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Author Topic: Does the cosmic microwave background radiation remain in a perfect vacuum?  (Read 2062 times)

Offline Thebox

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In a vacuum that all mediums have been removed, does CBMR still remain even in a ''dark'' vacuum?


added - if there was an ''energy'' present in the background of space, but this energy did not have enough intensity to allow human sight in the dark, if we add ''energy'' to intensify the background ''energy'', would this  allow us to see?

« Last Edit: 26/07/2015 10:17:04 by chris »


 

Offline evan_au

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Quote from: Thebox
In a vacuum that all mediums have been removed, does CBMR still remain even in a ''dark'' vacuum?
The CMBR was emitted by matter in the early universe; if there were no matter, there would be no CMBR.

The universe has now expanded to such an extent that most of the volume of the universe is a very good vacuum, especially between galaxies. But the CMBR still gets through with no impediment. This is because the electromagnetic field does not depend on matter or an "aether" to carry it.

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if there was an ''energy'' present in the background of space, but this energy did not have enough intensity to allow human sight in the dark, if we add ''energy'' to intensify the background ''energy'', would this  allow us to see?
Human vision is not extremely sensitive - at least 2 photons must strike the same cone cell within a very short time to produce the sensation of vision.

In contrast, photomultiplier tubes can turn just 1 photon into millions of photons. And the Charge-Coupled Devices used by astronomers are able to count 80% of the photons that land on them over a period of hours (the liquid nitrogen coolant they use to reduce thermal noise is a bit impractical on consumer-grade cameras!). Both of these devices (plus photographic film) have turned low-intensity visible light into light which is intense enough for humans to see. By exending energy in these sensitive light-sensitive detectors, we can produce human-visible images. These techniques do not change the energy of the individual photons, but just increases the number of photons up to levels that humans can perceive.

Another approach is taken by astronomers working in radio, microwave and infra-red bands. In this case, the photons being detected are individually too low in energy to trigger the human visual system, no matter how many strike our eyes. In this case, various types of microwave and infra-red detectors are used. These detectors have to be cooled (sometimes to liquid helium temperatures) to eliminate the noise emitted by objects at human body temperature, which would otherwise obscure the desired signal. It takes considerable power to detect the presence of the weak signals they receive. The intensity of these signals is analysed by computers, and turned into images which are presented to humans as visible images on computer screens.

Quote from: Carl Sagan
the total energy picked up by all the radio telescopes on the entire planet in all of history is less than the energy of "a single snowflake hitting the ground
A recent informal review suggests that we may now be up to 2 or 3 snowflakes.
 

Online alancalverd

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In a vacuum that all mediums have been removed, does CBMR still remain even in a ''dark'' vacuum?

Yes. Electromagnetic radiation does not require the presence of any medium to propagate.


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added - if there was an ''energy'' present in the background of space, but this energy did not have enough intensity to allow human sight in the dark, if we add ''energy'' to intensify the background ''energy'', would this  allow us to see?

We use image intensifiers to allow us to see objects illuminated by starlight. We use telescopes to condense the radiation from stars to a sufficient intensity for us to photograph them, either directly or by adding energy with an intensifier. We might detect the presence of a nearby dark object as a gap in the CMBR but since the source is effectively the entire universe, it is too diffuse and isotropic to generate an image of a distant object.
 

Offline Thebox

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thank you for the very interesting posts,

did cbmr exist before the big bang?
 

Offline Colin2B

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did cbmr exist before the big bang?
Did you read the first few lines of reply #1?
 

Offline Thebox

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Did you read the first few lines of reply #1?

Yes but matter can not exist without energy in the first place.
 

Offline Colin2B

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Yes but matter can not exist without energy in the first place.
Your question was about CMBR, which reply #1 was answering.
Matter does not need CMBR for formation, there would have been other sources of energy before that, assuming that was the process.
 

Offline Thebox

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Your question was about CMBR, which reply #1 was answering.
Matter does not need CMBR for formation, there would have been other sources of energy before that, assuming that was the process.

From my understanding CMBR is everywhere, could this be an energy medium conduit for light?

In a vacuum light speed test, what does the light travel through?  CMBR maybe

 

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