Exploring the Cosmic Microwave Background

In summary, the cosmic microwave background would look slightly different from different locations in the universe, but the change would be too slight to be detectable unless one were to travel a significant distance. As for time evolution, the changes are too slow for us to detect on a human-lifetime scale. It is theorized that one would need to jump to a vantage point about 10 million light years away to see a noticeable difference in the CMB. Additionally, as time goes on, the spherical shell of matter surrounding us expands, capturing a fresh slice of matter and potentially producing slightly different blotches on the CMB after millions of years. However, this evolution is also too slow for us to detect at our current technological capabilities.
  • #1
starkind
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I was looking at a map of the cosmic microwave background, and began wondering if the cmb would look the same from another vantage point, perhaps Pluto, or a nearby star. Or what about if it were seen from another galaxy? And, in a related question, does the cmb evolve with time?

I suppose no one knows. But has anyone done any speculation along these lines?

Thanks
 
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  • #2
it looks different from different locations of the Universe, but it order to have a different view you need to fly far away... Pluto, any nearby star or even Andromeda Galaxy are too close. You need to cross a significant part of the viible universe to see the difference.

From the same location, the picture becomes redder and redder and the picture slowly changes too.
 
  • #3
starkind said:
I was looking at a map of the cosmic microwave background, and began wondering if the cmb would look the same from another vantage point, perhaps Pluto, or a nearby star. Or what about if it were seen from another galaxy? And, in a related question, does the cmb evolve with time?

I suppose no one knows. But has anyone done any speculation along these lines?

Thanks

The change in perspective would be too slight to make a detectable difference.
Even if you could jump to a nearby galaxy say 1 million LY away, it would still look the same.

Also there is time evolution but it is too slow for us to detect on a human-lifetime scale.

I should give some explanation so that it won't just be a flat assertion on my part. I don't know how much explanation you want though. The basic thing about perspective is that when we look at CMB we are observing matter which is in a spherical shell around us with radius 46 billion LY.

The detectable variations in temp, the blotches, are over scales of 10 million to a billion LY.
My hunch is that we'd need to jump to a vantage point some 10 million LY from here in order to get a noticeably different CMB skymap. Someone else may perhaps be able to refine that rough estimate.

As time goes on the spherical shell gets larger and it has a different slice of matter on it. The radius of the surface-of-last-scattering increases faster than just ordinary Hubblerate expansion. So it encompasses a fresh slice of matter, and maybe after 10 million years that matter would be sufficiently different to have detectable different blotches. So there would be time evolution, but on too slow a scale for us as we currently think.
 
  • #4
thanks, Marcus and Dmitry67.
 

1. What is the cosmic microwave background (CMB)?

The 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. How was the CMB discovered?

The CMB was first predicted by physicist George Gamow in the 1940s. It was later accidentally discovered in 1965 by radio astronomers Arno Penzias and Robert Wilson, who were trying to eliminate background noise in their telescope.

3. What information does the CMB reveal about the universe?

The CMB carries information about the early universe, including its age, composition, and expansion rate. It also provides evidence for the Big Bang theory and supports the concept of inflation, the rapid expansion of the universe in its early stages.

4. How is the CMB studied?

Astronomers use specialized telescopes and instruments, such as the Planck satellite and the WMAP telescope, to study the CMB. They measure the temperature and polarization of the CMB to gather information about the early universe.

5. What implications does the CMB have for our understanding of the universe?

The CMB is one of the most important pieces of evidence for the Big Bang theory and has greatly expanded our understanding of the universe. It has also helped scientists confirm the existence of dark matter and dark energy, two mysterious components that make up a majority of the universe's mass and energy.

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