Energy is matter, matter is energy, it must be in one form or the other
Matter is a different thing than mass, and much more difficult to define. Energy is mass and mass is energy, and it's not that it must be one or the other, they are literally the same thing. Matter is generally things we consider to have rest mass, which isn't the same as mass. Rest mass is a form of energy (and thus mass, duh).
What you said about butane is right; it's heavier. It's not that there's more matter, but there is more mass, i.e. energy.
The potential energy of the weak nuclear force is what is exploited in nuclear fission. It was just an odd way of saying that us 'mericans are scared of teh nucular bogey mon.
So in the end, your comments sound like the same kind of navel-gazing that says "math is everywhere".... "Look, Bobby, see the Golden Ratio in the structure of this leaf? Math is everywhere!" "No dad, that is not math. That is a leaf. Math is how you think about the leaf."
Right. The leaf can be described by math. Math is the description, an abstract representation of the concept of how the leaf is structured.
A computer program is nothing more than an abstract representation of mathematical operations. "a:= b + c" is exactly the same as "ADD R1, R2, R3". Only the syntax is different. Convert that assembly instruction into binary so a computer understands it, and it is still nothing more than an abstract symbolic representation of a mathematical expression.
Most people write computer programs not because they want to run some clever bit of lambda calculus, but because they want to perform some function on information that can be applied in the real world. You can call it math if you want, but if I can write a program to do what I want to do, it makes no difference to me if it's math or not.
Well it is math, and it would help you in your quest to "perform some function on information", i.e. do math, if you realized that. Understanding the mathematical underpinning is quite useful for writing software. You can't study algorithms and their optimization and not study math; they're one and the same. How can you even conceive of determining a logically equivalent but simpler method of performing the same calculation without realizing that you are doing math? Okay you could just not think about it. But you're doing math.
To me a computer is not math, it's a physical tool designed to perform a job, just like a power drill, a tractor, or a cuckoo clock. They just work differently.
A computer is not math. A computer is a device which understands a mathematical language and can perform mathematical operations. A computer program is the math that you want the computer to perform. A computer is like a calculator. A program is like the sequence of buttons you push on the calculator to make it do math.
Being able to simulate and model something at a low level doesn't give you a high level understanding. A mathematician understands boolean logic, but that doesn't mean he has the knowledge and skills to design a CPU or program it. That knowledge and those skills aren't taught in mathematics, they are taught in computer science.
Yes, you are completely correct to say that the specific disciplines necessary to write computer programs, or to design a CPU (which is a combination of computer science and electrical engineering), are not taught in traditional mathematics programs in universities.
Nevertheless, computer programs are math, and nothing more.
Is math and is covered by mathematics degree programs are completely orthogonal properties.
No, look, invariant mass isn't the same thing as mass. The energy-momentum four-vector isn't the same thing as energy, which is a scalar. Energy is the same thing as mass. The amount of energy in a system is the same as its mass, and only by recognizing this can you correctly account for the mass of a system. When you're talking about the stress-energy tensor, you're calculating energy density and momentum flux, which also isn't the same as energy itself.
i guess in nuclear fission, no matter is converted in energy either because no protons neutrons and electrons are destroyed in the process.
Yes, that's exactly correct. Matter != mass. The mass of a uranium atom is greater than the rest mass of the protons etc that comprise it. The total mass of the fission byproducts, if you allow the fission energy to escape (as is usually the case) is less than what you started with.
Assembly language doesn't have a notion of types. For example, the Python expression [x + 5 for x in some_list] starts with a list (or other iterable item) and ends with a list. Assembly language has to explicitly loop over the elements, apply the operation, write back the result, and hope the rest of the program treats it as a list.
Or, in assembly, you could implement functions which verify the type of parameters and branch to exception code if they don't match. Which is exactly what Python is doing under the hood -- implementing these type checks in Assembly. Everything is ultimately in Assembly, because that's the only mathematical language the processor understands.
If you fool the type checks, and pass a function a value that is not of the expected type, then it will still operate on it as if it was. Because it's all just bits, and the function operates on bits.
Are there any known ways to convert "mass" not "rest mass" to kinetic energy?
Kinetic energy is mass. The earth is more massive due to its rotation than it would be otherwise.
Energy is mass. So when you ask "are there ways to convert 'mass' not 'rest mass' to kinetic energy', you're asking "are there ways to convert energy that isn't in the form of rest mass into kinetic energy" and the answer is yes, depending on the kind of energy, in a variety of ways you're already familiar with.
To equate mass with energy is an outrageous abuse of the terminology.
Except that is exactly what Einstein meant and has been verified experimentally, so anything but equating mass with energy is the abuse. We often refer to rest mass as mass because it is convenient and mostly correct in most situations we care about, but it is not truly accurate.
There is no mass other than invariant mass, the norm of the energy-momentum four-vector. Energy is the timelike component of the four-vector. They are plainly not equal.
Mass and invariant or rest mass are not the same thing. Energy always exhibits mass in any form, regardless of whether or not it has invariant mass. The planet earth exhibits a greater mass than its rest mass, and thus a greater gravitational attraction, due to its angular kinetic energy. If you only account for the earth's invariant mass, then you get the wrong answer. If you are calculating the weight of a block of uranium, and you only account for the invariant mass of the particles therein, you get the wrong answer. If you sum up the rest mass of the particles before fission and afterwards, then they are the same, but the total mass is less, because mass was lost in the form of energy.
No, particles are actually energy. Matter and energy are equivalent. Mass is just one form of energy
I think you meant "mass and energy are equivalent. Matter is just one form of energy". Energy and mass are the same thing. Some mass/energy is in the form of matter. Just trying to avoid confusion.
What E=mc^2 actually means is that energy includes a term involving mass. If you wanted to count up all the energy in something, you have to include some that is due to mass-energy. So suppose you want to get a bunch of kinetic energy to blow something up. One way to do that is to convert some chemical potential energy into kinetic energy; that's how dynamite works. Einstein is saying that there's another way: by converting some mass energy into kinetic energy; that's how a nuclear bomb works.
No, what it means are that mass and energy are literally the same, and "mass-energy" is redundant. An object with kinetic energy has more mass than an object with no kinetic energy. A compound with stored chemical energy has more mass than the elements that comprise the compound on their own. An atomic nucleus containing many protons and neutrons has more mass than the sum of those protons and neutrons individually.
Some things have a property called rest mass, which is different than mass. The "term involving mass" in energy calculations that you're thinking of is related to the rest mass (which is represented by m0, not just m). But in every dynamic system, if you use the rest mass instead of the mass when mass is called for, you will get the wrong answer.
Nuclear bombs don't actually convert mass into energy in any way different than that of chemical reactions. In both cases the mass that was lost was the mass of the energy that was released.
To suggest it is anything OTHER than mathematics is to prove you have absolutely no idea how computers actually work. In the real world- every computer is a universal turing machine. If you have any real doubt - just consider this: any program COULD be written in lisp. Lisp is DIRECTLY based on lambda-calculus - in fact the ONLY (minor) difference as small syntactical changes designed to make it easier to TYPE lambda on a computer (it was after-all designed for writing in).
That may satisfy the folks who can only recognize math if it is syntactically nearly identical to the math they would do with a pencil and paper. And it's a fine comparison to make, but as I'm sure you know it's not necessary.
For folks who deal with computers at a lower level and aren't confused by divergent syntax, consider a computer ISA.
An ISA is really just a description of a bunch of valid mathematical operators and the operations they perform. There's no reason that the ISA requires hardware that directly implements that ISA, or for that matter a computer of any kind, as long as the math is faithfully performed. That's what makes simulators like Simnow possible, because everything a computer does is just math and can be translated into any equivalent math and you'll get the same result. Even including the IO, since even the behavior of the hard drive, at least as it appears to a program, is simply a mathematical operation.
It's true that currently the most popular languages do not follow the lisp "look like the function you are" structure
I'm not sure I follow you there... the mathematical operations that comprise a function is the function it is, and nothing looks more like that than the underlying assembly. I do get the advantages of functional programming for multithreaded programming, just not sure what you're saying there.
Have a beer. That should take care of that final, pesky cell.
Believe me, there have been many such attempts on its life, and it has survived them all and come out stronger and more resilient. Following the Cliff Clavin Theory of Drinking, this is the most lean, efficient, and bad-ass brain cell in history. It is equal to a hundred normal brain cells. If my brain was a computer simulation, it would be The One.
It's still just one lonely brain cell though. Back to trying to kill it with beer!
The "older" standard is only tabs for indentation - You and Linus belongs in this camp:
Tabs are 8 characters, and thus indentations are also 8 characters.
Actually they aren't in the same camp.
Linus correctly observes that tabs are 8 characters in many contexts, and he's saying both that you use tabs and that indentation should be 8 characters. In this camp, it is almost irrelevant whether you use tabs or spaces because either way the indent spacing is defined to be 8 characters. Thus consistent formatting is possible.
The GP is in the "let's use tabs so we can each define our own code indentation level!" which breaks as soon as you try to do any formatting other than indenting new blocks.
Linus' camp is actually much closer to the "define an indent level and uses spaces" camp.
Personally I don't really care how much indentation is used, I want to view the code as the author intended, just like when reading a book.
Thus was created "indent", which converts code from all those other people's atrocious formatting styles into your preferred on and back.
Indent only indents, it doesn't insert or delete newlines or insert whitespace where needed to line things up for clarity. Ergo it fails at its job, as do tabs.
Yeah, yeah...this is religion to some. My argument is as moot as yours. Kinda what I'm pointing out.
Naw. How much to indent is a pointless religious argument. How wide the screen should be is pointless. Curly braces for new blocks on the same line as the if() or method declaration or their own line is a similar issue.
However, all those other issues are only unimportant arguments if you can get consistent formatting from the result by using spaces and not tabs.
It's pretty much the only argument that matters.:P
Thank you. People who indent with spaces should be shot. Indent with tabs all you want and I can view it the way I want (2 space, 4 space, etc.).
And the way you view it, if different than mine, will be broken and badly formatted and it won't be my fault, but yours.
How many characters wide is your screen? How many levels of indentation can you have, or how many intelligently-named variables can you have in a single if(), before you need to reformat the code (by using a multi-line if() for example)? Well, depending on how you use tabs and how wide your screen is, then my code could wrap well past your screen, or the next level of indentation could be before the second line of the if(). The code looks bad.
Correct and consistent formatting across viewing platforms and viewers is more important than each viewer being able to see it the "way they want". Why is "the way you want" to have exactly N spaces, and not to see the code as everyone else sees it, properly formatted as the author intended?
There's two basic aspects that inform code formatting: 1) page width 2) indent amount
The choice of where to break lines does not scale as a constant ratio of these two factors. That is why tabs -- at least, tabs that you change to suit your preferences rather than to an agreed upon value (which would be 8) -- cannot result in uniformly good formatting.
No. You indent by tabs to the correct level, and add spaces for effect afterwards where necessary. Even if you end up adding more spaces than a tab width. That way it looks right no matter the tab width.
And then they set their tab width to something less than you did, and then the next level of indentation is indented less than your split line. It no longer looks right, it now looks the opposite of right, as in wrong.
Tabs break things. If you use any tab stop other than exactly 8 spaces, and mandate that everyone else does to, you will break code formatting for someone, somewhere (terminals and line printers use 8-space tabs). And mandating 8 space-tabs breaks the alleged "advantage" of tabs in the first places.
Tabs are broken. Spaces are the only way to ensure anyone viewing your code will see it correctly formatted. This is vastly more important than being able to tailor other peoples' code to your preference.
With tabs each person can set their tabstop however they want.
And if they want it to look right, they need to set it to exactly what the original author did. Every time you decide to break up a line of code, you're making a decision that locks the reader into a particular spacing in order to have legible code.
Do you want to have legible code? Yes? Use spaces then. And if you can't handle reading code that doesn't use your "preferred" spacing, then it is you, not the code author, who has the puppy-killing control issues.
Slashdot Mirror
Duh, that was a late night brain fart of a post.
Energy is matter, matter is energy, it must be in one form or the other
Matter is a different thing than mass, and much more difficult to define. Energy is mass and mass is energy, and it's not that it must be one or the other, they are literally the same thing. Matter is generally things we consider to have rest mass, which isn't the same as mass. Rest mass is a form of energy (and thus mass, duh).
What you said about butane is right; it's heavier. It's not that there's more matter, but there is more mass, i.e. energy.
The potential energy of the weak nuclear force is what is exploited in nuclear fission. It was just an odd way of saying that us 'mericans are scared of teh nucular bogey mon.
So in the end, your comments sound like the same kind of navel-gazing that says "math is everywhere" .... "Look, Bobby, see the Golden Ratio in the structure of this leaf? Math is everywhere!" "No dad, that is not math. That is a leaf. Math is how you think about the leaf."
Right. The leaf can be described by math. Math is the description, an abstract representation of the concept of how the leaf is structured.
A computer program is nothing more than an abstract representation of mathematical operations. "a := b + c" is exactly the same as "ADD R1, R2, R3". Only the syntax is different. Convert that assembly instruction into binary so a computer understands it, and it is still nothing more than an abstract symbolic representation of a mathematical expression.
Most people write computer programs not because they want to run some clever bit of lambda calculus, but because they want to perform some function on information that can be applied in the real world. You can call it math if you want, but if I can write a program to do what I want to do, it makes no difference to me if it's math or not.
Well it is math, and it would help you in your quest to "perform some function on information", i.e. do math, if you realized that. Understanding the mathematical underpinning is quite useful for writing software. You can't study algorithms and their optimization and not study math; they're one and the same. How can you even conceive of determining a logically equivalent but simpler method of performing the same calculation without realizing that you are doing math? Okay you could just not think about it. But you're doing math.
To me a computer is not math, it's a physical tool designed to perform a job, just like a power drill, a tractor, or a cuckoo clock. They just work differently.
A computer is not math. A computer is a device which understands a mathematical language and can perform mathematical operations. A computer program is the math that you want the computer to perform. A computer is like a calculator. A program is like the sequence of buttons you push on the calculator to make it do math.
Being able to simulate and model something at a low level doesn't give you a high level understanding. A mathematician understands boolean logic, but that doesn't mean he has the knowledge and skills to design a CPU or program it. That knowledge and those skills aren't taught in mathematics, they are taught in computer science.
Yes, you are completely correct to say that the specific disciplines necessary to write computer programs, or to design a CPU (which is a combination of computer science and electrical engineering), are not taught in traditional mathematics programs in universities.
Nevertheless, computer programs are math, and nothing more.
Is math and is covered by mathematics degree programs are completely orthogonal properties.
No, look, invariant mass isn't the same thing as mass. The energy-momentum four-vector isn't the same thing as energy, which is a scalar. Energy is the same thing as mass. The amount of energy in a system is the same as its mass, and only by recognizing this can you correctly account for the mass of a system. When you're talking about the stress-energy tensor, you're calculating energy density and momentum flux, which also isn't the same as energy itself.
i guess in nuclear fission, no matter is converted in energy either because no protons neutrons and electrons are destroyed in the process.
Yes, that's exactly correct. Matter != mass. The mass of a uranium atom is greater than the rest mass of the protons etc that comprise it. The total mass of the fission byproducts, if you allow the fission energy to escape (as is usually the case) is less than what you started with.
Assembly language doesn't have a notion of types. For example, the Python expression [x + 5 for x in some_list] starts with a list (or other iterable item) and ends with a list. Assembly language has to explicitly loop over the elements, apply the operation, write back the result, and hope the rest of the program treats it as a list.
Or, in assembly, you could implement functions which verify the type of parameters and branch to exception code if they don't match. Which is exactly what Python is doing under the hood -- implementing these type checks in Assembly. Everything is ultimately in Assembly, because that's the only mathematical language the processor understands.
If you fool the type checks, and pass a function a value that is not of the expected type, then it will still operate on it as if it was. Because it's all just bits, and the function operates on bits.
Are there any known ways to convert "mass" not "rest mass" to kinetic energy?
Kinetic energy is mass. The earth is more massive due to its rotation than it would be otherwise.
Energy is mass. So when you ask "are there ways to convert 'mass' not 'rest mass' to kinetic energy', you're asking "are there ways to convert energy that isn't in the form of rest mass into kinetic energy" and the answer is yes, depending on the kind of energy, in a variety of ways you're already familiar with.
To equate mass with energy is an outrageous abuse of the terminology.
Except that is exactly what Einstein meant and has been verified experimentally, so anything but equating mass with energy is the abuse. We often refer to rest mass as mass because it is convenient and mostly correct in most situations we care about, but it is not truly accurate.
There is no mass other than invariant mass, the norm of the energy-momentum four-vector. Energy is the timelike component of the four-vector. They are plainly not equal.
Mass and invariant or rest mass are not the same thing. Energy always exhibits mass in any form, regardless of whether or not it has invariant mass. The planet earth exhibits a greater mass than its rest mass, and thus a greater gravitational attraction, due to its angular kinetic energy. If you only account for the earth's invariant mass, then you get the wrong answer. If you are calculating the weight of a block of uranium, and you only account for the invariant mass of the particles therein, you get the wrong answer. If you sum up the rest mass of the particles before fission and afterwards, then they are the same, but the total mass is less, because mass was lost in the form of energy.
No, particles are actually energy. Matter and energy are equivalent. Mass is just one form of energy
I think you meant "mass and energy are equivalent. Matter is just one form of energy". Energy and mass are the same thing. Some mass/energy is in the form of matter. Just trying to avoid confusion.
What E=mc^2 actually means is that energy includes a term involving mass. If you wanted to count up all the energy in something, you have to include some that is due to mass-energy. So suppose you want to get a bunch of kinetic energy to blow something up. One way to do that is to convert some chemical potential energy into kinetic energy; that's how dynamite works. Einstein is saying that there's another way: by converting some mass energy into kinetic energy; that's how a nuclear bomb works.
No, what it means are that mass and energy are literally the same, and "mass-energy" is redundant. An object with kinetic energy has more mass than an object with no kinetic energy. A compound with stored chemical energy has more mass than the elements that comprise the compound on their own. An atomic nucleus containing many protons and neutrons has more mass than the sum of those protons and neutrons individually.
Some things have a property called rest mass, which is different than mass. The "term involving mass" in energy calculations that you're thinking of is related to the rest mass (which is represented by m0, not just m). But in every dynamic system, if you use the rest mass instead of the mass when mass is called for, you will get the wrong answer.
Nuclear bombs don't actually convert mass into energy in any way different than that of chemical reactions. In both cases the mass that was lost was the mass of the energy that was released.
To suggest it is anything OTHER than mathematics is to prove you have absolutely no idea how computers actually work. In the real world- every computer is a universal turing machine.
If you have any real doubt - just consider this: any program COULD be written in lisp.
Lisp is DIRECTLY based on lambda-calculus - in fact the ONLY (minor) difference as small syntactical changes designed to make it easier to TYPE lambda on a computer (it was after-all designed for writing in).
That may satisfy the folks who can only recognize math if it is syntactically nearly identical to the math they would do with a pencil and paper. And it's a fine comparison to make, but as I'm sure you know it's not necessary.
For folks who deal with computers at a lower level and aren't confused by divergent syntax, consider a computer ISA.
An ISA is really just a description of a bunch of valid mathematical operators and the operations they perform. There's no reason that the ISA requires hardware that directly implements that ISA, or for that matter a computer of any kind, as long as the math is faithfully performed. That's what makes simulators like Simnow possible, because everything a computer does is just math and can be translated into any equivalent math and you'll get the same result. Even including the IO, since even the behavior of the hard drive, at least as it appears to a program, is simply a mathematical operation.
It's true that currently the most popular languages do not follow the lisp "look like the function you are" structure
I'm not sure I follow you there... the mathematical operations that comprise a function is the function it is, and nothing looks more like that than the underlying assembly. I do get the advantages of functional programming for multithreaded programming, just not sure what you're saying there.
You mean that you were unable to make your point without it also being flamebait.
When you put an irrationally absolutist statement into other peoples' mouths, you become guilty of the thing you are accusing them of.
Slashdot is anti-abuse-of-copyright-law or anti-excessive-draconian-copyright-law.
But thanks for demonstrating that good ol' inability to distinguish in black and white.
Have a beer. That should take care of that final, pesky cell.
Believe me, there have been many such attempts on its life, and it has survived them all and come out stronger and more resilient. Following the Cliff Clavin Theory of Drinking, this is the most lean, efficient, and bad-ass brain cell in history. It is equal to a hundred normal brain cells. If my brain was a computer simulation, it would be The One.
It's still just one lonely brain cell though. Back to trying to kill it with beer!
It takes the freedom to take away freedom.
I will never, ever, feel any sympathy for anyone who thinks they are actually less free as a consequence.
I know! Distinguishing between different situations is so hard! It strains my brain cell.
That the GPL is a valid license was never seriously in question.
Certainly not among competent contract lawyers. SCO lawyers might argue it isn't, sure, but that's what I mean.
That's why out of all the GPL cases the EFF has brought, so many are settled out of court and in the EFF's favor.
The "older" standard is only tabs for indentation - You and Linus belongs in this camp:
Tabs are 8 characters, and thus indentations are also 8 characters.
Actually they aren't in the same camp.
Linus correctly observes that tabs are 8 characters in many contexts, and he's saying both that you use tabs and that indentation should be 8 characters. In this camp, it is almost irrelevant whether you use tabs or spaces because either way the indent spacing is defined to be 8 characters. Thus consistent formatting is possible.
The GP is in the "let's use tabs so we can each define our own code indentation level!" which breaks as soon as you try to do any formatting other than indenting new blocks.
Linus' camp is actually much closer to the "define an indent level and uses spaces" camp.
Personally I don't really care how much indentation is used, I want to view the code as the author intended, just like when reading a book.
Thus was created "indent", which converts code from all those other people's atrocious formatting styles into your preferred on and back.
Indent only indents, it doesn't insert or delete newlines or insert whitespace where needed to line things up for clarity. Ergo it fails at its job, as do tabs.
Yeah, yeah...this is religion to some. My argument is as moot as yours. Kinda what I'm pointing out.
Naw. How much to indent is a pointless religious argument. How wide the screen should be is pointless. Curly braces for new blocks on the same line as the if() or method declaration or their own line is a similar issue.
However, all those other issues are only unimportant arguments if you can get consistent formatting from the result by using spaces and not tabs.
It's pretty much the only argument that matters. :P
Thank you. People who indent with spaces should be shot. Indent with tabs all you want and I can view it the way I want (2 space, 4 space, etc.).
And the way you view it, if different than mine, will be broken and badly formatted and it won't be my fault, but yours.
How many characters wide is your screen? How many levels of indentation can you have, or how many intelligently-named variables can you have in a single if(), before you need to reformat the code (by using a multi-line if() for example)? Well, depending on how you use tabs and how wide your screen is, then my code could wrap well past your screen, or the next level of indentation could be before the second line of the if(). The code looks bad.
Correct and consistent formatting across viewing platforms and viewers is more important than each viewer being able to see it the "way they want". Why is "the way you want" to have exactly N spaces, and not to see the code as everyone else sees it, properly formatted as the author intended?
There's two basic aspects that inform code formatting:
1) page width
2) indent amount
The choice of where to break lines does not scale as a constant ratio of these two factors. That is why tabs -- at least, tabs that you change to suit your preferences rather than to an agreed upon value (which would be 8) -- cannot result in uniformly good formatting.
No. You indent by tabs to the correct level, and add spaces for effect afterwards where necessary. Even if you end up adding more spaces than a tab width. That way it looks right no matter the tab width.
And then they set their tab width to something less than you did, and then the next level of indentation is indented less than your split line. It no longer looks right, it now looks the opposite of right, as in wrong.
Tabs break things. If you use any tab stop other than exactly 8 spaces, and mandate that everyone else does to, you will break code formatting for someone, somewhere (terminals and line printers use 8-space tabs). And mandating 8 space-tabs breaks the alleged "advantage" of tabs in the first places.
Tabs are broken. Spaces are the only way to ensure anyone viewing your code will see it correctly formatted. This is vastly more important than being able to tailor other peoples' code to your preference.
With tabs each person can set their tabstop however they want.
And if they want it to look right, they need to set it to exactly what the original author did. Every time you decide to break up a line of code, you're making a decision that locks the reader into a particular spacing in order to have legible code.
Do you want to have legible code? Yes? Use spaces then. And if you can't handle reading code that doesn't use your "preferred" spacing, then it is you, not the code author, who has the puppy-killing control issues.