# Cosmological Redshift

**Formula:**`z = (λ`

_{observed} - λ_{initial}) / λ_{initial}

## Introduction to Cosmological Redshift

Cosmological redshift is a key concept in astronomy, used to measure the expansion of the universe. It occurs when the wavelength of light from a distant source is stretched as the universe expands, shifting toward the red end of the spectrum. The formula for calculating cosmological redshift is given by z, where λ_{observed} is the observed wavelength and λ_{initial} is the initial (emitted) wavelength.

## Parameter Usage:

`initialWavelength`

: Initial (emitted) wavelength of the light`observedWavelength`

: Observed wavelength of the light

## Output:

`z`

: Cosmological redshift

## Data Validation

The wavelengths should be greater than zero.

## Summary

This formula helps astronomers quantify the change in wavelength of light from distant celestial objects due to the expansion of the universe, allowing for the measurement of cosmological distances.