Questions about the origin, history, evolution and fate of the Universe.

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6
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0answers
151 views

How to determine scalar-to-tensor ratio r from CMB polarization spectrum?

CMB polarization spectrum can tell us about the primordial scalar and tensor perturbation. By analyze B and E mode angular spectrum power spectrum and temperature power spectrum we can determine the ...
5
votes
0answers
46 views

Estimating the tangential and cross component of the galaxy's shear using Gnomonic projection

I would like to know how I can estimate the tangential and cross component of the galaxy's shear using Gnomonic projection of the right ascension and declination ...
3
votes
0answers
25 views

Why is the E-mode polarization spectrum out of phase with the Temperature spectrum?

The E-mode polarization power spectrum of the Cosmic Microwave Background displays the same acoustic peaks that can be seen in the (more famed) temperature power spectrum. However, they are out of ...
3
votes
0answers
35 views

Available data on the Milky way around 1920

In a book by Alexander Moszkowski, there is an Einstein quote about a hypothetical size of the universe (100 million Light years). Moszkowski claims that Einstein had deduced that from the ...
2
votes
0answers
107 views

Will Hubble's law always be accurate?

We have Hubble's law: v=Hd where H is the Hubble parameter, which is decreasing in value, but it will be constant in the distant future. So, assumming the Standard Model of Cosmology holds true, ...
2
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0answers
56 views

How exactly can the hypothetical conformal invariance of the CMB spectrum be established by analyzing tensor modes?

In the introduction of this paper at the top of p11, it is mentioned that a hypothetical enhancement of the scale invariance of the CMB spectrum to conformal invariance could potentially be ...
2
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0answers
72 views

Why can primordial tensor perturbations of the CMB be ascribed to gravitational waves?

Why can primordial tensor perturbations of the CMB be ascribed to gravitational waves? Is this attribution unique, or are there other michanisms that could lead to the ecitation of tensor modes? In ...
1
vote
0answers
46 views

Assumptions necessary for the strong form of Olber's Paradox

From Wikipedia, here's Lord Kelvin's statement of Olbers' Paradox: Were the succession of stars endless, then the background of the sky would present us a uniform luminosity, like that displayed ...
0
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0answers
43 views

$\Lambda$CDM Model and the early stages of the Universe

We know that the radiation dominant era lasted for 50,000 years, how? What equations give us the result of 50,000 years and how are we certain that we are talking about radiation dominant era, same ...