Convert Hand (hand) to Terameter (Tm) instantly.
About these units
Hand (hand)
The hand is a traditional unit of length equal to 4 inches, historically used to measure the height of horses. Its origins go back thousands of years, when people commonly relied on body-based measurements. While early hands varied from culture to culture, the modern standardized hand—set at exactly 4 inches—was adopted to bring uniformity to equine measurement worldwide. When measuring a horse, the height is taken at the withers, the ridge between the shoulder blades, because this location provides a stable and consistent point unaffected by head movement. Horse heights are often written in a mixed-unit style: for example, "15.3 hands" means 15 hands plus 3 inches, not 15.3 × 4 inches. Though rarely used outside the world of horsemanship, the hand has become deeply embedded in equestrian culture. It provides a system that is intuitive, easy to visualize, and respectful of longstanding tradition. In modern times, even highly scientific equine breeding and veterinary studies continue to quote measurements in hands.
Terameter (Tm)
A terameter equals one trillion meters (10¹² m) and is used when discussing distances that exceed the scale of the solar system but do not yet reach the interstellar unit category. Large-scale solar system phenomena—such as the size of the heliosphere, the influence boundary of the Sun's magnetic field, or trajectories of far-reaching spacecraft—may be expressed in terameters. While not widely used in astronomical literature (which often prefers astronomical units, light-years, or parsecs), the terameter provides a SI-based unit that aligns cleanly with metric prefixes. It is especially useful in theoretical physics or cosmological modeling where sticking to SI units simplifies equations.