<<<
>>>
The Doppler Shift: Time for some Math.
Δλ
λ
o
=
v
c
λ
o
= base wavelength
Δλ = change in wavelength
c = speed of light = 3 x 10
5
km/s
v = speed the object is moving
Example: We see a galaxy whose Sodium line (normally λ
o
=5890Å) is shifted to 5910Å. Thus, Δλ = 20Å. If we solve for the velocity:
v =
c Δλ
λ
o
=
(3 x 10
5
km/s) (20Å)
(5890Å)
=
1019 km/s
