| − | A '''dimension''' is a measurable extension in [[space]]. There are three commonly perceived dimensions, length, breadth, and width. For example a [[cube]] measuring 10 [[metre]]s in each dimension will have a [[volume]] of 1000 metres squared, i.e. 10 x 10 x 10 = 1000. Since the time of [[Albert Einstein]], it is believed by most physicists that space and [[time]] form a single entity, and that there is a fourth dimension, time itself. However, time in not measured in units of distance such as metres so this system remains incompatible with [[Isaac Newton|Newtonian]] physics. [[Quantum]] physicists propose a different theory, namely that there are more than three dimensions in space itself, perhaps as many as eleven. But dimension four and above are all curled up so tightly that they extend no further than the diameter of a [[subatomic particle|sub-atomic particle]], so we just don't notice them. | + | A '''dimension''' is a measurable extension in [[space]]. There are three commonly perceived dimensions: [[length]], [[breadth]], and [[width]]. For example a [[cube]] measuring 10 [[metre]]s in each dimension will have a [[volume]] of 1000 metres squared, i.e. 10 x 10 x 10 = 1000. Since the time of [[Albert Einstein]], it is believed by most physicists that space and [[time]] form a single [[continuum]], and that time is a fourth dimension. However, time in not measured in units of distance such as meters so this system remains incompatible with [[Isaac Newton|Newtonian]] physics. [[Quantum]] physicists propose a different theory, namely that there are more than three dimensions in space itself, perhaps as many as eleven. But dimension four and above are all curled up so tightly that they extend no further than the diameter of a [[subatomic particle]], so humans are unable to notice them with the naked eye. |