1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Spectrum of Light from Hydrogen

  1. Oct 17, 2013 #1
    The visible spectrum of light from hydrogen displays four wavelengths, 410 nm, 434 nm, 486 nm, and 656 nm normally.

    Which changes when a telescope is pointed at a Galaxy that is moving away?
  2. jcsd
  3. Oct 17, 2013 #2


    User Avatar
    Science Advisor
    Gold Member

    They all change; the same goes for the wavelengths which are not visible.

    The process is detailed here: http://www.astro.ucla.edu/~wright/doppler.htm

    Note that the ratio of observed over emitted wavelength is the same for all wavelengths; this is how we determine the red shift.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook