SPACE-TIME

space -time

      Space have 3 dimensions and time is independent from space. Everything in space is not stable all are moving with respect to time. 

        But we don't  say time is actually a dimensions bcoz every dimension made by negative side and positive side and also 0.

For example  length is positive, negative and zero so it is dimension. On the other hand time is only positive not negative. space have 3 dimensions and time .so in combination  we say space -time. So actually  we have to study about space - time more than only space. 

    just imagine..  

    

    You throw a stone in pond  as stone touch water in pond as it produce ripples around where the stone touch water  with 0 radius. 

     As stone going on depth as larger ripples radius  so ripples radius increase with respect to time. Mean space in ripples increase with respect to time.  

   

       Space time graph of ripples space and time

In space time this curve is light cone

      Just think  in above diagram point o  (Stone) describe  a event and observere  point (a) is distant from point o.  Point (a) affected by this event after some time when event actually happens in point point o.  If after some time point (a) is on light curve.  

If Point (a) never affected by what happened in point o then point (a) never come on light cone. 

     

           Take a example of sun and earth

       Initially t=0 sun produce a light  beam .

Instantly  light beam never come in earth(t=0). After 8 minutes and 27 sec light beam hit the earth so after this time the earth touch firstly light cone as you see. So light cone depend present  event. (like  sun's light beam t=0).it depends on event (like sun 's light beam).

      Actually present event decide future events and past events decide present event 

So graph is

Example    :        Suppose in past sun 's fuel is over.so in present  it try to contact. And in future it will convert in black hole. 

So it is space time.  

And also to be continued....... 

Thank you