Hubble's constant

American  

noun

Astronomy.

1. the ratio of the recessional velocity of galaxies to their distance from the sun, with current measurements of its value ranging from 50 to 100 kilometers per second per megaparsec.

---

Etymology

Origin of Hubble's constant

First recorded in 1950–55; after E. P. Hubble

Example Sentences

The universe is still expanding, at a rate of 73 kilometers per second per megaparsec, a metric known as Hubble's constant.

From Salon

Hubble’s law says the recession velocity of a galaxy is equal to its distance multiplied by a quantity called Hubble’s constant.

From Scientific American

To be precise, the time elapsed since the big bang is a function of the present value of Hubble’s constant and its rate of change.

From Scientific American

The value of Hubble’s constant seemed to be the same in all directions, a necessary consequence of uniform expansion.

From Scientific American

Hubble’s constant – proposed by Edwin Hubble in the 1920s – reveals by how much.

From The Guardian