Thomson Scattering In the Early Universe

In summary, Thomson scattering occurs in the early universe due to high temperatures and the stationary nature of electrons. The condition for Thomson scattering to occur is when the energy of the incident photon is much smaller than the rest mass energy of an electron. This condition is fulfilled in the early universe due to the high temperatures and the assumption that electrons are essentially stationary.
  • #1
bananabandana
113
5

Homework Statement


Why does Thomson scattering occur in the early universe?

Homework Equations



$$ e^{-} + \gamma \rightarrow e^{-} + \gamma $$
is a Thomson scattering process if:
$$ E_{\gamma} << m_{e}c^{2}$$
(Electrons are essenitally stationary)

The Attempt at a Solution


[/B]
Very confused - how is it possible that the condition is fulfilled? Surely in the early universe, we expect very high temperature, and therefore ## \langle E_{\gamma} \rangle ## is very large. And the assumption that the electrons are practically stationary also seems ridiculous!

Many Thanks :)
 
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  • #2
What exactly do you call "early universe", and how large were the temperatures back then?
 

1. What is Thomson scattering in the early universe?

Thomson scattering is a physical process in which photons (particles of light) are scattered by charged particles in a medium. In the early universe, this process played a significant role in the formation of galaxies and the cosmic microwave background radiation.

2. How does Thomson scattering contribute to the cosmic microwave background radiation?

During the early stages of the universe, when it was hot and dense, photons were constantly being scattered by the free electrons present in the plasma. As the universe expanded and cooled, the electrons combined with protons to form neutral atoms, allowing the photons to travel freely. The cosmic microwave background radiation we observe today is a remnant of these scattered photons from the early universe.

3. What information can we learn from studying Thomson scattering in the early universe?

By studying the pattern of the cosmic microwave background radiation, scientists can learn about the distribution of matter and energy in the early universe. This information can provide insights into the structure and evolution of the universe, as well as the nature of dark matter and dark energy.

4. Can we observe Thomson scattering in the present-day universe?

Yes, Thomson scattering still occurs in the present-day universe. It is responsible for the phenomenon of polarization in light, and can be observed in various astrophysical objects such as stars, galaxies, and interstellar dust clouds.

5. How does Thomson scattering affect the formation of galaxies?

Thomson scattering plays a key role in the process of galaxy formation by allowing matter to clump together. As photons are scattered by free electrons, they lose energy and become trapped in regions of higher matter density. This leads to the formation of structures such as galaxies and galaxy clusters in the early universe.

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