An absorption line in the spectrum of light from a distant galaxy, Galaxy Aurelia, is compared with the same spectral line measured in a laboratory on Earth.
The table below shows the wavelengths of this spectral line:
| Source | Wavelength |
|---|---|
| Laboratory reference (λ0\lambda_0λ0) | 486.0 nm486.0\text{ nm}486.0 nm |
| Galaxy Aurelia (λ\lambdaλ) | 510.3 nm510.3\text{ nm}510.3 nm |
Calculate the recessional speed, vvv, of Galaxy Aurelia.
Use the equation:
v=cΔλλ0 v = c \frac{\Delta\lambda}{\lambda_0} v=cλ0Δλ[ccc = speed of light = 3.0 × 108 m/s]