- #1
XilOnGlennSt
- 18
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- TL;DR Summary
- Cosmic Background Radiation studies by the WMAP project, concluded that the Universe has basically Euclidian flat curvature. Can someone sketch the reasoning behind this?
The Wilkinson Microwave Anisotropy Probe (WMAP) measured temperature differences across the sky in the cosmic microwave background (CMB). See --->(Wikipedia: https://en.wikipedia.org/wiki/Wilkinson_Microwave_Anisotropy_Probe#Main_result)
From these observations researchers concluded that the curvature of space is basically flat. I would love to gain insight into their reasoning. Maybe I can make this easier by exposing major points of my ignorance. Q1: How can spatial curvature be deduced from temperature variation? Q1A: Couldn't all sorts of uniform curvatures also produce uniform temperature variations?
So, the CMB witnessed by WMAP during nine years, took 13.8 billion years to catch up to 'us'. This despite the idea that the CMB pattern was formed at a time when the Universe, including our "position" in it, was much smaller. From this I imagine that the observed radiation would have originated only from a thin 'spherical' section of the original plasma at that time, consisting of points equidistant from our position. Q2: How can overall spatial curvature be deduced from such a select small sample.
Related questions:
Q3: Can we suppose that a similar CMB has been and will continue to be present in our skies?
Q4: We now witness gravitational lensing around black holes and stars. These would seem to be smaller-scale examples of non-flat space. Why wouldn't we expect that larger collective masses could have large-scale effects?
Q5: Wouldn't black holes themselves be examples of high-curvature spaces?
Thanks for your help!
From these observations researchers concluded that the curvature of space is basically flat. I would love to gain insight into their reasoning. Maybe I can make this easier by exposing major points of my ignorance. Q1: How can spatial curvature be deduced from temperature variation? Q1A: Couldn't all sorts of uniform curvatures also produce uniform temperature variations?
So, the CMB witnessed by WMAP during nine years, took 13.8 billion years to catch up to 'us'. This despite the idea that the CMB pattern was formed at a time when the Universe, including our "position" in it, was much smaller. From this I imagine that the observed radiation would have originated only from a thin 'spherical' section of the original plasma at that time, consisting of points equidistant from our position. Q2: How can overall spatial curvature be deduced from such a select small sample.
Related questions:
Q3: Can we suppose that a similar CMB has been and will continue to be present in our skies?
Q4: We now witness gravitational lensing around black holes and stars. These would seem to be smaller-scale examples of non-flat space. Why wouldn't we expect that larger collective masses could have large-scale effects?
Q5: Wouldn't black holes themselves be examples of high-curvature spaces?
Thanks for your help!