Convert A.U. of Length (a.u.) to Roman Actus (actus) instantly.
About these units
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.
Roman Actus (actus)
The Roman actus was an ancient Roman unit of length measuring 120 Roman feet, or about 35.5 meters. It played an essential role in Roman land surveying and agriculture, forming part of the system used to organize farms, roads, and territorial divisions in the expanding Roman world. The actus helped define a square unit of land known as the actus quadratus, which was used for taxation, distribution of land to soldiers, and standardizing plots throughout Roman colonies. Surveyors relied on tools like the groma to lay out straight lines based on actus subdivisions, giving Roman lands their characteristic grid patterns. Although long obsolete, the actus provides key insights into Roman engineering, colonial administration, and agricultural policy. Many European land patterns can trace their roots back to Roman measurement practices — a testament to the enduring legacy of Roman surveying.