Why Time is considered a 4 th dimension ? Why Gravity cannot be considered as a dimension ? What is a 5th dimension ?
In: Physics
Gravity is one of the essential forces in the universe.
A dimension is an axis that describes the position of an object. You may think we live in a 3-dimensional universe, but according to String theory, it has 10 dimensions but we only perceive a few. For now let’s only focus in 4 dimensions, X,Y,Z and Time.
Let’s put it this way. You could describe the position of a chair in a square room with 3 axis, X,Y and Z. Let’s call X the wall to the South, Y the wall to the West and Z the ground. If the chair was 1 meter tall and it was 2 meters away the South wall, 3 meters away the West wall, it’s coordenates would be (X=2, Y=3, Z=1). Right now it’s 17:30 and the chair is at the position (2,3,1). If I come 5 minutes later and move the chair 1 meter away from the south wall, it’s new coordenates would be (3,3,1) at 17:35.
But what if the chair was constantly and randonly moving? Every second that passes, the coordenates would change. How do we measure them? We could freeze time, check the coordenates for that time and write them down. So by 17:40, the coordenates were [insert random value]. That’s why time is a dimension. It’s required to describe the position of an object. That’s why in some physics or chemistry problems you may find “For T=0, the position of the body was [x,y,z]”.
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