Understanding Starlight: White Light, Double Slit Experiment, and Color Emission

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Discussion Overview

The discussion revolves around the nature of starlight, specifically focusing on whether all stars emit white light, the color emissions of different types of stars, and the implications of temperature on light emission. It includes aspects of theoretical understanding, conceptual clarification, and some experimental references.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question whether all stars produce white light and if red giants emit only red light while blue giants emit only blue light.
  • It is suggested that the sun produces white light due to its temperature, which allows it to emit a broad spectrum of visible wavelengths.
  • One participant notes that hotter stars emit more light and that their intensity peaks at higher frequencies, indicating a relationship between temperature and light emission.
  • There is a claim that all stars emit light across all types of wavelengths, with the sun having a relatively even distribution among visible wavelengths.
  • Some participants discuss the subjective nature of color perception, suggesting that the perception of the sun as white is influenced by human biology and evolutionary factors.

Areas of Agreement / Disagreement

Participants express differing views on the nature of starlight and color perception, indicating that multiple competing views remain. The discussion does not reach a consensus on whether all stars emit white light or how color perception influences the understanding of starlight.

Contextual Notes

Some claims depend on assumptions about temperature and light emission, and the discussion includes unresolved questions about the subjective nature of color perception and its implications for understanding starlight.

Zack K
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I've been recently watching videos about white light and the double slit experiment and how it creates a rainbow. It let me to some confusion and I would like some clarification.
My questions are: Do all stars like ours produce white light? Would red giants only emit red light and blue giants only emit blue light? Why does our sun produce white light and not all the types of visible light separately?
Some clarification would be amazing.
 
Science news on Phys.org
These might help:
http://csep10.phys.utk.edu/astr162/lect/light/spic-sun-ant.gif
BB_Spectra.jpg
 
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The basic reason stars emit light in the first place is because they are hot. Both the intensity and peak frequency increase with increasing temperature. Hotter stars emit more light and the intensity of that light peaks at a higher frequency than cooler stars. Note that in the top graph in Dave's post, the intensity has been normalized, meaning that each star's graph is scaled so that they peak at the same vertical distance. Spica actually puts out MUCH more light than the Sun does at all frequencies, as the bottom graph shows.

See this article: https://en.wikipedia.org/wiki/Thermal_radiation
 
So is the first graph indicating that our sun emits light from all types of wavelengths because of it's temperature?
 
Zack K said:
So is the first graph indicating that our sun emits light from all types of wavelengths because of it's temperature?
All stars emit light in all "types" of wavelengths

It so happens that the sun emits light with a quite even distribution among the so called visible wavelengths.

A star with surface temperature of 15 000 Kelvin will appear blue to us, because its spectrum contains a much larger fraction of blue wavelengths.

In fact, when one studies stars, the opposite is done. One obtains a spectrum and thus calculate the temperature of the star

(white light is also a biological effect, we think the sun is white because our eyes and brains have evolved on earth... the concept of color is subjective)
 
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malawi_glenn said:
(white light is also a biological effect, we think the sun is white because our eyes and brains have evolved on earth... the concept of color is subjective)
We are very subjective and a 'white' or grey surface will look white or grey to us under many different lighting conditions. It's quite amazing really. We can be looking at a 'red' sunset and things may have a reddish tinge to them but we can still recognise a grey as grey. Or brain is working overtime to be as consistent as possible with our colour perception. A vital evolutionary advantage (obviously).
 

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