宇宙膨胀率计算器
使用此宇宙膨胀率计算器快速获得准确的计算结果。
退行速度
7,000.00 km/s
Recession Velocity vs Hubble Constant (H0)
公式
## How the Cosmic Expansion Rate Works Edwin Hubble discovered that galaxies recede from us at speeds proportional to their distance. ### Hubble-Lemaitre Law **v = H0 * d** - *H0* is the Hubble constant (around 70 km/s/Mpc) - *d* is the co-moving distance in megaparsecs This linear relation holds for nearby galaxies; at cosmological distances, corrections from the Friedmann equations are needed.
计算示例
A galaxy sits 100 Mpc away with H0 = 70 km/s/Mpc.
- 01v = H0 * d
- 02v = 70 * 100
- 03v = 7 000 km/s
常见问题
What is the accepted value of H0?
Measurements from the Planck satellite give about 67.4 km/s/Mpc, while the distance-ladder method yields about 73 km/s/Mpc. This discrepancy is called the Hubble tension.
Does the Hubble law mean we are at the centre of the universe?
No. Every observer in an expanding universe sees all other galaxies receding. There is no special centre.
Can recession velocity exceed the speed of light?
Yes, for very distant objects. This does not violate relativity because it is the expansion of space itself, not motion through space.