It really seems to me that his concept of "spread" to measure the orientation of two lines is much less intuitive than angle. The concept of angle is just not hard to grasp compared to this weird construction of dropping perpendicular lines.
And it isn't true that you need calculus to understand cosines and sines, you just need some simple plane geometry (right angle triangles inscribed in circles and so on). You can even plot the cosine and sine functions without calculus.
Yeah I used ePix (on Linux) quite a bit for my thesis, even doing pseudo-3d stuff. It was very attractive being able to write C like code which generates a mathematically accurate postscript figure. I couldn't get it to work properly on OS X though unfortunately. With better 3d functions, this would be such a great tool.
Hmm. I wonder if this thing could output a Keynote presentation. Not sure whether this is much more useful than just using a laptop, but I suppose it could be in some circumstances.
I think there is a point beyond which something becomes too arcane and specialized to be classified as art. To anyone with eyes and a right brain, a work of visual art or music is appreciable almost immediately. A novel may take a few weeks or months to absorb for any reasonably educated person. But a computer program is only accessible to the few who happen to understand that particular language, and the particular problems of the implementation. In the same way, I don't think one could call a long, complicated mathematical proof "art".
What perhaps could be called art is the underlying core of ideas. In the case of programming, these would be the algorithms involved, which can be written in pseudocode, and proved to be optimal and perfect.
In the mathematical case, underneath the mass of symbols are insights (eureka moments) simple enough to be conveyed in a popular book. For example, this popular book explains the beautiful ideas in the proof of the four color theorem (all of the detailed steps are completely understandable with almost no symbols). The actual proof was done mostly on a computer and is practically unreadable by humans.
When you listen to a mathematician talk about their work, you get a sense of the artistry behind the technology.
What happens is that your widgets are paged out of memory if you leave them idle for a long time. It is a bit of a pain in my experience too, but I'm not sure what the solution is.
As an astronomer/physicist, I have to vote for http://www.astro.princeton.edu/~rhl/sm/, which produces graphs which just look much nicer than anything gnuplot or Matlab will spit out (with similar sort of effort, although maybe SM has a slightly weirder scripting language). Not free or open source, but it is, uh, obtainable, if you know what I mean.
Ordinary things are difficult in physics
on
How Ice Melts
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· Score: 1
Reading many of the responses to this post, along the lines of "Well, Duh! Big deal", reminds me of one of the frustrations of studying physics. You go in hoping to understand the mechanisms of, well, everything, and end up discovering that many things ordinary people think are simple are really terribly complex and ill-understood. My mother is not impressed that I can compute the specific heat of a degenerate fermionic gas. If I knew why water boils maybe I could convince her my education wasn't just a load of academic waffle. (Yes, I know it's a phase transition, but it's not understood fundamentally any more than melting).
I think your situation is covered by their model (if you follow their assumptions).
They resolve the grandfather paradox basically by saying you must have been born at some point for the feedback loop to start, so there is actually zero probability that you killed your father when you went back in time.
However they allow for another possibility because the model is quantum mechanical. It is possible for you to kill your father before he met your mother (thus preventing birth of the "baby you" in that timeline), but there must be a separate quantum possibility that you didn't kill your father, in superposition. In this case it seems that in order for consistency, the step backwards in time has to undo the killing of your father. (The fact that the backwards time travel has to perform this "undoing" for consistency seems pretty ad hoc - do they want to postulate this as an extra quantum rule or something?).
Anyway, I think your Strauss example could work in their model if there are two quantum timelines, in one of which Strauss composed the work from scratch, whereas in the other Strauss was given the score by you coming from the future (where you picked up the score in a music shop). In travelling back in time you would have to do this special step of undoing your education of Strauss and all the subsequent events. There is no paradox then because the timeline in which Strauss composed his work from scratch (and you were born hundreds of years later, found the score in a shop, built a time machine etc.) is still in existence, in superposition (it must exist in their model, which is how they get around the grandfather paradox too).
We introduce a quantum mechanical model of time travel which includes two figurative beam splitters in order to induce feedback to earlier times. This leads to a unique solution to the paradox where one could kill one's grandfather in that once the future has unfolded, it cannot change the past, and so the past becomes deterministic. On the other hand, looking forwards towards the future is completely probabilistic. This resolves the classical paradox in a philosophically satisfying manner.
Here's an idea. Instead of providing a surface to scatter off by rotating a surface in space, fill a vessel full of some gas and focus two lasers at the point you want to scatter the light. Arrange for the freqencies of the two beams to add up to the frequency of a transition from the ground state of the atoms in the gas to an excited state. Photons should be produced where the beams intersect. Then you could make an image by just scanning through the volume intersecting the beams in a grid. Conceivably color could be provided with a mixture of gases and various lasers.
Think about how this constitutes positive evidence for the theory of evolution. Consider how it says nothing whatsoever about the ID hypothesis, and what this implies about the nature of ID "science".
Being a virgin beats having your genitals infected with STDs, being completely pussy whipped by some fucking idiot whore, and destroying your life with obese parasitic pyschotic kids. Masturbation gives you a 10 times better orgasm and you don't feel guilty afterwards. And acne is fun to pop.
I can't believe Monsieur Cousteau actually used the words "retarded cousin". I suspect that's the american author of the article paraphrasing badly. French people don't use the word "retarded" to draw laughs. That's just in America, where the snickering "humour" of mindless frat-boy types (i.e. delightful mocking of some human frailty or suffering) is regularly co-opted into mainstream usage.
Wow, this software is great. I figure at 1 pixel per meter, assuming say 1 byte per pixel, that's about 100 Tb worth of data. So no real time viewing at full resolution I guess, unless you have a NASA supercomputer handy. In a few decades though, we'll all have that much HD on our laptops and the processor to crunch it.
Pity there's no Mac verson. I've written a little OS X app to view astronomical images on a globe interactively with OpenGL (only about 10^7 pixels at most...). I wonder if I can grab a low resolution version of the satellite data somewhere to paint on the sphere,,
Re:Axisymmetric simulation NOT correct
on
Bang But No Splash
·
· Score: 1
Sure, I was just thinking that if I was going to try doing this I'd start with the 2D problem because it'd be far easier to code.
Ah yes, you can recognize great ground-breaking research immediately... and this isn't it. Another example of the sheer pointlessness of the MIT media lab. A bunch of women who can't do math or science but are great at self publicizing some techno-gibberish guff.
What would be great is to check this phenomenon out with computer simulation. It might be tough to set up though, since you'd have to deal with a compressible gas phase and incompressible fluid phase, and keep track of the fluid surface to account for surface tension. I'm sure it could be done though. Axisymmetric simulation would probably be fine to start off.
Not so! Come on down to the Funk Shack behind that scree outcrop on Mesa 5. Tuesday night is hardcore jungle tunes, DJ Phage in da house spinnin' the wheels of steel. Phat ass bass, in yer face. Stillsuit recommended.
Non-baryonic dark matter has to be neutral, because if it had electromagnetic charge it would be able to interact with the baryons and then it wouldn't be dark matter (by definition).
I would say that there is a lot of really compelling evidence to support (really confirm) the basic big bang picture, e.g. the observed light element abundances, the CMB power spectra, simulations of structure formation yielding observed matter power spectrum (roughly). People were led to the idea of dark matter by several independent lines of evidence --- rotation curves of galaxies, dynamics of galaxies in clusters, need for CDM to explain structure formation. Since there are several *independent* tests confirming the basic picture, and very strongly suggesting the existence of dark matter, that is why everyone takes the idea seriously. Not to say it couldn't possibly be wrong, but the idea is not fanciful, it's based on concrete evidence and reasoning.
How for example would your plasma cosmology explain either the observed CMB peaks, or the light element abundances?
Slashdot Mirror
It really seems to me that his concept of "spread" to measure the orientation of two lines is much less intuitive than angle. The concept of angle is just not hard to grasp compared to this weird construction of dropping perpendicular lines.
And it isn't true that you need calculus to understand cosines and sines, you just need some simple plane geometry (right angle triangles inscribed in circles and so on). You can even plot the cosine and sine functions without calculus.
Yeah I used ePix (on Linux) quite a bit for my thesis, even doing pseudo-3d stuff. It was very attractive being able to write C like code which generates a mathematically accurate postscript figure. I couldn't get it to work properly on OS X though unfortunately. With better 3d functions, this would be such a great tool.
Hmm. I wonder if this thing could output a Keynote presentation.
Not sure whether this is much more useful than just using a laptop,
but I suppose it could be in some circumstances.
you and/or the parent poster should really write an email to Apple
linking to these posts. These are all great points.
I think there is a point beyond which something becomes too arcane and specialized to be classified as art. To anyone with eyes and a right brain, a work of visual art or music is appreciable almost immediately. A novel may take a few weeks or months to absorb for any reasonably educated person. But a computer program is only accessible to the few who happen to understand that particular language, and the particular problems of the implementation. In the same way, I don't think one could call a long, complicated mathematical proof "art".
What perhaps could be called art is the underlying core of ideas. In the case of programming, these would be the algorithms involved, which can be written in pseudocode, and proved to be optimal and perfect.
In the mathematical case, underneath the mass of symbols are insights (eureka moments) simple enough to be conveyed in a popular book. For example, this popular book explains the beautiful ideas in the proof of the four color theorem (all of the detailed steps are completely understandable with almost no symbols). The actual proof was done mostly on a computer and is practically unreadable by humans.
When you listen to a mathematician talk about their work, you get a sense of the artistry behind the technology.
But that was written referring to Mac OS 9 if i'm not mistaken.
What happens is that your widgets are paged out of memory
if you leave them idle for a long time. It is a bit of a pain in my experience too, but I'm not sure what the solution is.
As an astronomer/physicist, I have to vote for http://www.astro.princeton.edu/~rhl/sm/, which produces graphs which just look much nicer than anything gnuplot or Matlab will spit out (with similar sort of effort, although maybe SM has a slightly weirder scripting language). Not free or open source, but it is, uh, obtainable, if you know what I mean.
Reading many of the responses to this post, along the lines of "Well, Duh! Big deal", reminds me of one of the frustrations of studying physics. You go in hoping to understand the mechanisms of, well, everything, and end up discovering that many things ordinary people think are simple are really terribly complex and ill-understood. My mother is not impressed that I can compute the specific heat of a degenerate fermionic gas. If I knew why water boils maybe I could convince her my education wasn't just a load of academic waffle. (Yes, I know it's a phase transition, but it's not understood fundamentally any more than melting).
I think your situation is covered by their model (if you follow their assumptions).
They resolve the grandfather paradox basically by saying you must have been born at some point for the feedback loop to start, so there is actually zero probability that you killed your father when you went back in time.
However they allow for another possibility because the model is quantum mechanical. It is possible for you to kill your father before he met your mother (thus preventing birth of the "baby you" in that timeline), but there must be a separate quantum possibility that you didn't kill your father, in superposition. In this case it seems that in order for consistency, the step backwards in time has to undo the killing of your father. (The fact that the backwards time travel has to perform this "undoing" for consistency seems pretty ad hoc - do they want to postulate this as an extra quantum rule or something?).
Anyway, I think your Strauss example could work in their model if there are two quantum timelines, in one of which Strauss composed the work from scratch, whereas in the other Strauss was given the score by you coming from the future (where you picked up the score in a music shop). In travelling back in time you would have to do this special step of undoing your education of Strauss and all the subsequent events. There is no paradox then because the timeline in which Strauss composed his work from scratch (and you were born hundreds of years later, found the score in a shop, built a time machine etc.) is still in existence, in superposition (it must exist in their model, which is how they get around the grandfather paradox too).
http://xxx.lanl.gov/abs/quant-ph/0506027
Abstract:
We introduce a quantum mechanical model of time travel which includes two figurative beam splitters in order to induce feedback to earlier times. This leads to a unique solution to the paradox where one could kill one's grandfather in that once the future has unfolded, it cannot change the past, and so the past becomes deterministic. On the other hand, looking forwards towards the future is completely probabilistic. This resolves the classical paradox in a philosophically satisfying manner.
Here's an idea. Instead of providing a surface to scatter off by rotating a surface in space, fill a vessel full of some gas and focus two lasers at the point you want to scatter the light. Arrange for the freqencies of the two beams to add up to the frequency of a transition from the ground state of the atoms in the gas to an excited state. Photons should be produced where the beams intersect. Then you could make an image by just scanning through the volume intersecting the beams in a grid. Conceivably color could be provided with a mixture of gases and various lasers.
You recall incorrectly. Not insightful, sorry
Think about how this constitutes positive evidence for the theory of evolution. Consider how it says nothing whatsoever about the ID hypothesis, and what this implies about the nature of ID "science".
Hey that proves nothing - i've got 2 degrees in physics and I'm thick as pigshit
Being a virgin beats having your genitals infected with STDs, being completely pussy whipped by some fucking idiot whore, and destroying your life with obese parasitic pyschotic kids. Masturbation gives you a 10 times better orgasm and you don't feel guilty afterwards. And acne is fun to pop.
It's Wolfgang Haken, not Harken
I can't believe Monsieur Cousteau actually used the words "retarded cousin". I suspect that's the american author of the article paraphrasing badly. French people don't use the word "retarded" to draw laughs. That's just in America, where
the snickering "humour" of mindless frat-boy types (i.e. delightful mocking of some human frailty or suffering) is regularly co-opted into mainstream usage.
Wow, this software is great. I figure at 1 pixel per meter, assuming say 1 byte per pixel, that's about 100 Tb worth of data. So no real time viewing at full resolution I guess, unless you have a NASA supercomputer handy. In a few decades though, we'll all have that much HD on our laptops and the processor to crunch it.
Pity there's no Mac verson. I've written a little OS X app to view astronomical images on a globe interactively with OpenGL (only about 10^7 pixels at most...). I wonder if I can grab a low resolution version of the satellite data somewhere to paint on the sphere,,
Sure, I was just thinking that if I was going to try doing this I'd start with the 2D problem because it'd be far easier to code.
Ah yes, you can recognize great ground-breaking research immediately ... and this isn't it. Another example of the sheer pointlessness of the MIT media lab. A bunch of women who can't do math or science but are great at self publicizing some techno-gibberish guff.
What would be great is to check this phenomenon out with computer simulation. It might be tough to set up though, since you'd have to deal with a compressible gas phase and incompressible fluid phase, and keep track of the fluid surface to account for surface tension. I'm sure it could be done though. Axisymmetric simulation would probably be fine to start off.
Not so! Come on down to the Funk Shack behind that scree outcrop on Mesa 5. Tuesday night is hardcore jungle tunes, DJ Phage in da house spinnin' the wheels of steel. Phat ass bass, in yer face. Stillsuit recommended.
Non-baryonic dark matter has to be neutral, because if it had electromagnetic charge it would be able to interact with the baryons and then it wouldn't be dark matter (by definition).
I would say that there is a lot of really compelling evidence to support (really confirm) the basic big bang picture, e.g. the observed light element abundances, the CMB power spectra, simulations of structure formation yielding observed matter power spectrum (roughly). People were led to the idea of dark matter by several independent lines of evidence --- rotation curves of galaxies, dynamics of galaxies in clusters, need for CDM to explain structure formation.
Since there are several *independent* tests confirming the basic picture, and very strongly suggesting the existence of dark matter, that is why everyone takes the idea seriously. Not to say it couldn't possibly be wrong, but the idea is not fanciful, it's based on concrete evidence and reasoning.
How for example would your plasma cosmology explain either the observed CMB peaks, or the light element abundances?