distance (3 facts) - The distance to a celestial object measured from the center of the Earth or Sun, in units of parsec or lightyear
Galactocentric distance (3 facts) - A star's distance from the Galactic center. The Sun's Galactocentric distance is about 27000 light-years.
height (3 facts) - Elevation above ground or distance upwards from a given level (especially sea level) to a fixed point. (See altitude.)
mean free path (3 facts) - Mean length of the path of a particle between collisions., The mean distance traversed by a particle before undergoing a significant deflection or collision.
particle Compton wavelength (5 kinds, 35 facts) - The wavelength of a photon containing the rest energy of a particular particle.
Planck length (9 facts) (lP) - The dimension at which space is predicted to become "foamlike" and at which Einstein's theory is supposed to break down., The size limit at which normal notions of space-time are supposed to break down., The scale below which quantum fluctuations in the fabric of spacetime would become enormous. The size of a typical string in string theory.