sr.vinay Posted March 29, 2010 Posted March 29, 2010 We've all heard of the string theory and its reputation as the theory of everything. My question is that, according to the theory, strings are in continuous vibration. Is this vibration due to external energy supplied to it? If not, will it disobey the law of conservation of energy? Because they're in vibration all the time. Consider the theory to be true and answer this.
ajb Posted March 29, 2010 Posted March 29, 2010 You should think of it a like simple harmonic oscillators. There is no dampening nor driving force. Energy conservation holds, no energy is being leaked out or supplied for a free string.
sr.vinay Posted March 29, 2010 Author Posted March 29, 2010 Thus there is no friction at all? What about when strings split up? The divided strings do have different frequencies, yes, but isn't a lot of energy lost there?
ajb Posted March 29, 2010 Posted March 29, 2010 I don't know much about interacting strings, but I am sure you will still have conservation of energy.
mannzzu Posted March 29, 2010 Posted March 29, 2010 conservation is not violated!! we can assume the string is in closed system where in which it loses energy and absorbs the same and the cycle continues!! only question is abt the initial energy!! where does it gain it?????
sr.vinay Posted March 30, 2010 Author Posted March 30, 2010 That's my question. Where does the initial energy come from? Why and how do we consider a closed system?
MSTCkid Posted March 31, 2010 Posted March 31, 2010 Perhaps the initial energy was bound to the strings in their creation, it originated with the strings themselves, or it would gain energy by interacting with other strings, other particles. It is considered a closed system, because even if it began as an open system, the endpoints could still meet and create a closed system, therefore there can be no string theories that do not involve a closed system. As to the how, the endpoints meet creating a loop, an infinite sequence that must be closed, or else you would follow it to infinity, like the ant walking a mobius strip. Was this any help, or am I barking up the wrong tree?
Amr Morsi Posted March 31, 2010 Posted March 31, 2010 I think the energy in the strings (energy of all harmonics) is related to the energy of the particle involved. This includes the kinetic energy and the rest energy. Potential energy is included in the factors affecting the strings.
sr.vinay Posted April 1, 2010 Author Posted April 1, 2010 MSTCkid's ideas are conflicting. You're on two sides. When we consider a closed system, it's because strings vibrate with discrete frequencies for different objects. And, objects do have a boundary. But, the surface strings are always open looped and interact with other strings with different frequencies. Maybe, the strings are able to sustain the frequency because they're continuously interacting with each other, creating sort of a continuum, and with the surroundings.
Amr Morsi Posted April 3, 2010 Posted April 3, 2010 Maybe, the strings are able to sustain the frequency because they're continuously interacting with each other, creating sort of a continuum, and with the surroundings. For sure, strings are interacting with each others and are exchanging energy with each others. But, I don't think that this is the main reason. I think it has to do with the medium (or the surroundings); radiation and potential energy.
sr.vinay Posted April 4, 2010 Author Posted April 4, 2010 What about the continuum? Isn't that a possible aspect?
Amr Morsi Posted April 6, 2010 Posted April 6, 2010 For sure there is a partial continuum between strings for the same particle. But, it is not closed. In other words, it may lose or gain energy. An example of this continuum is a particle moving in circular motion and not radiating energy; the strings of 2 dimensions (or 3 to be accurate) are exchanging energy, depending upon velocity in each dimension.
sr.vinay Posted April 6, 2010 Author Posted April 6, 2010 How is the energy conserved in a process like splitting of strings?
toastywombel Posted April 6, 2010 Posted April 6, 2010 Okay, so there are closed strings and open strings Closed strings retain there energy because they are essentially like a loop. With the energy flowing along the string. Open strings are the problem, energy can leave the open string and simply vanish. This is where the conservation of energy problem comes up. Well at the end of open strings, according to string theory there are D-branes. D-branes, are a type of higher dimensional object called branes, these are like boundaries of the dimensions. So a one dimensional brane is simply a brane, two dimensional brane is a membrane, so on and so forth. This might be the medium that you guys are referring to. Open strings exist under two conditions. One is where an end of the string is not attached to a D-brane, but has no momentum escaping out the end. The other is where there is momentum, and because of this the open string must be attached to a D-brane, this is how the energy is conserved. The energy cannot escape the brane, or dimension, even if it escapes the string.
Amr Morsi Posted April 6, 2010 Posted April 6, 2010 Yes, toastywombel, D-branes are features of M-Theory. And, as you said, strings are connected to these D-branes. Doesn't this imply that they can exchange energy through the branes? And, I am wondering if closed strings can loose or gain energy sue to some factors. Do have an idea?
toastywombel Posted April 6, 2010 Posted April 6, 2010 Yes, toastywombel, D-branes are features of M-Theory. And, as you said, strings are connected to these D-branes. Doesn't this imply that they can exchange energy through the branes? And, I am wondering if closed strings can loose or gain energy sue to some factors. Do have an idea? Energy can be exchanged through strings connected to the same brane, or in the same dimension, but the idea is that only gravity can move through dimensions. This is one explanation as to why gravity is appears much weaker than all the other forces. As for closed strings gaining or losing energy, I don't think so, not sure I would have to do more reading, but I don't think so. But if a string exists in a dimension, then it is open from my understanding.
remelic Posted April 7, 2010 Posted April 7, 2010 The beauty of physics like this is that there is no evidence it exists so you cannot prove it or disprove it. To be honest with you I believe these kinds of physics are excuses and misleading the real reasons for the Universe. How can string theory explain how the universe began? How can string theory explain the center of galaxies? How can it explain Life? How does it explain the magnetic field or the Atom or molecules and why volcanoes erupt? It can't. Throw the books on string theory in the garbage because it has no grounds in the real world. The question is unanswerable because the string is not real. If you want an answer you might as well make something up like the inventor of this idea did. Cheers!
toastywombel Posted April 7, 2010 Posted April 7, 2010 The beauty of physics like this is that there is no evidence it exists so you cannot prove it or disprove it. To be honest with you I believe these kinds of physics are excuses and misleading the real reasons for the Universe. How can string theory explain how the universe began? How can string theory explain the center of galaxies? How can it explain Life? How does it explain the magnetic field or the Atom or molecules and why volcanoes erupt? It can't. Throw the books on string theory in the garbage because it has no grounds in the real world. The question is unanswerable because the string is not real. If you want an answer you might as well make something up like the inventor of this idea did. Cheers! I believe String Theory is simply a broad term used to reference unification theories that will unify the force of gravity with the other forces it does not attempt to explain everything, furthermore this topic is about string theory, and the poster had specific questions about string theory. If you want to debunk string theory start you might want to start your own post.
sr.vinay Posted April 7, 2010 Author Posted April 7, 2010 The beauty of physics like this is that there is no evidence it exists so you cannot prove it or disprove it. To be honest with you I believe these kinds of physics are excuses and misleading the real reasons for the Universe. How can string theory explain how the universe began? How can string theory explain the center of galaxies? How can it explain Life? How does it explain the magnetic field or the Atom or molecules and why volcanoes erupt? It can't. Throw the books on string theory in the garbage because it has no grounds in the real world. The question is unanswerable because the string is not real. If you want an answer you might as well make something up like the inventor of this idea did. Cheers! Hey, come on. Don't say things like these in a thread meant for string theory! Who knows? You've no proof that strings don't exist.
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