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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