The reality of energy.
in [Relativity]
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From: ben6993 on 1 Mar 2010 04:53 On Feb 28, 10:46 am, "Inertial" <relativ...(a)rest.com> wrote: > Though some proportion of the mass from a system with internal motion comes > from the relativistic mass of the moving components. A couple of questions: 1. Assume a photon sets out from a distant galaxy with energy at outset of E=hf. Although from its own point of view it keeps its energy constant, by the time it reaches us it has redshifted quite a long way and to us it appeard to have a reduced energy, can we think of that discrepancy between higher energy in its framework and its lower energy in our framework as being the entropy gain of the photon? I.e. can entropy be though of as the discrepancy of the same energy when viewed in two different frameworks? 2. Assume that a rocket was using the entire mass of the universe as fuel for its burners in order to accelerate closer and closer to speed c. (Need to overlook a few major, practical details which may be important, eg how does it pick up more fuel without slowing down, how does its engine use dark matter and dark energy?) The rocket cannot reach speed c, as the universe has a finite mass. But the universe cannot lose energy and so all that is left is the rocket travelling at immense speed with a relativistic mass the size of the universe. (Also overlooked is that not all energy can be useful.) The experiment started with a small rocket travelling at low speed in a massive universe (full of lots of useful energy in that universe, i.e. relative low entropy) and ended with a massive rocket travelling at very high speed (not much useful energy left in its framework as presumably entropy is now very high after all that work done has been done in accelerating the rocket.). Although there is very little useful energy left within its framework, if the rocket were to be able to collide with something outside its framework (eg neighbouring Big Bang 2 say) a rocket travelling at near speed c with the mass of the universe should be able to do quite a lot of work. There is probably a flaw in the above arguments. These are not fixed ideas ... I am just trying to learn.
From: Androcles on 1 Mar 2010 04:57 "ben6993" <ben6993(a)hotmail.com> wrote in message news:a0de316c-4d2b-48a5-b5fe-be7f9bf9b2de(a)q23g2000yqd.googlegroups.com... On Feb 28, 10:46 am, "Inertial" <relativ...(a)rest.com> wrote: > Though some proportion of the mass from a system with internal motion > comes > from the relativistic mass of the moving components. A couple of questions: 1. Assume a photon sets out from a distant galaxy with energy at outset of E=hf. Although from its own point of view it keeps its energy constant, by the time it reaches us it has redshifted quite a long way and to us it appeard to have a reduced energy, can we think of that discrepancy between higher energy in its framework and its lower energy in our framework as being the entropy gain of the photon? I.e. can entropy be though of as the discrepancy of the same energy when viewed in two different frameworks? 2. Assume that a rocket was using the entire mass of the universe as fuel for its burners in order to accelerate closer and closer to speed c. (Need to overlook a few major, practical details which may be important, eg how does it pick up more fuel without slowing down, how does its engine use dark matter and dark energy?) The rocket cannot reach speed c, as the universe has a finite mass. But the universe cannot lose energy and so all that is left is the rocket travelling at immense speed with a relativistic mass the size of the universe. (Also overlooked is that not all energy can be useful.) The experiment started with a small rocket travelling at low speed in a massive universe (full of lots of useful energy in that universe, i.e. relative low entropy) and ended with a massive rocket travelling at very high speed (not much useful energy left in its framework as presumably entropy is now very high after all that work done has been done in accelerating the rocket.). Although there is very little useful energy left within its framework, if the rocket were to be able to collide with something outside its framework (eg neighbouring Big Bang 2 say) a rocket travelling at near speed c with the mass of the universe should be able to do quite a lot of work. There is probably a flaw in the above arguments. These are not fixed ideas ... I am just trying to learn. =================================================== Take a math course, you won't learn anything from an ignorant idiot like "Inert" relativ...(a)rest.com.
From: Inertial on 1 Mar 2010 04:59 "ben6993" <ben6993(a)hotmail.com> wrote in message news:a0de316c-4d2b-48a5-b5fe-be7f9bf9b2de(a)q23g2000yqd.googlegroups.com... > On Feb 28, 10:46 am, "Inertial" <relativ...(a)rest.com> wrote: > >> Though some proportion of the mass from a system with internal motion >> comes >> from the relativistic mass of the moving components. > > A couple of questions: > > 1. Assume a photon sets out from a distant galaxy with energy at > outset of E=hf. OK. > Although from its own point of view it keeps its energy constant, Photons don't have a point of view (in the sense that they don't have any inertial frame of reference where they are at rest). The energy of a photon is what happens to some other object when the photon 'hits' it. > by the time it reaches us it has redshifted quite a long way and to us > it appeard to have a reduced energy, It always had reduced energy to us. > can we think of that discrepancy between higher energy in its > framework and its lower energy in our framework as being the entropy > gain of the photon? Nothing in the photon changed. The energy it 'has' in our frame is constant the whole time. The energy it 'has' in the frame of the star that emitted it is constant the whole time. There is no change > I.e. can entropy be though of as the discrepancy of the same energy > when viewed in two different frameworks? > > 2. Assume that a rocket was using the entire mass of the universe as > fuel for its burners in order to accelerate closer and closer to speed > c. OK. A tad impractical, of course :) > (Need to overlook a few major, practical details which may be > important, eg how does it pick up more fuel without slowing down, how > does its engine use dark matter and dark energy?) > The rocket cannot reach speed c, That's right > as the universe has a finite mass. > But the universe cannot lose energy and so all that is left is the > rocket travelling at immense speed with a relativistic mass the size > of the universe. > (Also overlooked is that not all energy can be useful.) Sorta > The experiment started with a small rocket travelling at low speed in > a massive universe (full of lots of useful energy in that universe, > i.e. relative low entropy) and ended with a massive rocket travelling > at very high speed (not much useful energy left in its framework as > presumably entropy is now very high after all that work done has been > done in accelerating the rocket.). I'm not sure how the mass gets into the rocket in this idea, if it wasn't there to start with. > Although there is very little useful energy left within its framework, > if the rocket were to be able to collide with something outside its > framework (eg neighbouring Big Bang 2 say) a rocket travelling at near > speed c with the mass of the universe should be able to do quite a lot > of work. And a good deal of damage > There is probably a flaw in the above arguments. These are not fixed > ideas ... I am just trying to learn. I'm not sure what the argument is.
From: Inertial on 1 Mar 2010 05:08 "Androcles" <Headmaster(a)Hogwarts.physics_u> wrote in message news:NcMin.107500$_W6.10982(a)newsfe30.ams2... > > "ben6993" <ben6993(a)hotmail.com> wrote in message > news:a0de316c-4d2b-48a5-b5fe-be7f9bf9b2de(a)q23g2000yqd.googlegroups.com... > On Feb 28, 10:46 am, "Inertial" <relativ...(a)rest.com> wrote: > >> Though some proportion of the mass from a system with internal motion >> comes >> from the relativistic mass of the moving components. > > A couple of questions: > > 1. Assume a photon sets out from a distant galaxy with energy at > outset of E=hf. > Although from its own point of view it keeps its energy constant, > by the time it reaches us it has redshifted quite a long way and to us > it appeard to have a reduced energy, > can we think of that discrepancy between higher energy in its > framework and its lower energy in our framework as being the entropy > gain of the photon? > > I.e. can entropy be though of as the discrepancy of the same energy > when viewed in two different frameworks? > > 2. Assume that a rocket was using the entire mass of the universe as > fuel for its burners in order to accelerate closer and closer to speed > c. > (Need to overlook a few major, practical details which may be > important, eg how does it pick up more fuel without slowing down, how > does its engine use dark matter and dark energy?) > The rocket cannot reach speed c, as the universe has a finite mass. > But the universe cannot lose energy and so all that is left is the > rocket travelling at immense speed with a relativistic mass the size > of the universe. > (Also overlooked is that not all energy can be useful.) > > The experiment started with a small rocket travelling at low speed in > a massive universe (full of lots of useful energy in that universe, > i.e. relative low entropy) and ended with a massive rocket travelling > at very high speed (not much useful energy left in its framework as > presumably entropy is now very high after all that work done has been > done in accelerating the rocket.). > > Although there is very little useful energy left within its framework, > if the rocket were to be able to collide with something outside its > framework (eg neighbouring Big Bang 2 say) a rocket travelling at near > speed c with the mass of the universe should be able to do quite a lot > of work. > > There is probably a flaw in the above arguments. These are not fixed > ideas ... I am just trying to learn. > =================================================== > Take a math course, you won't learn anything from an ignorant > idiot like "Inert" relativ...(a)rest.com. Far more than from a well known liar like Androcles, who cannot understand basic math and logic, let alone physics.
From: PD on 1 Mar 2010 09:46
On Feb 27, 8:13 pm, maxwell <s...(a)shaw.ca> wrote: > On Feb 27, 12:04 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Feb 27, 1:22 pm, ben6993 <ben6...(a)hotmail.com> wrote: > > > > > "Energy" is the ability to do work, an ability that is possessed by > > > > organized portions of matter. > > > > I have noticed a definition in wiki which seems to imply that energy > > > is more complicated than the definition above: > > > "The thermodynamic entropy S, often simply called the entropy in the > > > context of thermodynamics, can provide a measure of the amount of > > > energy in a physical system that cannot be used to do work." (http:// > > > en.wikipedia.org/wiki/Introduction_to_entropy) > > > > If energy is the ability to do work, but at the same time entropy > > > implies that some portion of energy is not available to do work, then > > > how do we re-define that portion of the energy in a system not > > > available to do work? Is there a more complex definition of energy? > > > That's actually an excellent point. Kinetic energy, one of the forms > > of energy, is divided into stochastic and collective energy. The > > collective energy is the kind of thing you would write (1/2)mv^2 for a > > baseball of mass m. Stochastic energy is that which is indicated (but > > not measured) by a thermometer; it is the *random* kinetic energy of > > the individual molecules in the body. The former can be wholly > > converted into work. The latter can only be partially converted, with > > the limit set by Carnot's Theorem. > > > In addition, rest energy (the energy associated with rest mass) can't > > be converted into work, but the entropic definition above has nothing > > to do with this. > > > I don't know of any other cases, off the top of my head. > > Defining energy in terms of work is just the 19th century macroscopic > approach to physics before the atomic basis of nature was available. > It is not logical to define the parts in terms of pieces of the > whole since this misses out the synergistic component of bringing > parts together: this is cookery. The macro (like averages) must be > defined in terms of the micro. This is why Maxwell's Equations of EM > is a statistical theory and NOT a fundamental theory of physics. Whaaaaaattt? |