Explaining 4D Space-Time in Simple Terms

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    4d Space-time Terms
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Discussion Overview

The discussion revolves around the concept of 4D space-time, with participants seeking simple explanations and examples to clarify their understanding. The scope includes conceptual clarification and examples related to the theory of space-time.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that 4D space-time can be understood as a combination of three spatial coordinates (x, y, z) and one temporal coordinate (t), forming an "event" represented as (t, x, y, z).
  • One participant provides an example involving an appointment, illustrating how spatial coordinates and a time coordinate are necessary to specify an event.
  • Another participant questions the need for additional examples, suggesting that asking for examples of space-time is akin to asking for examples of space itself.
  • There is a distinction made between an example of an event and an example of space-time, with some participants expressing differing views on the relevance of this distinction.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and interpretation of examples related to space-time. There is no consensus on the necessity or clarity of additional examples, and the distinction between events and space-time remains contested.

Contextual Notes

Some participants acknowledge that the examples provided may be common in layman physics literature, indicating a potential limitation in the originality of the explanations.

Omid
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Can anyone explain 4D space-time in a simple form ?
Some say the Hawking's expalanation is the simplest but I don't get it :biggrin:
 
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Omid said:
Can anyone explain 4D space-time in a simple form ?
Some say the Hawking's expalanation is the simplest but I don't get it :biggrin:
Sure. It takes 3 numbers to locate of an event in space - represent that as (x, y, z). The collection of all triplets (x , y, z) is called "space". It takes 1 number to specify the time of an event, t. Collect those two numbers into one set of numbers (t, x, y, z). That is called an "event". And event is a point in space at a given time. The collection of events (t, x, y, z) is called "spacetime".

Pete
 
Can you give me some examples ?
Thanks
 
I know this example has probably been beaten to death by numerous layman physics books, but it is very simple and it works to illustrate the concept of spacetime. Let's say you have an appointment in a particular office located in a particular building, which itself located at a particular street junction. To get to your appointment, you have to know three coordinates for space (the x and y coordinates are used to locate the building, while the z coordinate is used to locate which floor the office in the building is located.) And one coordinate for time (the time the appointment takes place.) Simple, no?
 
Yes.
Thank you.
 
Omid said:
Can you give me some examples ?
Thanks
One example is the same as the other. What you're asking is analogous to asking us for an example of space. Can you give me an example of space?

Pete
 
Gza said:
I know this example has probably been beaten to death by numerous layman physics books, but it is very simple and it works to illustrate the concept of spacetime. Let's say you have an appointment in a particular office located in a particular building, which itself located at a particular street junction. To get to your appointment, you have to know three coordinates for space (the x and y coordinates are used to locate the building, while the z coordinate is used to locate which floor the office in the building is located.) And one coordinate for time (the time the appointment takes place.) Simple, no?

That is an example of an event. Not an example of spacetime.

Pete
 
pmb_phy said:
That is an example of an event. Not an example of spacetime.

Pete

I don't care whether it is an event or an example of space time. :smile:
Because it is exactly what I meant. I don't know how GZA always gives me exactly the right thing.
Anyway, Pete, thank you very much.
 

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