Cosmic Flatness Deduced from CMB

In summary, the Wilkinson Microwave Anisotropy Probe (WMAP) measured temperature differences in the cosmic microwave background (CMB) and showed that the curvature of space is flat. This conclusion was reached through acoustic modeling based on assumptions about the primordial-plasma universe and comparing it to observations of the CMB. Further research on this subject has provided insight into the dominate sound wavelengths and their correlation to spatial curvature. This discovery is a remarkable achievement for theorists and provides a better understanding of the universe's origins.
  • #1
XilOnGlennSt
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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!
 
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  • #2
As soon as I posted this, I was guided to all sorts of information on this subject. I'll start there.

Still, comments are welcome. Thanks
 
  • #3
XilOnGlennSt said:
As soon as I posted this, I was guided to all sorts of information on this subject.
Can you provide a link for other readers of this thread?
 
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  • #4
Basically it is about drawing triangles and measuring the angles of those triangles. The scale of variations can be inferred so that together with the travel distance gives you three legs of a triangle. Measuring the angular size of variations gives you an angle. Compare with what the angle would be in Euclidean space for the same side lengths. A larger angle means closed universe, a smaller open.
 
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  • #5
bapowell said:
So, this post helped me appreciate the depth of theory around this question. Here are my take-aways:
  • Acoustic modeling can be accomplished based on assumptions about the primordial-plasma universe.
  • Such models give different values for dominate sound wavelengths based on its spatial curvature.
  • Observation of the CMB shows dominate wave forms which match those predicted for flat curvature.
This is all news to me, and I'm glad to have a better mental sketch.

If the theory was all settled prior to the observations, then I would say that this is a marvelous triumph for the theorists! Horay!

In any case, congratulations to these researchers. Thanks for the information.
 

FAQ: Cosmic Flatness Deduced from CMB

What is the Cosmic Flatness Deduced from CMB?

The Cosmic Flatness Deduced from CMB refers to the observation and analysis of the cosmic microwave background (CMB) radiation, which is the leftover thermal radiation from the Big Bang. This analysis has led scientists to conclude that the universe is spatially flat.

How is the Cosmic Flatness Deduced from CMB determined?

The Cosmic Flatness Deduced from CMB is determined through precise measurements of the temperature fluctuations in the CMB. These fluctuations are analyzed using mathematical models and statistical methods to determine the curvature of the universe.

What does it mean for the universe to be "spatially flat"?

A spatially flat universe means that the geometry of the universe is flat, like a sheet of paper, rather than curved like a sphere or saddle. This suggests that the universe is infinite in size and will continue to expand forever.

What are the implications of the Cosmic Flatness Deduced from CMB?

The Cosmic Flatness Deduced from CMB has significant implications for our understanding of the universe. It supports the theory of cosmic inflation, which explains the rapid expansion of the universe after the Big Bang. It also suggests that the total energy of the universe is precisely balanced, known as the "flatness problem."

Are there any challenges to the Cosmic Flatness Deduced from CMB?

While the Cosmic Flatness Deduced from CMB is supported by a vast amount of evidence, there are still some challenges and debates within the scientific community. Some researchers argue that there may be slight deviations from flatness, while others suggest alternative explanations for the CMB data. However, the majority of evidence and research supports the conclusion of a spatially flat universe.

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