How Far Away Is The Moon?

[TheQuestionMan]

It really is funny how many myths people believe. After reading about the different ways that "science" has claimed to measure the earth to moon distance, I find this to be more "Covid" type science propaganda for the gullible masses than anything real. I remember my Astronomy 101 class, and shaking my head at how the entire universe is constructed based off the Astronomical Unit of our Sun to Earth distance; it just takes faith in one number, plus plugging that number into mathematical formulas, to reveal a mathematical universe.

This Wikipedia article gives a nice breakdown of their deceptions over time:
https://en.wikipedia.org/wiki/Lunar_dis ... astronomy)

History of measurement

Until the late 1950s all measurements of lunar distance were based on optical angular measurements: the earliest accurate measurement was by Hipparchus in the 2nd century BC. The space age marked a turning point when the precision of this value was much improved. During the 1950s and 1960s, there were experiments using radar, lasers, and spacecraft, conducted with the benefit of computer processing and modeling.[32]

This section is intended to illustrate some of the historically significant or otherwise interesting methods of determining the lunar distance, and is not intended to be an exhaustive or all-encompassing list.

Parallax
The oldest method of determining the lunar distance involved measuring the angle between the Moon and a chosen reference point from multiple locations, simultaneously. The synchronization can be coordinated by making measurements at a pre-determined time, or during an event which is observable to all parties. Before accurate mechanical chronometers, the synchronization event was typically a lunar eclipse, or the moment when the Moon crossed the meridian (if the observers shared the same longitude). This measurement technique is known as lunar parallax.

For increased accuracy, certain adjustments must be made, such as adjusting the measured angle to account for refraction and distortion of light passing through the atmosphere.

Lunar eclipse
Early attempts to measure the distance to the Moon exploited observations of a lunar eclipse combined with knowledge of Earth's radius and an understanding that the Sun is much further than the Moon. By observing the geometry of a lunar eclipse, the lunar distance can be calculated using trigonometry.

The earliest accounts of attempts to measure the lunar distance using this technique were by Greek astronomer and mathematician Aristarchus of Samos in the 4th century BC[33] and later by Hipparchus, whose calculations produced a result of 59–67 R🜨 (376000–427000 km or 233000–265000 mi).[34] This method later found its way into the work of Ptolemy,[35] who produced a result of 64+1⁄6 R🜨 (409000 km or 253000 mi) at its farthest point.[36]

Meridian crossing
An expedition by French astronomer A.C.D. Crommelin observed lunar meridian transits on the same night from two different locations. Careful measurements from 1905 to 1910 measured the angle of elevation at the moment when a specific lunar crater (Mösting A) crossed the local meridian, from stations at Greenwich and at Cape of Good Hope, which share nearly the same longitude.[37] A distance was calculated with an uncertainty of 30 km, and this remained the definitive lunar distance value for the next half century.

Occultations
By recording the instant when the Moon occults a background star, (or similarly, measuring the angle between the Moon and a background star at a predetermined moment) the lunar distance can be determined, as long as the measurements are taken from multiple locations of known separation.

Astronomers O'Keefe and Anderson calculated the lunar distance by observing four occultations from nine locations in 1952.[38] They calculated a semi-major axis of 384407.6±4.7 km (238,859.8 ± 2.9 mi). This value was refined in 1962 by Irene Fischer, who incorporated updated geodetic data to produce a value of 384403.7±2 km (238,857.4 ± 1 mi).[7]

Radar
An experiment was conducted in 1957 at the U.S. Naval Research Laboratory that used the echo from radar signals to determine the Earth-Moon distance. Radar pulses lasting 2 μs were broadcast from a 50-foot (15 m) diameter radio dish. After the radio waves echoed off the surface of the Moon, the return signal was detected and the delay time measured. From that measurement, the distance could be calculated. In practice, however, the signal-to-noise ratio was so low that an accurate measurement could not be reliably produced.[39]

The experiment was repeated in 1958 at the Royal Radar Establishment, in England. Radar pulses lasting 5 μs were transmitted with a peak power of 2 megawatts, at a repetition rate of 260 pulses per second. After the radio waves echoed off the surface of the Moon, the return signal was detected and the delay time measured. Multiple signals were added together to obtain a reliable signal by superimposing oscilloscope traces onto photographic film. From the measurements, the distance was calculated with an uncertainty of 1.25 km (0.777 mi).[40]

These initial experiments were intended to be proof-of-concept experiments and only lasted one day. Follow-on experiments lasting one month produced a semi-major axis of 384402±1.2 km (238,856 ± 0.75 mi),[41] which was the most precise measurement of the lunar distance at the time.

Laser ranging

Lunar Laser Ranging Experiment from the Apollo 11 mission
An experiment which measured the round-trip time of flight of laser pulses reflected directly off the surface of the Moon was performed in 1962, by a team from Massachusetts Institute of Technology, and a Soviet team at the Crimean Astrophysical Observatory.[42]

During the Apollo missions in 1969, astronauts placed retroreflectors on the surface of the Moon for the purpose of refining the accuracy and precision of this technique. The measurements are ongoing and involve multiple laser facilities. The instantaneous precision of the Lunar Laser Ranging experiments can achieve few millimeter resolution, and is the most reliable method of determining the lunar distance to date. The semi-major axis is determined to be 384,399.0 km.[2]

Amateur astronomers and citizen scientists

Due to the modern accessibility of accurate timing devices, high resolution digital cameras, GPS receivers, powerful computers and near-instantaneous communication, it has become possible for amateur astronomers to make high accuracy measurements of the lunar distance.

On May 23, 2007 digital photographs of the Moon during a near-occultation of Regulus were taken from two locations, in Greece and England. By measuring the parallax between the Moon and the chosen background star, the lunar distance was calculated.[43]

A more ambitious project called the "Aristarchus Campaign" was conducted during the lunar eclipse of 15 April 2014.[17] During this event, participants were invited to record a series of five digital photographs from moonrise until culmination (the point of greatest altitude).

The method took advantage of the fact that the Moon is actually closest to an observer when it is at its highest point in the sky, compared to when it is on the horizon. Although it appears that the Moon is biggest when it is near the horizon, the opposite is true. This phenomenon is known as the Moon illusion. The reason for the difference in distance is that the distance from the center of the Moon to the center of the Earth is nearly constant throughout the night, but an observer on the surface of Earth is actually 1 Earth radius from the center of Earth. This offset brings them closest to the Moon when it is overhead.

Modern cameras have now reached a resolution level capable of capturing the Moon with enough precision to perceive and more importantly to measure this tiny variation in apparent size. The results of this experiment were calculated as LD = 60.51+3.91
−4.19 R🜨. The accepted value for that night was 60.61 R🜨, which implied a 3% accuracy. The benefit of this method is that the only measuring equipment needed is a modern digital camera (equipped with an accurate clock, and a GPS receiver).

Other experimental methods of measuring the lunar distance that can be performed by amateur astronomers involve:

Taking pictures of the Moon before it enters the penumbra and after it is completely eclipsed.
Measuring, as precisely as possible, the time of the eclipse contacts.
Taking good pictures of the partial eclipse when the shape and size of the Earth shadow are clearly visible.
Taking a picture of the Moon including, in the same field of view, Spica and Mars – from various locations.

[Christopher Shilts]

So you don't think the Lunar Eclipse method of measurement taken over 2,000 years ago is accurate? It seems to have come up with a figure within range of the modern one. There's a bunch of others listed here that also came up with something pretty close the the modern value. If not 384399 km, what do you suppose the real value is, and how would you propose measuring it?

[TheQuestionMan]

I would love to hear how you measure the ground to moon distance through the use of this "Lunar Eclipse Method" from a magical 2000 years ago? This is CARTOON stuff that only highly brainwashed people can believe without thinking, it's part of a religion that includes apples falling on a guys head (eve eats an apple), magical ships that fall over curved water (walking on water), 12 American disciples walking on a cheese moon (12 disciples eating supper), magical Apollo space carpets to the moon, magical Perseverance driving on Mars etc...

I challenge ANYONE to use the cartoon "Lunar Eclipse Method" to come up with a figure for the ground to moon distance... This should be FUN!!!

Lets use the SCIENTIFIC METHOD and put it to the test. LOL.