Lunar Transient Phenomena

From The Space Library

Through the ages lunar observers have reported seeing strange lights or color changes on the Moon’s surface. Various explanations have been proposed for these observations but confirmation of such sightings and their possible cause has been elusive. There are a string of apocryphal impact stories which all seem to have originated from the Beta Taurids. The most notorious happened on June 25th 1178 when an observer noticed a large impact on the moon, "It was after sunset. The bright new moon had become visible. Suddenly its upper horn split in two. A lengthy flaming torch sprang up, spewing out fire, hot coals and sparks. The moon writhed and throbbed like a wounded snake. This happened again and again, 12 times or more, turning the moon black along its whole length." It is now believed that this object may have been as much as a mile across and created what is known today as Giordano Bruno crater, a hole over 20 kilometers wide. The moon just happened to be in the way that day in the twelfth century, blocking the hammer blow from space and undoubtedly saving the human race from extinction in the process.

Prior to the Apollo Program many lunar scientists believed that most of the observed craters were of volcanic origin. Thus, it was probable that the sightings were the result of emissions from still active volcanoes. As the Soviet Union and the United States began their highly publicized programs to explore the Moon more and more eyes, both amateur and professional astronomers, were trained on the Moon leading to frequent reports of transient phenomena being seen.

In November, 1958, Soviet astronomer Nikolai A. Kozyrev, while looking for volcanic phenomenon on the moon, observed a mist-like crimson cloud within the crater Alphonsus. He recorded a spectra of the area and claimed it showed C2 gas possibly associated with the crater’s central peak. He believed it was the result of volcanic activity. However, his observations were never confirmed despite many others carefully observing the crater in later years.

In October, 1963, James Greenacre and Edward Barr, employed by the U. S. Air Force Lunar Mapping Program, using the telescope at the Lowell Observatory near Flagstaff, Arizona, reported an exciting observation at the crater Aristarchus. Below is the report made by James Greenacre: "Early in the evening of October 29, 1963, Mr. Edward Barr and I had started our regular lunar observations ....When I started to observe at 1830 MST... I concentrated on the Cobra Head of Schroeter’s Valley. ... at 1850 MST I noticed a reddish-orange color over the dome-like structure on the southwest side of the Cobra Head. Almost simultaneously I observed a small spot of the same color on a hilltop across the valley. Within two minutes these colors had become quite brilliant and had considerable sparkle. I immediately called Mr. Barr to share this observation with me. His first impression of the color was a dark orange. No other color spots were noted until 1855 MST when I observed an elongated streaked pink color along the southwest rim of Aristarchus. ...at approximately 1900 MST I noticed the spots of color at the Cobra Head and on the hill across the valley had changed to a light ruby red....I had the impression that I was looking into a large polished gem ruby but could not see through it. Mr. Barr’s impression of the color at this time was that it was a little more dense than I had described it...By 1905 MST it was apparent that the color was fading...." (1)(2)

Greenacre and Barr did not advance any theories on what may have caused the colors observed; however, John Hall, Director of the Lowell Observatory, in a contemporaneous report, vouched for the authenticity of the sighting, calling Greenacre "a very cautious observer" and that Greenacre’s boss, William Cannell "stated that he could not recall that Greenacre had ever plotted a lunar feature which was not later confirmed by another observer."(3)

Thus was reported the first sighting, confirmed by two observers, of a lunar transient event and, most importantly, made by highly qualified personnel. A second sighting by Greenacre and Barr at the same Aristarchus location, was recorded one lunar month later on November 27, 1963. This observation was confirmed by Hall and Fred Dungan, a scientific illustrator on the staff and a qualified telescopic observer. This color feature was reported to be somewhat larger than that observed in October. It seemed, beyond a doubt, that something was going on near Aristarchus. Other observers, after Greenacre and Barr, recorded similar activity in the vicinity.

Immediately following the Greenacre and Barr sightings, Donald A. Beattie at NASA Headquarters contacted Goddard Space Flight Center (GSFC) astronomer Dr. Winifred C. Cameron and proposed establishing a worldwide network of amateur and professional astronomers to provide continuous observations of the lunar surface. Funding was provided to Dr. Cameron by Beattie’s office to develop standard reporting protocols and to design a camera especially suited to record sightings to be attached to a telescope. The network, named Moon Blink, began operation in 1965 under the management of the Smithsonian Astrophysical Observatory at Harvard.(4)

Reports came flooding in after Moon Blink became operational. Dr. Cameron published several reports on the sightings.(5) Others at NASA also became involved in recording LTP sightings with the objective of targeting them for possible Apollo landing sites.(6) The Apollo Alpha Particle Spectrometer experiment, placed in the Command and Service Module SIM bay, was designed to record radon emissions possibly associated with ongoing volcanic activity on the lunar surface. The experiment was able to take readings over large areas of the Moon during the CSMs many orbits. Dr.Cameron continued her research after retiring from NASA.(7)

In recent years astronomers at NASA’s Marshall Space Flight Center have been monitoring lunar impacts using 14 inch and 20 inch telescopes. Their efforts have been recording small concussions at the rate of almost 50 a year, mostly due to the Quadrantid and Perseid meteor showers.

(Source: Donald A. Beattie - 2013)

1. Report also published in Sky and Telescope 26, 6 (1963)
2. Lunar Color Phenomena, ACIC Technical Paper 12, May 1964
3. John Hall, “Supplementary Report,” Lowell Observatory, November 5, 1963
4. W.C. Cameron, “An Appeal for Observations of the Moon,” Journal of the Royal Astronomical Society of Canada 59, (1965): 219.
5. W.C. Cameron, “Observations of Changes on the Moon,” Proceedings of the Working Group on Extraterrestrial Resources 47-56, Fifth Annual Meeting, March 1-3, 1967.
6. B.M. Middlehurst, J.M. Burley, P.A. Moore and B.L. Weither, “Chronological Catalog of Reported Lunar Events,” G-807, NASA 1967.
7. W.C. Cameron, “Lunar Transient Phenomena (LTP): Manifestations, Site Distribution, Correlations and Possible Causes,” Physics of the Earth and Planetary Interiors 14 (1977); 194-216.