The significance of the Hubble constant is that:
- AIt gives the luminosity of galaxies
- BIt determines the mass of black holes
- CIt estimates the age of stars
- DIt measures the rate of expansion of the universe
Show answer and explanation
Correct answer: (d) It measures the rate of expansion of the universe
Explanation
The Hubble constant (H₀) is the constant in Hubble's law, v = H₀d: a galaxy moves away from us with a speed (v) proportional to its distance (d).
So H₀ measures how fast the universe is expanding. Its present value is about 70 km/s per megaparsec. Since it gives the rate of expansion, its inverse (1/H₀) also gives a rough estimate of the age of the universe, about 14 billion years. Edwin Hubble reported this relation in 1929.