Microwave BG vs Expansion vs Hydrogen Microwave Emission

In summary: If the CMB is due to the Big Bang, then shouldn't we be able to locate the point of origin, or should I believe that the Big Bang was spread uniformly across the universe?That's a difficult question. It's possible that the radiation from the big bang was more intense in some places than others, but it's impossible to say for sure.
  • #1
Buckeye
165
2
With 90% of the observable matter in the universe being Hydrogen (H2), why is it that the microwave background is attributed to the big band and not the emission of microwaves from excited state hydrogen?
 
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  • #2
Good question. Assuming the cosmic background radiation is coming from the temperature of hydrogen gas within the last billion years, we would expect to see it gathered around visible galaxies. This is not the case, as the cosmic background radiation is nearly uniform in every direction. Furthermore, the intensity of the cosmic background radiation at 2.725 kelvin happens to fit perfectly with the big bang theory's prediction!

Another way of answering you is to say that the cosmic background radiation IS being attributed to BOTH "the big bang" and to "the emission from excited hydrogen". You see, about half a million years after the big bang, the universe had cooled enough for it to be transparent to light. When this happened, photons generated by hot hydrogen ions (read: protons) were created in abundance. These photons are still out there to this day, on their long journey to end up in one of our telescopes.
 
  • #3
gendou2 said:
Good question. Assuming the cosmic background radiation is coming from the temperature of hydrogen gas within the last billion years, we would expect to see it gathered around visible galaxies. This is not the case, as the cosmic background radiation is nearly uniform in every direction. Furthermore, the intensity of the cosmic background radiation at 2.725 kelvin happens to fit perfectly with the big bang theory's prediction!

Another way of answering you is to say that the cosmic background radiation IS being attributed to BOTH "the big bang" and to "the emission from excited hydrogen". You see, about half a million years after the big bang, the universe had cooled enough for it to be transparent to light. When this happened, photons generated by hot hydrogen ions (read: protons) were created in abundance. These photons are still out there to this day, on their long journey to end up in one of our telescopes.

From the "inverse emission" image provided on Wiki (link http://upload.wikimedia.org/wikipedia/commons/2/28/WMAP_2008.png), I can not easily resolve where the microwaves are coming from. Based on that image, it seems difficult to justify the interpretation.

When you write that the CMB is nearly uniform in every direction, should I interpret that as "as far as we can measure from the surface of the planet earth" ?

If the CMB is due to the Big Bang, then shouldn't we be able to locate the point of origin, or should I believe that the Big Bang was spread uniformly across the universe?

When you write "end up in one of our telescopes." Does that mean that there are many telescopes equipped to receive Microwaves?
 
  • #4
CMB are located everywhere. Compare with the CNB (Cosmic neutrino background).

Big bang happened everywhere, there are MANY threads on this fourm that deals with that question "where did big bang occur?", "where is the centre of the universe" and so on.
 
  • #5
Buckeye said:
From the "inverse emission" image provided on Wiki (link http://upload.wikimedia.org/wikipedia/commons/2/28/WMAP_2008.png), I can not easily resolve where the microwaves are coming from. Based on that image, it seems difficult to justify the interpretation.
That's a plot of the microwave background in galactic coordinates.

When you write that the CMB is nearly uniform in every direction, should I interpret that as "as far as we can measure from the surface of the planet earth" ?
Well, no, since the satellites that measure it are not on the earth.

If the CMB is due to the Big Bang, then shouldn't we be able to locate the point of origin, or should I believe that the Big Bang was spread uniformly across the universe?
There is no "point of the big bang". This is a common misconception of the big bang theory: there is neither a centre of the universe, nor a point at which the big bang happened.

Note that I have moved this to the Cosmology forum.
 
  • #6
Buckeye said:
From the "inverse emission" image provided on Wiki (link If the CMB is due to the Big Bang...sts. They call it the cosmological principle.
 
  • #7
Another way of answering you is to say that the cosmic background radiation IS being attributed to BOTH "the big bang" and to "the emission from excited hydrogen".

If we were in a static universe we would see radiation from all the matter around us at whatever the average temperature was, say 2.7 kelvin (maybe this is not correct?). There must be some difference between that black body radiation and the big bang radiation, otherwise people would not have been so startled by the discovery. How would/did/do they differ? I realize that we are demonstrably not in a static universe, but I'm not sure it was such a secure fact when the CMB was first discovered. Something about it got everybody's attention, but I've never understood exactly what it was.
 

1. What is Microwave Background Radiation and how is it related to the Big Bang?

Microwave Background Radiation (MBR) is a type of electromagnetic radiation that is present throughout the universe. It is a remnant of the Big Bang, which is the event that is believed to have initiated the expansion of the universe. MBR is often referred to as the "afterglow" of the Big Bang because it is the oldest light in the universe, dating back to about 380,000 years after the Big Bang occurred.

2. How does expansion play a role in the formation of Microwave Background Radiation?

Expansion is a crucial factor in the formation of Microwave Background Radiation. As the universe expanded after the Big Bang, the hot, dense matter that filled the early universe began to cool down. This cooling process caused the wavelengths of the radiation to stretch, shifting it from visible light to microwaves, which is why it is now referred to as Microwave Background Radiation.

3. What is hydrogen microwave emission and how does it contribute to our understanding of the universe?

Hydrogen microwave emission is the radiation emitted by hydrogen atoms at specific wavelengths in the microwave range. This emission is significant because it allows us to map the distribution of hydrogen gas in the universe. By studying the distribution of hydrogen, we can gain insights into the structure and evolution of the universe, as well as the formation of galaxies and other cosmic structures.

4. How do scientists use microwave background radiation to study the early universe?

Scientists use microwave background radiation to study the early universe in several ways. One method is by analyzing the slight temperature variations in the cosmic microwave background, which can provide information about the density and distribution of matter in the early universe. Additionally, scientists can use the polarization of the radiation to study the effects of gravitational waves and the presence of dark matter in the early universe.

5. Is there a connection between Microwave Background Radiation and the cosmic microwave background?

Yes, Microwave Background Radiation and the cosmic microwave background (CMB) are often used interchangeably. The CMB refers to the radiation that is present throughout the entire universe, while Microwave Background Radiation specifically refers to the radiation that is detectable in the microwave spectrum. In other words, the CMB is a subset of Microwave Background Radiation.

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