Calculating Temperature of Radiation at t1

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Discussion Overview

The discussion revolves around calculating the temperature of radiation at a specific time, referred to as t1, in the context of background radiation, specifically mentioning a hypothetical temperature of 1.95K. Participants explore the implications of this temperature in relation to cosmic background radiation (CMB) and the age of the universe, while questioning the appropriateness of the Stefan-Boltzmann law for this calculation.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions how to calculate the temperature of radiation at t1, suggesting that knowing t1 is necessary and expressing doubt about the applicability of the Stefan-Boltzmann law.
  • Another participant interprets the mention of 1.95K as potentially related to the CMB and discusses its implications for the age of the universe, noting that a lower temperature would suggest an older universe.
  • Some participants clarify that the 1.95K figure was a hypothetical example used to frame the question about measuring radiation temperature, not a sourced value.
  • There is confusion expressed regarding the distinction between calculating temperature at t1 and measuring current temperature, indicating a lack of clarity in the original question.

Areas of Agreement / Disagreement

Participants express differing interpretations of the question and its implications, with no consensus on the methodology for calculating or measuring the temperature of radiation at t1. The discussion remains unresolved regarding the appropriate approach and the significance of the hypothetical temperature.

Contextual Notes

Participants highlight potential misunderstandings regarding the definitions and implications of temperature measurements in cosmological contexts, as well as the need for clarity in the original inquiry.

NebulaBilly
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If there was background radiation of say 1.95K what would be the correct way to calculate the temperature of radiation at t1? Do we need to know what t1 is and also i have looked at Stefan Boltzmann law but i do not think that formula would be appropriate for what is trying to be achieved here.
 
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NebulaBilly said:
If there was background radiation of say 1.95K what would be the correct way to calculate the temperature of radiation at t1? Do we need to know what t1 is and also i have looked at Stefan Boltzmann law but i do not think that formula would be appropriate for what is trying to be achieved here.
What is the significance of ANY characteristic at "t1" (assuming you mean one second after the singularity) ?

Are you talking about the CMB? If that were 1.95K then the universe would be MUCH younger than it is currently measured to be with a CMB of about 2.7 degrees.

OH. Wait. You're saying 1.95Kelvin. I stupidly read that as 1.95 thousand. Never mind :smile:

If the CMB were 1.95K instead of 2.7K then that would imply that the universe is older than we now think it is.
 
phinds said:
If the CMB were 1.95K instead of 2.7K then that would imply that the universe is older than we now think it is.

I just used a made up figure, just to ask the question how i would measure the temperature of radiation if i have a background radiaiton on 1.9K, its not a figure i have got anywhere i just used it for the purpose of the question
 
NebulaBilly said:
I just used a made up figure, just to ask the question how i would measure the temperature of radiation if i have a background radiaiton on 1.9K, its not a figure i have got anywhere i just used it for the purpose of the question
You seem to be mixing apples and oranges here. First you ask how to calculate the temperature at t1 and now you are asking how to measure the temperature now. I'm not clear on WHAT you are asking.
 

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