Layman's question on Cosmic Microwave Background

In summary, the cosmic microwave background radiation is just a remnant of the Big Bang, and it is mostly blocked by the Earth's atmosphere. However, it does contain a small amount of radiation that is detectable by satellites.
  • #1
FalkonJenova
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Hi everyone, I'm a lowly computer programmer who has been interested in the CMB lately and recently became curious about one thing...

As I understand it, the CMB is the left-over radiation from the Big Bang spread uniformly throughout the universe.

Does this mean that this radiation is also touching my body and everything I see right now?
Does the Earth's atmosphere somehow prevent it from reaching the surface?

If it is touching me, then does that also mean that the CMB is also occupying the empty space in my atoms?
Or does my body keep it out?

Thanks to anyone who sacrifices their time!
 
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  • #2
FalkonJenova said:
Hi everyone, I'm a lowly computer programmer who has been interested in the CMB lately and recently became curious about one thing...

As I understand it, the CMB is the left-over radiation from the Big Bang spread uniformly throughout the universe.

Does this mean that this radiation is also touching my body and everything I see right now?
Does the Earth's atmosphere somehow prevent it from reaching the surface?

If it is touching me, then does that also mean that the CMB is also occupying the empty space in my atoms?
Or does my body keep it out?

Thanks to anyone who sacrifices their time!

Yes it surrounds your body and must go a little ways in. But it's harmless

The peak wavelength is 1.1 millimeter
http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation

Out of curiosity I looked at http://en.wikipedia.org/wiki/Microwave_oven and learned that CMB is 100 times higher frequency than microwave oven radiation. The shorter wavelength probably means it is less penetrating so I would imagine that most common liquid or solid material would block it. Your skin probably stops all but a tiny fraction of it.

But atmosphere is not a good shield. The CMB was originally detected by an antenna on the ground.
 
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  • #3
FalkonJenova said:
Hi everyone, I'm a lowly computer programmer who has been interested in the CMB lately and recently became curious about one thing...

As I understand it, the CMB is the left-over radiation from the Big Bang spread uniformly throughout the universe.

Does this mean that this radiation is also touching my body and everything I see right now?
Does the Earth's atmosphere somehow prevent it from reaching the surface?

If it is touching me, then does that also mean that the CMB is also occupying the empty space in my atoms?
Or does my body keep it out?

Thanks to anyone who sacrifices their time!
Just to reiterate Marcus' point, the temperature of the CMB is just 2.7K, or 2.7C above above absolute zero. So it basically would have no impact on your body. Also, the vast majority of it is blocked by our atmosphere anyway (this is why we have satellites to observe the CMB).
 
  • #4
I believe I've seen a figure of 400 million photons of the CBMR per cubic meter.

So at a guess, you've got about that many in you at any moment.
 
  • #5
alexg said:
I believe I've seen a figure of 400 million photons of the CBMR per cubic meter.

So at a guess, you've got about that many in you at any moment.

How does this compare to the number of photons of sunlight per cubic meter?
 
  • #6
alexg said:
I believe I've seen a figure of 400 million photons of the CBMR per cubic meter.

So at a guess, you've got about that many in you at any moment.
Not quite, because as I mentioned above, most of those are blocked by the atmosphere!

But yes, in the older-style analog TV sets, some fraction of the static in the TV is due to CMB.
 
  • #7
About 1% of RF static can be attributed to the CMB. It is stll pretty pathetic. To put this into perspective, a 100 watt light light source emits about 2.5E+20 photons per second - which is a lot more than 400 million [4E+08] photons.
 
  • #8
Chronos said:
About 1% of RF static can be attributed to the CMB. It is stll pretty pathetic. To put this into perspective, a 100 watt light light source emits about 2.5E+20 photons per second - which is a lot more than 400 million [4E+08] photons.
Although to be fair to the CMB, it contains something like 98% of all the light ever emitted in the history of the universe. It's just that the universe is quite big now and that light is spread over the vast emptiness of space.
 

FAQ: Layman's question on Cosmic Microwave Background

What is the Cosmic Microwave Background (CMB)?

The Cosmic Microwave Background (CMB) is a faint, ubiquitous radiation that fills the entire universe. It is the residual heat left over from the Big Bang, which is believed to be the event that initiated the expansion of the universe about 13.8 billion years ago.

How was the CMB discovered?

The CMB was first discovered in 1965 by two radio astronomers, Arno Penzias and Robert Wilson, who were studying radio waves emanating from the Milky Way. They found a persistent background noise that was coming from every direction, which they initially thought was due to interference. However, after ruling out all possible sources of interference, they realized that they had discovered the CMB.

How does the CMB provide evidence for the Big Bang?

The CMB is considered to be one of the strongest pieces of evidence for the Big Bang theory. The CMB is extremely uniform, with a temperature of 2.7 Kelvin (just above absolute zero) in every direction. This uniformity suggests that at some point in the past, the entire universe was in a state of extreme heat and density, which eventually expanded and cooled down to its current state.

What information does the CMB contain?

The CMB contains valuable information about the early universe, such as its age, composition, and energy. It also provides insights into the formation and evolution of galaxies and other large-scale structures in the universe. Scientists also study the slight temperature variations in the CMB to learn more about the distribution of matter and energy in the universe.

How is the CMB used in scientific research?

The CMB is used by scientists to test and refine theories about the early universe, such as the Big Bang theory and the inflationary model. It is also used to study the properties of dark matter and dark energy, which make up about 95% of the universe's total energy. Additionally, the CMB is used to map the large-scale structure of the universe and to study the formation and evolution of galaxies and galaxy clusters.

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