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Natural Science Forum / Physics / General Physics / July 2008FTL possible?
If we somehow could align strongly repelling magnets in a straight plast tube along a 300 000 km line in space. We then push the first one how long time would it take before our gaussmeter in the other end noticed a change in the flux? On Jul 18, 2:29 pm, jonas.thornv...@hotmail.com wrote: > If we somehow could align strongly repelling magnets in a straight > plast tube along a 300 000 km line in space. > > We then push the first one how long time would it take before our > gaussmeter in the other end noticed a change in the flux? It would take at least 1 second, measured in the inertial frame of the person moving the initial magnet. As the changes in electromagnetic fields (and, we guess, any other type of fields such as those responsible for the strong nuclear force or gravity) propagate at most at the speed of light in vacuum, it couldn't take anything less than a second. On 19 Juli, 00:09, byungk...@gmail.com wrote: > On Jul 18, 2:29 pm,jonas.thornv...@hotmail.com wrote: > [quoted text clipped - 11 lines] > or gravity) propagate at most at the speed of light in vacuum, it > couldn't take anything less than a second. Well for the sake of simplicity let bend the plast tube to a noneclosed ring so we have accurate synchronisations in each end. I know the light postulate say so but is their any experimental evidence for gravity and magenetic fields travel with the speed of light? *If we could* measure the magnetic field of a red giant that go nova 65lightyear away, you tell that it would take 65 years until the field collapsed in our end because the field is propagating towards us at the speed of light. I think that is bullshit, when a gravitational or magnetic field collaps there is no remniscents that travel space. What kind of particles would that be? have they ever found these particles that make up magnetic and gravitational *field* in any lab? > I know the light postulate say so but is their any experimental > evidence for gravity and magenetic fields travel with the speed of > light? Be very careful to define what you mean be a field "travelling". If we take the usual operational definition of the magnetic B field, it's a function of position (and time) that give us the magnetic part of the force on a moving charged particle according to the Lorentz force law. Essentially, it's a vector-valued function of position (and time). Does it travel? If you're talking about _changes_ in a magnetic field, then you're talking about EM waves, for which we have about 120 years of combined solid theory+experiment. Even then, you still need to be careful about what you mean by the speed of the EM wave: phase speed (easy to have superluminal phase speeds), group speed (possible to have superluminal group speeds), or other speeds, such as the "front speed" (so far, no superluminal front speed appears possible).  SignatureTimo On Jul 19, 10:38 pm, "Timo A. Nieminen" <t...@physics.uq.edu.au> wrote: > > I know the light postulate say so but is their any experimental > > evidence for gravity and magenetic fields travel with the speed of [quoted text clipped - 17 lines] > -- > Timo Precisely correct. Most of us learn about this by reading a textbook, and not some crackpot's Website posted on the Internet. Harry C. > If we somehow could align strongly repelling magnets in a straight > plast tube along a 300 000 km line in space. > > We then push the first one how long time would it take before our > gaussmeter in the other end noticed a change in the flux? Even galactic size jets with magnetic field that dwarf yours are restricted by the cosmic speed limit, c... so says the observations.... and the theory. > jonas.thornv...@hotmail.com wrote: > > If we somehow could align strongly repelling magnets in a straight [quoted text clipped - 6 lines] > are restricted by the cosmic speed limit, c... so says the > observations.... and the theory. I always thought that those magnetic size jets was fields of charged particles that travel space, i am talking about measure the interchanging field between *two objects* or *a chain of linked objects creating one field*. Well for the sake of simplicity let bend the plast tube to a noneclosed ring so we have accurate synchronisations in each end. I know the light postulate say so but is their any experimental evidence for gravity and magenetic fields travel with the speed of light? *If we could* measure the magnetic field of a red giant that go nova 65lightyear away, you tell that it would take 65 years until the field collapsed in our end because the field is propagating towards us at the speed of light. I think that is bullshit, when a gravitational or magnetic field collaps there is no remniscents that travel space. What kind of particles would that be? have they ever found these particles that make up magnetic and gravitational *field* in any lab? In sci.physics, Sam Wormley <swormley1@mchsi.com> wrote on Fri, 18 Jul 2008 22:26:12 GMT <7M8gk.259685$yE1.110617@attbi_s21>: >> If we somehow could align strongly repelling magnets in a straight >> plast tube along a 300 000 km line in space. [quoted text clipped - 5 lines] > are restricted by the cosmic speed limit, c... so says the > observations.... and the theory. Not to mention the OhMyGod particle, which despite its phenomenal energy (for a particle) is still traveling at only lightspeed (within measurement error). Signature#191, ewill3@earthlink.net Useless C++ Programming Idea #889123: std::vector<...> v; for(int i = 0; i < v.size(); i++) v.erase(v.begin() + i); ** Posted from http://www.teranews.com ** > If we somehow could align strongly repelling magnets in a straight > plast tube along a 300 000 km line in space. > > We then push the first one how long time would it take before our > gaussmeter in the other end noticed a change in the flux? Hey stupid - pop a flash bulb. If you wnat a tighter pulse, Q-switch a laser. Tighter pulse still? Chirp the Q-switch output. SignatureUncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) http://www.mazepath.com/uncleal/lajos.htm#a2 > jonas.thornv...@hotmail.com wrote: > [quoted text clipped - 10 lines] > Uncle Alhttp://www.mazepath.com/uncleal/ > (Toxic URL! Unsafe for children and most mammals)http://www.mazepath.com/uncleal/lajos.htm#a2 I always thought that those magnetic size jets was fields of charged particles that travel space, i am talking about measure the interchanging field between *two objects* or *a chain of linked objects creating one field*. Well for the sake of simplicity let bend the plast tube to a noneclosed ring so we have accurate synchronisations in each end. I know the light postulate say so but is their any experimental evidence for gravity and magenetic fields travel with the speed of light? *If we could* measure the magnetic field of a red giant that go nova 65lightyear away, you tell that it would take 65 years until the field collapsed in our end because the field is propagating towards us at the speed of light. I think that is bullshit, when a gravitational or magnetic field collaps there is no remniscents that travel space. What kind of particles would that be? have they ever found these particles that make up magnetic and gravitational *field* in any lab? On 19 Juli, 00:27, Uncle Al <Uncle...@hate.spam.net> wrote: >What kind of particles would that be? have they ever found these >particles that make up magnetic and gravitational *field* in any lab? As I understand it magnetic fields involve virtual photons but there is a bit of a problem detecting gravitons. First stop the Higgs. > If we somehow could align strongly repelling magnets in a straight > plast tube along a 300 000 km line in space. > > We then push the first one how long time would it take before our > gaussmeter in the other end noticed a change in the flux? http://www.physlink.com/Education/AskExperts/ae445.cfm Question Has the speed of propagation of a magnetic force field been measured? If so what is it? Asked by: Colin Coulton Answer The term magnetic force field implies the application of a force on a distant object, say a piece of iron, by a magnetic field. In order to generate a magnetic field that can be said to propagate, it is necessary to produce a changing field by turning on an electromagnet or removing a magnet from a magnetic shield such as a superconducting box. Changing magnetic fields are also produced around all radio transmitter antennas due to the changing current flowing in them. When a magnetic field is changing, it is always accompanied by a transverse electric field, i.e., it is an electromagnetic wave. The relationships between changing magnetic and electric fields are summarized in the well-known Maxwell's equations. Click here http://www.phys.virginia.edu/classes/109N/more_stuff/Maxwell_Eq.html for a more detailed mathematical derivation and description. The speed of electromagnetic waves is certainly known and is defined to be exactly 299,792,458 m/s in vacuum (same as the speed of light). Answered by: Scott Wilber, President, ComScire - Quantum World Corporation On Jul 19, 5:11 pm, "Cwatters" <colin.wattersNOS...@TurnersOakNOSPAM.plus.com> wrote: > <jonas.thornv...@hotmail.com> wrote in message > [quoted text clipped - 35 lines] > exactly 299,792,458 m/s in vacuum (same as the speed of light). > Answered by: Scott Wilber, President, ComScire - Quantum World Corporation Bravo (sound of applause in the background). No. I am not going to cite the analogy of a kink propagating down a rope, but somone else may. I believe that the comprehension problem that some readers encounter is that they simply do no realize that any change in a magnetic field is also accompanied by an electric field. Consequently, many readers do not realize that any time varied intensity of a magnetic or electric field constitutes an and ectromagnetic field with propagate the the velocity of light in that particular medium. The odd thing is that I have met 8-year old kids that when this is explained to them, they immediately grasp the concept. No, I did not attempt to teach any 8-year olds about Maxwell's Equations because of their limited math skill, but most will appreciate Faraday when taught to them in terms which they understand, and the effect are demonstrated to them though simple demonstrations. I have a 9-year old boy that lives next to me, and we sit sometimes for hour on the front porch discussing this stuff. Trust me, this kid is now more competent to tell anyone how a generator or motor functions, and the priciples of induction. Now what scares me is that he attend a public school, and likely already knows more about basic circuits and electromagnetism than likely does his future General Science teacher in middle school. The consequnce is predictable, unfortunately. The next time I speak to his dad, I'm going to suggest that this kid be placed in private school, if the family can afford it. Otherwise.... Then too, I will suggest that the kid undergo some admission testing, and if my guess is correct, he may be granted a full tuition scholarship, which is what I hope for. Actually, my pet frustation is the posters on sci.physics that have never read a physics textbook in their life, yet take it upon themselves to post their ignorant speculation and questions here on the newsgroup. Harry C. |
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