The cosmic microwave background (CMB) is the electromagnetic radiation in the microwave band which can be observed throughout the whole universe, not connected to any astronomical object. Its spectrum follows a very precise black-body radiation with a temperature of about 2.7 K.

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Redshift of Cosmic Microwave Background

Does the cosmic microwave background radiation have a red shift parameter z? If so what is the value for z?
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Peaks and dips position in the Planck CMB

I am currently looking for the values of the firsts peaks and dips (at least the first 3) in terms of l and angular size for the CMB angular power spectrum measured from Planck. But the only thing I ...
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When was the cosmic background radiation in the visible spectrum?

From what I understand about the Cosmic Microwave Background Radiation is that it was from the big bang, and since space has streched and become bigger since then the wavelength of the CMBR has ...
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Redshift 1+z - CMB Temperature lower?

I know that $\frac{\lambda_2}{\lambda_1} = 1 + z$ Suppose a galaxy had redshfit $z=3$. Does this mean that the wavelength becomes $4\lambda$? Then by wien's law where $\lambda \propto \frac{1}{T}$, ...
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The initial conditions of the CMB spectrum

The CMB spectrum shows the intensity of fluctuation at a certain angular scale: The achievement is the correspondence between the predicted power spectrum and the observed one. My question is as ...
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Why is absolute zero considered to be asymptotical? Wouldn't regions such as massive gaps between galaxy clusters have temperatures of absolute zero?

Why is absolute zero considered to be asymptotical? Wouldn't regions such as massive gaps between galaxy clusters have temperatures of absolute zero? I just do not see why our model must work the way ...
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Frequency of cosmic microwave background

Some people refer to cosmic microwave background's (CMB) frame of reference as an absolute one. If I understand correctly, we can measure 'absolute' velocity in this frame by using the Doppler effect. ...
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$\Delta^+$ decay in GZK process

The dominant channels in the GZK process are $$p+\gamma_{\rm CMB}\to\Delta^+\to p+\pi^0,$$ $$p+\gamma_{\rm CMB}\to\Delta^+\to n+\pi^+.$$ According to the pdg, $\Delta\to N+\pi$ makes up essentially ...
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Why are no CMB experiments able to measure the whole range of multipole moments?

Have a look at the following diagram: This shows measurements of the CMB by various experiments, with multipole moment $l$ on the x-axis and the temperature of the corresponding moment on the ...
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How did WMAP measure the flatness of space? [duplicate]

I read that WMAP constrained $\Omega_0$ to be $1$ within $1%$. I realize that the baryon acoustic oscillations will produce a preferred scale on the CMB. Knowing $H_0$ one could measure the angle of ...
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Spectrum of CMB vs. duration of last scattering

The epoch of last scattering took over 100,000 years. The Visibility Function has maximum at about 370,000 years after the Big Bang when the temperature was about 5,600 K. 50,000 years earlier the ...
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Do COBE, WMAP, or Planck data show time-variance of the CMB's anisotropies? [duplicate]

What limits on the time-variance of the CMB do the COBE, WMAP, or Planck data put? In other words, I am looking for a peer-reviewed paper that would answer this question: If I made maps of, say, WMAP ...
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Do COBE, WMAP, and Plack have design flaws? [duplicate]

MRI expert Pierre-Marie Robitaille on the design flaws of COBE, WMAP, & Planck and the violation Kirchhoff's Law: Here are his talks: Pierre-Marie Robitaille: The Cosmic Microwave Background ...
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Do oceans produce the cosmic microwave background?

A guy who has a career in medical physics named Pierre-Marie Robitaille argues in two recently published papers in “Progress in Physics”, that the CMB is not from the big bang but from the oceans. ...
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What Did Nobelaureate Smoot Mean by “Modern Efforts to Find Violations of Special Relativity”

In George Smoot's 2006 Nobel Lecture, having won the Nobel prize for his research on the Cosmic Microwave Background (CMB), he refers to the possibility of the CMB being a special frame stating ...
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Is cosmic background radiation absolute [duplicate]

Now that we don't have permeating Ether anymore, why don't we consider the omnipresent Cosmic background radiation in place of it? and measure Speeds with respect to the CMBR? In that way an object ...
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What's the total Cosmic Microwave Background energy?

This is a part of my wider attempts at accounting matter in the observable universe. The total light ever emitted by stars and other space objects is capped around 1% of baryonic mass (in energy ...
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Correlation between large-scale galaxy structure and CMB fluctuations?

During a relatively non-technical astronomy seminar the other day, the speaker displayed the famous WMAP full-sky image as an aid to describing what the CMB is, the scale of its fluctuations, etc. ...
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How can we detect cosmic background radiation?

From what I understand, CMB is the left over radiation from the Big Bang. As all matter, including the Earth, was made during the Big Bang and then as the universe expanded that matter/energy got ...
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How does the Cosmic Microwave Background give us information about the Big Bang?

I was reading about CMB after this new breakthrough last week and I could not figure this out. The CMB did not exist before the epoch of Last Scattering. They were just photons which were formed at ...
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Immediately after the Big Bang, was the universe in a state of extremely low or extremely high entropy?

Phase space theory suggests that the largest course-graining region, $p$, in a phase space, $P$, is the point in the phase space with the highest entropy. As such, it is in thermal equilibrium with ...
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What are the implications of the possibility that the BICEP2 results are caused by a self ordering scalar field transition?

I've found this interesting paper that mentions another possible way to interpret the recent BICEP2 results, and that hadn't been ruled out yet 1. As interesting as the possibility that the BICEP2 ...
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The gravity waves from the big bang? How can we know?

The latest news says that scientists detected gravitational waves from the Big Bang. My question is how do they know the waves originated in the big bang verses any number of supernovae and or ...
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What does BICEP2's results tell us about gravitation waves and quantum gravity?

The BICEP2 results, unless I am mistaken, are a measurement of CMB polarization, i.e. photon polarization. That is, taken at face value they say nothing about gravity directly. Now, we can start to ...
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What's the $\ell$ in the Bicep2 paper mean?

The BICEP experiment's recent announcement included the preprint of their paper, BICEP2 I: Detection of $B$-mode polarization at degree angular scales. BICEP2 Collaboration. To be submitted. ...
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CMB curly B-modes and dark matter

I raised a question a while ago regarding weak gravitational lensing of galaxies and the CMB. With all the fuzz with the BICEP2 data, I think it is time to raise even more questions about this amazing ...
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How big of an area of the sky is the BICEP2 survey?

So here is the BICEP2 picture: How big is that? How much of the sky? Say, compared to this picture of the CMB by Planck:
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Is Λ-CDM and no inflaton field compatible with the observed value of the scalar spectral index?

From the cosmic microwave background, one can extract the scalar spectral index $n_s$. It is measured to be smaller than 1 by several standard deviations. Wikipedia says that it is a parameter of the ...
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What do the names “E mode” and “B mode” mean? Where do they come from?

This has been bugging me a bit since the BICEP announcement, but if there are any resources that answer my question in a simple way, they've been buried in a slew of over-technical or over-popularized ...
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BICEP2 and string theory

Can anybody elaborate on the implications of the BICEP2 result for string theory? The discussion here What experiment would disprove string theory? suggests that refuting string theory is rather ...
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Connection between BAO und CMB Spectrum

I have a problem understanding the connection between the accoustic peaks in the CMB spectrum and the baryon oscillation picture. On the one hand it is stated, that the odd accoustic peaks (1,3,5..) ...
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BICEP2 experiments

How was the polarization experimentally measured in the BICEP2 experiments and why did they look specifically at B-modes? Why is it implying the existence of gravitational waves and the need to ...
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What do the BICEP2 results mean for string gas cosmology and the ekpyrotic universe?

The imprint of gravitational waves created shortly after the big bang may offer direct evidence for inflation theory, according to a discovery by the BICEP2 experiment at the South Pole and released ...
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What experiments compete with BICEP 2, and when are their results expected?

The recent results of the BICEP 2 experiment published on March 17th 2014, has generated a lot of media attention, with the general consensus being that "this is a major discovery" perhaps leading to ...
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What do the line segments on the BICEP2 B-mode polarization map mean?

The first image of BICEP2 visuals shows the "BICEP2 B-mode Signal", described as follows: Gravitational waves from inflation generate a faint but distinctive twisting pattern in the ...
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What was the major discovery on gravitational waves made March 17th, 2014, in the BICEP2 experiment?

The Harvard-Smithsonian Centre for Astrophysics held a press conference today to announce a major discovery relating to gravitational waves. What was their announcement, and what are the implications? ...
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Meaning of $k$ in Sachs-Wolfe formula for angular power spectrum

I've seen the formula for the angular power spectrum of the CMB written as $$C_\ell = \frac2\pi \int\left|\Theta_\ell(k) \right|^2 k^2dk, $$ where $\Theta_\ell(k)$ is the temperature contrast at a ...
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why does the CMB change so slowly

If anisotropies of the CMB originated from "quantum fluctuations of matter in a very tiny space that expanded to the size of the observable universe we see today" (quote from Wikipedia) would they ...
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CMB radiation and holography

If in principle someone have the exact data of the CMB of our universe and unlimited computability power, to what extent it is possible to determine how the universe should look like? Does it fully ...
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Did Penzias and Wilson need such a large horn antenna to discover the CMB?

Penzias and Wilson discovered the 2.7K Cosmic Microwave Background (CMB) Radiation using a 6 meter horn antenna, along with a cryogenic low-noise detector measuring at 4 GHz: ...
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Angles in cosmology

We have several definitions of distances in cosmology. Take angular diameter distance. $$d_A = a(t)\int \frac{dt}{a(t)}\;.$$ If an object has proper length $L$ then the angle $\theta$ it is seen at ...
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Where is radiation density in the Planck 2013 results?

I've been looking at the Planck 2013 cosmological parameters paper, trying to update my toy cosmology simulator with the most recent data. Most of the interesting values such as $H_0$, $\Omega_m$, ...
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Is it reasonable to assume that de Sitter temperature will stop growing when it reaches equilibrium with the temperature of CMB?

Is it reasonable to assume that de Sitter temperature will stop growing when it reaches equilibrium with the temperature of CMB? Currently the de Sitter temperature (the temperature of the Universe's ...
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What is the de Sitter temperature as of now?

It is claimed that de Sitter temperature is $$T=\frac{1}{2\pi}H,$$ where $H$ is the Hubble constant. I presume it is expressed in natural units with which I am not familiar. So what it will be in ...
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What speed should have an alone planet to have a habitable zone due to relic radiation?

What speed should have an alone planet to have a habitable zone due to relic radiation, without any star involvement? How much time the planet will be able to remain in the habitable zone before the ...
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Temperature of relic radiation and thermal equilibrium

The temperature or relic radiation is 2.7 K. Does it mean that any flying body sufficiently far from any stars will reach this temperature? As I understand it, you can warm up water with sufficient ...
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Temperature of thermally isolated space region

If we thermally isolate a region in space, say using a hypothetical material of $0$ conductivity, and measure the region's temperature, will it be 2.7K?
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Weak gravitational lensing multispectral, multibackground correlations

My understanding of weak gravitational lensing is that it assumes random alignment distribution of galaxies in order to estimate statistical shear and convergences, which are used to estimate matter ...
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Could there have been two “Big Bangs”?

A couple of years ago, I remember seeing a documentary on the big bang theory. The theory presented was that to explain the cosmic microwave background radiation, there needed to have been two big ...
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Would the microwave background radiation have an “observer effect” on all systems in the universe due to its permeation?

Or more specifically, does the CMB radiation have an observer effect on us in our local system due to gravitational lensing? Acknowledging this effect, if any would be nearly negligible I have an ...