Convert Earth's Polar Radius (R⊕ (p)) to Fathom (fath) instantly.
About these units
Earth's Polar Radius (R⊕ (p))
The Earth's polar radius is approximately 6,356.8 km, slightly shorter than the equatorial radius due to the Earth's flattening at the poles. This measurement is critical in modeling Earth's shape, gravity field, and rotation. It impacts satellite orbits, geodetic surveys, and global positioning systems (GPS). The difference between the equatorial and polar radii also explains phenomena such as centrifugal force variations, equatorial bulges, and sea level differences across latitudes. Understanding R⊕ (p) is essential for precision navigation, Earth science, and astronomy.
Fathom (fath)
A fathom is equal to 6 feet and is historically associated with maritime measurement. Its origins may lie in the approximate span of a fully outstretched human arms, which was convenient for measuring rope lengths by hand aboard ships. Sailors used the fathom to estimate water depth through weighted lines, giving rise to the practice of "sounding" the depths. The fathom became a cornerstone unit in nautical life because it fits the human scale while also being large enough to measure significant underwater distances. Charts, sonar readings, and older depth gauges frequently utilized fathoms, although modern equipment increasingly displays depths in meters. Still, many mariners—particularly in regions using imperial measurements—continue to think instinctively in fathoms when estimating safe anchoring or navigating shallow waters. The unit persists as an important piece of maritime history and remains in active use by traditional sailors, divers, and some fishing industries. Its survival reflects the enduring cultural heritage of nautical practice.