Kiloparsec
A kiloparsec (kpc) is a unit of distance used in astronomy equal to 1,000 parsecs, or about 3,260 light-years. It is commonly used to measure distances within and between galaxies. For example, the Milky Way galaxy is about 30 kiloparsecs in diameter. Kiloparsecs help astronomers describe large-scale structures in space more conveniently than using light-years alone. The symbol for kiloparsec is "kpc". It’s an important unit for understanding the size and scale of galaxies and their components.
X-unit
The X-unit (symbol: xu) is a very small unit of length used primarily to measure wavelengths of X-rays and gamma rays. It was introduced in the early 20th century for precision measurements in X-ray crystallography.
1 X-unit ≈ 0.1 picometers (pm) or 10⁻¹³ meters
It allows scientists to express extremely small wavelengths typical of X-rays, which are on the order of atomic spacing
The exact definition has varied historically, but the unit remains useful for comparing wavelengths in X-ray spectroscopy and crystallography
Though largely replaced by the picometer or ångström in modern usage, the X-unit played a crucial role in early developments of atomic-scale measurement.
No conversions available for length.