Coordinate and time transformations

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Discussion Overview

The discussion revolves around the Galilean and Lorentz transformations, focusing on the implications of coordinate and time assignments in relation to the transmission of information about events in spacetime. Participants explore the conceptual understanding of how events can be described using coordinates despite the limitations of information transmission speed.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how events occurring away from an observer can be described instantaneously by coordinates, given that information can only travel at the speed of light, suggesting a potential disconnect between theory and practical measurement.
  • Another participant argues that coordinates are merely labels assigned to events in spacetime, independent of the actual transmission of information.
  • A different viewpoint emphasizes the role of an observer in an inertial reference frame, suggesting that events are recorded at specific locations rather than transmitted to a central observer.
  • One participant draws an analogy to assigning coordinates to the Earth, stating that systematic labeling allows for the description of events that may not yet be observed, highlighting the distinction between observation and assignment of coordinates.
  • A later post reiterates concerns about measuring distances and the necessity of traveling to a location to gather data, indicating that comparisons of recorded data are essential for determining simultaneity of events.

Areas of Agreement / Disagreement

Participants express differing views on the nature of coordinates and their relationship to information transmission. There is no consensus on the implications of these transformations or how they relate to the practical measurement of events.

Contextual Notes

Participants acknowledge limitations in understanding how events can be described without direct observation, as well as the dependence on systematic assignment of coordinates. The discussion does not resolve these issues, leaving several assumptions and conditions unaddressed.

Who May Find This Useful

Readers interested in the conceptual foundations of coordinate systems in physics, particularly in the context of relativity and measurements in spacetime, may find this discussion relevant.

Ahmed1029
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In describing the Galelian or Lorentz transformations, All books I've read keep talking about clocks and meter sticks, but I don't see how an event happening away from the observer could be instantaneously described by a set of coordinates and a point in time; information conveying the event travels at most at the speed of light and measurement is only going to be detecting its past. In the light of this, what do those transformations really say?
 
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Coordinates have nothing to do with information actually being transmitted. It is an assignment of number labels to events in spacetime.
 
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When you talk about an observer in an inertial reference frame, you can imagine that there is an observer, stationary at every point of his reference frame, who records events. It is really a matter of how events would be recorded at those locations in his reference frame, not how that information would be transmitted to him at a central location.
 
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There is nowhere you can stand where you can see the whole surface of the Earth, yet somehow we manage to assign coordinates to all of it (excluding one point, for the pedantic).

Coordinates are just labels we assign to events. As long as we assign them systematically we can assign them to events we can't see yet. We don't know what happened (if anything) at those events until we see them, but that doesn't matter. It's just the same as drawing a grid and filling in the map as we explore.
 
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Ahmed1029 said:
In describing the Galelian or Lorentz transformations, All books I've read keep talking about clocks and meter sticks, but I don't see how an event happening away from the observer could be instantaneously described by a set of coordinates and a point in time; information conveying the event travels at most at the speed of light and measurement is only going to be detecting its past. In the light of this, what do those transformations really say?
When you measure the distance to something at some point you actually have to travel the distance to get there in order to measure it. (Or some other similar method.) You might think of it as the events that are talked about in these problems are times people recorded at certain positions and the data are compared later when the people get together. When the data are compared, only then we can start making statements about if the times for events are simultaneous or not.

Then once the theory is proven we can just use the Mathematics to figure out speeds and distances and such.

-Dan
 
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Thank you guys I got the point!
 
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