An astrophysicist compares the Hydrogen-alpha (Hα\text{H}\alphaHα) absorption line of a terrestrial laboratory reference with the spectra obtained from three high-redshift galaxies, Alpha, Beta, and Gamma, as shown in the diagram below.
The reference wavelength, λ0\lambda_0λ0, for this spectral line is 656 nm.
Estimate the change in wavelength, Δλ\Delta\lambdaΔλ, for this spectral line in the light observed from Galaxy Beta.