1. What is Hubble's Law?

Hubble's Law describes the relationship between the recession velocity of galaxies and their distance from Earth. It is a fundamental principle in cosmology that provides evidence for the expansion of the universe.

2. How Does the Calculator Work?

The calculator uses Hubble's Law equation:

Where:

• \( v \) — Recession velocity (km/s)
• \( H_0 \) — Hubble constant (km/s/Mpc)
• \( d \) — Distance to galaxy (Mpc)

Explanation: The equation shows that the velocity at which a galaxy is receding from us is directly proportional to its distance from Earth.

3. Importance of Hubble's Law

Details: Hubble's Law is crucial for understanding the expansion rate of the universe, estimating distances to faraway galaxies, and calculating the age of the universe.

4. Using the Calculator

Tips: Enter the Hubble constant in km/s/Mpc and the distance in megaparsecs (Mpc). All values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the current accepted value for H₀?
A: The current accepted value is approximately 70 km/s/Mpc, though measurements range from 67-74 km/s/Mpc depending on the method used.

Q2: What units are used for distance in Hubble's Law?
A: Megaparsecs (Mpc) are commonly used, where 1 Mpc equals approximately 3.26 million light-years.

Q3: Does Hubble's Law apply to all galaxies?
A: Hubble's Law applies to distant galaxies beyond our Local Group, where the expansion of the universe dominates over local gravitational effects.

Q4: What is the Hubble tension?
A: The Hubble tension refers to the discrepancy between measurements of H₀ from the early universe (CMB) and late universe (supernovae).

Q5: Can Hubble's Law be used to measure very large distances?
A: Yes, Hubble's Law is one of the primary methods for measuring cosmological distances to faraway galaxies and quasars.