michel123456 Posted October 7, 2019 Share Posted October 7, 2019 (edited) e are living in an accelerated world: have a look at the picture below We know that the distance between the poles is D. What appears to us is d4 larger than d3, larger than d2, larger than d1 etc If you are looking toward a motorcycle coming at you at constant velocity, what will you see? You will see the bike travelling d1 in say 1 sec, d2 in 1 sec, d3 in 1 sec, d4 in 1 sec. IOW you will see it coming slowly from far away, then progressively accelerating and suddenly wizzz in front of your eyes, then vanishing slowly to the horizon on the other direction. Like this: (link to a FB page with a Kawa at high speed) https://www.facebook.com/Kawasakicontact/videos/2728924687158606/UzpfSTEwMDAwMzIzNDE0NjE4NToyNjQwNjg1Mzk2MDQ5MjM5/?id=100003234146185&__tn__=%2CdlC-R-R&eid=ARBelMYfc-RJjAd_mXYlZx6caClxobLbN35at8MbKRlvdlHP8Er__IHh671LLBzYt5XUo6uQ7NtRryeG&hc_ref=ARSdLXkLSE5Ur04hkZaY8o5B1UndaVN0aNDCH7aAba-95_DHRFTDMStvEIKfKkQ23hQ It means that the effect of perspective transforms the constant motion into accelerated motion, for anything coming from far away in your direction. It means that even photons that reach your eyes must appear accelerated. Edited October 7, 2019 by michel123456 Link to comment Share on other sites More sharing options...
dimreepr Posted October 7, 2019 Share Posted October 7, 2019 3 minutes ago, michel123456 said: e are living in an accelerated world: have a look at the picture below We know that the distance between the poles is D. What appears to us is d4 larger than d3, larger than d2, larger than d1 etc If you are looking toward a motorcycle coming at you at constant velocity, what will you see? You will see the bike travelling d1 in say 1 sec, d2 in 1 sec, d3 in 1 sec, d4 in 1 sec. IOW you will see it coming slowly from far the accelerating and suddenly wizzz in front of your eyes. Like this: https://www.facebook.com/Kawasakicontact/videos/2728924687158606/UzpfSTEwMDAwMzIzNDE0NjE4NToyNjQwNjg1Mzk2MDQ5MjM5/?id=100003234146185&__tn__=%2CdlC-R-R&eid=ARBelMYfc-RJjAd_mXYlZx6caClxobLbN35at8MbKRlvdlHP8Er__IHh671LLBzYt5XUo6uQ7NtRryeG&hc_ref=ARSdLXkLSE5Ur04hkZaY8o5B1UndaVN0aNDCH7aAba-95_DHRFTDMStvEIKfKkQ23hQ It means that the effect of perspective transforms the constant motion into accelerated motion, for anything coming from far away in your direction. It means that even photons that reach your eyes must appear accelerated. Well, it's useful when crossing the road. Link to comment Share on other sites More sharing options...
MigL Posted October 7, 2019 Share Posted October 7, 2019 That has to do with how light converges into your eye ( or a camera ), not with any acceleration. Link to comment Share on other sites More sharing options...
Strange Posted October 7, 2019 Share Posted October 7, 2019 28 minutes ago, michel123456 said: It means that the effect of perspective transforms the constant motion into accelerated motion, for anything coming from far away in your direction. And when a ship sails away into the distance, you can hear the screams of the passengers being crushed as it gets smaller. Link to comment Share on other sites More sharing options...
swansont Posted October 7, 2019 Share Posted October 7, 2019 1 hour ago, michel123456 said: e are living in an accelerated world: have a look at the picture below We know that the distance between the poles is D. What appears to us is d4 larger than d3, larger than d2, larger than d1 etc Which is due to geometry, not acceleration. Notice how the poles are getting shorter, too. Is that supposed to be acceleration as well? 1 hour ago, michel123456 said: It means that even photons that reach your eyes must appear accelerated. No. Link to comment Share on other sites More sharing options...
Eise Posted October 8, 2019 Share Posted October 8, 2019 16 hours ago, michel123456 said: It means that the effect of perspective transforms the constant motion into accelerated motion, for anything coming from far away in your direction. The angular velocity, from your position, increases, but the linear velocity does not change. 16 hours ago, michel123456 said: It means that even photons that reach your eyes must appear accelerated. No idea why that would follow. What about the Doppler effect? Link to comment Share on other sites More sharing options...
michel123456 Posted October 8, 2019 Author Share Posted October 8, 2019 2 hours ago, Eise said: No idea why that would follow. What about the Doppler effect? Because it behaves like the bike (have you clicked the link?). 18 hours ago, swansont said: Which is due to geometry, not acceleration. Notice how the poles are getting shorter, too. Is that supposed to be acceleration as well? The poles look like getting shorter yes. Due to geometry, yes. The poles are not accelerated, but an object going from one pole to the other looks like accelerating. At the horizon, the object motion will look null (zero motion). Next to you the motion will look maximum. In order to get from zero to maximum, acceleration must have taken place (as observed). Link to comment Share on other sites More sharing options...
Strange Posted October 8, 2019 Share Posted October 8, 2019 6 minutes ago, michel123456 said: Because it behaves like the bike (have you clicked the link?). If a bike is coming towards you then the wheels will not look circular which, by your reasoning, would mean a very bumpy ride. Link to comment Share on other sites More sharing options...
michel123456 Posted October 8, 2019 Author Share Posted October 8, 2019 18 hours ago, swansont said: No. I like your argumentation. Link to comment Share on other sites More sharing options...
Strange Posted October 8, 2019 Share Posted October 8, 2019 In case anyone else is reluctant to follow the link, it is just a video of a motorbike. It makes as much sense as the rest of the opening post (ie none). 19 hours ago, michel123456 said: It means that even photons that reach your eyes must appear accelerated. What does an “accelerated photon” look like? How much faster than c do you think it is going? Link to comment Share on other sites More sharing options...
michel123456 Posted October 8, 2019 Author Share Posted October 8, 2019 (edited) 41 minutes ago, Strange said: In case anyone else is reluctant to follow the link, it is just a video of a motorbike. What video format is compatible to upload directly here? (not from Youtube) Look at the video again. First second, the bike is far away. At about sec 3 the bike is still away. At about sec 4 the bike suddenly appears and wizzzz. The same thing happens when you are in motion. I suggest to take attention the next time you will drive your car, and notice how the poles appear slowly in the background and look like accelerating when you pass them. Look at the poles & the bushes at the extreme right of the video. They disappear in a glimpse. At the center (the vanishing point at the horizon) the seem motionless. I know it is so usual that it is difficult to analyze. I understand your sarcastic comments. All the objects look like expanding as they approach. The distance between the objects looks like expanding too. But the time needed to go from one object to the other remains the same. An increased ratio of distance versus time is an acceleration. As observed because of geometry. Edited October 8, 2019 by michel123456 Link to comment Share on other sites More sharing options...
Sensei Posted October 8, 2019 Share Posted October 8, 2019 I have deja vu.. Many years ago there was a thread about it.. Link to comment Share on other sites More sharing options...
Eise Posted October 8, 2019 Share Posted October 8, 2019 (edited) 1 hour ago, michel123456 said: 4 hours ago, Eise said: No idea why that would follow. What about the Doppler effect? Because it behaves like the bike (have you clicked the link?). The photons must accelerate because the bike does??? And no, I did not look at the link, because it is on facebook. 1 hour ago, michel123456 said: At the horizon, the object motion will look null (zero motion). Next to you the motion will look maximum. It looks like that, but it isn't. The bike looks smaller, but it is not. 1 hour ago, michel123456 said: In order to get from zero to maximum, acceleration must have taken place (as observed). 'As observed', yes, but not in reality. The poles look closer to each other, but they are not. If you from your position could see how many poles the bike would pass per time, it would not change. The only thing you do is describing the movement of the bike in polar coordinates. But a constant velocity, described in polar coordinates, does not lead to a constant angular velocity. A change of coordinate system does not change what is actual occurring. 1 hour ago, michel123456 said: I like your argumentation. You did not argue for your view point, that's why I am asking: why do 'photons that reach your eyes must appear accelerated'? Under these circumstances Swansont's 'No' suffices. Does this drawing help? Edited October 8, 2019 by Eise Link to comment Share on other sites More sharing options...
Strange Posted October 8, 2019 Share Posted October 8, 2019 50 minutes ago, michel123456 said: Look at the video again. First second, the bike is far away. At about sec 3 the bike is still away. At about sec 4 the bike suddenly appears and wizzzz. Perspective has been known about for several centuries. 51 minutes ago, michel123456 said: I understand your sarcastic comments. Do you? Do you realise that your claims of "acceleration" is exactly as sensible as worrying that the passengers in a cruise ship will be crushed as it sails off into the distance? Link to comment Share on other sites More sharing options...
swansont Posted October 8, 2019 Share Posted October 8, 2019 1 hour ago, michel123456 said: The poles look like getting shorter yes. Due to geometry, yes. The poles are not accelerated, but an object going from one pole to the other looks like accelerating. But it's the same effect of geometry. Why is one acceleration and the other isn't? Quote At the horizon, the object motion will look null (zero motion). Next to you the motion will look maximum. In order to get from zero to maximum, acceleration must have taken place (as observed). Because of geometry. The change in angle gets smaller as the distance increases (as Eise's drawing demonstrates). But acceleration is not defined in terms of angles. Link to comment Share on other sites More sharing options...
Strange Posted October 8, 2019 Share Posted October 8, 2019 1 hour ago, michel123456 said: As observed because of geometry. Are you trying to make some point about relativity (where the effects are also due to geometry)? Link to comment Share on other sites More sharing options...
michel123456 Posted October 8, 2019 Author Share Posted October 8, 2019 54 minutes ago, Strange said: Do you realise that your claims of "acceleration" is exactly as sensible as worrying that the passengers in a cruise ship will be crushed as it sails off into the distance? I am talking about observation, not about what "really" happens. Of course the passengers are not crushed. Exactly as in Relativity, the pilot of the spaceship is not crushed by length contraction. Both are an effect of geometry as observed. 33 minutes ago, Strange said: Are you trying to make some point about relativity (where the effects are also due to geometry)? That was not my intention. The question about the observed state of motion is enough. Link to comment Share on other sites More sharing options...
J.C.MacSwell Posted October 8, 2019 Share Posted October 8, 2019 1 hour ago, Sensei said: I have deja vu.. Many years ago there was a thread about it.. I think FatherTed straightened us out in that one: 1 Link to comment Share on other sites More sharing options...
Eise Posted October 8, 2019 Share Posted October 8, 2019 14 minutes ago, michel123456 said: The question about the observed state of motion is enough. So again: why would that lead to you observing photons getting faster? Link to comment Share on other sites More sharing options...
swansont Posted October 8, 2019 Share Posted October 8, 2019 49 minutes ago, michel123456 said: I am talking about observation, not about what "really" happens. Of course the passengers are not crushed. Exactly as in Relativity, the pilot of the spaceship is not crushed by length contraction. Both are an effect of geometry as observed. But lengths measured by the ship are actually shorter than lengths measured by a stationary observer. If you measured the lengths between posts in your diagram (e.g. by bouncing photons off of them and measuring the time interval), they would be equal. Link to comment Share on other sites More sharing options...
Strange Posted October 8, 2019 Share Posted October 8, 2019 1 hour ago, michel123456 said: I am talking about observation, not about what "really" happens. OK. So you agree that nothing is really accelerated by perspective. So... Quote It means that even photons that reach your eyes must appear accelerated. What does an accelerated photon look like? And, as you agree it is not "really" accelerated, why mention it? Link to comment Share on other sites More sharing options...
MonDie Posted October 8, 2019 Share Posted October 8, 2019 (edited) Maybe I should be a psychological physicist. We humans try to subjectively model the objective world that we must survive in, and we generally communicate in objective terminology such that the only motion is the objective motion that is the same for all observers, although we might occasionally discuss (inter)subjective motion with a person who shares our perspective. That is, subjective motion isn't really motion in the same way that the alien in AVP doesn't really exist. The more interesting quandary is not that subjective thought is accomodating the objective world it occupies, but that objective laws have constrained the way that we see the objective world. Factor analysis techniques might suggest that, psychologically, the concept of dimensionality might be more fundamental than the concept of space. Spatially, we don't see a two-dimensional world, but a three dimensional one. This tendency/ability is measured by the Mental Rotation Task (BTW girls are still better at algebra, statistically). I think we intuitively, and mistakenly, associate three-dimensionality with the cube—perhaps this reflects our bilateral, rather than radial, physiological organization, or merely our third-grade indoctrination with Cartesian coordinate grids—, but squares are polygons and there are no polygons below the triangle. What we really have is two circular lenses placed upon a spherically moving head, but the planet might be a better example. We live in cubical homes and use four-directional compasses that reflect our two-dimensional system of longitude-and-latitude, but we also move altitudinally up above or down below. Below motion is with gravity and toward our planet's center and above motion is against or away, and nobody can dispute the profound relevance of this axis of movement. However, why do we always plaster our globes with a checkered, longitude/latitude surface? With three directions, we get a honey-combed surface, and with three dimensions (six directions), we might have something like longitude/latitude. It seems more reasonable to illustrate two-dimensional, circularly-oriented movement of an entity who is placed upon a two-dimensional, spherical surface which exists within a three-plus-dimensional world. What remains unclear to me is how we could use this terminology to describe the subjective-objective interplay of your examples. The spherical perspective still permits applications of the inverse square law (although one might wonder why it isn't an inverse honeycomb law!?!?!). This allows for the objective space being covered to expand as the distance from the observer increases. This means could explain why the objective motion looks like less motion subjectively. October 8th, 11:45 AM CST Edited October 8, 2019 by MonDie Link to comment Share on other sites More sharing options...
michel123456 Posted October 8, 2019 Author Share Posted October 8, 2019 4 hours ago, Strange said: OK. So you agree that nothing is really accelerated by perspective. So... What does an accelerated photon look like? And, as you agree it is not "really" accelerated, why mention it? Replace the photon with a bullet. the bullet will look like accelerating, until it hits your retina (and you are dead). So with the photon it is likewise. Except you do not die, you see. Link to comment Share on other sites More sharing options...
Strange Posted October 8, 2019 Share Posted October 8, 2019 1 minute ago, michel123456 said: Replace the photon with a bullet. the bullet will look like accelerating, until it hits your retina (and you are dead). So with the photon it is likewise. Except you do not die, you see. How is an "accelerating photon" different from one that is not accelerating? Link to comment Share on other sites More sharing options...
michel123456 Posted October 8, 2019 Author Share Posted October 8, 2019 1 hour ago, Strange said: How is an "accelerating photon" different from one that is not accelerating? The only photon you can directly observe is the one that hits your eye. Link to comment Share on other sites More sharing options...
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