Secret dimensions
In everyday life, we inhabit a space of three dimensions – a vast 'cupboard' with height, width and depth, well known for centuries. Less obviously, we can consider time as an additional, fourth dimension, as Einstein famously revealed.
What dimensional universe do we live in?
In 1905, Albert Einstein showed in his Special Theory of Relativity that space is intimately connected to time via the cosmic speed limit of light and so, strictly speaking, we live in a Universe with four dimensions of space-time.
Are humans 3D or 4D?
Thus, each human face possesses concurrently a unique volumetric structure and surface pattern in three dimensions (or 3D) and a temporal pattern across time in four dimensions (or 4D).
