1. What is Redshift?

Redshift (z) is a measure of how much the wavelength of light from an astronomical object is stretched (shifted toward the red end of the spectrum) due to the expansion of the universe or the object's motion away from the observer.

2. How Does the Calculator Work?

The calculator uses the redshift equation:

Where:

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

Explanation: The equation compares the observed wavelength of light to the wavelength that would be measured if the source were at rest relative to the observer.

3. Importance of Redshift Calculation

Details: Redshift is crucial for measuring distances to astronomical objects, studying the expansion of the universe, and determining the velocity of celestial bodies moving away from Earth.

4. Using the Calculator

Tips: Enter both wavelengths in meters. The rest wavelength is typically known from laboratory measurements of spectral lines. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What does a negative redshift mean?
A: A negative redshift (called blueshift) indicates the object is moving toward the observer, compressing the light waves.

Q2: What are typical redshift values?
A: Nearby galaxies might have z ≈ 0.003-0.1, while distant quasars can have z > 6. The cosmic microwave background has z ≈ 1089.

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

Q4: What's the difference between cosmological and Doppler redshift?
A: Doppler redshift is due to motion through space, while cosmological redshift results from the expansion of space itself.

Q5: Can redshift be used to measure distance?
A: Yes, in an expanding universe, redshift is correlated with distance, though the exact relationship depends on cosmological parameters.