Hydrogen 21 cm line time?

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Discussion Overview

The discussion revolves around the interpretation of the 21 cm hydrogen line and its relation to the speed of electrons in hydrogen atoms. Participants explore concepts related to the hyperfine structure of hydrogen, the implications of electron spin, and the validity of using classical models like the Bohr model to describe electron behavior.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant calculates the speed of an electron in a hydrogen atom using the circumference of the Bohr radius and the time associated with the 21 cm line, arriving at a value of 9.7 x 10^-25 m/s.
  • Another participant questions the meaning of the statement regarding the 21 cm line occurring every 10 million years, seeking clarification.
  • A different participant challenges the notion of discussing the speed of a bound electron, suggesting that momentum is a more useful concept in this context.
  • One participant explains that the hyperfine structure of hydrogen involves changes in electron spin and relates this to the emission of the 21 cm line, providing a detailed calculation that mirrors the first participant's result.
  • Several participants express skepticism about the validity of the calculations and the use of the Bohr model, with one stating that it is "complete nonsense" to discuss the speed or position of a bound electron.

Areas of Agreement / Disagreement

There is no consensus among participants. While some engage in calculations and explanations regarding the 21 cm line and electron behavior, others strongly disagree with the underlying assumptions and the applicability of the Bohr model to the discussion.

Contextual Notes

Participants highlight limitations in the classical understanding of electron behavior, particularly in relation to the Bohr model, and the implications of using classical speed calculations for bound electrons. The discussion remains unresolved regarding the validity of the initial claims.

jv11
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TL;DR
Hydrogen line 21 cm happens every 10 milion years .
For Bohr radius circumference and this time
Does formula S/t=v
Applies for this ?
I think this is silly question ,
But I need second opinion about it.
From time t=0.34x10^15 sec(21 cm hydrogen time )
And C=33.22x10^-11 ( Bohr radius circumference)

Would the speed of electron inside the hydrogen cloud be calculated :

Ve=C/t
Ve=33.22x10^-11/0.34x10^15
Ve=9.7x 10^-25m/s

Tx
 
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jv11 said:
Hydrogen line 21 cm happens every 10 milion years .
What does this statement even mean?
 
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jv11 said:
Would the speed of electron inside the hydrogen cloud....
What do you mean by "the hydrogen cloud"?

But no matter what you mean by that, it makes no sense to talk about the speed of a bound electron. It may be possible to apply the notion of speed to a free electron, but nearly always momentum is more useful/informative.
 
Hi
HYPERFINE structure of hydrogen happens when electron spin inside the cloud changes direction (to protons spin).
It happens in f=2.9x10^-15 1/sec
Or t‎ = 0.34x10^15
The 21cm line is produced by a change in the direction of the electron's spin within this ground state.
The lowest possible energy level for an electron in a hydrogen atom is -13.6 eV, which corresponds to the ground state (n=1) in the Bohr model). At this energy level, the electron is closest to the proton, and its distance is described by the Bohr radius (approximately 0.53 x 10^-10 meters).
From average Bohr radius circumference and time t
We can calculate the speed of electron at Rb.
Ve=C/t
Ve=33.22x10^-11/0.34x10^15
Ve=9.7x10^-25m/s
If there is 9.7 x10^25 hydrogen atoms in close vicinity,every second
21 cm like will be emitted.
From this we can conclude that 1 electron inside the cloud travels the same time t=0.34x10^15s.
 
Does this make any sense to experts ?
 
jv11 said:
Does this make any sense to experts ?
No. I am sorry to say that it is complete nonsense.
The Bohr was abandoned long ago because it does not adequately describe electrons and cannot be used to develop further understanding of their behaviors. It makes no sense to talk about the speed or position of a bound electron.

As this thread is based on a misconception it is closed.
 

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