Does the CMB move or is it static?

In summary, the conversation discusses the concept of the Cosmic Microwave Background (CMB) and its expected movement due to quantum fluctuations. The speaker wonders if it is possible to capture a visual of this movement, since all we currently have is a still photograph. They also consider the difficulty of detecting movement at such vast distances and question the potential speed of objects necessary for their movement to be visible. The conversation ends with a technical question about the angle of a triangle formed by an object traveling at 0.5c over one year.
  • #1
MarcJo
2
0
If the CMB is quantum fluctuations of the primordial universe, I would expect it to move, not be static like a photograph. Quantum fluctuations do not hold still, nor has time itself seem to have dilated to the point where it would look constant.

Can somebody take a movie of it and see? All that we see is the famous photograph, but no one has seen the motion picture.

Thanks,

Marcjo
 
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  • #2
MarcJo said:
If the CMB is quantum fluctuations of the primordial universe, I would expect it to move, not be static like a photograph. Quantum fluctuations do not hold still, nor has time itself seem to have dilated to the point where it would look constant.

Can somebody take a movie of it and see? All that we see is the famous photograph, but no one has seen the motion picture.

Thanks,

Marcjo

At a distance of dozens of billions of light years, just how fast would any part of it have to be moving in order for us to see visible movement in the few decades we have been observing?


Hint: it is difficult enough for us to visually detect movement of stars in our own galaxy, some millions of times closer.
 
  • #3
We are looking at CMB photons that were separated by by much closer distances, when the universe was only 380,000 years old. I would expect much more motion than the stars, which don't seem to move on day to day human time scales. How much motion, I don't know.
 
  • #4
MarcJo said:
We are looking at CMB photons that were separated by by much closer distances, when the universe was only 380,000 years old. I would expect much more motion than the stars, which don't seem to move on day to day human time scales. How much motion, I don't know.
The point is, at a distance of 14 billion light years, things would have to be traveling at outrageous speeds for their motion to be visible at all over such a short time frame.

What is the angle of a triangle whose short side is .5 light years wide and 14 billion light years long? That is the angle an object would subtend traveling at .5c over one year.
 

1. What is the CMB?

The CMB, or cosmic microwave background, is a faint glow of light that permeates the entire universe. It is the oldest light in the universe, dating back to just 380,000 years after the Big Bang.

2. Is the CMB moving?

Yes, the CMB is moving. It is expanding along with the rest of the universe, and its movement is influenced by the gravitational pull of galaxies and other large structures.

3. How is the CMB measured?

The CMB is measured using specialized telescopes and detectors that can pick up the faint microwave radiation. Scientists use this data to create maps of the CMB and study its properties.

4. Can the CMB be used to study the early universe?

Yes, the CMB is an important tool for studying the early universe. It contains valuable information about the density and temperature of the universe when it was just a few hundred thousand years old.

5. Is the CMB static or constantly changing?

The CMB is not static, but it is constantly changing. Over time, the universe expands and the CMB shifts to longer wavelengths, making it appear cooler. In addition, the CMB contains tiny fluctuations that can provide insights into the structure and evolution of the universe.

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