If a train is not aging faster than the station
in [Physics]
|
From: Sam Wormley on 9 Aug 2010 11:11 On 8/9/10 8:54 AM, Mathal wrote: > On Aug 8, 8:40 pm, Sam Wormley<sworml...(a)gmail.com> wrote: >> On 8/8/10 10:27 PM, Mathal wrote: >> >>> Given two objects passing in space, nothing can be said about their >>> velocities unless there is some shared history . >> >> Doppler radar. Laser ranging. > > You deliberately 'cut out' this statement from the whole post. I'm not > going to waste my time finding the post and cutting and pasting it > back together again. > > Sam, anything taken out of context can be misunderstood. > > Given, two frames that have a history but are presently unaware of it > encountering each other. > Each can take itself as stationary and the other frame as moving and > calculate the time frame the other will "appear" to be operating in > relative to their own. Each will 'believe' the other is moving in a > slower time frame if he takes himself to be stationary. There is no > way to determine their 'actual' velocity WRT that historical shared > frame- with any scientific instruments. > Therefore they will not be able to tell what the 'actual' difference > in each frames time is without that history. If WRT the historic frame > they are both moving at the same velocity there is no contraction in > either frame WRT each other- WRT the historical frame there is. > In the case of the twins it will be obvious to them when they meet who > was moving more than the other (from the shared frame). > Mathal How do you think we measure radial velocity of stars and galaxies. Don't need no history.
From: Inertial on 9 Aug 2010 20:28 "Mathal" wrote in message news:f134b6a8-4250-4c61-97e6-f369cf4a51ff(a)s24g2000pri.googlegroups.com... On Aug 8, 9:00 pm, "Inertial" <relativ...(a)rest.com> wrote: > "Mathal" wrote in message > > news:a75e62b4-3301-404f-b390-15921e6934f9(a)l25g2000prn.googlegroups.com... > > > In BURT's first post in this thread he stated that the train was > > moving and the station is relatively stationary. > > In the stations frame ... yes > > > Both Ken and BURT are > > probably addressing the idea that either frame can be considered the > > rest frame and the motion ascribed to the other frame. > > Which other frame? The train frame? In that frame the train is > stationary > and the station rushing toward it. > > > When the train > > is interpreted as motionless and the station moving- an illusion > > That's not an illusion > > > one > > sometimes gets of another train by the window when you start moving- > > anyway the station should have a slower time rate in this 'case'. > > Nope .. the cases are identical and symmetrical. However. whichever is > stationary in a given frame will measure whichever is moving as ticking at > a > slower rate. Both train and station see the other as moving. Both will > measure a slower rate for the others clock. (though BURT has failed the > challenge of describing how they would determine that) > > > This > > is really just an example of GIGO. > > GIGO from BURT and Key .. yes > > >SR will happily churn out 'yes > > you're right the moving station is in a slower time frame than the > > "stationary" train' because SR is mindless > > It is a theory.. it doesn't have a mind. > > >-give it a garbage > > hypothesis of events and it will give you a garbage interpretation of > > the events. > > There was no garbage hypothesis there > > > Given two objects passing in space, nothing can be said about their > > velocities unless there is some shared history > > Each can say something about the others velocity relative to them > > > . If they stop and > > compare histories they can determine if one or the other was moving > > faster > > They would find both were moving at the same (but opposite) speed > > > or if they were travelling at the same velocity -i.e. no time > > dilation. > > No .. you get time dilation dependent on speed. > > > Ken thinks SR can be and needs to be fixed. > > I dont. > > Neither do I, as it isn't broken. Your understanding of it (and physics) > seems to be. >Put synchronized clocks on the train and the station. Fine. And you'll get mutual time dilation. In particular (from station point of view .. train view you simply reverse the labels) .... If you have observers at either end of the station with synchronised clocks both looking at a single clock on the train, who each take a reading from the train clock as it passes them, will calculate that the train clock is running slow Conversely, a single observer on the station looking at two clocks on the train (one at front and one at back of train) who takes a reading of each clock as it passes him, will calculate that the train clocks are running fast >If you want to >treat the station as moving and the train as stationary the clocks >will show you that you're mistaken. Wrong. You can't tell which is moving at all. Clearly you don't understand SR and the physics involved. > Given -a history of two ships. They start stationary and move away >from each other at the same velocity and return similarly. Then there will be no difference in ages .. its the same profile > If they >measure their velocity WRT each other they can determine the >"apparent" contraction in the other frame which will differ from the >"apparent" contraction from the initial rest frame. What contraction . length contraction? Or do you mean time dilation (which is what we're talking about? > When they come to >a stop and compare their synchronized clocks, Is this when they turn around to return .. or when they have returned to meet? >the clocks of the moving >ships (relative to the "stationary' initial frame) will show less time >than the stationary clock but the two moving ships will be identical >because they were in the same time frame- their clocks moved at the >same rate throughout their journey. I know .. this is not related to the train and station scenario at all though > If you're having difficulty with > this I don't have any difficulty at all .. you seem confused though > consider the two ships moving in the same direction. Then you > will plainly see that the moving ships clocks will display identical > time throughout their journey. Yeah yeah .. all well knows .. and not relevant [snip more waffle] You really need to think some more here .. you don't yet get SR.
From: Mathal on 10 Aug 2010 10:07 On Aug 9, 8:11 am, Sam Wormley <sworml...(a)gmail.com> wrote: > On 8/9/10 8:54 AM, Mathal wrote: > > > > > > > On Aug 8, 8:40 pm, Sam Wormley<sworml...(a)gmail.com> wrote: > >> On 8/8/10 10:27 PM, Mathal wrote: > > >>> Given two objects passing in space, nothing can be said about their > >>> velocities unless there is some shared history . > > >> Doppler radar. Laser ranging. > > > You deliberately 'cut out' this statement from the whole post. I'm not > > going to waste my time finding the post and cutting and pasting it > > back together again. > > > Sam, anything taken out of context can be misunderstood. > > > Given, two frames that have a history but are presently unaware of it > > encountering each other. > > Each can take itself as stationary and the other frame as moving and > > calculate the time frame the other will "appear" to be operating in > > relative to their own. Each will 'believe' the other is moving in a > > slower time frame if he takes himself to be stationary. There is no > > way to determine their 'actual' velocity WRT that historical shared > > frame- with any scientific instruments. > > Therefore they will not be able to tell what the 'actual' difference > > in each frames time is without that history. If WRT the historic frame > > they are both moving at the same velocity there is no contraction in > > either frame WRT each other- WRT the historical frame there is. > > In the case of the twins it will be obvious to them when they meet who > > was moving more than the other (from the shared frame). > > Mathal > > How do you think we measure radial velocity of stars and galaxies. > Don't need no history. We are measuring the relative velocity of stars and galaxies WRT us. We can only speculate about their and our actual velocity from a shared rest frame- say the universe at the moment before the big bang . Mathal
From: Sam Wormley on 10 Aug 2010 10:34 On 8/10/10 9:07 AM, Mathal wrote: > We are measuring the relative velocity of stars and galaxies WRT us. > We can only speculate about their and our actual velocity from a > shared rest frame- say the universe at the moment before the big > bang . > Mathal The actual velocity measures are quite accurate! The observer's frame is sufficient for the measurements.
From: BURT on 10 Aug 2010 20:31
On Aug 9, 5:28 pm, "Inertial" <relativ...(a)rest.com> wrote: > "Mathal" wrote in message > > news:f134b6a8-4250-4c61-97e6-f369cf4a51ff(a)s24g2000pri.googlegroups.com... > > On Aug 8, 9:00 pm, "Inertial" <relativ...(a)rest.com> wrote: > > > > > > > "Mathal" wrote in message > > >news:a75e62b4-3301-404f-b390-15921e6934f9(a)l25g2000prn.googlegroups.com.... > > > > In BURT's first post in this thread he stated that the train was > > > moving and the station is relatively stationary. > > > In the stations frame ... yes > > > > Both Ken and BURT are > > > probably addressing the idea that either frame can be considered the > > > rest frame and the motion ascribed to the other frame. > > > Which other frame? The train frame? In that frame the train is > > stationary > > and the station rushing toward it. > > > > When the train > > > is interpreted as motionless and the station moving- an illusion > > > That's not an illusion > > > > one > > > sometimes gets of another train by the window when you start moving- > > > anyway the station should have a slower time rate in this 'case'. > > > Nope .. the cases are identical and symmetrical. However. whichever is > > stationary in a given frame will measure whichever is moving as ticking at > > a > > slower rate. Both train and station see the other as moving. Both will > > measure a slower rate for the others clock. (though BURT has failed the > > challenge of describing how they would determine that) > > > > This > > > is really just an example of GIGO. > > > GIGO from BURT and Key .. yes > > > >SR will happily churn out 'yes > > > you're right the moving station is in a slower time frame than the > > > "stationary" train' because SR is mindless > > > It is a theory.. it doesn't have a mind. > > > >-give it a garbage > > > hypothesis of events and it will give you a garbage interpretation of > > > the events. > > > There was no garbage hypothesis there > > > > Given two objects passing in space, nothing can be said about their > > > velocities unless there is some shared history > > > Each can say something about the others velocity relative to them > > > > . If they stop and > > > compare histories they can determine if one or the other was moving > > > faster > > > They would find both were moving at the same (but opposite) speed > > > > or if they were travelling at the same velocity -i.e. no time > > > dilation. > > > No .. you get time dilation dependent on speed. > > > > Ken thinks SR can be and needs to be fixed. > > > I dont. > > > Neither do I, as it isn't broken. Your understanding of it (and physics) > > seems to be. > >Put synchronized clocks on the train and the station. > > Fine. And you'll get mutual time dilation. > > In particular (from station point of view .. train view you simply reverse > the labels) .... > > If you have observers at either end of the station with synchronised clocks > both looking at a single clock on the train, who each take a reading from > the train clock as it passes them, will calculate that the train clock is > running slow > > Conversely, a single observer on the station looking at two clocks on the > train (one at front and one at back of train) who takes a reading of each > clock as it passes him, will calculate that the train clocks are running > fast > > >If you want to > >treat the station as moving and the train as stationary the clocks > >will show you that you're mistaken. > > Wrong. You can't tell which is moving at all. Clearly you don't understand > SR and the physics involved. > > > Given -a history of two ships. They start stationary and move away > >from each other at the same velocity and return similarly. > > Then there will be no difference in ages .. its the same profile > > > If they > >measure their velocity WRT each other they can determine the > >"apparent" contraction in the other frame which will differ from the > >"apparent" contraction from the initial rest frame. > > What contraction . length contraction? Or do you mean time dilation (which > is what we're talking about? > > > When they come to > >a stop and compare their synchronized clocks, > > Is this when they turn around to return .. or when they have returned to > meet? > > >the clocks of the moving > >ships (relative to the "stationary' initial frame) will show less time > >than the stationary clock but the two moving ships will be identical > >because they were in the same time frame- their clocks moved at the > >same rate throughout their journey. > > I know .. this is not related to the train and station scenario at all > though > > > If you're having difficulty with > > this > > I don't have any difficulty at all .. you seem confused though > > > consider the two ships moving in the same direction. Then you > > will plainly see that the moving ships clocks will display identical > > time throughout their journey. > > Yeah yeah .. all well knows .. and not relevant > > [snip more waffle] > > You really need to think some more here .. you don't yet get SR.- Hide quoted text - > > - Show quoted text - The twins age differently but the slow is mutual? No. Mitch Raemsch |