astromony question

[asdf1]

There's an astromony question that I'm stuck on~
" A distant galaxy in the constellation Hydra is receding from the earth at 6.12*10^7 m/s. By how much is a green spectral line of wavelength 500nm (1nm=10^(-9) )emitted by this galaxy shifted toward the red end of the spectrum?

[neurocomp2003]

what knowledge do you have?

[Andrew Mason]

There's an astromony question that I'm stuck on~
" A distant galaxy in the constellation Hydra is receding from the earth at 6.12*10^7 m/s. By how much is a green spectral line of wavelength 500nm (1nm=10^(-9) )emitted by this galaxy shifted toward the red end of the spectrum?

Just use the relativistic doppler effect:

\nu_{obs}/\nu_{source} = \sqrt{\frac{1+\beta}{1-\beta}}

where \beta = v/c = .204 and \nu_{source} = c/\lambda_{source}

AM

[asdf1]

How did you think of to use the Doppler effect?

[Nylex]

Probably because the question is about the Doppler effect (well, it's about red shift, which is to do with the Doppler effect). Also, you mean "astronomy", not "astromony".

[asdf1]

I see~
Thanks for correcting my spelling mistake!