Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How inflation can give rise to irregularities

  1. Jan 30, 2012 #1
    I can understand how can inflation give rise to the isotropy of the CMB, but that it can give rise also to the irregularities in the CMB...!?
    Please, can any one explain me this?
  2. jcsd
  3. Jan 31, 2012 #2


    User Avatar
    Science Advisor

    Well, the quantum fluctuations in the field that drives inflation get blown up by the rapid expansion to tremendous scales. These teeny tiny quantum fluctuations, then, become the seeds that grow to form the differences in temperature we see in the CMB.
  4. Jan 31, 2012 #3
    What a nice and succinct answer!
    Last edited: Jan 31, 2012
  5. Jan 31, 2012 #4
    Inflation is exponential expansion, and this expansion makes nearby parts of the Universe gets dragged across one's event horizon. Quantum fluctuations are no exception. They get frozen into place when they get stretched beyond the event-horizon size. Beyond that size, there is no way to communicate across the fluctuation's size.

    When it stops, then distant parts of the Universe can return across one's event horizon.

    Inflation and the CMB - C.H. Lineweaver
    An Exposition on Inflationary Cosmology - G.S. Watson
  6. Feb 1, 2012 #5


    User Avatar
    Gold Member

    Exclusive of later effects like baryon acoustic oscillations, what are the estimated values of primordial fluctuations in the fractional value of ρ that lead to the observed CMB? For example, over a distance equivalent to 10 Glyr now, was the early variation something like an abiabatic 1 part in 105? Any papers on this?
  7. Feb 2, 2012 #6
    thank you every body
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook