Discussion Overview
The discussion centers around the possibility of detecting radiation with temperatures lower than that of the Cosmic Microwave Background Radiation (CMBR), which is approximately 2.5 K. Participants explore whether experiments could identify such radiation and the implications of doing so.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- Noel questions whether a WMAP-type experiment could detect radiation signatures at temperatures lower than the CMBR, such as 2 K, 1.5 K, or 1 K.
- Vanadium challenges the premise by comparing the measurement of the CMBR to measuring the temperature of boiling water, suggesting that the CMBR's temperature is fixed.
- Noel clarifies that he is not suggesting a different temperature for the CMBR but is inquiring about the existence of other radiation at lower temperatures.
- Marcus explains that while lower energy, longer wavelength photons could be detected, they would still conform to the same black body radiation curve associated with the CMBR.
- Chronos mentions that cooler objects at lesser redshifts could theoretically be detected, but they would produce faint signals.
- Noel seeks clarification on whether the "lopsided bell curve" mentioned by Marcus refers to the black body power spectrum representation.
- Marcus confirms that the curve can be plotted with either frequency or wavelength on the x-axis and discusses the implications of the power spectrum shape related to temperature variations.
- A participant speculates about the existence of a "dark" radiation component that interacts weakly with ordinary matter and could have a temperature lower than the CMBR.
- Another participant cautions against personal speculation regarding dark radiation, referencing forum rules.
- Noel inquires about the relationship between frequency and power in the context of radiation measurements and seeks further reading on the distinction between energy and power.
Areas of Agreement / Disagreement
Participants express differing views on the existence and detectability of radiation colder than the CMBR. While some agree on the characteristics of the CMBR and its associated power spectrum, others propose speculative ideas about dark radiation. There is no consensus on whether radiation at lower temperatures can be definitively detected.
Contextual Notes
Participants discuss the limitations of current detection methods and the assumptions underlying the measurements of the CMBR and related radiation. The discussion includes unresolved questions about the nature of radiation and the implications of potential discoveries.