1. What is the Redshift Parameter?

The redshift parameter (z) is a measure of how much the light from an astronomical object has been stretched to longer wavelengths due to the expansion of the universe. It's a fundamental quantity in observational cosmology.

2. How Does the Calculator Work?

The calculator uses the redshift formula:

Where:

• \( z \) — Redshift parameter (dimensionless)
• \( \lambda_{obs} \) — Observed wavelength (meters)
• \( \lambda_{rest} \) — Rest wavelength (meters)

Explanation: The equation compares the observed wavelength of light to its known wavelength when emitted, showing how much it has been redshifted.

3. Importance of Redshift Calculation

Details: Redshift measurements are crucial for determining distances to galaxies, studying the expansion rate of the universe, and investigating dark energy.

4. Using the Calculator

Tips: Enter both wavelengths in meters. The rest wavelength is typically known from laboratory measurements of spectral lines.

5. Frequently Asked Questions (FAQ)

Q1: What does a negative redshift mean?
A: A negative redshift (blueshift) indicates the object is moving toward the observer rather than away.

Q2: What are typical redshift values?
A: Nearby galaxies might have z ≈ 0.001-0.1, while distant quasars can have z > 6. The cosmic microwave background has z ≈ 1100.

Q3: How is redshift related to velocity?
A: For small redshifts (z < 0.1), v ≈ z × c (speed of light). For larger redshifts, relativistic effects become important.

Q4: Can redshift be used to measure distance?
A: Yes, through Hubble's law for nearby objects, though at cosmological distances the relationship becomes more complex.

Q5: What causes redshift?
A: Three main causes: Doppler effect (motion), gravitational (strong gravity), and cosmological (expansion of space).