In classrooms, we learn that the sky is blue because blue is a short wavelength and air molecules scatter short wavelengths of light better than long wavelengths. Violet has a shorter wavelength than blue, but our eyes aren’t very sensitive to violet light. Blue light is less polarized than the other colors because it scatters more times and multiple scatterings destroy polarization.
This is a convincing explanation, but before I accept the conventional wisdom about anything, I always like to rule out some alternatives and try to say the same thing in other languages, even if it sounds silly.
What if the sky is blue because charged particles from the solar wind collide with air molecules? Both photons and electrons can collide with air molecules and make blue light. In fact, the northern lights are produced by the charged particles that leak around to the dark side of the planet, so I’m not sure that this possibility has been ruled out. When one considers the similarities between light and charged particles, maybe the distinction isn’t all that important.
A beam of charged particles glows blue when it is in contact with air.
What if the sky is blue because Cerenkov light is emitted when charged particles from the solar wind travel faster than the average speed of light in the atmosphere? If the atmosphere is treated as a continuous medium instead of as a collection of discrete scattering centers, perhaps this could be an equally valid explanation. Gravity bends light, so it has an index of refraction relative to gravity-free space and, in this context, the solar wind doesn’t have to be moving at a ridiculous speed to emit blue, Cerenkov light when the gravitational field of our planet slows it down. Going one step further, when the charged particles’ trajectory is bent by the Earth’s magnetic field, it is more appropriate to call the resulting radiation synchrotron light rather than Cerenkov light.
Two forms of radiation result from deceleration of a charged particle:
Cerenkov radiation from charged particles traveling faster than light in water.
Synchrotron radiation from charged particles’ trajectory bending in a magnet.
Perhaps this concept can be inverted to give us yet another explanation.
What if we imagine the molecules in our atmosphere moving relative to a gravity-free reference frame. They create a sort of optical grating which polarizes and filters the light from the sun as it travels through the aetheric, blue, electromagnetic wakes trailing behind by the molecules.
Backing up a bit, we now have four, independent explanations for one thing. The sky is blue because
- shorter wavelengths scatter off of molecules in the atmosphere
- charged particles scatter off of molecules in the atmosphere
- Cerenkov radiation and synchrotron radiation
- air molecules trace out aetheric wakes which filter solar light
Only one of these explanations is well-supported by the scientific literature, but since it is possible for multiple, independent explanations to be true at the same time, we often choose our favorite explanation based on simplicity and predictive power, qualities which depend on perspective. But if no single theory can simultaneously describe the part and the whole, one must always be of two minds to understand anything, so which two out of the four would you choose?
I don’t really care what the right answer is. I’d rather sing a song or read a book!
The image in the header is of beautiful underwater clouds captured by the legendary surf/underwater photographer Swilly (Simon Williams). Printed on premium metallic photo paper. …
I first posted this content on quora.com
Kirsten Hacker 
Dear Kirsten,
I model spacetime as a superfluid of low energy particles, such as low energy photons or neutrinos. Perhaps the superfluid is dominated by some other composite particle that forms out of low energy photons and neutrinos – such as a graviton. My model is classical, with real particles, of which there are just two fundamentally: the electrino and the positrino. I model them at 1/6th the charge of the electron and positron, respectively.
Spacetime is a superfluid with a black body temperature distribution of 2.8 Kelvin. Thus the superfluid is responsible for the energy that scientists have called the cosmic microwave background (CMB) and erroneously attributed to remnants of the mythical Big Bang.
To tie in to your post Kirsten, refraction IS the root cause of gravitational lensing. You see, in my model, the temperature of a particle of spacetime superfluid is the net energy impinging on that particle which has traveled from all other radiating matter-energy sources in the universe (I think this is a Machian view, with a twist that not all matter-energy is capable of radiating – in particular the interior of Planck cores of SMBH).
So how does spacetime superfluid cause refraction? We know refraction is due to variation in the speed of light. We know that the speed of light can be calculated from the permittivity and permeability of a medium. Therefore, following this logic, the permittivity and permeability of the spacetime superfluid must vary based upon the local temperature (energy) of the superfluid. So, we have a continuously varying speed of light around massive objects, where c is dominated by function of radius from nearby matter-energy and the radiated mass energy from the object.
I wrote more about this subject here: https://johnmarkmorris.com/2019/07/17/brainstorming-the-speeds-of-light/
Best,
Mark
p.s. As a fun exercise, consider a large star being absorbed by a galaxy center SMBH and eventually joining a Planck core, which is not capable of radiating mass. From the perspective of all other objects in the galaxy, a large mass at the galaxy center has effectively disappeared. What are the implications? Do the orbits of all objects in the galaxy increase in radius somewhat due to the mass disappearance? What are the implications for galaxy rotation curves and the search for dark matter?
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Thank you for your comments. It is nice to be understood. I see what you mean about the story arcs and the importance of introducing each character (idea) in a measured way that can be easily understood by the sort of person who might read a novel. In the books I’m writing, I’m trying to do this by creating narrative tension between Galilean and Lorentzian frameworks. Entropy is a wily character that plays different roles in each framework. My challenge is to avoid getting lost in the details so that the story (big picture) shines through. That is the biggest flaw of physics instruction, myopic detail without a clear (dramatic) narrative connecting it together. If drama it is invoked, it is through false mysteries and jargon like dark matter. I think we can do better than that.
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You are welcome. I’m having a blast reading your writings and engaging on ideas. Even in your response to my comment there is so much I want to say that I think I need to write a blog article because otherwise it would be too long for a comment. The gist is:
1. Sixty orders of magnitude from Planck length to size of the observable universe. To tell the story of nature requires the imagination and freedom of mind to quickly, nimbly, and comfortably scale up and down 60 orders of magnitude with ease.
2. I believe entropy is actually conserved in the universe once we take into account the spacetime superfluid. The second law can be tightened up to equality. I wrote an article about Entropy here: https://johnmarkmorris.com/2019/06/15/fresh-thinking-on-entropy/
3. Lorentzian is the key. I imagine the composite particles of the standard model as electrino/positrino shells surrounding a payload, like electrons orbit the nucleus of the atom in a wave function. Particles with empty shells are Majorana – like the neutrinos and the photon. Anyway, I have this intuition that the velocity of the particles in each shell is somehow related via a Lorentzian function to the local speed of light. So a lot of energy could be stored in a shell if it is spinning at or near the local speed of light. Also the shell radius could go through a Lorentzian expansion from Planck scale to what we see in our world at the low end of the temperature scale.
Ahh, it’s already getting long. I’ll add more to this in a post soon. Thank you Kirsten!
Best,
Mark
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I cleaned up, added to, and embellished my comments in a longer post here: https://johnmarkmorris.com/2019/10/14/kirsten-hacker-blue-skies/
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