> Light isn't in the form of mass.
>>
>> Yes it is. Photons have mass. Indeed, the reason they go the speed of
>> light is (sloppily speaking) that they are *all* energy, so they
>> *have* to go the speed of light just to have mass to hold the energy.
>>
>>> Sound isn't in the form of mass.
>>
>> The atoms move to make sound. Sound is kinetic energy, which is mass
>> due to relativistic movement.
>>
>>> Electricity isn't in the form of mass.
>>
>> Electrons move, hence kinetic energy, hence mass.
>>
>>> Magnetism isn't in the form of mass.
>>
>> Magnetism consists of photons. Photons have mass.
>>
>>> E=mc^2 means that the amount of energy stored in a given mass can be
>>> determined by multiplying the mass by the speed of light squared.
>>
>> Equally, it says that the amount of energy can be determined by
>> multiplying the amount of mass by the speed of light squared. That's
>> an equal sign there. That's how relativity works.
>>
>> Where does the kinetic energy in a moving asteroid go if I accelerate
>> my spaceship up to the same speed? Does the stationary observer see
>> more energy than the observer moving at the same speed? Wouldn't that
>> mean that energy can be created and destroyed at will, just by moving
>> the observer without changing the experiment? Do you understand why
>> leaving a gravity well makes you heavier?
>>
>> I know what you're trying to say. You're trying to say that there is
>> energy that's not the equivalent of mass, and that E=mc^2 only applies
>> to mass, not energy.
>
> No, I'm trying to say that...mass is a specific form of energy, as are
> all those other forms of energy, but they aren't each other. Sound is
> not light, because it has defining properties that are different.
> Otherwise we'd just call everything 'energy'. It's like...number sets.
> Energy is the set of all numbers, mass is the set of all positive
> integers, light is the set of all negative primes, and so forth. You
> can convert one to another with a bit of fiddling, but they aren't
> congruent subsets.
>
Energy IS mass! It's just that in everyday experiance, that mass is aparently to
small to be perceived.
Take an electron, accelerate it suficiently, and you can make it's mass grow to
rival that of a TRAIN or even a SUPER TANKER! Where does this mass increase
comes from? Uniquely from the kynetic energy of that speeding electron.
Now, take that electron and make it collide with any other particle. You will
get a HUGE gamma burst. Gamma radiation is light. The kynetic energy mass gets
transformed into light. And remember: light can push objects. It's just that
this push is normaly to small for you to notice, but it can easily be
demonstrated with a very simple experiment.
Take an empty globe of glass, place a needle holding a light rotor made from a
glass axis and holding 3 or 4 blades, white on one side, black on the other.
Place the rotor on the needle. Remove all air from the globe. Have ANY light
shining on that rotor, even a candle light, and the rotor will spinn. That
experiment is over 100 years old!
--
Alain
-------------------------------------------------
An unbreakable toy is useful for breaking other toys.
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Bill Pragnell wrote:
> Warp was trying to clarify his understanding of momentum (which can be a
> tricky concept to separate from energy if you've not learned physics to
> quite a high level) and this isn't likely to help him. :-)
I plead guilty to drifting off-topic on p.off-topic! :-)
--
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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Darren New wrote:
> Bill Pragnell wrote:
>> Warp was trying to clarify his understanding of momentum (which can be
>> a tricky concept to separate from energy if you've not learned physics
>> to quite a high level) and this isn't likely to help him. :-)
>
> I plead guilty to drifting off-topic on p.off-topic! :-)
Ha, that's nothing, they're discussing rendering algorithms further
down. Now that's definitely off-topic for this group... ;-)
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Bill Pragnell wrote:
> Darren New wrote:
>> Bill Pragnell wrote:
>>> Warp was trying to clarify his understanding of momentum (which can
>>> be a tricky concept to separate from energy if you've not learned
>>> physics to quite a high level) and this isn't likely to help him. :-)
>>
>> I plead guilty to drifting off-topic on p.off-topic! :-)
>
> Ha, that's nothing, they're discussing rendering algorithms further
> down. Now that's definitely off-topic for this group... ;-)
But.. if it's off-topic, then doesn't it just belong here? ;)
-- Arttu Voutilainen
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"Alain" <ele### [at] netscapenet> wrote in message
news:47274dcc@news.povray.org...
> ... Gamma radiation is light. The kynetic energy mass gets transformed
> into light. And remember: light can push objects. It's just that this push
> is normaly to small for you to notice, but it can easily be demonstrated
> with a very simple experiment.
> Take an empty globe of glass, place a needle holding a light rotor made
> from a glass axis and holding 3 or 4 blades, white on one side, black on
> the other. Place the rotor on the needle. Remove all air from the globe.
> Have ANY light shining on that rotor, even a candle light, and the rotor
> will spinn. That experiment is over 100 years old!
I saw that experiment in a high-school physics lab three decades ago. I was
mightily impressed -- in fact it was one of my first "WOW" moments in
science. It completely turned my mind to suddenly realise that:
a. Light actually has a mass that exerts force on "solid" matter.
b. Even at typical levels, light's force on macro-scale objects is strong
enough that I could stand in an average lab in an average country-town
high-school and watch a finely-balanced vane turn in a vacuum, impelled by
nothing but light.
Until then, I'd thought that the effects of things down at quantum
dimensions could not be observed so simply at our size.
--
Brian
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Brian Elliott wrote:
> "Alain" <ele### [at] netscapenet> wrote in message
> news:47274dcc@news.povray.org...
>> ... Gamma radiation is light. The kynetic energy mass gets transformed
>> into light. And remember: light can push objects. It's just that this
>> push is normaly to small for you to notice, but it can easily be
>> demonstrated with a very simple experiment.
>> Take an empty globe of glass, place a needle holding a light rotor
>> made from a glass axis and holding 3 or 4 blades, white on one side,
>> black on the other. Place the rotor on the needle. Remove all air from
>> the globe. Have ANY light shining on that rotor, even a candle light,
>> and the rotor will spinn. That experiment is over 100 years old!
>
> I saw that experiment in a high-school physics lab three decades ago. I
> was mightily impressed -- in fact it was one of my first "WOW" moments
> in science. It completely turned my mind to suddenly realise that:
>
> a. Light actually has a mass that exerts force on "solid" matter.
>
> b. Even at typical levels, light's force on macro-scale objects is
> strong enough that I could stand in an average lab in an average
> country-town high-school and watch a finely-balanced vane turn in a
> vacuum, impelled by nothing but light.
>
> Until then, I'd thought that the effects of things down at quantum
> dimensions could not be observed so simply at our size.
>
It is impressive but the understanding that the rotation is caused by
light pressure in the way you recall is incorrect.
The commonly known instrument is a Crookes Radiometer
(http://en.wikipedia.org/wiki/Crookes_radiometer) and the rotation is
due to a thermal effect in the thin gas near the vanes. It is
definitely not a vacuum inside. In fact if the gas pressure is reduced
to approach a vacuum the effect disappears.
Light pressure would not produce a strong enough effect to show up here.
Also you'll find that the white/silver sides rotate towards the light
rather than the reverse that you would expect if the cause was momentum
being transferred by light bouncing off the more reflective side of the
vanes.
The proper explanation can be found in the Wikipedia article.
A true light pressure effect was measured using a Nichols radiometer
(http://en.wikipedia.org/wiki/Nichols_radiometer). Not nearly as
spectacular or easy to produce in the typical classrooms.
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Arttu Voutilainen wrote:
> Bill Pragnell wrote:
>> Darren New wrote:
>>> Bill Pragnell wrote:
>>>> Warp was trying to clarify his understanding of momentum (which can
>>>> be a tricky concept to separate from energy if you've not learned
>>>> physics to quite a high level) and this isn't likely to help him. :-)
>>> I plead guilty to drifting off-topic on p.off-topic! :-)
>> Ha, that's nothing, they're discussing rendering algorithms further
>> down. Now that's definitely off-topic for this group... ;-)
>
> But.. if it's off-topic, then doesn't it just belong here? ;)
Checkmate. You win again, gravity! :-)
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Alain <ele### [at] netscapenet> wrote:
> Take an empty globe of glass, place a needle holding a light rotor made from a
> glass axis and holding 3 or 4 blades, white on one side, black on the other.
> Place the rotor on the needle. Remove all air from the globe. Have ANY light
> shining on that rotor, even a candle light, and the rotor will spinn. That
> experiment is over 100 years old!
AFAIK that's the same kind of flawed experiment as the "measure the weight
of an empty balloon, then fill it with air and then weight it again" which
supposedly demonstrates the weight of air. (In actuality that's completely
silly. It's like trying to demonstrate the weight of water underwater by
weighting an empty balloon and a balloon filled with water: You won't get
any difference. What this air balloon experiment actually demonstrates is
the compressibility of air and that compressed air inside the balloon has
a higher density.)
AFAIK that "experiment" does *not* work in complete vacuum and, moreover,
makes the blades rotate in the wrong direction. The real reason for the
rotation is that the black sides get heated while the white sides don't,
and the heated black sides heat up the air close to them, making the air
push that side of the blade.
AFAIK photon pressure would not be even near enough to cause the rotation
of such small blades with such (relatively) huge mass.
--
- Warp
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And lo on Tue, 30 Oct 2007 14:54:20 -0000, Jim Henderson
<nos### [at] nospamcom> did spake, saying:
> On Mon, 29 Oct 2007 15:17:18 -0500, Warp wrote:
>
>> Then wikipedia is horribly wrong, I suppose.
>
> Wikipedia isn't always right....
Blasphemer! May a thousand sysops poop on your head :-)
--
Phil Cook
--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com
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Brian Elliott wrote:
> Until then, I'd thought that the effects of things down at quantum
> dimensions could not be observed so simply at our size.
Here's another one:
Go into a place selling polarized sunglasses. Hold up two pairs a few
inches apart at right angles. No light comes thru, obviously.
Now, without moving those glasses, put a third one in between at a
45-degree angle. Suddenly, light comes thru.
When I see a ray-tracer do *that*, I'll believe in "using physical
equations". ;-)
--
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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Darren New a écrit :
> Brian Elliott wrote:
>> Until then, I'd thought that the effects of things down at quantum
>> dimensions could not be observed so simply at our size.
>
> Here's another one:
>
> Go into a place selling polarized sunglasses. Hold up two pairs a few
> inches apart at right angles. No light comes thru, obviously.
>
> Now, without moving those glasses, put a third one in between at a
> 45-degree angle. Suddenly, light comes thru.
>
> When I see a ray-tracer do *that*, I'll believe in "using physical
> equations". ;-)
>
If you are really into that kind of things, there is at least a paper
about that here:
http://www.cg.tuwien.ac.at/research/publications/2001/wilkie-2001-crp/
So it has been done, just not in a widely known renderer... Perhaps
because the effect is not so ubiquitous in everyday life yet ;-)
--
Vincent
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On Wed, 31 Oct 2007 16:56:23 +0000, Phil Cook wrote:
> And lo on Tue, 30 Oct 2007 14:54:20 -0000, Jim Henderson
> <nos### [at] nospamcom> did spake, saying:
>
>> On Mon, 29 Oct 2007 15:17:18 -0500, Warp wrote:
>>
>>> Then wikipedia is horribly wrong, I suppose.
>>
>> Wikipedia isn't always right....
>
> Blasphemer! May a thousand sysops poop on your head :-)
Ah, well, that's already happened. (I was a SysOp on CompuServe years
ago <g>)
Jim
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Jim Henderson escribió:
> On Mon, 29 Oct 2007 15:17:18 -0500, Warp wrote:
>
>> Then wikipedia is horribly wrong, I suppose.
>
> Wikipedia isn't always right....
Then edit it.
I hate people saying "don't use wikipedia because it's wrong". Make it
right instead of whining!
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>> Friction against what? Newton's 3rd law...
>
> Against the ground
Equal and opposite torque on the person and the Earth ... angular momentum
is still conserved.
> and the air.
Same for the air - assuming you take the air as being part of the "Earth".
If not, then well you've got an external force on the system and angular
momentum will not be conserved (but at some point the air will have some
other effect on the Earth that will cancel out, the wind can't keep getting
faster and faster for ever).
> Friction causes heat, and the energy for that heat must come from
> somewhere.
> I cannot be produced from nothing.
The heat is produced from the energy you need to maintain the force over
time (ie work done), eg from your food that you use to push your legs, or
the electricity in some electric motor. Without that there would be no
force against the frictional force and the spinning would eventually stop.
Momentum (both angular and linear) is ALWAYS conserved in a system with no
external forces, always always always. It's simply impossible to change the
momentum of a system without applying some external force (or torque).
Energy is also always conserved, but you have to consider ALL the energy
going into and out of the system, including heat, kinetic, any potentials in
gravitational/magnetic fields, chemical etc. Look up the laws of
thermodynamics for further info.
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"Warp" <war### [at] tagpovrayorg> wrote in message
news:472379eb@news.povray.org...
> Ok, here's an easy way of stopping the rotation of an object in a closed
> system:
>
> Construct a cannon on the surface of the object so that it will shoot
> in the direction of the tangent, towards the rotation direction. Shoot
> a heavy-enough object fast enough so that the recoil of this shot will
> stop the rotation of the main object. (If you are worried about possible
> effects of having just one such cannon on the surface of the object then
> just put another identical cannon at the opposite side of the object,
> aimed towards the opposite direction, ie. still at the direction of
> rotation at that side, and fire both cannons simulatenously.)
>
> The projectile is attached to a cable connected to the object at a
> point where the pull caused by the object when it reaches the cable
> length causes an even force on the center of mass of the object. (Such
> a point must exist because there are two extremes: Attaching the cable
> on the object at the point where the cannon is would effectively negate
> the whole operation. However, attaching the cable on the opposite side
> of the object would actually make it start rotating in the opposite
> direction compared to the original one. A balance point must thus exist
> somewhere in between.)
>
> When the projectile has thus been stopped, just pull it back to the
> surface of the object. The rotation of the whole system will have stopped
> without permanently ejecting any material.
>
> (Where did all the angular momentum go? Well, stopping the projectile(s)
> will require energy. The majority of this energy will be dissipated as
> heat from the cable.)
This violates one of the fundamental principles of dynamics, the principle
of conservation of momentum.
When you "pull it back", this will cause the object to start spinning again,
and you'll find that when you have the projectiles back where they started,
the spin will be exactly the same as when you started.
The energy you lost in friction/heat will be identical to the energy you
used to fire the cannons in the first place.
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> So you are effectively saying that regardless of heat produced by
> friction, angular momentum is always conserved.
Yes.
> This would effectively
> make a spinning object an infinite source of energy.
Why infinite? You slow it down until it stops, then how do you propose to
get out any more energy?
Note that this has nothing to do with angular momentum, as the angular
momentum of something else must have been increased the exact same amount as
the momentum of the spinning object was reduced.
Imagine a spinning ball in space, if you grabbed it in your hand (thus
stopping it spinning and creating some friction heat) then the overall
momentum would remain constant - ie you'd start spinning a bit. No momentum
has been lost, that is impossible without any external force (which you
don't have if you're both floating in space). Some of the rotational energy
has been converted to heat though. Do the sums, rotational energy is
1/2*I*w^2 (I is moment of inertia, w is angular velocity in radians per
second), and angular momentum is I*w. You will see that during the
"collision", the energy is reduced even though the momentum remains
constant.
> Two objects with no angular momentum at all collide off-center, and
> they get stuck to each other. The resulting union of masses will start
> spinning because of the collision.
A very good example of conservation of angular momentum... You do realise
that two objects travelling in a straight line "off-center" have non-zero
angular momentum as a system?
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And lo on Thu, 01 Nov 2007 17:49:40 -0000, Nicolas Alvarez
<nic### [at] gmailisthebestcom> did spake, saying:
> Jim Henderson escribió:
>> On Mon, 29 Oct 2007 15:17:18 -0500, Warp wrote:
>>
>>> Then wikipedia is horribly wrong, I suppose.
>> Wikipedia isn't always right....
>
> Then edit it.
>
> I hate people saying "don't use wikipedia because it's wrong". Make it
> right instead of whining!
Except of course when you correct it and someone then reverts your
changes, then you revert it back, and then they revert it, and so on and
so forth until you get fed-up and the wrong information just stays there.
--
Phil Cook
--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com
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On Thu, 01 Nov 2007 14:49:40 -0300, Nicolas Alvarez wrote:
> Jim Henderson escribió:
>> On Mon, 29 Oct 2007 15:17:18 -0500, Warp wrote:
>>
>>> Then wikipedia is horribly wrong, I suppose.
>>
>> Wikipedia isn't always right....
>
> Then edit it.
I'm unwilling to go through the process necessary to set an account up
and become recognised as having good enough information for them. And
with regards to this particular topic, I'm unqualified to submit an
expert opinion on the subject - however, what I recall from my college
courses, the information that's there is not 100% accurate. It would
take me research time and energy (neither of which I have, though I *do*
have mass ;) ) to sufficiently correct the content.
> I hate people saying "don't use wikipedia because it's wrong". Make it
> right instead of whining!
Um, that's not what I said. I do in fact use Wikipedia quite a bit, and
even consider many of the articles to contain sufficient information to
be authoritative on the subject they're about.
At the same time, people pointing to Wikipedia as the end-all be-all of
all knowledge and wisdom is equally as ridiculous.
Jim
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Jim Henderson escribió:
> On Thu, 01 Nov 2007 14:49:40 -0300, Nicolas Alvarez wrote:
>> Then edit it.
>
> I'm unwilling to go through the process necessary to set an account up
> and become recognised as having good enough information for them.
I have done many edits anonymously (most minor, like typos or fixing
links to disambiguation pages). At least, leave a message on the talk
page saying something is wrong.
>> I hate people saying "don't use wikipedia because it's wrong". Make it
>> right instead of whining!
>
> Um, that's not what I said.
I didn't say *you* did, but I heard people saying that many times.
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On Sat, 03 Nov 2007 19:12:42 -0300, Nicolas Alvarez wrote:
> Jim Henderson escribió:
>> On Thu, 01 Nov 2007 14:49:40 -0300, Nicolas Alvarez wrote:
>>> Then edit it.
>>
>> I'm unwilling to go through the process necessary to set an account up
>> and become recognised as having good enough information for them.
>
> I have done many edits anonymously (most minor, like typos or fixing
> links to disambiguation pages). At least, leave a message on the talk
> page saying something is wrong.
There again, I don't have the personal expertise to provide specific
examples - nor the time (I need about another 10 hours per day just to do
the things I'm behind on) or the energy to keep up with the discussion.
>>> I hate people saying "don't use wikipedia because it's wrong". Make it
>>> right instead of whining!
>>
>> Um, that's not what I said.
>
> I didn't say *you* did, but I heard people saying that many times.
Well, in the context of this discussion, it sounded like you were
directing the comment at me.
Jim
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> > Jim Henderson escribió:
> >> On Thu, 01 Nov 2007 14:49:40 -0300, Nicolas Alvarez wrote:
> >>> Then edit it.
> >>
> >> I'm unwilling to go through the process necessary to set an account up
> >> and become recognised as having good enough information for them.
I tried to work on wikipedia.
They say you must have verifiable citations is all. And even though I provided
citation from federation proceedinge (experimental biology) they would not
accept it.
I am not going to into details of the event. But I was convinced that they were
no less than puppets for an evil pharmaceutical industry, and had to give up
trying disseminate real information thru wiki.
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