Mirrors on the Moon ?

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Mirrors on the Moon ?

Postby NotRappaport on October 8th, 2017, 6:27 am

We’ve all heard the same claim, by defenders of ‘Official Truth’, that the Apollo missions and space travel are real because corner cube array retroreflectors are known to be on the Moon, and therefore proves some sort of spacecraft must have journeyed to the Moon in order to place them there.

What’s wrong with this claim is as follows:

It is effectively impossible for anyone to unambiguously demonstrate that any such retroreflector is actually present on the Moon!

“Why,” you ask? Ah, the Devil is in the details:

First of all, no amateur anywhere can ever hope to test for the presence of these supposed retroreflectors. (see here for a reddit “Ask Science” discussion).

In order have any chance (in theory, mind you) of firing a laser at a lunar retroreflector and detecting even a single return photon back on Earth, you need access to an enormous (3.5 meter minimum) observatory telescope, an extremely powerful 532nm (green) laser with a gigawatt of peak power that can output pulses of 120 picosecond duration at 20Hz, customized detection electronic hardware, and the specialized computer hardware and software to collect and statistically interpret the so-called “data”.

There are only EIGHT (8) observatories in the entire world equipped to do these lunar ranging experiments!
APOLLO, Macdonald, and Hawaii (all USA), Grasse (France), Wetzel (Germany), Matera (Italy), Hartebeesthoek (South Africa), and Mount Stromlo (Australia).
https://ilrs.cddis.eosdis.nasa.gov/scie ... lunar.html

Further, once you delve into the nuts and bolts of how this apparatus supposedly works, you discover that it requires you already know - in advance - the exact earth-moon distance before you set it up and run the test – so it can then tell you the earth-moon distance! Talk about circular reasoning (not to mention confirmation bias)! I know it sounds ridiculous, but its right there in the write-up:

From “The Apache Point Observatory Lunar Laser-Ranging Operation (APOLLO)”, page 6:
...the APD [Avalanche Photo-Diode] is “gated on” only for short intervals (~100ns) around the expected pulse return time.


The reason given for such a “gated” design on the detector, combined with the 20Hz pulse rate, is to filter out the huge amount of “noise” that would result from local reflections of the laser light off surfaces such as the telescope itself, dust particles, insects, birds, clouds, etc. This is done by adjusting the frequency of laser pulses so that the (theoretical) return pulse timing will be 180° out of phase with the outgoing pulses (meaning the detector is never on at the same time the laser is sending a pulse).

Most people who believe in the lunar retroreflectors know nothing of these nuances. But that’s neither here nor there.

"But doesn't the fact that they detect anything prove the light is bouncing off the reflectors?"
NO! In fact that leads us to the largest and never discussed problem! This intractable problem presents itself in the form of ambient 532nm light which does not originate from the laser at all: The sun, as it happens, outputs its peak intensity at around 500nm!

Sunlight Spectrum
Image

This results in the lunar surface being aglow with reflected sunlight containing the same wavelength you are attempting to detect as having come from your laser! And yes, they do run these lunar ranging experiments during all lunar phases! The APOLLO observatory schedule for 4th quarter of 2017: http://35m-schedule.apo.nmsu.edu/2017-1 ... /AP01.html

Even when the experiment is done at those times when the supposed retroreflector location is not in sunlight, there is still the problem of ambient light from the lit portion of the Moon striking things like ice crystals, dust, clouds, etc in the line of sight to the Moon.

How do they account for this tremendous amount of ambient noise?
How do they isolate their theoretical single return photon from the thousands of times larger noise photons of identical wavelength?
How do you detect a moth fart in a hurricane? :blink:
The answer? Statistics! Curve-fitting! Residual analysis! (the same methods that allows bolsheviks climatologists to "unambiguously" claim, based on sparse and skewed temperature data, carbon dioxide rises since the industrial revolution will have us all living on waterworld! :lol: )

So, in short, I see no reason to acquiesce to claims that there are mirrors on the Moon. It cannot be tested or verified. It requires faith, so I have two words for the idea of lunar retroreflectors: "PLONK, FLUSH!"
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Re: Mirrors on the Moon - a Hoax?

Postby patrix on October 8th, 2017, 8:21 am

So are you saying it's not likely we can laser range the Moon at all? Regardless of mirrors?

Regarding reflectors/mirrors, I think this article from National Geographic is interesting (Pdf link):
http://picsandfiles.connectedcomputer.c ... heMoon.pdf

It talks about how they laser ranged the Moon in 1962. Long before they claimed there where reflectors up there.
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Re: Mirrors on the Moon - a Hoax?

Postby NotRappaport on October 8th, 2017, 8:52 am

patrix » October 7th, 2017, 11:21 pm wrote:So are you saying it's not likely we can laser range the Moon at all? Regardless of mirrors?

Regarding reflectors/mirrors, I think this article from National Geographic is interesting (Pdf link):
http://picsandfiles.connectedcomputer.c ... heMoon.pdf

It talks about how they laser ranged the Moon in 1962. Long before they claimed there where reflectors up there.

The Nat'l Geographic story is scant on any details and I would need to be able to review the details before coming to a conclusion. The full text was apparently titled "Optical Echoes From the Moon" in Nature v194. Online it is unfortunately locked behind a paywall.

Based on the requirements in terms of laser power and subsequent detection problems over ambient light, I'm inclined to suspect the 1962 version suffers in the same way.

EDIT: I found this webpage, with what appears to be the text of the Nature article. I must say if this is the original text, it is extremely poorly described and not very detailed at all. The laser description is "ruby optical maser radiating pulses of approximately 50 joules energy" and that the transmitting system "included a Cassegrain telescope of 12-inch diameter" (what else did it include?). Other details, like the unequal number of "flashes" vs "intervals" along with the minuscule number of runs make it seem poorly planned/designed. It mentions at the end that it was "supported in part by the U.S. Army Signal Corps, the Air Force Office of Scientific Research, and the Office of Naval Research." <_<
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Re: Mirrors on the Moon - a Hoax?

Postby NotRappaport on October 8th, 2017, 9:24 pm

NotRappaport » October 7th, 2017, 11:52 pm wrote:
patrix » October 7th, 2017, 11:21 pm wrote:So are you saying it's not likely we can laser range the Moon at all? Regardless of mirrors?

Regarding reflectors/mirrors, I think this article from National Geographic is interesting (Pdf link):
http://picsandfiles.connectedcomputer.c ... heMoon.pdf

It talks about how they laser ranged the Moon in 1962. Long before they claimed there where reflectors up there.

The Nat'l Geographic story is scant on any details and I would need to be able to review the details before coming to a conclusion. The full text was apparently titled "Optical Echoes From the Moon" in Nature v194. Online it is unfortunately locked behind a paywall.

Based on the requirements in terms of laser power and subsequent detection problems over ambient light, I'm inclined to suspect the 1962 version suffers in the same way.

EDIT: I found this webpage, with what appears to be the text of the Nature article. I must say if this is the original text, it is extremely poorly described and not very detailed at all. The laser description is "ruby optical maser radiating pulses of approximately 50 joules energy" and that the transmitting system "included a Cassegrain telescope of 12-inch diameter" (what else did it include?). Other details, like the unequal number of "flashes" vs "intervals" along with the minuscule number of runs make it seem poorly planned/designed. It mentions at the end that it was "supported in part by the U.S. Army Signal Corps, the Air Force Office of Scientific Research, and the Office of Naval Research." <_<


Although I must say I don't see any obvious reason for them to lie about bouncing a laser off the Moon in a way that doesn't rely on bolstering the belief in space travel.

It's strange that the 1962 experiment doesn't seem to be repeated anywhere. Perhaps someone in the NASA story department came up with the idea of claiming they were going to put mirrors up there and put out the word that any more laser ranging experiments had to be held off until after that time?
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Re: Mirrors on the Moon - a Hoax?

Postby Flabbergasted on October 11th, 2017, 11:53 pm

NotRappaport wrote:I must say if this is the original text, it is extremely poorly described and not very detailed at all.

The publication is apparently just a short letter to the editor!
https://sci-hub.cc/https://www.nature.c ... 1267a0.pdf
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Re: Mirrors on the Moon - a Hoax?

Postby NotRappaport on October 12th, 2017, 6:48 am

Flabbergasted » October 11th, 2017, 2:53 pm wrote:
NotRappaport wrote:I must say if this is the original text, it is extremely poorly described and not very detailed at all.

The publication is apparently just a short letter to the editor!
https://sci-hub.cc/https://www.nature.c ... 1267a0.pdf


Great find! I've saved it for posterity.

Honestly, the more I think about it, the more it seems that the 1962 "optical echo" experiment was more likely to work, as it isn't predicated on the reflection coming only from a teeny 1 meter square retroreflector, but instead from all reflections off surfaces everywhere within the several km radius laser "spot" size on the Moon. Detection over ambient light still seems problematic, with the "signal" being mere fractions of single photon.

Maybe the guy who wrote the letter to Nature was later made to sign some non-disclosure agreement (along with anyone else involved with such experiments in the future). This would explain the complete lack of follow-up experiments in science journals, and indeed the fact that full details on the 1962 experiment are not available.
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Re: Mirrors on the Moon - a Hoax?

Postby patrix on October 12th, 2017, 8:04 am

as it isn't predicated on the reflection coming only from a teeny 1 meter square retroreflector, but instead from all reflections


If I recall correctly, in the movie "A funny thing happened on the way to the Moon" (Which is of course an obvious shill movie that tries to reinforce the lie that we can reach lower orbit, by revealing the Moon Hoax. The best lies are 80% true) or perhaps it was one called "Did we go"? Anyway there is a scene where they go to a Nutwork church and perform the holy Nutwork ritual "Laser ranging the Moon". And the way it works, according to the movie, is that they point the laser in the general direction of a reflector and then simply assume the laser echos is from a reflector if they get one since everybody knows you can only get a reflection from a mirror although they didn't seem to have that problem in 1962 according to that NG article.
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Re: Mirrors on the Moon - a Hoax?

Postby ObamaSimLaden on October 13th, 2017, 3:31 am

patrix » October 12th, 2017, 2:04 am wrote:
as it isn't predicated on the reflection coming only from a teeny 1 meter square retroreflector, but instead from all reflections


If I recall correctly, in the movie "A funny thing happened on the way to the Moon" (Which is of course an obvious shill movie that tries to reinforce the lie that we can reach lower orbit, by revealing the Moon Hoax. The best lies are 80% true) or perhaps it was one called "Did we go"? Anyway there is a scene where they go to a Nutwork church and perform the holy Nutwork ritual "Laser ranging the Moon". And the way it works, according to the movie, is that they point the laser in the general direction of a reflector and then simply assume the laser echos is from a reflector if they get one since everybody knows you can only get a reflection from a mirror although they didn't seem to have that problem in 1962 according to that NG article.


Contrary to sheeple belief a laser doesn't stay as a tiny beam over that distance (at least human made ones). By the time it gets to the moon it might be 200 miles in diameter (I can't remember the exact figure, but it's a pretty wide cone) and enough photons from the moons surface bounce back to get the measurement, similar to radar. I don't really see how a little mirror could improve accuracy that much. Even if it was to a minor degree, terrain variation/elevation would offset that by a greater amount as well as the global position on the moon relative to it's equator.

Not to mention the mirror would need to be on the equatorial region of the moon to be the most accurate (90 degrees from earthbound laser also near equator or azimuth of earthbound viewpoint). Perhaps they factor all that in, but regardless the mirror doesn't seem necessary. It was much more crucial to have a dune buggy on the mood for joyrides and golf clubs. ;)

If the laser was just a centimeter wide hitting a mirror on the moon, the mirror would have to be very precisely angled back to a single receiver on earth, which would then be affected by the seasonal wobble or else it would deflect off into space missing earth or at a minimum missing the dish back on earth. That means the laser could only be used during certain times of the year. Correct me if my logic is wrong.

This is one of the arguments people use to dismiss the notion of the moon landings being faked. Anyone ever go on Quora? Even there, supposedly smart people are loaded with groupthink and throw out the "nutter" "tinfoil hat" "conspiracy" "flat earth association" if you dare question the "facts".
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Re: Mirrors on the Moon - a Hoax?

Postby NotRappaport on October 13th, 2017, 6:32 am

ObamaSimLaden » October 12th, 2017, 6:31 pm wrote:If the laser was just a centimeter wide hitting a mirror on the moon, the mirror would have to be very precisely angled back to a single receiver on earth, which would then be affected by the seasonal wobble or else it would deflect off into space missing earth or at a minimum missing the dish back on earth. That means the laser could only be used during certain times of the year. Correct me if my logic is wrong.

Well the purported "mirror" is more accurately described as a retroreflector made up of an array of corner cube reflectors. These are designed so that any light entering the corner cube is internally reflected three times off three mutually orthogonal mirrors such that after the third reflection the light is always returned in the exact opposite trajectory that it entered the corner cube, towards the original source. As long as the angle of the incoming light isn't so oblique that it can't undergo the three reflections, it gets reflected back at the source.

The Wikidpedia article is reasonably accurate description of how retroreflectors work. https://en.wikipedia.org/wiki/Retroreflector

Although there is still divergence on the returned light beam because the internal mirrors cannot be physically perfect nor can their mutually orthogonal alignment be exactly perfect.

According to the Official Story the laser going toward the Moon diverges by 1 arcsecond and is 2km wide when it reaches the moon, and the returning beam reflected by the corner cube array diverges by 8 arcseconds and is 15km wide when it reaches earth. It seems they discount all other potential reflections off lunar surfaces in the 2km spot size.

Illustration from http://tmurphy.physics.ucsd.edu/apollo/basics.html
Image

What's funny about the "300 quadrillion photons per pulse, 1 in 30 million photons hitting the reflector, and 1 in 30 million of the reflected photons hitting the telescope" is if you do the math - 300 quadrillion divided by 30 million = 10 billion, 10 billion divided by 30 million is 333.3333333.... :rolleyes:
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Re: Mirrors on the Moon ?

Postby Maarten Rossaart on October 14th, 2017, 12:03 am

So, help me out.

I don’t get the straight line to-and-from in the illustration of the bouncing laser light. Both the Earth and the Moon are rotating on their axes. The Moon is 238,900 miles from Earth, which means the roundtrip is 477,800 miles. Light travels at 186,282 miles per second. This means that a little over 2.56 seconds pass between initial laser flash and the return bounce.

In this time the Earth has rotated (varying distances depending on the latitude of the observatory) and so has the Moon. At the equator, a point on Earth’s surface moves at 1000 miles per hour. In one second that point moves about a quarter of a mile; in 2.56 seconds that point on the equator has moved a little over seven-tenths of a mile, or less as latitude goes up.

If angle of incidence = angle of reflection, then the illustration should show a zigzag line to express the fact that the center of the alleged bounceback beam will strike at a spot somewhat to the west of the origination point. I suppose it is still within the 15km spread that is postulated for the return beam. But what is there—seven-tenths of a mile or so west of the origination point—to record the photons of the return beam? Not the observatory anymore ...
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Re: Mirrors on the Moon ?

Postby Intothevoid on October 14th, 2017, 2:08 am

I can tell you for a fact if you point a simple IR temperature gun (Infrared, sold at most auto parts stores) directly at the Moon you will notice an increase in temperature from that of the surrounding atmosphere. Just be sure no planes are flying near at the time. ;)
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Re: Mirrors on the Moon ?

Postby NotRappaport on October 14th, 2017, 3:42 am

Intothevoid » October 13th, 2017, 6:08 pm wrote:I can tell you for a fact if you point a simple IR temperature gun (Infrared, sold at most auto parts stores) directly at the Moon you will notice an increase in temperature from that of the surrounding atmosphere.

I haven't performed that experiment, but that result is expected since moonlight contains infrared wavelengths. Just an FYI, the laser on those IR temperature guns are not what reads the temperature, it's just to let the user see where the gun is aimed.
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Re: Mirrors on the Moon ?

Postby Intothevoid on October 14th, 2017, 10:54 am

NotRappaport » October 13th, 2017, 9:42 pm wrote:
Intothevoid » October 13th, 2017, 6:08 pm wrote:I can tell you for a fact if you point a simple IR temperature gun (Infrared, sold at most auto parts stores) directly at the Moon you will notice an increase in temperature from that of the surrounding atmosphere.

I haven't performed that experiment, but that result is expected since moonlight contains infrared wavelengths. Just an FYI, the laser on those IR temperature guns are not what reads the temperature, it's just to let the user see where the gun is aimed.


You are correct about the laser and I tend to agree with you. The experiment may help you with data collection to prove your point. Interesting read so far.
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Re: Mirrors on the Moon - a Hoax?

Postby Altair on October 14th, 2017, 12:10 pm

NotRappaport » October 13th, 2017, 6:32 am wrote:
ObamaSimLaden » October 12th, 2017, 6:31 pm wrote:If the laser was just a centimeter wide hitting a mirror on the moon, the mirror would have to be very precisely angled back to a single receiver on earth, which would then be affected by the seasonal wobble or else it would deflect off into space missing earth or at a minimum missing the dish back on earth. That means the laser could only be used during certain times of the year. Correct me if my logic is wrong.


Well the purported "mirror" is more accurately described as a retroreflector made up of an array of corner cube reflectors. These are designed so that any light entering the corner cube is internally reflected three times off three mutually orthogonal mirrors such that after the third reflection the light is always returned in the exact opposite trajectory that it entered the corner cube, towards the original source. As long as the angle of the incoming light isn't so oblique that it can't undergo the three reflections, it gets reflected back at the source.

The Wikidpedia article is reasonably accurate description of how retroreflectors work. https://en.wikipedia.org/wiki/Retroreflector

Although there is still divergence on the returned light beam because the internal mirrors cannot be physically perfect nor can their mutually orthogonal alignment be exactly perfect.


Still, I don't think it's possible to make a retroreflector with such precision, much less back then in 1969. Please note that at 384000 Km, a deviation of just 1,3 millionths of a radian means 1 km off target. Make it 130 millionths (still a barely measurable angle) and you're 100 kms off. Even more: that would be for a single mirror pointed to the observer. If we take into account that in a retroreflector you have three consecutive reflections, the total deviation is times three.

For the curious, the maths involved:
d = 2 · D · sin ( a ), where d = deviation of the bounced ray, D = distance to mirror, and a = bounced ray angle.
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Re: Mirrors on the Moon - a Hoax?

Postby NotRappaport on October 14th, 2017, 10:32 pm

Altair » October 14th, 2017, 4:10 am wrote:Still, I don't think it's possible to make a retroreflector with such precision, much less back then in 1969.

Each corner cube itself is a prism of fused silica (quartz), the crystalline structure of which ensures surface alignment that is very near perfect, and reflector units said to be left on the Moon are each composed of an array of 100 of these corner cubes (except Apollo 15's, which had an array of 300). I see no reason to doubt that the Apollo retroreflectors were manufactured to the claimed specifications by engineers who probably believed the item they produced was going to be placed on the Moon.

Incidentally, you can now buy (for about 125.00 USD) corner cube prisms that produce beam deviations of only 3 arcseconds

Please note that at 384000 Km, a deviation of just 1,3 millionths of a radian means 1 km off target. Make it 130 millionths (still a barely measurable angle) and you're 100 kms off. Even more: that would be for a single mirror pointed to the observer. If we take into account that in a retroreflector you have three consecutive reflections, the total deviation is times three.

Those numbers are way off. At 384,000km, a deviation of 0.00000013 radians is only 0.0499 (about 50 meters). Also the deviation given by the specification is for the return beam after it has undergone 3 reflections.

For the curious, the maths involved:
d = 2 · D · sin ( a ), where d = deviation of the bounced ray, D = distance to mirror, and a = bounced ray angle.

You should be taking the tangent of the angle, not the sine. The sine of the angle is the ratio of the opposite side to the hypotenuse, but we need the ratio of the opposite side to the adjacent side. Either way its a small difference because the angle is so acute, so I'm not sure how you get the above numbers unless maybe degrees were used in a formula that expects radians. d = D*tan(a) gives the correct result and matches the claimed 15km wide dispersion of light from the retroreflector when it reaches Earth.

To be clear, the problem I am pointing out about the lunar retroreflectors (other than the fact that they aren't there because its impossible to fly anything to the Moon) has to do with detecting the near infinitesimal faintness of the reflected light "signal" coming from the retroreflector when the same wavelength of light is already present in much greater abundance as "noise" fully visible to the naked eye (moonlight for sunlit parts of the Moon, reflected earthshine for unlit parts). It's analogous to aiming a small penlight at a far away building that is fully lit up by a bright spotlight behind you and trying to detect only penlight reflected off one particular mote of dust on the surface of that building.
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