MPMin

Thank you for your answer. You state that both observers A and C see each other’s respective clocks ticking slower. Is that because they are effectively moving away from each other? Does the apparent slower ticking occur because the photons take longer to reach each observer, and if so, does that mean each observer is seeing fewer photons because they are arriving less frequently due to the Doppler effect, and does that mean that red shifted light is inherently dimmer than the original source?

Thank you for the link. I have not yet been able to establish an answer to my query from the other discussions. Perhaps if i restate the thought experiment and ask questions about that might make it clearer to my understanding. The thought experiment is as follows: Let’s assume there are two clock towers facing each other along a straight track. All conditions effecting the two clock towers are negligible. Let’s also assume there is a train positioned at one end of the track and lets assume there is an observer at each clock tower and on the train, and the observer on the train also has a clock. Lets also assume that all observers can see all clocks all the of the time. The train will travel from one clock tower to the other, however, before the train leaves, the train is stationary at one end of the track right next to one of the clock towers. Let’s call the point of origin clock tower A and observer A, the destination clock tower B and observer B and the clock on the train clock C and observer C. To be clear, each observer remains in with their respective clocks and while the train is stationary at clock tower A all clock appear to tick at the same rate to all observers. Let’s assume the train has left clock tower A (point of origin) travelling towards clock tower B (point of destination) and has reached a constant velocity towards clock tower B, the following questions are with reference to this situation. How does observer A (at point of origin) perceive the ticking rate of clock C (on the train) How does observer B (at point of destination) perceive the ticking rate of clock C (on the train) How does observer C (on the train) perceive the ticking rate of clock A (at origin), B (at destination) and C (on the train) just wondering if the observer on the train perceives any difference to the ticking rate of the clock on the train? Edited for spelling and grammar.

Continuing with the thought experiment, if Einstein were to turn around to observe the clock on the tower that the train was heading towards, would the approaching clock on the tower appear to tick slower or faster?

If I understand Einstein’s clock tower thought experiment correctly, Einstein saw himself on a train traveling away from a clock that was situated on a clock tower. From Einstein’s perspective, the hands of the receding clock would have appeared to be moving slower, hence, giving the illusion that the clock’s time had slowed down. Is this correct? If my understanding of the thought experiment is correct, does that also mean that the clock should have red shifted towards the red spectrum as well? I apologise if I’ve posted this in the incorrect section. My question is a theoretical physics question.

The purpose of life is to make choices

By launching do you mean the launching movement through space is what causes the desynchronisation?

With reference to space expansion, what would an observer see if they were between myself and the distant point? My understanding of synchronised means the two clocks indicate the same amount of time has passed, in phase just means they are ticking at exactly the same time. If as per my analogy, if you were an observer between the two clocks that were originally synchronised on earth but now one is in orbit, it would now seem that if you could see both clocks while being between them they would no longer be in synch?

Does the ‘own frame of reference’ perspective mean that the timing of the engine (or atomic clock) for the purposes of time keeping are consistent with its own perspective or experience of time? My uncertainty about ‘frame of reference’ when referencing ones own perspectives/experience causes me to wonder when do the clocks actually diverge from each other? Does the disparity between the clocks only occur when the clocks are reunited because that’s the only time they can be compared or does half of the disparity between the clocks occur when one of the clocks is half way through it’s journey to space and back? I’m also wondering, when considering ones own frame of reference, would one always experience time to be the same (unchanging) regardless of their position or environment changing, and, would that also mean you wouldn’t notice space contracting or expanding either?

To help me better understand I’d like to explore the following hypothetical. Assuming this engine was a precision piece of engineering that ran at a perfectly constant RPM, you could then consider the engine to be a time piece of sorts as well as an engine. If you now had two of these engines perfectly synchronised on earth and sent one of the engines in to outer space (excluding all the practical factors required to make an engine run) to be in the same orbital plane around the sun as the earth and outside of the earth’s influence of gravity, the engine on the earth would run a little faster than the one in space even though both engines are moving through space at the same velocity relative to each other. Would the engine on earth continue to gain RPM’s over the engine in space or would the disparity in RPMs remain constant once the engine that was sent to space was in a stable orbit around the sun? What I’m essentially asking with reference to hypothetical is does the disparity in RPM occur because the engine that was sent into space experienced a different path through space to arrive at it’s new position or does the RPM disparity occur because the engine on the earth is in earth’s gravity well or do both factors cause a disparity in the RPMs?

Thank you all for reacting to my questions. My reaction is firstly, it was not my intention to start a new thread. The subject of ‘flat universe’ was raised in my previous thread and I asked for clarification. I do however appreciate this new thread to further expand my learning. On the subject of the universe with reference to parallel lines, there seems to be some definitive wriggle room due to colloquialisms. My understanding of parallel lines is that two parallel lines do not intersect or diverge on a two dimensional plane. However, when considering parallel lines in a three dimensional context then the parallel lines require another qualifying feature to contextualise the lines for the purpose of the intended discussion. The word ‘straight’ must accompany the term parallel when describing the lines in the context of converging or diverging when travelling through the three dimensional universe. I’d argue that lines following the contour of a sphere may be parallel in some respects but they can not be considered as being straight lines and as such are out of context when considering ‘parallel straight’ lines travelling through the universe. My understanding of ‘parallel straight lines’ (or ‘straight parallel lines’ grammar aside) is that they will never intersect or diverge unless acted upon by an external force or influence. Perhaps the whole is the universe flat debate is just a confusion of the terms with reference to geodesic lines because if the lines were truly flat and straight then there’s no reason for them to intersect or diverge unless they weren’t truly straight and parallel to begin with just like the lines of longitude and latitude are not truly straight and parallel. To my understanding, the key issue is the lines must be straight and parallel simultaneously. I would therefore deduce that if two lines were truly straight and parallel and never intersected or diverged (unless acted upon) then the universe must be infinite.

Perhaps I’m just not getting the concept of time. I cant see how time is inextricably linked to space as described by the ‘space time’ model because; for example, two identical clocks that are side by side on earth experience the same time as each other and consequently identically indicate that the same amount of time has past. However, if you then send one of those two clocks out into space and bring it back to it’s place of origin the two clocks will no longer show that the same amount of time has past. It would appear to me that the clock that went to space and back experienced less time because there is less of it (or perhaps the frequency of time is less) out in space than it is on earth.

I don’t want to go off track understanding time but I think I’m getting confused over the ‘universe is flat’ perspective. Does the universe being ‘flat’ just mean it is infinite in every direction?

Yes, and I understand that’s correct if you completely accept the current model of space time. I’m not asking if ‘time’ being attracted to gravity is likely, I’m just asking if time being attracted to gravity is in any way possible as an alternative hypothesis to the current model? In other words, in consideration of the fact that the current model is a theory, without specifically referencing the current theory, what’s the independently observable reason that time can not be attracted to gravity?

Aside from time being considered as part of the standard model of ‘space time’ is there any reason why as an alternative hypothesis that time could not be attracted to gravity?

Does that mean that em waves leaving the sun’s surface are of a higher frequency than when they reach an observer at the edge of the solar system?

Does the electromagnetic radiation climbing out of a gravity well only stretch while climbing out of the gravity well or does it stay stretched even after it’s left the gravity well? To help me understand this better, if you were able to shine two beams of light with exactly the same frequency, if you were to shine one of the beams of light from Jupiter to an observer in feee space and the other identically produced beam of light from a place with no gravity to the observer, would the beam of light from Jupiter be red shifted from the observer’s point of view? also assuming all distances remained constantly the same

Perhaps where I’m going wrong is referring to the very large mass as a black hole because what I’m getting is it wouldn’t be a black hole by definition if anything could escape it. So to revise my questioning, instead of referring to black holes in my questions I meant to refer to very large masses that are capable of significantly reducing radiation because I’m trying to understand if radiation is red shifted when emitted from very large masses?

But hypothetically speaking, for the sake of my understanding, assuming Gammas were being emitted from within a black hole and assuming the gravity of the black hole was not strong enough to reduce the frequency of the gammas to nil but only strong enough to reduce the gammas to a lesser frequency then could it be hypothetically possible the gammas to be emitted as visible light?

If I understood a previous explanation properly, it suggest that gravity reduces the frequency of electromagnetic radiation as it moves away from the source of gravity. If I’ve understood this correctly then hypothetically speaking, if gamma rays were being emitted inside a black hole, assuming the gravity of the black hole was not great enough to reduce the frequency of the gamma rays to nil, the gamma ray’s frequency could be reduced to a visible light frequency hypothetically speaking.

To help me better understand this concept, hypothetically speaking, gamma rays could potentially escape as visible light? Would we then expect to see a narrow circular rainbow at the event horizon?

Thanks for the explanation

I still find it unintuitive that gravity doesn’t slow light down. Considering some light at the event horizon of a black hole. I’d intuitively think that light just escaping the event horizon would be slower than light out in space. When I imagine a fast moving object in space passing by a planet, the planets’s gravity would alter its trajectory and gravity does a similar thing to light in similar circumstances. I don’t understand why gravity can slow an object with mass down or speed it up (accelerate/decelerate depending on the direction) but can’t do the same to light when apparently all these affects are caused by the geometry of space time. It seems to me that the geometry of space time can change the direction of light and moving objects in a similar way when they are passing by a large mass but the geometry of space time only applies to objects with mass and not light when they move toward or away from a large mass

That’s interesting in itself. If I’m not mistaken, the gravity of a black hole is so great that it can prevent light from leaving it. I find it odd that gravity can stop light but can’t slow it down.

I don’t think the twins observing the clocks paradox invalidates my hypothesis as light would travel at the same speed in both directions in any event I think. In the Space Time Model, Gravity can bend light as it passes near a large object, the light travels around this geometric path which can be visualised as moving past the upper edge of a funnel causing a deviation from a straight path. My hypothesis suggests there is no space time continuum. Space is just space ( I would suspect that nothing would exist without space let alone time) and time is just time. If you consider the space time geometry of gravity and how it can bend light, does light travel slower as it’s leaving a large mass and then accelerate once it’s out of the gravitational field?

I’m positing this post about time as a hypothesis for consideration only. If it needs to be moved to a more appropriate place please do so. The current accepted model of time is that it’s linked to space called the space time continuum. But instead of it being seen a fabric of space time, what if time is just attracted to gravity just like matter is? My hypothetical view of time being attracted to gravity suggests that time becomes denser the closer time is to large masses in a similar way the atmosphere is denser closer to earth. Im proposing that time takes longer to pass through closer to earth because it’s denser than time in space. Does looking at time from the point of view that it’s attracted to gravity rather than being seen as a part of the fabric of space actually change anything?