Planck's Law, Color & Sun: Can We See It Greener?

In summary, the conversation discusses the color of the sun and the concept of peak wavelength in Planck's law. There is a question about why the intensity of electromagnetic waves is used instead of the number of photons with specific wavelengths, as the distributions for both are different. The speaker also wonders if it is possible to see the sun as slightly greener from space or in an ideal case. A source is mentioned, but it is unclear if the reason for using intensity is due to the limitations of measuring devices.
  • #1
Vrbic
407
18
I was thinking about the color of the sun. I would like to talk about an ideal case, no atmosphere etc. I looking for the peak in Planck's law in wavelengths (wl), i.e., the most radiated wl (or from Wien's law). But if I'm thinking about how we see that photons hitting our eyes and what wl is dominated such color we see. Why is the intensity of the electromagnetic waves (energy) used? And not the number of photons with specific wl? Distributions for both are different. What am I missing?
Is possible to see the Sun a bit greener than white from the space or in some ideal case or it is impossible for our eyes to recognize it?
 
Physics news on Phys.org
  • #2
Vrbic said:
Why is the intensity of the electromagnetic waves (energy) used? And not the number of photons with specific wl? Distributions for both are different
Are the distributions different? Do you have a source for this?
 
  • #3
Nugatory said:
Are the distributions different? Do you have a source for this?
I google it in english so I found first this http://hep.ph.liv.ac.uk/~hock/Teaching/StatisticalPhysics-Part5-Handout.pdf, but it is in any other textbook. Here equations 59 vs 60. I don't know, maybe reason is that devices measure intensity (energy) not number of photons. But I suppose human eyes no.
 

1. What is Planck's Law?

Planck's Law, also known as the Planck radiation law, is a fundamental law of physics that describes the spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature.

2. How does Planck's Law relate to color?

Planck's Law helps to explain the relationship between color and temperature. It states that the intensity of radiation at different wavelengths is directly proportional to the temperature. This means that as the temperature of a black body increases, it emits more radiation at shorter wavelengths, which our eyes perceive as blue and violet colors. As the temperature decreases, the radiation shifts to longer wavelengths, which we perceive as red and eventually, infrared.

3. Can we see the color of the sun as greener?

No, the sun's color cannot be perceived as green. The sun emits radiation at a peak wavelength of around 500 nanometers, which falls within the visible spectrum and is perceived by our eyes as yellow-white. While the sun does emit some radiation in the green portion of the spectrum, it is not enough to change its overall color from yellow-white to green.

4. How does the sun's color change throughout the day?

The sun's color changes throughout the day due to changes in its temperature. As the sun rises and reaches its maximum temperature at midday, it emits more blue and violet radiation, giving it a slightly bluish tint. As the sun sets and cools down, it emits more red and orange radiation, giving it a reddish-orange hue. This is known as the "golden hour."

5. Does the sun emit radiation at all wavelengths?

Yes, the sun emits radiation at all wavelengths, but the majority of its radiation falls within the visible spectrum, with a peak in the green-yellow region. However, the sun also emits radiation in the ultraviolet and infrared portions of the spectrum, which are invisible to the human eye.

Similar threads

I Planck's law in wavenumber vs. wavelength
    • Quantum Physics
Replies
20
Views
3K
I Physics of colors and our perception
    • Other Physics Topics
Replies
18
Views
2K
I Planck Emission Spectrum
    • Quantum Physics
Replies
23
Views
2K
B Can we say a photon doesn't exist until the wavefunction collapses?
    • Quantum Physics
Replies
16
Views
1K
I Color Theory - What does blue + yellow make?
    • Classical Physics
Replies
21
Views
939
Seeing colors: photons vs waves
    • Quantum Physics
Replies
5
Views
2K
I Investigating a 3D Color Hue Phenomenon with Blender and Just Color Picker
    • Optics
Replies
2
Views
1K
I Blackbody radiation and the cosmic microwave background
    • Classical Physics
Replies
29
Views
2K
B Blackbody Radiation: Explaining Ultraviolet Catastrophe & Planck's Solution
    • Quantum Physics
Replies
3
Views
1K
I Why is the Sun Yellow/Orange and Not White?
    • Astronomy and Astrophysics
Replies
11
Views
2K

Hot Threads

Recent Insights

Back
Top