# Explain to me the concept of space time?

1. Nov 4, 2004

### fizzzzzzzzzzzy

would someone explain to me the concept of space time? i know what it is but am having problems understanding it

2. Nov 4, 2004

### James R

An "event" is specified by giving its location in space and time. For example, we could say that a balloon burst at 10.30 am at a particular lattitude, longitude and altitude. The four numbers taken together (time, lattitude, longitude, altitude) characterise the event, and are referred to as the "spacetime coordinates" of the event.

3. Nov 6, 2004

### da_willem

Also in Special Relativity spacetime is introduced because of their intimate relation. Time and space are relative; but the 'interval' wich combines spatial and time intervals is a quantity everyone agrees upon.

There is this interpretation of special relativity wich shows how space and time are connected in a spacetime. You could say all objects move with the same speed through spacetime namely c, the speed of light. If you move through space you move less through time because your speed through spacetime is constant. This is called time dilation. A photon for example as it moves with c through space can be thought of as not aging at all, it does not move through time.

(mathematically the 'magnitude' of the velocity four-vector is c:
$$v_\mu v^\mu = c^2 = c^2 (\frac{dt}{d\tau})^2 - (\frac{d x}{d\tau})^2$$
And these two terms can be thought of as described above)

So the concepts of space, time and velocity are relative, but combined in a 'spacetime' they are useful and can yield absolute quantities

Last edited: Nov 7, 2004
4. Nov 6, 2004