Cosmic Microwave Background Surveys

In summary, the conversation discusses the relationship between surveys of the Milky Way and the concept of it being a 'closed' system. The question of whether the surveys were based on data from the visible Universe or restricted to data within the Milky Way is also brought up. It is clarified that the Cosmic Microwave Background (CMB) is present everywhere in the universe, originating from the Big Bang and currently located 45 billion light years away from the Milky Way.
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Martyn Arthur
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TL;DR Summary
Is the survey Universally representative?
If I understand correctly, by reference say here, the results seem to relate to a survey of the Milky Way.
1. Is the Milky Way a 'closed' system?
2. Whether or not, were the surveys based on data from the visible Universe, or restricted in all or part to the data form 'within' the Milky Way.
 
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Apologies, I intended to post only the link, not realizing it would start the video off!
 
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The CMB is everywhere in the universe. The radiation comes from the hot plasma of the Big Bang and has been travelling since then. The stuff that emitted the radiation we now see as the CMB is currently around 45 billion light years away, far beyond the Milky Way.
 
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  • #4
That is very clear thank you
martyn
 
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FAQ: Cosmic Microwave Background Surveys

What is the Cosmic Microwave Background (CMB)?

The Cosmic Microwave Background (CMB) is the thermal radiation left over from the Big Bang. It is the oldest light in the universe, dating back to about 380,000 years after the Big Bang, when the universe cooled enough for protons and electrons to combine into neutral hydrogen atoms, allowing photons to travel freely.

Why are Cosmic Microwave Background surveys important?

Cosmic Microwave Background surveys are crucial for understanding the early universe and its subsequent evolution. They provide a snapshot of the universe at a very young age, allowing scientists to test theories about the Big Bang, the formation of cosmic structures, and the fundamental properties of the universe, such as its geometry, composition, and rate of expansion.

How do scientists measure the Cosmic Microwave Background?

Scientists measure the Cosmic Microwave Background using specialized telescopes and instruments that can detect microwave radiation. These instruments are often placed on satellites, high-altitude balloons, or ground-based observatories in remote locations to minimize interference from Earth's atmosphere. The data collected is then analyzed to create detailed maps of the CMB's temperature and polarization.

What have we learned from Cosmic Microwave Background surveys?

From Cosmic Microwave Background surveys, we have learned a great deal about the universe's age, composition, and structure. For example, the CMB has provided strong evidence for the Big Bang theory, revealed the existence of dark matter and dark energy, and helped refine measurements of the Hubble constant, which describes the universe's rate of expansion. It has also provided insights into the initial conditions that led to the formation of galaxies and large-scale cosmic structures.

What are some of the major Cosmic Microwave Background experiments?

Some of the major Cosmic Microwave Background experiments include the COBE (Cosmic Background Explorer), WMAP (Wilkinson Microwave Anisotropy Probe), and Planck satellites. COBE first detected the CMB's blackbody spectrum and anisotropies, WMAP provided a detailed map of temperature fluctuations, and Planck delivered the most precise measurements of the CMB to date, including detailed maps of both temperature and polarization.

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