Difference between timelike and space like events

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Discussion Overview

The discussion centers on the distinction between timelike and spacelike events in the context of spacetime intervals. Participants explore the definitions and properties of these concepts, providing examples and clarifications related to their mathematical underpinnings.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants assert that an event itself is neither timelike nor spacelike; these properties apply to pairs of events based on their spacetime interval.
  • One participant explains that if two events can be occupied by a massive object, such as a clock, the interval is timelike, allowing for a measurable time period between them.
  • Another participant notes that if a ruler can measure the spatial distance between two events with equal time coordinates, the interval is spacelike.
  • It is mentioned that if neither condition is met, the interval is null or lightlike, indicating that a photon could be present at both events.
  • Some participants emphasize that the distinction between timelike and spacelike is a property of the separation between pairs of events, not of the events themselves.

Areas of Agreement / Disagreement

Participants generally agree that timelike and spacelike are properties of pairs of events, but there is disagreement on the necessity of defining events in terms of these properties. Some participants challenge the need for examples, suggesting that the mathematical definitions are sufficient.

Contextual Notes

Participants reference the importance of light cones in determining the separation of events and the implications for their classification as timelike or spacelike. There is an acknowledgment of the mathematical framework underlying these concepts, though some assumptions about the nature of events and their separations remain implicit.

Who May Find This Useful

This discussion may be useful for individuals interested in the foundational concepts of relativity, spacetime geometry, and the mathematical relationships between events in physics.

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hi, I need an explanatory difference between timelike and space like events . examples will do, i know the mathematics
regards
 
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First of all, an event by itself is neither timelike or spacelike. You have to have a pair of events and then the spacetime interval between those two events can be timelike or spacelike or null, depending on the specific events.

Recall that an event has four coordinate, one of time and three of space. If the two events in question can be occupied by a single small inertial object with mass, such as a clock, then the spacetime interval is timelike and the period measured by the clock is the interval.

If it is not possible for a massive object to be present at both events, then the question is can a ruler measure the spatial distance between the two event such that the time coordinates for the two events are equal. In this case the spacetime interval is spacelike and the ruler measures the interval.

If neither of the above are true, then the spacetime interval is null, meaning that it isn't either of the above. Sometimes it is called lightlike, meaning that a photon can be present at both events.

It's important to realize that the spacetime interval for any two events is either a space interval or a time interval or it's not an interval.
 
No such thing - events are points in space-time and so are neither time-like nor space-like.
If you know the maths then you already know the difference between time-like and space-like intervals.
JIC: https://www.physicsforums.com/showthread.php?t=195101

[edit] beaten to it :)
 
An event in itself cannot be time- or space-like. This is a property of a pair of events that can have time- or space-like separation. Time-like separated events are within each other's light cones and will always occur at different times in all frames while events with space-like separation are outside of each other's light cones and will be at different spatial points in all frames.
 

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