Cosmic background Definition and 25 Threads

I was reading this paper (https://academic.oup.com/mnras/article/288/2/387/960778) where they analysed how CMB radiation is affected by evolving voids in an expanding spacetime (particularly through the Rees-Sciama effect and the integrated Sachs-Wolfe effect). This effect predicts that photons...

I'm trying to get a better understanding of CBR. Unfortunately the internet has limited information, I guess it's not a cool enough of a topic to discuss. This is some of what I found, is it correct? CBR is electromagnetic radiation. Microwaves travel at the speed of light. CBR was a result of...

Is the cosmic backround radiation incident on a black hole sufficient to make up for the energy lost through Hawking radiation? And what if we include the average energy flux from discrete objects like galaxies, as seen in intergalactic space?

Homework Statement For a power spectrum density fluctuations ##P(k) \propto k^n##, I need to find the scaling (with respect to ##a##) of the horizon wavenumber ##\frac{2\pi}{\chi_H}## in a matter dominated universe in terms of ##n##. ##\chi_H(a)## is the evolving particle horizon, in a flat...

I am interested to know if cosmic microwave (160 Ghz) or cosmic radio (20-50 Mhz) background radiation has ever been measured/detected underground or underwater? This may seem like an odd question as you’d expect lots of rock and water to attenuate or block the cosmic radiation photons, but I...

If intelligent life had evolved on some planet 6.8 billion years ago (half the time to the big bang 13.6 bilion years ago) and they had sent the equivalent of the COBE / Planck satellite to map the cosmic background radiation, where in the electromagnetic spectrum would they have seen the...

In a discussion with a friend I am unable to explain to him why at this moment we still can detect cosmic background radiation. According to his reasoning the radiation that originated from the big bang should have passed us long ago. Where in fact does this radiation that we now detect come...

I have embarked in trying to really do my homework and understand cosmology. From what I understand one of the ways that we can measure expansion is the the cosmic background radiation doesn't expand thereby providing something to compare observed expansion to. Have I got that wrong? tex

bapowell submitted a new PF Insights post A Poor Man's CMB Primer. Part 2: The Birth of a Cosmic Background Radiation Continue reading the Original PF Insights Post.

At one time, I read that the universe was, on a very large scale, essentially the same in all directions. Recently I have learned about the Cold Spot in the fairly uniform Cosmic Background Radiation map. Scientists have attributed the artifact to a very very large void in the ordinary matter...

I was wondering what experiments or observations have shown that the cosmic microwave background radiation exists outside our galaxy in intergalactic space. Have we detected it emanating from sources outside the galaxy? I know we've detected it here on Earth.

What operator acting on the vacuum state (vacuum state of the box?) gives a m^3 box of cosmic background radiation at 2.7K? As the temperature 2.7K slowly drops (wait a million years) must our operator above change in time? Do photons scatter via gravitions so that their energy changes...

Could anyone clarify where is gone the energy lost by CBR as the universe expands? Thank you in advance and happy new year

All stars and Galaxies appear to give off the whole spectrum of electromagnetic radiation. If one views images of the distribution of background radiation in detail it appears to be filimetary in nature. Also if one views the distribution of visible matter in the universe it also appears...

Greetings, I have heard that one can not know one's absolute velocity, only one's velocity relative to other objects. But wouldn't the cosmic background radiation be blueshifted in the direction of motion and redshifted in the oposite direction? Thanks

If the Cosmic background radiation was emitted at approximately 384,000 years after the big bang, and it travels the speed of light, with mattter moving at a slower speed, how is it possible that the cosmic rays are still with us and haven't already passed beyond us 13 billion years later...

I've been trying to find out more about cosmic background radiation, but I am unable to find any information on the variations in the measured cosmic background radiation. I'm talking about these WMAP images. Most of the images you'll find on Internet are the versions after being corrected...

If we look around us with the right instruments, we see CBR all around and it is fundamentally isotropic, that means on average the temperature and frequency is the same no matter which direction we look. (Doesn't it?) Say we are passed by someone traveling at 0.6c. At the moment that...

I am wondering how it is possible that we see CBR. Here's why: When the big bang occured, there was a sea of particles that gave off radiation. Now, if we are now made out of those particles, then how are we seeing their radiation now? The only way I see this happening is if matter traveled...

How does this stuff works (CBR)

Problaby a silly thought but if the cosmic microwave backgroud radiation got created in the big bang and traveled outwards at the speed of light, and so did everything else, but traveled at less than the speed of light, would'nt it be "ahead" of us. Or alternatively if the radiation is absorbed...

Guys, I really have been wondering how cosmic background radiation has been generated. I mean, as far as i understand it this is just red shifted photons that we receive from very distant places.It cannot come from distant stars because this radiation is a black body spectrum. But the red...

Dear All, I am trying to understand SPECIFICALLY the physics HOW and WHY the discovery of the 2 Bell scientists is hailed as something like the cosmological equivalent to the "missing link" as regard the Big Bang Theory ? I am looking for any and all links that explain this connection...

Hi, I was wondering if somebody could tell me in what way the following paragraph is incorrect (if it is). Thanks. According to Einstein’s theory, when radio waves travel from one place to another, and both places have a different time flow, the frequency will appear to change. When...

I've had this idea for years but never had a forum. How do we know we aren't merely measuring the energy emitted by our sun's http://science.nasa.gov/ssl/pad/solar/images/heliosph.gif ?