The Hubble length or Hubble distance is a unit of distance in cosmology, defined as cH0−1 — the speed of light multiplied by the Hubble time. It is equivalent to 4,550 million parsecs or 14.4 billion light years. (The numerical value of the Hubble length in light years is, by definition, equal to that of the Hubble time in years.) The Hubble distance would be the distance between the Earth and the galaxies which are currently receding from us at the speed of light, as can be seen by substituting D = c/H0 into the equation for Hubble's law, v = H0D.
| Definition | Relation to SI units |
|---|---|
≈ 14.4 billion light-years ≈ 4.55 gigaparsecs |
| pace | gigameter | league (land) | zettameter | rod | finger | spat | hand |
|---|---|---|---|---|---|---|---|
| 1 | 7.62 × 10-10 | 0.0001578 | 7.62 × 10-22 | 0.1515152 | 34.2857143 | 7.62 × 10-13 | 7.5 |
| 1,312,335,958.0052 | 1 | 207,125.1035626 | 1.0 × 10-12 | 198,838,781.51595 | 44,994,375,703.037 | 0.001 | 9,842,519,685.0394 |
| 6,335.9580052 | 4.828 × 10-6 | 1 | 4.828 × 10-18 | 959.9936372 | 217,232.8458943 | 4.828 × 10-9 | 47,519.6850394 |
| 1.3123359580052 × 1021 | 1 000 000 000 000 | 2.0712510356255 × 1017 | 1 | 1.9883878151595 × 1020 | 4.4994375703037 × 1022 | 1 000 000 000 | 9.8425196850394 × 1021 |
| 6.6 | 5.0292 × 10-9 | 0.0010417 | 5.0292 × 10-21 | 1 | 226.2857143 | 5.0292 × 10-12 | 49.5 |
| 0.0291667 | 2.2225 × 10-11 | 4.6033554266777 × 10-6 | 2.2225 × 10-23 | 0.0044192 | 1 | 2.2225 × 10-14 | 0.21875 |
| 1,312,335,958,005.2 | 1 000 | 207,125,103.56255 | 1.0 × 10-9 | 198,838,781,515.95 | 44 994 375 703 037 | 1 | 9,842,519,685,039.4 |
| 0.1333333 | 1.016 × 10-10 | 2.1043910521955 × 10-5 | 1.016 × 10-22 | 0.0202020 | 4.5714286 | 1.016 × 10-13 | 1 |
| Symbol | Definition |
|---|---|
| ≡ | exactly equal |
| ≈ | approximately equal to |
| = | equal to |
| digits | indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …) |
| 1 Hubble length | = 1.3623160903026E+26 meters |
| 1.5 Hubble length | = 2.0434741354539E+26 meters |
| 2 Hubble length | = 2.7246321806052E+26 meters |
| 2.5 Hubble length | = 3.4057902257565E+26 meters |
| 3 Hubble length | = 4.0869482709078E+26 meters |