Final answer:
To find the radial speed of galaxy NGC 7319, the difference in observed wavelength and rest wavelength due to the Doppler effect is used, yielding a speed of approximately 41,400 km/s, indicating the galaxy is moving away from Earth.
Step-by-step explanation:
The student is asking about the radial speed of galaxy NGC 7319 relative to Earth as inferred from Doppler shift measurements. The Doppler shift in the wavelength of light from the galaxy indicates its motion with respect to the observer. In this case, the emission has been redshifted, implying that the galaxy is moving away from Earth. To calculate the radial speed (v), we use the formula v = c × (Δλ/λ0), where c is the speed of light, λ0 is the original (rest) wavelength, and Δλ is the change in wavelength.
Using this formula and the given wavelengths, we have Δλ = 544 nm - 475 nm = 69 nm. Assuming the rest wavelength, λ0, is similar to measurements from other galaxies at approximately 500 nm:
v = c × (69 nm / 500 nm) = (3.00 × 108 m/s) × (69 × 10-9 m / 500 × 10-9 m) = 41,400 km/s.
The radial speed of NGC 7319 relative to Earth is therefore approximately 41,400 kilometers per second.