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

In summary, stars emit light because of their high temperatures, with the intensity and peak frequency increasing as the temperature increases. Our sun emits white light because its temperature allows for a fairly even distribution of all wavelengths, while other stars may appear blue or red depending on their temperature. The concept of color is subjective and influenced by our biological makeup.
  • #1
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.
 
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  • #2
These might help:
http://csep10.phys.utk.edu/astr162/lect/light/spic-sun-ant.gif
BB_Spectra.jpg
 
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  • #3
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
 
  • #4
So is the first graph indicating that our sun emits light from all types of wavelengths because of it's temperature?
 
  • #5
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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  • #6
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).
 

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

What is the source of light produced by stars?

The source of light produced by stars is nuclear fusion. This is a process where hydrogen atoms in the star's core fuse together to form helium, releasing huge amounts of energy in the form of light and heat.

How is the color of light from stars determined?

The color of light from stars is determined by their temperature. Hotter stars appear bluer, while cooler stars appear redder. This is because hotter objects emit more high-energy, shorter-wavelength light, while cooler objects emit more low-energy, longer-wavelength light.

Why do stars twinkle?

Stars twinkle because of the Earth's atmosphere. As light from the star travels through the atmosphere, it is refracted or bent by the different layers of air with varying temperatures and densities. This causes the light to appear to flicker or twinkle to an observer on Earth.

How far does light from stars travel?

Light from stars can travel very long distances. The closest star to Earth, the sun, is about 93 million miles away. However, the farthest stars visible to the naked eye are hundreds of thousands of light years away, and some stars are even billions of light years away.

Can we see light from stars that have died?

Yes, we can see light from stars that have died. Since light takes time to travel through space, we are seeing light from stars that died long ago. For example, the light from the nearest star to Earth, Proxima Centauri, takes about 4 years to reach us, so we are seeing the star as it was 4 years ago.

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