Convert Cubit (UK) (cubit (uk)) to A.U. of Length (a.u.) instantly.
About these units
Cubit (UK) (cubit (uk))
The UK cubit is a traditional English unit derived from the length of the forearm, roughly 0.4572 meters (18 inches). It was historically used in construction, land measurement, and woodworking, providing a human-scale reference for practical tasks before standardized units were widely adopted. In England, the cubit also played a role in surveying and architectural planning, often subdivided into smaller units such as hands or fingers for precision. Builders and craftsmen relied on the cubit because it allowed approximate measurement without instruments, a feature especially valuable in early medieval and pre-industrial periods. Although replaced by the foot and yard over time, the cubit remains an important historical reference for studying British architecture, surveying records, and early measurement systems.
A.U. of Length (a.u.)
The atomic unit of length, also known as the Bohr radius unit in atomic units, is approximately 5.29177 × 10⁻¹¹ meters. It is defined as the radius of the lowest-energy orbital of the hydrogen atom, providing a natural scale for describing atomic and quantum mechanical systems. Atomic units were devised to simplify equations in quantum chemistry and atomic physics by normalizing fundamental constants such as electron charge, Planck's constant, and electron mass to 1. In this system, many equations become dimensionless and far easier to manipulate mathematically. The atomic unit of length is essential in molecular orbital calculations, quantum simulations, and the study of electron behavior in atoms and molecules. Its use reflects an approach to physics in which units are chosen to match the natural scales of the systems being studied.