How inflation can give rise to irregularities

  • Thread starter Thread starter houhou.trad
  • Start date Start date
  • Tags Tags
    Inflation Rise
AI Thread Summary
Inflation leads to the isotropy of the Cosmic Microwave Background (CMB) by rapidly expanding quantum fluctuations, which become the initial seeds for temperature variations observed in the CMB. These quantum fluctuations are stretched beyond the event horizon during inflation, freezing them in place. Once inflation ends, distant regions of the universe can interact again, allowing these fluctuations to manifest as irregularities in the CMB. The discussion also touches on the estimated values of primordial fluctuations and their impact on the CMB, with inquiries about relevant research papers. Understanding these processes is crucial for comprehending the early universe's structure and evolution.
houhou.trad
Messages
16
Reaction score
0
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 anyone explain me this?
thanks.
 
Space news on Phys.org
houhou.trad said:
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 anyone explain me this?
thanks.
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.
 
Chalnoth said:
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.

What a nice and succinct answer!
 
Last edited:
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
 
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?
 
thank you every body
 
https://en.wikipedia.org/wiki/Recombination_(cosmology) Was a matter density right after the decoupling low enough to consider the vacuum as the actual vacuum, and not the medium through which the light propagates with the speed lower than ##({\epsilon_0\mu_0})^{-1/2}##? I'm asking this in context of the calculation of the observable universe radius, where the time integral of the inverse of the scale factor is multiplied by the constant speed of light ##c##.
The formal paper is here. The Rutgers University news has published a story about an image being closely examined at their New Brunswick campus. Here is an excerpt: Computer modeling of the gravitational lens by Keeton and Eid showed that the four visible foreground galaxies causing the gravitational bending couldn’t explain the details of the five-image pattern. Only with the addition of a large, invisible mass, in this case, a dark matter halo, could the model match the observations...
Why was the Hubble constant assumed to be decreasing and slowing down (decelerating) the expansion rate of the Universe, while at the same time Dark Energy is presumably accelerating the expansion? And to thicken the plot. recent news from NASA indicates that the Hubble constant is now increasing. Can you clarify this enigma? Also., if the Hubble constant eventually decreases, why is there a lower limit to its value?
Back
Top