Convert Furlong (fur) to Planck Length (ℓₚ) instantly.
About these units
Furlong (fur)
A furlong, equal to 10 chains or 660 feet, originated as the distance a team of oxen could plow before needing rest. Its name derives from "furrow-long," indicating the length of a typical plowed furrow in medieval agriculture. This agricultural basis linked the furlong to the acre: a rectangle one furlong long and one chain wide equaled one acre in area. Today, the furlong is most notably used in horse racing, where race distances are often measured in furlongs rather than miles. This tradition reflects both the unit's historical importance and its suitability for describing moderate distances. While archaic in most contexts, the furlong remains a culturally iconic measure that connects modern sports to medieval agricultural practices.
Planck Length (ℓₚ)
The Planck length, approximately 1.616 × 10⁻³⁵ meters, is perhaps the most conceptually profound unit in physics. It represents the scale at which classical notions of space and time cease to exist and quantum gravity effects dominate. Below this length, it is believed that spacetime becomes "foamy," subject to fluctuations predicted by quantum field theory and speculative models such as string theory. The Planck length is derived from fundamental constants: the speed of light, Planck's constant, and Newton's gravitational constant. These constants combine to yield a natural scale where both quantum mechanics and general relativity must merge into a unified theory. No experiment has ever probed distances anywhere near the Planck scale — it is many orders of magnitude smaller than even the size of protons — but it plays a crucial role in theoretical cosmology, black hole physics, and models of the early universe. The Planck length stands as a symbol of the limits of physical measurement and the frontier of fundamental physics.