Space time

[Omid]

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:

[pmb_phy]

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

[Omid]

Can you give me some examples ?
Thanks

[Gza]

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?

[Omid]

Yes.
Thank you.

[pmb_phy]

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

[pmb_phy]

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

[Omid]

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.