| 释义 |
> as lemmasHubble constant Hubble constant n. (or †Hubble factor, Hubble's constant, †Hubble's factor) the ratio of the recessional speed of a galaxy to its distance, usually expressed in km. per second per megaparsec; (also) the reciprocal of this, usually expressed in years and capable of being interpreted as the time that has elapsed since the galaxies first began to recede (at constant speeds) from a single point.< |