Explaining 4D Space-Time in Simple Terms

AI Thread Summary
4D space-time is explained as a combination of three spatial coordinates (x, y, z) and one temporal coordinate (t), forming an "event" that represents a point in space at a specific time. The collection of all such events is referred to as "spacetime." An example illustrates this concept by describing an appointment that requires knowing the location of the office in three dimensions and the time of the appointment. While some participants seek further examples, the discussion emphasizes the clarity of the initial explanation. Overall, the conversation highlights the simplicity of understanding 4D space-time through relatable scenarios.
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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