I use throughout with both time and space. (Temporal and spatial references)
Throughout the day
Throughout the state of Virginia. Spanish is used throughout northern Virginia.
I use over with a time span.
Over the past six months
Over three generations
I also use over with a spatial region.
Rain spread over the eastern portion of Maryland.
High temperatures prevailed over the European continent.
To use over with world I would write the following:
English is used all over the world.
Arabic is read all over the world.