One fact which I’ve known about for some time, is that Astronauts have left reflectors on the moon, which Scientists have subsequently been able to bounce laser-pulses off, to measure changes in the distance, of the moon’s orbit.
One fact which I’ve only learned about tonight, is the existence of multiple reflectors, at multiple sites.
Another fact which I’ve only learned about tonight, is that during a full moon, apparently, the reflected pulses seem to disappear. Apparently, this phenomenon has baffled some thinkers.
My mind conjures a plausible explanation for this phenomenon, in less time than it takes to state what the phenomenon is.
Science and Technology today has specialized in devising complex circuits, which have feedback loops, non-linearities, and gain-adjustment behaviors, which we don’t even keep track of anymore.
During a full moon, the angle of the sun’s light is approximately the same, as the angle of light from lasers on the Earth.
This could mean that the reflectors also send some of the sun’s light, that hits them, into the direction of the measuring base set up, as the source of laser-pulses.
What I imagine Scientists have done is to feed the output from highly sensitive amplifiers, through a high-pass filter, so that only changes in the intensity of the light, short enough to correspond to a laser-pulse, will pass through the high-pass filter. But then, if the gain of the amplifier that precedes the high-pass filter decreases for any reason, the intensity of the HF component, of the signal, should also decrease.
During a full moon, as seen by an actual telescope, the lunar landing sites in question should seem like ‘little pieces of glitter’, because these corner-cubes are also sending some of the sun’s light, back to the observer on Earth. It would actually be a major accomplishment, if the laser-equipped bases were able to make out reflections of their lasers, during this time.
I suppose a counter-point to this idea might be, that ‘The precision with which the corner-reflectors have been made, should be accurate enough to distinguish between the direction of the sun’s light, and that of the laser-equipped base.’ But I believe that in response to this latter subject, the fact that there could be dust on the reflectors, may get in the way.
With lunar dust settled on them, the reflectors’ behavior may be such, ‘To reflect 98% of incident light back, almost-exactly along the path that it came, but To reflect 1% of the incident light, back as though through a cone, that could be 5⁰ or 10⁰ wide.’ As the amount of dust increases, those numbers could become only 94% (directly-back) and 5% (conical)…
This might not have an immediately-noticeable effect on the ability to measure laser-pulses, during most calendar-days, because the sensor located at the laser-equipped base on Earth, would still be receiving an accurate return-pulse with 94% of its intended amplitude. Under those conditions, automatic gain-adjustment of the circuits would do their job, and researchers would simply continue to pay attention to the timing of the pulses… But if light from the sun itself became superimposed with that at 5% intensity, this could completely obscure the signal being sought.
This problem can be translated into something, which common people are more familiar with. The red shrouds over the tail-lights of cars, as well as certain multi-layered foils, also have tiny corner-cubes in them, that act to reflect light back, along the path it came from.
The intended effect of this is, that even if some car doesn’t have its tail-lights on at night, due to the light of our own headlamps, the other car’s tail-light ornament will seem to ‘glow in the dark’.
Well if we simply accepted the statement, that every corner-cube reflects light back “exactly in the direction it came from” – and that is an exact quotation – then, the light from our headlamps should simply be reflected back, into our headlamps. We shouldn’t see anything.
But precisely because the direction in which light is reflected is approximate, some of that light hits our windshields, and not just our own headlamps. And that’s also why we can recognize these reflective surfaces.
Imagine the light from an ordinary flashlight being reflected “exactly back in the direction it came from”, and therefore being reflected back into the flashlight, in such a way that the person holding the flashlight doesn’t see it. This is the way in which NASA describes, corner-cubes work.
There’s also no reason fw reflectors that have been sitting on the surface of the Moon for decades, should heat up considerably on one specific Earth-day. The length of the day as seen from the Moon, corresponds to half the period of its orbit around the Earth, and so those reflectors have 14 days to heat up.
I’ve observed that the degree of inaccuracy, and therefore the cone with which corner-cubes return light, get wider, as the corner-cubes become smaller – Until microscopic corner-cubes become ineffective. This would be a main reason, why special foils tend to be less-efficient in this capacity, than actual tail-lamp shrouds…
Along those lines, the reason fw Engineers made the prisms left on the moon large, was probably to keep their optical accuracy high.
But to what extent might it be possible, that natural crystals could act as corner-cubes by themselves? A lot of thinking is based on the assumption, that Man’s artificial corner-cubes are the only ones on the moon. But if the lunar dust has a cubic crystal-structure, then the back-side of crystals could act as natural corner-cubes as well.
This could be similar to how freshly-fallen snow sometimes seems to glitter in sunlight.
And in that case, the smaller, naturally-occurring instances would also return light in a more-approximate way, than the larger, artificial ones were initially designed to do. And so again, instruments on Earth could be dazzled, by sunlight that is almost reflected in the direction it came from.
Yet, this natural amount of glitter could also be useless for measurement purposes, because the pulses of returned light that need to be measured, might only be several centimeters long by design. Pulses that scatter off (Lunar) terrain would also be spread out in time, and their amplitude would therefore not pass through the (assumed) high-pass filter.
But, one reason I myself have doubt, in any naturally-occurring corner-cubes, is the fact that in order for real corner-cubes to work, they essentially need to have a cubic set of rear-facing mirrors – mutually at 90⁰ – as well as one single forward-facing surface, so that any refraction with which light enters this corner-cube, cancels out again, when the returned beam exits.
As soon as a crystal has not 1 but 3 forward-facing surfaces, the refraction with which light is returned, should no longer cancel the refraction with which it entered. Yet, there could still exist phenomena somewhere, which we did not expect with our Science, yet which can be explained.