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!

Homework Help: Cosmic red shift

  1. Oct 29, 2009 #1

    The cosmic microwave background (CMB) radiation detected by Penzias
    and Wilson at Bell Labs in 1965 has the spectrum of a blackbody, with an
    observed peak at λ = 1 mm. It is believed that when the light was emitted
    the spectrum peaked at a wavelength of λ = 1000 nm (close to the peak of
    the spectrum of the Sun). The cosmological redshift is directly connected to
    the scale factor that we discussed

    So, the CMB gives us a picture of the infant universe, when the universe was
    just a fraction of its current size. By what factor was the universe smaller
    when the CMB was emitted than it is today?

    The emission of the CMB occurred when the universe was 389,000 years
    old. Its current age is 13.7 billion years. If we compare the universe to a
    person of age 80, from what age (in days) do our ‘baby pictures’ come?

    2. Z = (lambda_observed - lambda_emitted)/lambda_emitted

    a(t) = 1 + z

    3. I just got out of my second exam today and I am fairly retarded at the moment. Can someone get me started?
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted