The cmb tag has no wiki summary.
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2answers
68 views
Cosmological triangle with PLANCK results
Is there an updated version of the cosmological triangle with recent PLANCK results included?
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0answers
15 views
CMB anisotropies and tightly coupled limit
Sorry if this is a technical question. I am studying the origin of CMB anisotropies and the tightly coupled limit of the Boltzmann equations. We have a fluid composed of ionized electrons and photons.
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4
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1answer
71 views
How the CMB anisotropy is linked to the existence of cold dark matter and dark energy?
After the data from the cosmic microwave background has been collected by WMAP or Planck, what types of analysis is needed to conduct in order to deduce the cold dark matter density and the ...
4
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2answers
295 views
Why cosmic background radiation is not ether?
why cosmic background radiation is not ether? I mean it's everywhere and it' a radiation then we can measure Doppler effect by moving with a velocity.
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1answer
59 views
What does Planck/WMAP/COBE actually measure when studying the CMB?
I have been reading a lot about Cosmological experiments such as Planck or WMAP that aim to investigate the CMB's power spectrum. I am unclear though as to what theses sky surveys actually measure, is ...
5
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2answers
144 views
What's the significance of large-scale anomalies in CMB
What's the significance of large-scale anomalies in CMB that are confirmed by Planck? I've read somewhere that the cold spots can provide support for string theory or it may be due to a parallel ...
2
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1answer
89 views
Inflation and scalar spectral index
I've been reading that the results from the Planck satellite constrain a number called the "scalar spectral index" to be 0.96 rather than 1 at the 5-sigma level.
This is supposed to be big news, but ...
3
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2answers
92 views
How/why can the cosmic background radiation measurements tell us anything about the curvature of the universe?
So I've read the Wikipedia articles on WMAP and CMB in an attempt to try to understand how scientists are able to deduce the curvature of the universe from the measurements of the CMB.
The Wiki ...
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2answers
132 views
Is cosmic background radiation dark-matter and/or dark-energy?
Dumb question alert: Is it possible that the cosmic background radiation might be the source of dark-matter and/or dark-energy? What is the mass of the background radiation in the known universe?
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3answers
145 views
Does Unruh Radiation replace the cosmic horizon radiation?
A recent paper, titled Inertia from an Asymmetric Casimir Effect, discusses the universal horizons relative to an accelerating observer (Rindler space). A figure it used to demonstrate its point ...
1
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1answer
176 views
Relation between multipole moment and angular scale of CMB
What is the relation between multipole moment $l$ and angular scale $\theta$ of the Cosmic Microwave Background? Somewhere on the web I found that $\theta\propto\frac{180^{\circ}}{l}$ but I need exact ...
4
votes
1answer
68 views
thermodynamics of a dual-face surface in space
This question is a continuation from this one.
A material disk have two sides, one that is reflective and another absorptive of electromagnetic radiation in the range where the background cosmic ...
1
vote
1answer
82 views
How precisely can we date the recombination?
The early universe was hot and opaque. Once it cooled enough, protons and electrons were able to form hydrogen atoms. This made the universe transparent, and was known as recombination. We can see the ...
3
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1answer
128 views
How could we experience multiverse through cosmic background radiation?
I'm reading a book about string theory, and it tells me in the future it could be possible to detect existence of other bubble universes through cosmic background radiation. Is this true? What could ...
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2answers
72 views
$\Omega_{r}$ from WMAP results?
To do some Friedmann-Lemaître cosmology calculations, I would like to know an estimation of $\Omega_{r_0}$ ($\Omega$ radiation today). WMAP 7 give estimation of $\Omega_{b}$, $\Omega_{c}$ and ...
7
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1answer
260 views
Plotting the CMB power spectrum - Why $C_\ell \ell (\ell+1)$ rather than only $C_\ell$?
I can't find any convincing answer for the following question :
Why do we always (or often) plot the CMB power spectrum in this way?
I mean the y axis is $C_\ell \ell (\ell+1)$ and not only ...
0
votes
1answer
126 views
Proportion of energy compared to mass in universe
In Wikipedia (http://en.wikipedia.org/wiki/Dark_matter), there is a picture that shows us the proportion of matter and energy in the current universe - CMB.
It seems to suggest there is nothing that ...
5
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2answers
86 views
Why did the WMAP mission last so much longer than Planck?
NASA endorsed 9 years of data taken with the Wilkinson Microwave Anisotropy Probe (WMAP). The High Frequency Instrument aboard the Planck satellite ran out of coolant at the start of 2012, after about ...
6
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3answers
154 views
Where does the light of the Big Bang come from?
I'm wondering whether the residual light of the Big Bang comes from one particular direction and what possibilities do we have to detect its position?
5
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2answers
114 views
What will we see between the CMB and the current oldest object seen?
The cosmic background radiation (CMB) is estimated to be from 13.7 billion years ago (BYA), and very shortly after the big bang compared to that time frame. The oldest coherent objects we've detected ...
2
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2answers
158 views
What are the limitations of the FLRW metric?
I was wondering, given how in any other area of life making an explosion spherically symmetric is more or less impossible is there any reason to expect that the universe is? I appreciate that the FLRW ...
3
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1answer
37 views
Did Penzias and Wilson use Wein's law (or data based on it) to determine the temperature of CMB?
I'm writing a paper and I used them as an example, but then reconsidered . . . maybe I'm not getting it right!
thanks!
3
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2answers
204 views
Big Bang and Cosmic microwave background radiation?
One of the experimental evidence that supports the theory of big bang is cosmic microwave background radiation (CMBR). From what I've read is that CMBR is the left over radiation from an early stage ...
9
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2answers
587 views
Is the CMB rest frame special? where does it come from?
It seems that we are moving relative to the universe at the speed of ~ 600 km/s.
This is the speed of our galaxy relative to the cosmic microwave background.
Where does this rest frame come from? Is ...
3
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1answer
183 views
Is the number of wavelengths of light spanning a distance invarient with respect to spacetime distortion?
I was recently asked by a friend how the expansion of spacetime effects photons. I gave him what I feel is a satisfactory general response, but it got me wondering how, exactly to calculate this ...
4
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1answer
40 views
How fast is the Cosmic Microwave Background Radiation (CMBR) changing?
I know that the Cosmic Microwave Background Radiation (CMBR) is the leftover radiation from the "surface of last scattering".
However, at every instant the surface is changing (at the rate of flow ...
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2answers
43 views
Could the cosmic microwave background radiation (CMBR) map be used as a backup for GPS navigation?
Using a sextant and a clock you can navigate by measuring the position of the observable stars and comparing them with the known map of the fixed stars. However, if it was cloudy couldn't you ...
4
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1answer
36 views
Relationship between the cosmic microwave background (CMB) radiation and the visible universe
I know that the cosmic microwave background radiation (CMBR) is the leftover radiation from the Big Bang. Have we been able to make a concrete map of the radiation and the objects in the visible ...
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5answers
402 views
Radio waves within an atom
What effect does the quantum world have on radio waves? For example, if I could shrink myself down and stand on the nucleus (or even smaller sub atomic particles making up the nucleus) with a device ...
5
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2answers
556 views
What is the cosmic “Axis of Evil” problem?
What is the cosmic "axis of evil" problem?
Apparently it is a more modern version of the old cluster mass discrepancy problem, where masses determined by gravitational lensing are always higher than ...
7
votes
3answers
32 views
Cosmic background radiation vs superfluids
I've been reading a lot about superfluids lately (fluids that are cooled to such a degree that they no longer obey the standard laws of physics) in various physics journals and realized that the ...
5
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4answers
102 views
Why is there still radiation left from the Big Bang now? [duplicate]
Possible Duplicate:
Why can we see the cosmic microwave background (CMB)?
We all have seen evidence of radiation left from the Big Bang, but how is it still detectable? Why didn't it ...
5
votes
1answer
333 views
Inflation Scale via CMB Polarization
COBE, WMAP, and now PLANCK, have or are in the process of measuring anisotropies in the cosmic microwave background. WMAP has dectected E-mode polarization from electron Thomson scattering, but not ...
9
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2answers
465 views
Why can we see the cosmic microwave background (CMB)?
I understand that we can never see much farther than the farthest galaxies we have observed. This is because, before the first galaxies formed, the universe was opaque--it was a soup of subatomic ...
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1answer
101 views
Total power of CMBR
Could you check me on this: if I'm interested in total power (summed over all frequency) of CMBR absorbed by a black body in empty space, would that be proportional to the surface of BB?
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1answer
1k views
When will PLANCK release all-sky CMB anisotropy measurements?
After hearing so much about PLANCK, people these days are still constraining models with WMAP results. When will PLANCK finally release its much more superior data?
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4answers
409 views
strange modulation of radiactive decay rates with solar activity
Recently i found out this uber strange article about nuclear decay rates being somehow showing seasonal variations with a high correlation with sun activity. Two very precise questions:
1) has this ...
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2answers
529 views
What exactly is meant by the “Gaussianity” of CMBR?
What does it mean when we say that the CMBR is mostly gaussian? What are non-gaussianities in CMBR? How does evaluation of 3-point correlation functions of the inflaton field tells us that there is ...
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3answers
266 views
Effect of expansion of space on CMB
Is it true that the expansion of space time cause the CMB to become microwaves from a shorter wavelength. If it is has the amplitude been increased?
Seeing as the amplitude has decreased; why hasn't ...
4
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1answer
727 views
Where does CMB come/emit from?
Where exactly does CMB come from. I've seen it in documentaries as a huge sphere with Earth in the middle. But if all this radiation was ejected from the start of the universe some time after the big ...
