You know, I am all for freedom and diversity of religion, but there comes a point to which it just no longer works, for instance these African witch doctors that screw people over and make them kill other people and fuel wars like the LRC thing I was talking about. I bring this up again because of this article, on CNN today.
I don't have time to write about it now, but it just makes me mad.
Sunday, November 29, 2009
Wednesday, November 25, 2009
landfills, virtual water
I read in a magazine that the third biggest element of landfills is wasted food.
That's first of all ridiculous because there are people starving while food is rotting away in landfills. That's second of all ridiculous because food has a high virtual water content (ie water that goes into producing it), and we're going to run out of fresh water unless we reallocate resources.
It would also help if people in affluent countries quit eating so much meat, or became largely vegetarian (plug for vegetarianism). It seems inevitable that our world will run out of resources. But at least we can try to make it less painless for the people that are alive right now.
Anyway, landfills should *not* contain so much food. Don't waste food! I'm a college student. This is ingrained in my neocortex.
That's first of all ridiculous because there are people starving while food is rotting away in landfills. That's second of all ridiculous because food has a high virtual water content (ie water that goes into producing it), and we're going to run out of fresh water unless we reallocate resources.
It would also help if people in affluent countries quit eating so much meat, or became largely vegetarian (plug for vegetarianism). It seems inevitable that our world will run out of resources. But at least we can try to make it less painless for the people that are alive right now.
Anyway, landfills should *not* contain so much food. Don't waste food! I'm a college student. This is ingrained in my neocortex.
Sunday, November 22, 2009
there are just some things i hope i never understand about the world
I'm reading a book right now by Peter Eichstaedt about child soldiers in the Lord's Resistance Army in Northern Uganda (mainly there anyway). This was after reading a book last year about the genocide in Rwanda. And while these kinds of atrocities may terrify me less than psychopathic killers, they disgust me more.
The book is of course just a long saga of kids getting kidnapped and forced to kill people for... no reason really. I mean, a long time ago there was a reason for the LRA, but it seems like these days the reason is just a tradition of warfare.
I don't know. It disgusts me that a man could give a boy a gun and tell him to shoot another little kid, tell him if he doesn't he'll be shot, and really mean it, really do it, or rape a little girl out of selfish sexual needs. It disgusts me that people in Rwanda could kill their neighbors for no reason other than ancient tribal feudalism ingrained by colonialists. It disgusts me that people in Germany could turn on the gas chambers and throw the bodies in the trenches (for what... religion? The Aryan race? Anti-semitic notions?). But it disgusts me more than there could be calculating men behind all of these things who know exactly what they're doing and do it anyway. From Hitler, Kony on down, all of those men (and women) that could make the decisions that they made in cold blood... that's one part of humanity that I pray I'll never understand.
The book is of course just a long saga of kids getting kidnapped and forced to kill people for... no reason really. I mean, a long time ago there was a reason for the LRA, but it seems like these days the reason is just a tradition of warfare.
I don't know. It disgusts me that a man could give a boy a gun and tell him to shoot another little kid, tell him if he doesn't he'll be shot, and really mean it, really do it, or rape a little girl out of selfish sexual needs. It disgusts me that people in Rwanda could kill their neighbors for no reason other than ancient tribal feudalism ingrained by colonialists. It disgusts me that people in Germany could turn on the gas chambers and throw the bodies in the trenches (for what... religion? The Aryan race? Anti-semitic notions?). But it disgusts me more than there could be calculating men behind all of these things who know exactly what they're doing and do it anyway. From Hitler, Kony on down, all of those men (and women) that could make the decisions that they made in cold blood... that's one part of humanity that I pray I'll never understand.
Saturday, November 21, 2009
long, hastily (and probably poorly) written paper about string theory
String Theory: Overview, Main Characteristics, and Problems
While the standard model paints a picture of particle constituents as isolated points in space, string theory views particles as composed of strings that occupy roughly a Planck length in one dimension. String theory posits that the properties of the particles we observe are bestowed by the different vibrational frequencies of these strings. For instance, lighter particles are composed of strings with fewer oscillations. String theory also explains constraints on particle masses: the number of possible heavy particles is limited by upper limits on vibrational frequency due to high string tension. Given this high string tension, unique particles in string theory are predicted to be too heavy to be detected in current particle accelerators, although the reopening of the LHC poses some hope for detection. String theory predicts both open and closed strings, although the nature of the parameter differs between the different subtypes of the theory. The essential sameness of the constituents of all matter allows string theory to unify all of the disparate particles in the standard model, and unlike the standard model, it provides reasons for the properties of those particles. Thus string theory claims to unify all forces at high energy levels, a feat required for a grand unified theory that can explain the universe from its more homogeneous origin.
The history of string theory has been fraught by both great excitements and great disappointments. It commenced in 1968 when the Italian physicist Gabriele Veneziano realized the Euler beta function described strongly interacting particles. In 1970, physicists Yoichiro Nambu of the University of Chicago, Holger Nielson of the Niels Bohr institute, and Leonar Susskin of Stanford refined Veneziano’s idea by announcing that if matter were made up of tiny vibrating strings, it could be described by the Euler beta function. This original version of string theory was specific to bosons, and it predicted a vibrational frequency corresponding to a particle dubbed the tachyon. The tachyon had a negative mass and thus traveled faster than the speed of light. Because this didn’t mesh well with special relativity, it was a great problem with the theory. Physicists Ramond, Neveu, and Schwarz solved this problem by suggesting that the strings were supersymmetric, or containing particle pairs that differed by a spin of ½. This allowed the theory to account for fermions, particles with a spin of ½. John Schwarz and Joel Schenk discovered in 1974 that the modified model also predicted a particle with a spin of 2 whose vibrational properties were consistent with a graviton, the force-carrying particle associated with gravity. This discovery made string theory a candidate for the unification of relativity and quantum theory. It was also discovered that supersymmetry only made mathematical sense (producing non-negative probabilities) in ten dimensions. Physicists Gross, Harvey, and Martinec further improved the theory with the idea of the heterotic superstring, a chiral theory that treated different wave directions differently and yielded more predictions. However, the theory only retained its chirality if the six non-visible dimensions were not curled up as supposed, an existent theory of manifold dimensions that dated back to Kaluza in the early 20th century. So in 1985 Philip Candelas, Gary Horowitz, Andy Strominger, and Edward Witten suggested that the dimensions are actually curled up in Calabi-Yau manifolds, more complicated six-dimensional structures. This first superstring revolution occurred from 1984 to 1986. The revolution was characterized by the exciting emergence of the standard model from string theory. However, the approximation methods used to complete the immensely complicated mathematics of the theory soon became insufficient. 1995 showed the beginning of the second superstring revolution, or rather the era of M-theory/brane-theory, an idea suggested by Edward Witten as a means to unite the differing string theories through dualism. Modern research in string theory consists in elucidating the implications of M-theory.
One of the techniques used to make string theory consistent is super symmetry. Super symmetry is the idea that particles come in different spins, i.e. that for each vibrational frequency there are two particles with spins differing by ½. Since no known particles fit the characteristics of these predicted particles, there must be as-yet unobserved super-symmetric partners to all observed particles. Super symmetry is suggested by cancellations that occur in the quantum mechanical contributions of fermions and bosons. These cancellations can be explained by adjusting parameters in the standard model, but they can be more cleanly explained by super symmetry. Super symmetry can also modify the strength of forces at small distances, allowing for unification between these forces, an ever-present goal of physics. Super symmetry seems to bring physics closer to the tantalizing goal of unification. The more compelling reasons for the implication of super symmetry, however, were already briefly mentioned: super symmetry allows for spin ½ particles (by predicting pairs of particles that differ by spin ½), and it also eliminates the prediction of the tachyon. Thus there are compelling arguments for super symmetry both outside of and within string theory.
Another important characteristic of string theory is the requirement for extra dimensions. Extra dimensions within string theory allow for more directions of vibration necessary for the diversity of predicted particles. It also contributes to symmetry by making a choice of coordinates on the world sheet swept out by the string through time equivalent to any other choice. Additionally, without extra dimensions, string theory math would yield negative probabilities. The idea of extra dimensions began with Kaluza and Klein in 1919. They suggested a tiny, curled dimension, or manifold, in addition to the three spatial dimensions and the time dimension. Additional modifications of this theory use spheres or the donut-shaped torus for the manifolds. The specific geometry of these manifolds predicts the properties of particles in string theory. When the general Kaluza-Klein model didn’t fit with the chirality of the heterotic string or the properties of observed particles, Calabi-yau spaces were suggested. Calabi-yau manifolds are six-dimensional shapes whose physical properties yield the properties of the particles that we observe. Thus extra dimensions were necessary in string theory to explain the properties of our universe and make the string theory mathematics consistent.
Despite all of the predictions and promises of string theory, it also contains a lot of problems. Perhaps the largest problem is that there are many worlds consistent with string theory, and the actual constants that arise in our universe are arbitrary within the theory. String theory gives us a landscape of possibilities rather than predicting our exact universe. This can be countered with the anthropic principle, the idea that there are other worlds but we just happen to be in this one, but that is a weak scientific argument with little explanatory power. Additionally, there are multiple ways of incorporating super symmetry into string theory, partially creating the different subtypes of the theory. There is also the issue that super symmetry itself is not observed in our low-energy universe, but if it is considered broken, then string theory predicts the cosmological constant inaccurately (predicting that it is non-positive when it is experimentally shown to be positive). Along the same lines, there are many possible parameters for the Calabi-yau spaces, and the selection of these parameters also seems arbitrary. The number of dimensions is also chosen in order to make the theory consistent rather than for any physical reason. Another problem is that string theory doesn’t explain the vacuum energy that accounts for the slow acceleration of space. It also doesn’t predict dark energy, discovered in 1998. Finally, it lacks a method of empirical proof, although there is some putative evidence that could arise at LHC.
The modern improvement upon string theory is brane theory, the subject of the second revolution. Brane theory adds an extra dimension, making a total of eleven dimensions, and allows for both the existence of two-dimensional membranes of all shapes and sizes as well as one-dimensional strings which are attached to the membranes. Gauge bosons and fermions are the result of open strings (both ends attached to the membrane), so they are confined to the brane, but gravitons are the result of closed strings, so they can travel between branes within the dimensions (strings stretch between branes). The reason brane theory was so exciting was that it proposed dualities that unified the subtypes of string theory. First, there is a duality of strongly interacting 10-dimensional superstring theory and weakly interacting brane theory, meaning it is the same theory with different descriptions. This duality allows calculations made within one theory to apply to the other theory. The different subtypes of 10-dimensional string theory are also connected by dualism. One type of dualism is S duality, which is a symmetry between the strong and weak coupling regimes. Some of the types of string theories are related by S duality. T duality occurs when swapping momentum modes with strong interactions yields equivalent states. Some of the types of string theory are related by T duality. The discovery of these relations between the subtypes of string theory and between string theory and brane-theory show that all of these theories are only superficially different; they are actually equivalent theories.
Although string theory has a fascinating history and promises to produce a feasible unified theory of gravity, it contains many problems that have caused modern physicists to abandon the effort in lieu of more contemporarily promising alternatives such as loop quantum gravity. Despite its shortcomings, however, string theory, and its consummation M-theory, has allowed for great advancements in the field of theoretical physics and seems likely to offer more in the future.
Works Consulted
Greene, Brian. The Elegant Universe Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory. New York: Vintage, 2000. Print.
Greene, Brian. The Fabric of the Cosmos Space, Time, and the Texture of Reality. New York: Vintage, 2005. Print.
Randall, Lisa. Warped Passages Unraveling the Mysteries of the Universe's Hidden Dimensions. New York: Harper Perennial, 2006. Print.
Smolin, Lee. The Trouble With Physics The Rise of String Theory, The Fall of a Science, and What Comes Next. New York: Mariner Books, 2007. Print.
Stephen, Webb,. Out of this world colliding universes, branes, strings, and other wild ideas of modern physics. New York: Copernicus Books in association with Praxis, 2004. Print.
While the standard model paints a picture of particle constituents as isolated points in space, string theory views particles as composed of strings that occupy roughly a Planck length in one dimension. String theory posits that the properties of the particles we observe are bestowed by the different vibrational frequencies of these strings. For instance, lighter particles are composed of strings with fewer oscillations. String theory also explains constraints on particle masses: the number of possible heavy particles is limited by upper limits on vibrational frequency due to high string tension. Given this high string tension, unique particles in string theory are predicted to be too heavy to be detected in current particle accelerators, although the reopening of the LHC poses some hope for detection. String theory predicts both open and closed strings, although the nature of the parameter differs between the different subtypes of the theory. The essential sameness of the constituents of all matter allows string theory to unify all of the disparate particles in the standard model, and unlike the standard model, it provides reasons for the properties of those particles. Thus string theory claims to unify all forces at high energy levels, a feat required for a grand unified theory that can explain the universe from its more homogeneous origin.
The history of string theory has been fraught by both great excitements and great disappointments. It commenced in 1968 when the Italian physicist Gabriele Veneziano realized the Euler beta function described strongly interacting particles. In 1970, physicists Yoichiro Nambu of the University of Chicago, Holger Nielson of the Niels Bohr institute, and Leonar Susskin of Stanford refined Veneziano’s idea by announcing that if matter were made up of tiny vibrating strings, it could be described by the Euler beta function. This original version of string theory was specific to bosons, and it predicted a vibrational frequency corresponding to a particle dubbed the tachyon. The tachyon had a negative mass and thus traveled faster than the speed of light. Because this didn’t mesh well with special relativity, it was a great problem with the theory. Physicists Ramond, Neveu, and Schwarz solved this problem by suggesting that the strings were supersymmetric, or containing particle pairs that differed by a spin of ½. This allowed the theory to account for fermions, particles with a spin of ½. John Schwarz and Joel Schenk discovered in 1974 that the modified model also predicted a particle with a spin of 2 whose vibrational properties were consistent with a graviton, the force-carrying particle associated with gravity. This discovery made string theory a candidate for the unification of relativity and quantum theory. It was also discovered that supersymmetry only made mathematical sense (producing non-negative probabilities) in ten dimensions. Physicists Gross, Harvey, and Martinec further improved the theory with the idea of the heterotic superstring, a chiral theory that treated different wave directions differently and yielded more predictions. However, the theory only retained its chirality if the six non-visible dimensions were not curled up as supposed, an existent theory of manifold dimensions that dated back to Kaluza in the early 20th century. So in 1985 Philip Candelas, Gary Horowitz, Andy Strominger, and Edward Witten suggested that the dimensions are actually curled up in Calabi-Yau manifolds, more complicated six-dimensional structures. This first superstring revolution occurred from 1984 to 1986. The revolution was characterized by the exciting emergence of the standard model from string theory. However, the approximation methods used to complete the immensely complicated mathematics of the theory soon became insufficient. 1995 showed the beginning of the second superstring revolution, or rather the era of M-theory/brane-theory, an idea suggested by Edward Witten as a means to unite the differing string theories through dualism. Modern research in string theory consists in elucidating the implications of M-theory.
One of the techniques used to make string theory consistent is super symmetry. Super symmetry is the idea that particles come in different spins, i.e. that for each vibrational frequency there are two particles with spins differing by ½. Since no known particles fit the characteristics of these predicted particles, there must be as-yet unobserved super-symmetric partners to all observed particles. Super symmetry is suggested by cancellations that occur in the quantum mechanical contributions of fermions and bosons. These cancellations can be explained by adjusting parameters in the standard model, but they can be more cleanly explained by super symmetry. Super symmetry can also modify the strength of forces at small distances, allowing for unification between these forces, an ever-present goal of physics. Super symmetry seems to bring physics closer to the tantalizing goal of unification. The more compelling reasons for the implication of super symmetry, however, were already briefly mentioned: super symmetry allows for spin ½ particles (by predicting pairs of particles that differ by spin ½), and it also eliminates the prediction of the tachyon. Thus there are compelling arguments for super symmetry both outside of and within string theory.
Another important characteristic of string theory is the requirement for extra dimensions. Extra dimensions within string theory allow for more directions of vibration necessary for the diversity of predicted particles. It also contributes to symmetry by making a choice of coordinates on the world sheet swept out by the string through time equivalent to any other choice. Additionally, without extra dimensions, string theory math would yield negative probabilities. The idea of extra dimensions began with Kaluza and Klein in 1919. They suggested a tiny, curled dimension, or manifold, in addition to the three spatial dimensions and the time dimension. Additional modifications of this theory use spheres or the donut-shaped torus for the manifolds. The specific geometry of these manifolds predicts the properties of particles in string theory. When the general Kaluza-Klein model didn’t fit with the chirality of the heterotic string or the properties of observed particles, Calabi-yau spaces were suggested. Calabi-yau manifolds are six-dimensional shapes whose physical properties yield the properties of the particles that we observe. Thus extra dimensions were necessary in string theory to explain the properties of our universe and make the string theory mathematics consistent.
Despite all of the predictions and promises of string theory, it also contains a lot of problems. Perhaps the largest problem is that there are many worlds consistent with string theory, and the actual constants that arise in our universe are arbitrary within the theory. String theory gives us a landscape of possibilities rather than predicting our exact universe. This can be countered with the anthropic principle, the idea that there are other worlds but we just happen to be in this one, but that is a weak scientific argument with little explanatory power. Additionally, there are multiple ways of incorporating super symmetry into string theory, partially creating the different subtypes of the theory. There is also the issue that super symmetry itself is not observed in our low-energy universe, but if it is considered broken, then string theory predicts the cosmological constant inaccurately (predicting that it is non-positive when it is experimentally shown to be positive). Along the same lines, there are many possible parameters for the Calabi-yau spaces, and the selection of these parameters also seems arbitrary. The number of dimensions is also chosen in order to make the theory consistent rather than for any physical reason. Another problem is that string theory doesn’t explain the vacuum energy that accounts for the slow acceleration of space. It also doesn’t predict dark energy, discovered in 1998. Finally, it lacks a method of empirical proof, although there is some putative evidence that could arise at LHC.
The modern improvement upon string theory is brane theory, the subject of the second revolution. Brane theory adds an extra dimension, making a total of eleven dimensions, and allows for both the existence of two-dimensional membranes of all shapes and sizes as well as one-dimensional strings which are attached to the membranes. Gauge bosons and fermions are the result of open strings (both ends attached to the membrane), so they are confined to the brane, but gravitons are the result of closed strings, so they can travel between branes within the dimensions (strings stretch between branes). The reason brane theory was so exciting was that it proposed dualities that unified the subtypes of string theory. First, there is a duality of strongly interacting 10-dimensional superstring theory and weakly interacting brane theory, meaning it is the same theory with different descriptions. This duality allows calculations made within one theory to apply to the other theory. The different subtypes of 10-dimensional string theory are also connected by dualism. One type of dualism is S duality, which is a symmetry between the strong and weak coupling regimes. Some of the types of string theories are related by S duality. T duality occurs when swapping momentum modes with strong interactions yields equivalent states. Some of the types of string theory are related by T duality. The discovery of these relations between the subtypes of string theory and between string theory and brane-theory show that all of these theories are only superficially different; they are actually equivalent theories.
Although string theory has a fascinating history and promises to produce a feasible unified theory of gravity, it contains many problems that have caused modern physicists to abandon the effort in lieu of more contemporarily promising alternatives such as loop quantum gravity. Despite its shortcomings, however, string theory, and its consummation M-theory, has allowed for great advancements in the field of theoretical physics and seems likely to offer more in the future.
Works Consulted
Greene, Brian. The Elegant Universe Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory. New York: Vintage, 2000. Print.
Greene, Brian. The Fabric of the Cosmos Space, Time, and the Texture of Reality. New York: Vintage, 2005. Print.
Randall, Lisa. Warped Passages Unraveling the Mysteries of the Universe's Hidden Dimensions. New York: Harper Perennial, 2006. Print.
Smolin, Lee. The Trouble With Physics The Rise of String Theory, The Fall of a Science, and What Comes Next. New York: Mariner Books, 2007. Print.
Stephen, Webb,. Out of this world colliding universes, branes, strings, and other wild ideas of modern physics. New York: Copernicus Books in association with Praxis, 2004. Print.
Tuesday, November 17, 2009
scientific spiritualism
We were infinite once, I think.
Because all of the particles inside of us were around in the form of radiation energy right after the big bang (conservation of energy/mass gives us that much), and back when the energy of the particles inside of us was much less than the temperature of the universe times the boltzmann constant, our particles behaved like massless particles and contributed to the cosmic background radiation.
At that point I think that the mass of the particles probably still made the time dilation non-finite, but you could at least think of the interactions of those particles forming energy in the form of photons, and photons have infinite time dilation due to zero rest mass.
So at one point, even if only abstractly, the things inside of us were infinite.
Because all of the particles inside of us were around in the form of radiation energy right after the big bang (conservation of energy/mass gives us that much), and back when the energy of the particles inside of us was much less than the temperature of the universe times the boltzmann constant, our particles behaved like massless particles and contributed to the cosmic background radiation.
At that point I think that the mass of the particles probably still made the time dilation non-finite, but you could at least think of the interactions of those particles forming energy in the form of photons, and photons have infinite time dilation due to zero rest mass.
So at one point, even if only abstractly, the things inside of us were infinite.
Saturday, November 14, 2009
hey NASA, it's your birthday...
Without making myself sound a little bit too geeky, I must inform you that this discovery of water on the moon is the realization of my childhood dreams. I was very, very into space when I was a kid (dead set on being an astronomer after I realized my eyes etc weren't quite up to par to be an astronaut), and I was especially interested in water on the moon. We would get out the telescope (my father and I), and look at the craters, and talk about all of the most recent articles and discoveries.
This is SO amazing. Nobody in the general public is going to appreciate how amazing it is.
As for me, having water discovered on the moon *and* the LHC up and running again all in the same week makes me feel like it's my birthday six months early. :-)
This is SO amazing. Nobody in the general public is going to appreciate how amazing it is.
As for me, having water discovered on the moon *and* the LHC up and running again all in the same week makes me feel like it's my birthday six months early. :-)
Wednesday, November 11, 2009
yay
LHC is up and running! (For the moment at least.) I know I wasn't the only person who got really excited about it last year only to have it break down nine days after opening. Hopefully this time's for real. It seems like every time I read about some far-out theoretical physics idea, it says, "Well, we'll have to wait for the LHC for proof." So a lot of stuff is on the line right now, and I'm excited, the Higgs boson of course being one of the more popular items.
Okay I don't have time to write right now, I have to go get my laundry and continue plodding through my neuroscience studying, but I just thought I'd take a moment to celebrate.
Okay I don't have time to write right now, I have to go get my laundry and continue plodding through my neuroscience studying, but I just thought I'd take a moment to celebrate.
Subscribe to:
Posts (Atom)
