Understanding Primordial B-modes and Cosmic Inflation

  • Context: Graduate 
  • Thread starter Thread starter connorp
  • Start date Start date
  • Tags Tags
    Inflation
Click For Summary

Discussion Overview

The discussion centers on the concepts of primordial B-modes and cosmic inflation, exploring the theoretical implications of gravitational waves, spacetime, and the symmetry of inflation. Participants express curiosity and seek clarification on these complex topics within cosmology.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether spacetime must have existed before the Big Bang for primordial B-modes to be produced, suggesting a conflict with the idea that inflation is the expansion of spacetime itself.
  • The same participant raises concerns about how gravitational waves could be generated by cosmic inflation, given that inflation is considered isotropic and therefore symmetrical, while gravitational waves require asymmetrical objects.
  • Several participants share links to articles and resources that provide basic information on cosmic inflation and primordial B-modes, indicating a desire for foundational understanding.
  • Another participant emphasizes the value of reading materials from reputable sources, particularly those with educational domains, to enhance comprehension of the topic.

Areas of Agreement / Disagreement

The discussion does not appear to reach consensus, as participants express differing viewpoints and uncertainties regarding the relationship between spacetime, gravitational waves, and cosmic inflation.

Contextual Notes

Participants acknowledge that much of the discussion is theoretical and may involve unresolved assumptions about the nature of spacetime and the mechanisms of inflation.

connorp
Messages
30
Reaction score
2
So this rumor over the detection of primordial B-modes has got me thinking. Gravitational waves are caused by perturbances in spacetime by asymmetrical objects. So for them to travel, they have to be propagated by something: spacetime. The primordial B-modes are supposedly the result of cosmic inflation. So two things don't make sense to me. Wouldn't spacetime had to have existed pre-Big Bang as to have B-modes produced from the inflation? Assuming spacetime is a result of the Big Bang, inflation would have been the expansion of spacetime itself, meaning no gravitational waves could be generated by inflation as they couldn't be propagated in the same spatial and temporal dimensions as their medium.

Also, since "objects" must be asymmetrical to create gravitational waves, how could cosmic inflation produce them, since inflation is considered to be isotropic, and therefore, in a sense, symmetrical?

I know the majority of what I'm asking is purely theoretical, but please explain as best as possible. And feel free to correct me anywhere, as I am no where near being a cosmological expert. Thanks.
 
Last edited:
Space news on Phys.org
This Sky and Telescope article seems fairly basic and might get you started until the experts get out of bed.

http://www.skyandtelescope.com/news/Proof-of-Inflationary-Universe-To-Be-Announced-Monday-250522521.html
 
Last edited by a moderator:
  • Like
Likes   Reactions: 1 person
Spinnor said:
This Sky and Telescope article seems fairly basic and might get you started until the experts get out of bed.

http://www.skyandtelescope.com/news/Proof-of-Inflationary-Universe-To-Be-Announced-Monday-250522521.html

Nice article and a witty comment. And thanks! my subscription for their newsletter was confirmed just now :-)
 
Last edited by a moderator:
Spinnor said:
Some more basic reading,

http://www.washingtonpost.com/natio...c21850-adfc-11e3-9627-c65021d6d572_story.html

http://www.newscientist.com/article...ipples-from-universes-birth.html#.Uye2gKhdWSo

http://background.uchicago.edu/~whu/polar/webversion/node8.html

http://background.uchicago.edu/~whu/polar/webversion/node9.html

http://cosmology.berkeley.edu/~yuki/CMBpol/CMBpol.htm

http://astrobites.org/2013/07/24/lensing-b-modes-in-the-cosmic-microwave-background-polarization/

Those are excellent reading materials especially those with .edu in the url, besides that I'm also reading what matt strassler and sean carroll are telling about that.
http://profmattstrassler.com/2014/03/18/if-its-holds-up-what-might-bicep2s-discovery-mean/
http://www.preposterousuniverse.com...nal-waves-in-the-cosmic-microwave-background/
 

Similar threads

High School Cosmic Graviton Background and Primordial Gravitational Waves
  • · Replies 2 ·
Replies
2
Views
3K
High School Does dark energy or cosmic inflation explain flatness?
  • · Replies 37 ·
2
Replies
37
Views
6K
Undergrad ....Alternatives to Inflation in Primordial Power Spectrum
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Some questions about Cosmic Inflation
  • · Replies 4 ·
Replies
4
Views
5K
Undergrad What does the cosmic inflation theory actually say about flatness?
  • · Replies 9 ·
Replies
9
Views
3K
Graduate Starobinsky Inflation and Supergravity
  • · Replies 10 ·
Replies
10
Views
2K
High School Why doesn't cosmic inflation violate conservation of energy?
  • · Replies 3 ·
Replies
3
Views
4K
Undergrad Is Inflation unlikely or likely?
  • · Replies 8 ·
Replies
8
Views
2K
Graduate Calculating the Gravitational wave spectrum with Inflation as a source
  • · Replies 3 ·
Replies
3
Views
2K
Graduate Why does inflation generate gravity waves?
  • · Replies 5 ·
Replies
5
Views
2K