# QuestionTurning on the light traveling through the dark space!

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#### Hartmann352

Here is some further reading on the selection and absorption of light.

According to Classical Theory Of Reflection Of Light, light always travels the least action path. This is Fermat's Principle. Thus, when it hits a smooth surface, angle of incidence is always equal to angle of reflection.

Light is an electromagnetic wave. The oscillating electromagnetic field causes the electrons in a material to oscillate. In general, whether they be bound or free electrons, the total charge of the material is neutral. As the electrons are lighter than the positive charges, the electron motion relative to the heavy nucleus will constitute an oscillating dipole, which re-radiates the light. As the material can be considered have a uniform distribution of dipoles all oscillating in phase, the net effect is a reflected wave.

Light is an electromagnetic wave that travels through space and transports energy. The intensity of the electric field of a light wave is exactly proportional to the square of its amplitude, hence energy per unit area and unit time is defined as intensity. This energy is delivered in discrete units called photons rather than in a continuous stream. Light particles are called photons. The energy carried by each photon can be calculated by the formula of energy of the photon, which is given as E (Photon energy) = h (Plank’s Constant) x f (electromagnetic frequency). This energy of the photon equation is also known as Planck-Einstein Relation.

Regarding the single photon response of a mirror. This is usually never directly treated quantum mechanically because it is evident that mirrors work in exactly the same way for single photons as for any light. However, we run into trouble if we try to interpret the interaction as an absorption and reemission event involving a single atom in the material. That's because we lose the mechanism that directs the reemitted photon in the reflected direction. A single atom can radiate in a wide range of directions according to the scattering crossection, whereas the reflected direction is very precise. When treating reflection at the atomic scale, you need to include the photon spatial mode function and then the interaction of all the constituent atoms with the distributed photon spatial mode. This means all the atoms that overlap the mode will be synchronously driven by the photon. The mathematics will include the coherent addition of the scattering amplitudes of all emitters. The scattering amplitudes will in turn comprise an integral that samples all atomic transitions, although no particular transition will be excited. The overall effect will be as described, all the atoms acting coherently as a phased array of antennae.

Note the coherent addition of many emitters is actually used in modern phased array radars, rather than use the traditional radar dish. This is exactly the same principle as how a mirror works.

Reflection is rather interesting from a quantum perspective. That's because we can see reflections, or at least perceive reflections, yet the interaction with a mirror does not count as a measurement!

In quantum mechanics, the measurement defines how we perceive the quantum world. In fact, the measurement makes the quantum world appear classical. However, we know that there is quantum strangeness lurking underneath through the observation of interference effects. That's most well-known in the Young's double slit experiment. Yet, more prosaically, it also underlies the phenomenon of reflection.

Reflection is not the same as absorption and reemission of the light. It is a coherent phenomenon that relies on a nonlocal distribution of dipoles all radiating in phase. This is where the single photon as a point particle fails. A single photon can only be reflected if it coherently interacts with the entire reflecting surface, not just a single atom in the material.

Furthermore, if we want a little more detail; the mirror response is linear, which means that the incoming light can be arbitrarily mixed with random frequency and phase, but the medium will respond precisely in a way that is consistent with the light being a sum of coherent parts, and reflect all parts equally.

Now, comes the Quantum Theory Of Reflection Of Light. Sir Richard Feynman came for help here. He did a great contribution in Quantum Electrodynamics. According to him, light travels every possible path after getting reflected from the smooth surface and all are least action paths with certain probabilities. We measure all possible paths through a measurement tool of time ticking.
For every frequency of light, there is a particular time ticking. We note the ticking taken by light to cover the first path from source to detector and we get a certain direction. We repeat it for every path taken by light and add all directions using Addition Of Vectors Concept*.

We will see that the direction of vector is more inclined to the path where angle of incidence is equal to angle of reflection. There is great certainty for this to happen compared to other paths taken by light. In this way, we conclude that light has maximum chances to follow the path where angle of incidence is equal to angle of reflection.

The incident ray interferes on the material surface. The wavefront suffers a 180 degree shift, on striking the surface, because it encounters “resistence” (if the beam is below the critical angle, we get total reflection). Superficially similar to the geometric optics case, because the slight imperfections in the mirror and the material properties can mean that the reflected wavefront is shifted in wavelength, distorted, and certainly attenuated.

See: https://www.quora.com/What-is-the-quantum-theory-of-reflection-of-light

See: https://collegedunia.com/exams/photon-energy-definition-formula-properties-and-solved-examples-chemistry-articleid-1781

* Addition of Vectors Concept: We cannot add two vectors directly like numbers to get the result as they have magnitude as well as direction.

A variety of mathematical operations can be performed with and upon vectors. One such operation is the addition of vectors. Two vectors can be added together to determine the result (or resultant). This process of adding two or more vectors has already been discussed in an earlier unit. Recall in our discussion of Newton's laws of motion, that the net force experienced by an object was determined by computing the vector sum of all the individual forces acting upon that object. That is the net force was the result (or resultant) of adding up all the force vectors.

Assume that a car is moving 10 miles to the north and then 10 miles to the south. We can easily evaluate the total distance traveled by car by adding these two numbers like 20 miles. But in the case of vector addition, the result is zero.

The reason is that the north and south directions are opposite to each other, which is why they cancel out, and so the vector sum will be zero. For the addition of 2 vectors, we can say that “vector sum.”

Here are some tips to remember for vector addition:
• The addition of vectors is accomplished geometrically but not algebraically.
• Vector quantities should behave as independent of each other quantities before the addition.
• From the vector addition, we only conclude the resultant of a number of vectors propagated on a body.
• From vector addition, we obtain the resultant vector, which is not dependent on order of the summation of vectors as
→A+→B=→B+→A
Generally, the vectors are added following two methods which are namely analytical and graphical methods. These methods can be used for both addition and subtraction of vectors. We know that the addition of two vectors is done with the help of the Triangle Law and Parallelogram Law of addition of vectors.

See: https://www.vedantu.com/iit-jee/addition-of-three-vectors

See: https://www.physicsclassroom.com/class/vectors/Lesson-1/Vector-Addition

See: https://www.vedantu.com/physics/addition-of-vectors

All materials containing electrons and nuclei will respond to an incident electromagnetic field. The field will distort the charge distribution in direct proportion to the strength of the field. For an oscillating electromagnetic field, the distortion is periodic and comprises an effective distribution of oscillating dipoles in the mirror. The oscillations of the distribution are all synchronised with the light so they act as the source for a reflected field. The direction of the reflected field is determined by the phase gradient along the distribution, which determines the angle of reflection.
Hartmann352

#### Hayseed

The speed of light is the surest of all of science's narratives and theories. All of our units and references are based on this velocity.

But no one has ever directly measured it's speed. We have always measured it's bounce. The only measured path is from A to B, and then from B back to A. A reflection. Two paths.

No one has ever measured from A to B. one length over time. We would need two synced clocks for that measurement. This is a huge problem, electric sync signals are too slow for the speed we are trying to measure. So we bounce it, and only need one clock.

Some say this is not a true measurement. Some even say, light might travel at different speeds in different directions. And of course there is math for the possibility. AND does it take any time to turn around? Mass has de-acceleration time and acceleration time. A duration of bounce.

So, to eliminate some of these doubts, I suggest a spinning shaft, to give two or more clocks, an absolute time, for measurement. This should clear up the different direction different speed possibility. And reflection duration......with a direct measurement.

Of course we would still be measuring a flux, and the result would be an average.

A spinning shaft is immune to space time. It can sync vertical clocks. A shaft is just one spin or rotation, with a very thick plane. A cylinder. The rotation is instant from end to end. Much faster than light.

Faster than light action and information at a distance........a simple shaft. Instant planetary communication. It's a mechanic universe.

Imagine a mechanical rotating shaft computer. Mechanical superpositions of spins on a nanosize scale.

It would be faster than quantum, and error free, for it has no probability.

We need some out of the box thinking.

#### F. M. Mossa

F.M. Mossa might find the following of interest:

Some of the earliest accounts of light reflection originate from the ancient Greek mathematician Euclid, who conducted a series of experiments around 300 BC, and appears to have had a good understanding of how light is reflected. However, it wasn't until a millennium and a half later that the Arab scientist Alhazen proposed a law describing exactly what happens to a light ray when it strikes a smooth surface and then bounces off into space.

The amount of light reflected by an object, and how it is reflected, is highly dependent upon the degree of smoothness or texture of the surface. When surface imperfections are smaller than the wavelength of the incident light (as in the case of a mirror), virtually all of the light is reflected equally. However, in the real world most objects have convoluted surfaces that exhibit a diffuse reflection, with the incident light being reflected in all directions. Many of the objects that we casually view every day (people, cars, houses, animals, trees, etc.) do not themselves emit visible light but reflect incident natural sunlight and artificial light. For instance, an apple appears a shiny red color because it has a relatively smooth surface that reflects red light and absorbs other non-red (such as green, blue, and yellow) wavelengths of light. The reflection of light can be roughly categorized into two types of reflection. Specular reflection is defined as light reflected from a smooth surface at a definite angle, whereas diffuse reflection is produced by rough surfaces that tend to reflect light in all directions. There are far more occurrences of diffuse reflection than specular reflection in our everyday environment.

Light will dim based on the inverse square law, which states that a doubling of the distance will reduce the emitted phon flux by four times.

In general, we therefore multiply the distance with itself in order to calculate the enlargement of that surface area. However, a larger surface area leads to a light intensity that is inversely proportional to the square of the distance, since the same amount of light has to be distributed onto a larger surface area respectively.

Therefore, we see a decrease in light intensity.

In technical terms the inverse-square law reads as follows: The energy (in our case: light intensity) at location A (subject area) decreases inversely proportional to the square of A’s distance to the energy source.

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Per this law, light loses its brightness or luminosity as it moves away from the source. For example: when you switch on the light in one corner of the room and when you move away from the source, the light appears dim or less bright due to an increase in the distance (away from the source).

The formula of inverse-square law is given as,

View attachment 2173

See: https://petapixel.com/inverse-square-law-light/

Why the sky above the Earth is bright, but space is mostly black except for stars, galaxies, planets and so on. Why isn’t space bright?

To understand that, start with why the sky s bright and blue on the Earth. It turns out most of the molecules in our atmosphere don’t really have much in the way of absorption bands in the visible spectrum. This means that light comes through the atmosphere.

Of course, if clouds and rain and volcanic ash are in the air, this changes. But consider “clear, dry air.” In that case, the molecules are smaller than wavelength of light. They don’t interact with light much because of that. But, there is an awful lot of air. Each molecule has a small probability of scattering the light a little bit. The sum total of that is that each meter of air scatters a few parts per billion of the light. But there are tens of thousands of meters of air between you and space. That means that a few percent of sunlight are scattered. Not really enough to notice the missing light at midday, but certainly enough to notice that the sky is blue. Why blue? Because the shorter the wavelength, the more likely it is that the light will be scattered by molecules. (This is not the case for larger particles. They scatter all visible light about equally. Clouds are a good example.)

But in space, unless there is a nebula or planetary atmosphere, there is not much to scatter light.

As a result, unless there is a light source at a particular position, the sky is going to be pretty dark on the Moon or outside a spacecraft.

If you were in deep space inside our galaxy, you would see stars everywhere in all directions. They would be as bright as a cloudless night on Earth, and would not twinkle. They would shine steady like planets do. Since the stars were below you as well as above, you would be able to see yourself weakly illuminated, though it wouldn't be enough to see colors.

Space is mostly just that: empty space. While it's true that space is not a perfect vacuum, but close enough that there is very little light scattering.

The term albedo comes from the Latin word albus, which means white. Albedo generally refers to visible light. However, albedo may sometimes involve infrared radiation (think heat).

Albedo is a unitless, non-dimensional value that ranges on a scale from 0 to 1. A value of 1 means that an object or surface reflects all incoming solar radiation. Surfaces that absorb all of the sunlight have a value of 0.

Surfaces like snow that reflect more light have a high albedo. Black asphalt has a low albedo because it absorbs much of the sunlight.

The overall albedo of the Moon is frequently quoted as being about 7%. This is actually the so-called Bond albedo at visible wavelengths, which refers to the fraction of the total energy impinging on a surface that is reflected in all directions. It is a concept which is useful in studies of planetary enegy balance, but has little relevance to perceived brightness, which depend entirely on the intensity reflected in a specific direction.

The NASA Moon Fact Sheet gives the Bond albedo of the Moon (presumably averaged over the entire solar spectrum, including non-visible wavelengths) as 0.11. However the CERES Earth orbiting satellite climate radiometers have measured the value to be higher and somewhere between 0.136 and 0.137, at a lunar phase angle of seven degrees.

A concept more closely related to the variations in the perceived brightness of planets due to variations in surface properties is the geometric albedo, or sometimes called the visual geometric albedo when referring specifically to the band of visible wavelengths. Geometric albedo is determined by comparing the light received from an entire spherical planet to that expected from an idealized "perfect" reflectance diffusing disk of the same same cross section, with a light source directly behind the detector. This is an indication, for example, of the total intensity of moonlight reflected back towards the Earth near Full Moon. The NASA Moon Fact Sheet gives the visual geometric albedo of the Moon as 0.12. However this number probably doesn't include the opposition surge which can increase the reflectance of the lunar surface by 50% or more when the light source and detector are precisely aligned.

A third concept is the normal albedo (or visual normal albedo) which is still more closely to the variation in in the perceived brightness of individual surface features due to variations in their reflectances. The word "normal" is used here to mean "with illumination perpendicular to the surface". Normal albedo is obtained by comparing a small sections of a planetary surface to what would be expected from a perfect diffusing reflector of the same area. Such a concept can be used to differentiate bright (high albedo) features, like the lunar highlands, from dark (low albedo) features, like the maria. However again, the retroreflectivity of many lunar materials makes it difficult to assign universally meaningful numbers. Unlike an ideal diffuser of a given reflectance, two lunar features that have equal reflectances when observed with the detector exactly aligned with the light source may be less similar when viewed at a different angle. Also the amount of brightening observed as the phase angle decreases varies with wavelength. A list of what are presumably visual normal albedo measurements can be found under Brightness of Selected Features, although it might be noted that only features near disk center are actually being evaluated at normal incidence near Full Moon.

Reflection and transmission of light waves occur because the frequencies of the light waves do not match the natural frequencies of vibration of the objects. When light waves of these frequencies strike an object, the electrons in the atoms of the object begin vibrating. But instead of vibrating in resonance at a large amplitude, the electrons vibrate for brief periods of time with small amplitudes of vibration; then the energy is reemitted as a light wave. If the object is transparent, then the vibrations of the electrons are passed on to neighboring atoms through the bulk of the material and reemitted on the opposite side of the object. Such frequencies of light waves are said to be transmitted. If the object is opaque, then the vibrations of the electrons are not passed from atom to atom through the bulk of the material. Rather the electrons of atoms on the material's surface vibrate for short periods of time and then reemit the energy as a reflected light wave. Such frequencies of light are said to be reflected.

The color of the objects that we see is largely due to the way those objects interact with light and ultimately reflect or transmit it to our eyes. The color of an object is not actually within the object itself. Rather, the color is in the light that shines upon it and is ultimately reflected or transmitted to our eyes. We know that the visible light spectrum consists of a range of frequencies, each of which corresponds to a specific color. When visible light strikes an object and a specific frequency becomes absorbed, that frequency of light will never make it to our eyes. Any visible light that strikes the object and becomes reflected or transmitted to our eyes will contribute to the color appearance of that object. So the color is not in the object itself, but in the light that strikes the object and ultimately reaches our eye. The only role that the object plays is that it might contain atoms capable of selectively absorbing one or more frequencies of the visible light that shine upon it. So if an object absorbs all of the frequencies of visible light except for the frequency associated with green light, then the object will appear green in the presence of ROYGBIV. And if an object absorbs all of the frequencies of visible light except for the frequency associated with blue light, then the object will appear blue in the presence of ROYGBIV.

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Transparent materials are materials that allow one or more of the frequencies of visible light to be transmitted through them; whatever color(s) is/are not transmitted by such objects, are typically absorbed by them. The appearance of a transparent object is dependent upon what color(s) of light is/are incident upon the object and what color(s) of light is/are transmitted through the object.

In general, reflection, transmission and absorption depend on the wavelength of the affected radiation. Thus, these three processes can either be quantified for monochromatic radiation (in this case, the adjective "spectral" is added to the respective quantity) or for a certain kind of polychromatic radiation. For the latter, the spectral distribution of the incident radiation has to be specified. In addition, reflectance, transmittance and absorptance might also depend on polarization and geometric distribution of the incident radiation, which therefore also have to be specified.The reflectance r is defined by the ratio of reflected radiant power to incident radiant power. For a certain area element dA of the reflecting surface, the (differential) incident radiant power is given by the surface's irradiance Ee, multiplied with the size of the surface element, thus

dFe,incident = Ee dA

and the (differential) reflected radiant power is given by the exitance Me, multiplied with the size of the surface element:

dFe,reflected = Me dA

Total reflectance is further subdivided in regular reflectance rr and diffuse reflectance rd, which are given by the ratios of regularly (or specularly) reflected radiant power and diffusely reflected radiant power to incident radiant power. From this definition, it is obvious that

r = rr + rd

Being defined as ratios of radiant power values, reflectance, transmittance and absorptance are dimensionless.

Quantities such as reflectance and transmittance are used to describe the optical properties of materials. The quantities can apply to either complex radiation or to monochromatic radiation.

The optical properties of materials are not a constant since they are dependent on many parameters such as:

• thickness of the sample
• surface conditions
• angle of incidence
• temperature
• the spectral composition of the radiation (CIE standard illuminants A, B, C, D65 and other illuminants D)
• polarization effects

See: https://www.wave3.com/2021/01/22/behind-forecast-albedo-reflecting-reflecting-sunlight/

See: https://the-moon.us/wiki/Albedo

See: https://www.physicsclassroom.com/class/light/Lesson-2/Light-Absorption,-Reflection,-and-Transmission

See: https://micro.magnet.fsu.edu/primer/lightandcolor/reflectionintro.html

Light, and its corresponding photons, need a surface to be reflected from in order to be visible, and its reflectivity is determined by the surface albedo. Though flowing through space from a source, it will not be visible until reflected. A spectrum of the elected light will determine the light absorbed and the frequencies, and hence the color, of the reflected light and the color in which we view the object.
Hartmann352
Are the equations affected by the fact that light on Earth travels through a medium, Earth's atmosphere? Are there any experiments that dealt with the dimming of light while traveling through empty space or a vacuum?

#### F. M. Mossa

"Why should light dim while traveling at a speed of 300 thousand km per second through empty space?"

The propagation of light has a radial direction. Radii are not parallel. Think of spokes on a wheel, the farther from the center, the greater the spread or distance between the tips of the spokes.

That is why light dims. They call this spread divergence. Light loses it's density(intensity) with distance.

It dims.
Are the equations affected by the fact that light on Earth travels through a medium, Earth's atmosphere? Are there any experiments that dealt with the dimming of light while traveling through empty space or a vacuum?

#### write4u

Question: Is there an actual vacuum? If the fabric of space consists of fields then clearly there is no such thing as a pure vacuum.

Consider that the Higgs Field is so dense that something travelling through it actually acquires mass. Perhaps this is what forces a photon to travel @ SOL and gives it its virtual mass.

I am not qualified to assert this, but it seems a reasonable possibility?

#### Hayseed

"Are the equations affected by the fact that light on Earth travels through a medium, Earth's atmosphere?"

Yes. The atmosphere scatters light. This measures out as a decrease in light's velocity and it is called the velocity factor. EM fields have this velocity factor when traveling thru a medium. Science even use a velocity factor for space, but it is described in a different manner. The impedance of space. The narrative cause is e0 and u0. But this is a false narrative too.

"Are there any experiments that dealt with the dimming of light while traveling through empty space or a vacuum?"

I am sure there are. But there are plenty of practical examples. Like the intensity from other planets as they change distance with us.

"Question: Is there an actual vacuum?"

Yes there is. It is the only thing that can fill infinity. It can not be found in or around this universe because of static, which are orphan emissions. This static energy is not from space, it only temporarily occupies space. This superposition is constantly changing, in both amplitude and direction.

"Consider that the Higgs Field is so dense that something travelling through it actually acquires mass."

The Higgs field is nothing but a short duration of EM superposition and it is meaningless. Does not have time to do anything, but dissolve away into space, like all other CERN "particles".

No matter how dense you manufacturer an EM emission, it will only gain momentum, it will never gain mass. Mass can not travel at c, naturally.

#### write4u

"Question: Is there an actual vacuum?"

Yes there is. It is the only thing that can fill infinity. It can not be found in or around this universe because of static, which are orphan emissions. This static energy is not from space, it only temporarily occupies space. This superposition is constantly changing, in both amplitude and direction.
But the spacetime geometry is not infinite. And spacetime is not a pure vacuum. It is a dynamically expanding object filled with stuff and energy.

The pure vacuum state exists in an infinite dimensionless and timeless permittive condition (nothingness), outside the universe and allows the universe to expand infinitely if that is energetically permitted.

#### F. M. Mossa

True or not: were the Sun emitting hot radiations, the outermost layers of the planets’ atmospheres would have been hotter than the inner ones, and the inner parts of the Sun’s corona would have been hotter than the outer parts?

#### Hartmann352

Stelar physics are pretty involved describing the the Sun's surface temperature vis a vis the temperature of the corona.

Are the equations affected by the fact that light on Earth travels through a medium, Earth's atmosphere? Are there any experiments that dealt with the dimming of light while traveling through empty space or a vacuum?
The “Dimming Effect” describes the change of the number of photons arriving per unit of time. In non-relativistic systems, the “Dimming effect” may occur due to the growing distance of light sources moving away from the receiver. This means that due to the growing distance, the photons continuously require more time to reach the receiver, which reduces the number of received photons per time unit compared to the number of emitted photons.

The “Dimming effect” may occur due to the growing distance of light sources moving away from the receiver. This means that due to the growing distance, the photons continuously require more time to reach the receiver, which reduces the number of received photons per time unit compared to the number of emitted photons.Understandably, the proposed “Dimming effect” must be tested (confirmed or rejected) through observations

Don't confuse "dimming" with photonics energy.

Photon energy is the energy carried by a single photon. The amount of energy is directly proportional to the photon's electromagnetic frequency and thus, equivalently, is inversely proportional to the wavelength. The higher the photon's frequency, the higher its energy. Equivalently, the longer the photon's wavelength, the lower its energy.

Very very dim
(about 3000 photons)
Very dim Dim
Getting brighter Bright Very bright
(over 30,000,000 photons)

Dimming or brightening of an object is directly proportional to the number of photons striking the object and being reflected.

"Photon flux," is the number of photons per second in a beam.

Brightness is just the number of photons per second hitting your eye - all the other properties of the light are the same.
Perceived brightness is the number of 'detected' photons hitting your eye per second!

Random (incoherent) light sources, such as stars and light bulbs, emit photons with random arrival times and a Bose-Einstein distribution.

Laser (coherent) light sources, on the other hand, have a more uniform (but still random) distribution: Poisson.

In accordance to the “Dimming effect”, observers on Earth will view 1.0001 more photons per time unit emitted by stars located near the ecliptic plane in the direction of the Earth orbiting the Sun. And, in contrast, observers will view only 0.9999 photons per time unit emitted by stars located near the ecliptic plane in the direction opposite to the Earth orbiting the Sun.

Calculating precise measurements of the same stars within a 6-month period can possibly detect this difference. These changes in brightness are not only for specific stars, as the change in brightness takes place for all stars near the ecliptic in the direction of the Earth’s orbit around the Sun and in the opposite direction.

The “Dimming effect” can possibly be detected in a physics laboratory using a moving light source (or mirror) and photon counters located in the direction of travel and in the opposite direction.

The dilation of time can also be used for testing the existence of the “Dimming effect.” However, in experiments on Earth this effect appears in only the 14th digit after the decimal point and testing does not appear to be feasible.

See: https://www.researchgate.net/publication/348139515_Methods_to_Test_the_Dimming_Effect_Produced_by_a_Decrease_in_the_Number_of_Photons_Received_from_Receding_Light_Sources

See: https://physics.stackexchange.com/questions/16910/whats-the-difference-between-dim-and-bright-light

See: https://www.sciencegate.app/document/10.21203/rs.3.rs-138372/v1

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#### Hartmann352

write4u and F.M. Mossa might enjoy the following:

"Collapse" is a misleading term in describing wavefunctions, means a change in the wavefunction as interactions happen.

The idea of the wave function in quantum mechanics and its indeterministic collapse during a "measurement" is without a doubt among the three most controversial problems in quantum physics today, the others being the two-slit experiment and entanglement..

So it is very important to understand the importance of what Dirac called the projection postulate in quantum mechanics. The “collapse of the wave function” is also known as the “reduction of the wave packet.” This describes the change from a system that can be seen as having many possible quantum states (Dirac’s principle of superposition) to its randomly being found in only one of those possible states.

Although the collapse is historically thought to be caused by a measurement, and thus dependent on the role of the observer in preparing and running the experiment, collapses can occur whenever quantum systems interact (e.g., collisions between particles) or even spontaneously (e.g., in the decay of radioactive nuclei).

The claim that an observer is needed to collapse the wave function has injected a severely anthropomorphic element into quantum theory, suggesting that nothing happens in the universe except when physicists are making measurements. An extreme example is Hugh Everett’s Many Worlds theory, which says that the universe splits into two nearly identical universes whenever a physical measurement is made.

Take this first order in the expansion Feynman diagram, for electron electron scattering

"Collapse" of the wave function can be considered between input electrons and outgoing electrons.

This is pair production (always needs an interaction with an electromagnetic field from a nucleus or other field for momentum conservation)

The energy is transferred between external lines where four vectors with the invariant mass of the particle hold true. Energy and momentum variables within the integrations implied, are variable under the limits of integration. The fields in field theory are like a different type of coordinates on which the interaction can be modeled. There is no energy exchange with the fields that can be measured experimentally.

Let me use Einstein, my favorite physicist. As Einstein’s blackboard drawing at the Solvay Conference* shows us, the wave function propagates like a light wave, but when the particle appears, it is found at a single point P.

Using Einstein’s idea of “objective reality,” without any interactions that could change the momentum, the particle must have traveled in a straight line from the origin to the point where it is found.

Einstein tells us the wave represents the probability of finding the particle. (Today it is the absolute square of the complex wave function Ψ that gives us the probability.) All directions are equally probable until the moment when the particle is found somewhere. At that moment, the probability of its being elsewhere goes to zero.

This has been interpreted as a “collapse.” If the wave had been carrying energy in all directions, or matter as Schrödinger thought, energy and matter would indeed have had to “collapse” to the point.

See: https://physics.stackexchange.com/questions/524177/collapse-of-the-wave-function

See: https://www.informationphilosopher.com/quantum/collapse/

* Solvay Conference - conferences on physics and chemistry held in Brussels by the International Solvay Institutes for Physics and Chemistry. Belgian chemist and industrialist Ernest Solvay founded the conferences, with the first in physics occurring in 1911 and the first in chemistry in 1922. They were interrupted by World Wars I and II but since then have kept to a three-year schedule, with a physics conference in the first year, no conference in the second year, and a chemistry conference in the third year. The conferences are usually divided into morning and afternoon sessions that open with one or two reviews of a subject followed by extensive time for discussion.

The most famous conference was the October 1927 Fifth Solvay International Conference on Electrons and Photons, where the world’s most notable physicists met to discuss the newly formulated quantum theory. The leading figures were Albert Einstein and Niels Bohr.

Einstein, disenchanted with Heisenberg’s uncertainty principle, remarked “God does not play dice”. Bohr replied: “Einstein, stop telling God what to do”. 17 of the 29 attendees were or became Nobel Prize winners, including Marie Curie, who alone among them, had won Nobel Prizes in two separate scientific disciplines.

This conference was also the culmination of the struggle between Einstein and the scientific realists, who wanted strict rules of the scientific method as laid out by Charles Peirce and Karl Popper, versus Bohr and the instrumentalists, who wanted looser rules based on outcomes. Starting at this point, the instrumentalists won, instrumentalism having been seen as the norm ever since.

Back to front, left to right:

Back:
Auguste Piccard, Émile Henriot, Paul Ehrenfest, Édouard Herzen, Théophile de Donder, Erwin Schrödinger, JE Verschaffelt, Wolfgang Pauli, Werner Heisenberg, Ralph Fowler, Léon Brillouin.

Middle: Peter Debye, Martin Knudsen, William Lawrence Bragg, Hendrik Anthony Kramers, Paul Dirac, Arthur Compton, Louis de Broglie, Max Born, Niels Bohr.

Front: Irving Langmuir, Max Planck, Marie Curie, Hendrik Lorentz, Albert Einstein, Paul Langevin, Charles-Eugène Guye, CTR Wilson, Owen Richardson.

See: https://www.edge-of-knowledge.com/edge-blog/2021/11/18/the-solvay-conference

See: https://www.britannica.com/event/Solvay-Conferences

The physics of lightwave propagation and the wave function have always fascinated me. And I have always found that Einstein was able, as few others, to cut to the crux of a problem and offer a solution comprehendible by many.
Hartmann352

#### Hartmann352

F.M. Mossa said,"... what we call light is a result produced when some invisible radiations, emitted by a hot body, meet a material."

In general, electromagnetic radiation may be divided into visible and invisible portions of the electromagnetic spectrum.

Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to visible light, the visible spectrum visible to the human eye. Visible light is usually defined as having wavelengths within the 400–700 nanometers (nm) range.

Electromagnetic radiation in the visible light region consists of quanta (called photons) at the lower end of the energies capable of causing electronic excitation within molecules, which leads to changes in the bonding or chemistry of the molecule.

Photons are categorized according to their energies, from low-energy radio waves and infrared radiation, through visible light, to high-energy X-rays and gamma rays.

See: https://www.nuclear-power.com/nuclear-power/reactor-physics/atomic-nuclear-physics/radiation/visible-and-invisible-radiation/

At the lower end of the visible light spectrum, electromagnetic radiation becomes invisible to humans (infrared) because its photons no longer have enough individual energy to cause a lasting molecular change (a change in conformation) in the visual retinal molecule in the human retina, whose changes triggers the sensation of vision. To view infrared light, infrared goggles filter out most of the visible light spectrum, allowing your eyes to absorb a sufficient amount of infrared light to affect retinal molecular changes to enable vision in the frequency band. Night vision goggles and night vision scopes pick up even the faintest fragments of light, including infrared, amplifying them until the threshold to visibility is surpassed. Starlight scopes and goggles amplify faint visible light to create a coherent image of the surroundings for the user.
Hartmann352

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#### F. M. Mossa

F.M. Mossa said,"... what we call light is a result produced when some invisible radiations, emitted by a hot body, meet a material."

In general, electromagnetic radiation may be divided into visible and invisible portions of the electromagnetic spectrum.

Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to visible light, the visible spectrum visible to the human eye. Visible light is usually defined as having wavelengths within the 400–700 nanometers (nm) range.

Electromagnetic radiation in the visible light region consists of quanta (called photons) at the lower end of the energies capable of causing electronic excitation within molecules, which leads to changes in the bonding or chemistry of the molecule.

Photons are categorized according to their energies, from low-energy radio waves and infrared radiation, through visible light, to high-energy X-rays and gamma rays.

See: https://www.nuclear-power.com/nuclear-power/reactor-physics/atomic-nuclear-physics/radiation/visible-and-invisible-radiation/

At the lower end of the visible light spectrum, electromagnetic radiation becomes invisible to humans (infrared) because its photons no longer have enough individual energy to cause a lasting molecular change (a change in conformation) in the visual retinal molecule in the human retina, whose changes triggers the sensation of vision. To view infrared light, infrared goggles filter out most of the visible light spectrum, allowing your eyes to absorb a sufficient amount of infrared light to affect retinal molecular changes to enable vision in the frequency band. Night vision goggles and night vision scopes pick up even the faintest fragments of light, including infrared, amplifying them until the threshold to visibility is surpassed. Starlight scopes and goggles amplify faint visible light to create a coherent image of the surroundings for the user.
Hartmann352
All the radiations emitted by the Sun are invisible to us in the vacuum outer space: you would see the space between you and the Sun DARK if you could look towards the Sun from the Moon's surface; and all the radiations emitted by the Sun have no effect of heating until they contact with a material: if you could "fly" a meter high above the Moon's ground, you would suffer the coldness of outer space, and you would not feel the seething heat of the Moon's surface, since heat will not transfer through the one-meter-distance vacuum separating between you and the Moon's ground.

#### F. M. Mossa

Do the radiations emitted by the Sun have no effect of illumination nor of heating up until they come in touch with a substance: is it for this reason that outer space remains dark and at minus 270 centigrade?
What would be the digit recorded by a thermometer suspended in the shade in a hit-by-sunrays site on the Moon, bearing in mind that the thermometer would be in a vacuum, as there is no air on the Moon, and that the seething temperature of the surroundings would have no effect on the thermometer, as heat does not transfer through a vacuum?

#### F. M. Mossa

What would be the digit recorded by a thermometer suspended in the shade in a hit-by-sunrays site on the Moon, bearing in mind that the thermometer would be in a vacuum, as there is no air on the Moon, and that the seething temperature of the surroundings would have no effect on the thermometer, as heat does not transfer through a vacuum?
One centimeter above the ground and upward anywhere on the Moon, whether the site is sunlit or shaded, it is -457° F, as there is no medium through which the heat of the Moon's surface can transfer upwardly.

#### Hartmann352

Information from NASA's Lunar Orbiter seems to indicate the temperatures below.

- 457F equates to absolute zero, the temperature at which all molecular motion stops.

At any given point in our universe photons, other particles, including virtual particles which pop in and out of existence due to the vacuum energy, some energy will always be present. And these energies translates as ‘particles in motion’, so the coldest temperatures in the cosmos in that deep freeze between the galaxies, temperature will be at least 1 or 2 degrees above absolute zero.

There is no atmosphere on the moon, which means there is no air temperature. The surface of the moon, however, has a vast variation of temperatures depending on whether or not it faces the sun.

The bright side of the moon is the one which is visible because the sun is hitting it. The surface of the moon in areas getting sunlight can be as hot as 253.4 degrees Fahrenheit (123° C). Keep in mind that water boils at 212 degrees Fahrenheit (100° C). The average daytime temperature of the moon is 224.6 degrees Fahrenheit (107° C).

The far side of the moon that is without sunlight is extremely frigid. The average temperature of the far side of the moon is -243.4 degrees Fahrenheit (-153° C). Water freezes at 32 degrees Fahrenheit (0° C). There are some areas of the moon where there are craters which sunlight never gets to, and these areas are as cold as the far side of the moon.

Because of the lack of atmosphere, there is no air temperature on the moon. Rather, it is measured by surface temperature. Different areas of the moon will have extreme temperatures, varying from boiling hot to freezing cold depending on whether the area is being hit by sunlight or if it is not.

As our nearest neighbor, the Moon is a natural laboratory for investigating fundamental questions about the origin and evolution of the Earth and the solar system. With the Lunar Reconnaissance Orbiter (LRO), NASA has returned to the Moon, enabling new discoveries and bringing the Moon back into the public eye. LRO launched on an Atlas V rocket on June 18, 2009, beginning a four-day trip to the Moon. LRO spent its first three years in a low polar orbit collecting detailed information about the Moon and its environment. After this initial orbit, LRO transitioned to a stable elliptical orbit, passing low over the lunar south pole.

While in orbit, LRO observations have enabled numerous groundbreaking discoveries, creating a new picture of the Moon as a dynamic and complex body. These developments have set up a scientific framework through which to challenge and improve our understanding of processes throughout the solar system.

The data in this dataset is from the The Diviner Lunar Radiometer Experiment, a multi-channel solar reflectance and infrared radiometer that maps the temperature of the lunar surface at 500-meter horizontal scales. Diviner data sets are produced by the Diviner Science Team at UCLA.

The Diviner instrument uses seven thermal infrared channels to measure temperatures on the surface of the Moon. These maps represent lunar surface temperatures at different points in the Moon's orbit around the Earth, compiled from data taken from the Lunar Reconnaissance Orbiter. Since Diviner can only take thin strips of data with each orbit, scientists needed to combine data collected over the course of three years to recreate a snap shot of global temperature.

Data Source, Permalink to Data Source, LRO Diviner

As the Moon moves around the Earth, different portions of the lunar surface are illuminated by sunlight, causing the phases of the Moon and a significant change in surface temperature. Areas illuminated by the Sun (white and red) can reach temperatures hot enough to boil water, while areas in shadow (blue) reach temperatures hundreds of degrees below freezing.

The extreme temperature environment on the Moon is of interest for planning future human and robotic exploration missions because engineers must design equipment to withstand the drastic shifts in temperature over the course of a lunar day (28 Earth days).

Scientists also study the Moon's temperature in order to determine where water might be stable at or below the surface. The Diviner instrument has identified permanently shadowed areas inside crater rims near polar regions as the most likely places to find surface and subsurface water ice.

Diviner is also mapping compositional variations in lunar rocks and soil by measuring the intensity of infrared light measured in three channels, distinct from the thermal channels described above. This information helps scientist unravel the Moon's geologic history and understand how it formed.

See: https://sos.noaa.gov/catalog/datasets/moon-surface-temperature/

When illuminated by the sun, the surface of the moon can reach up to 127 degrees Celsius (260 F). When the illuminated side moves into darkness, the temperature falls significantly. Since the sun no longer heats the surface, the moon’s surface can drop to -232 Celsius (-387 F). These are the coldest temperatures in our solar system, which means the surface of the moon can quickly become colder than that of Pluto.
Hartmann352