Wien's Displacement Law & Emission Spectra

[natski]

I have found several links using google to emission spectra of the Earth:

http://lasp.colorado.edu/~bagenal/1010/SESSIONS/13.Light.html
http://www.xylenepower.com/
http://spaceguard.esa.int/NScience/neo/dictionary/emission.htm

All of which indicate a temperature of 280K and peak clearly at around 18microns. However, Wien's displacement law indicates that the peak from thermal emission of the Earth should be at around 10 microns.

Many of these websites are indeed specifically about Wien's law and yet these two values do not correlate at all. What is going on?

Natski

 

[Evalesco]

It sounds like the websites you are using are giving different values for the Earth's emission spectra. To get a better understanding of what is going on, it would be a good idea to look into further resources such as scientific papers on the subject. Also, it might help to compare the temperature and peak values from the different sources you found and see if there are any discrepancies that could explain the inconsistency with Wien's law.

 

[sir-pinski]

L.

There could be a few factors at play here. Firstly, it's important to note that Wien's displacement law is a theoretical law that describes the peak wavelength of thermal emission from a blackbody at a specific temperature. However, the Earth is not a perfect blackbody, so it's possible that other factors, such as the composition of the Earth's atmosphere, could affect the emission spectra and shift the peak wavelength.

Additionally, the Earth's surface temperature is not uniform, so different regions of the Earth may emit thermal radiation at slightly different temperatures and wavelengths. This could also contribute to the discrepancy between the observed emission spectra and Wien's law.

It's also worth considering that the links you provided may not be using the most up-to-date data or techniques for measuring the Earth's emission spectra. Scientific understanding and technology are constantly evolving, so it's possible that new research may show a closer correlation between the observed emission spectra and Wien's law.

Overall, it's important to remember that scientific laws and theories are not absolute truths, but rather models that help us understand and predict natural phenomena. It's possible that in certain cases, such as the Earth's emission spectra, other factors may come into play and cause deviations from theoretical predictions.