Historically, outgassing has often been discussed by scientists, but many have considered the moon volcanically dead despite moonquakes and episodes of gas, such as argon, observed coming from the lunar surface. Until now, Crotts says two factors have worked against researchers solving the mystery of TLPs. While the exact composition of this gas is largely unknown, he explains, hints from previous measurements indicate that it might contain substances beneficial for future moon explorations, especially water. “The result,” says Crotts “shows that some lunar event sites that were the focus of great observer excitement over recent decades disappeared from the more highly refined list of TLP sites.” Crotts used two catalogs of such sightings amassed and edited three decades ago by now retired astronomers Barbara Middlehurst and Winifred Cameron.Ĭrotts says this research might lead to optical imaging of the lunar surface that could monitor how, when and where gas escapes from the moon. The pattern was further strengthened after Crotts performed a statistical test to rid the sample list of false reports and one time events that might not represent true outgassing sources. What he discovered was a remarkable similarity in the pattern of outgassing event locations recorded by spacecraft across the face of the moon and reported TLP sites. To arrive at his theory, Crotts correlated TLPs with known gas outbursts from the lunar surface as seen by several spacecraft, particularly NASA’s Apollo 15 mission in 1971 and the robotic Lunar Prospector in 1998. “People over the years have attributed TLPs to all sorts of effects: turbulence in Earth’s atmosphere, visual physiological effects, atmospheric smearing of light like a prism, and even psychological effects like hysteria or planted suggestion” says Crotts, “but TLPs correlate strongly with radon gas leaking from the moon. Outgassing occurs when gases trapped beneath a moon or planet are released and, if only briefly, become part of the object’s atmosphere.

The TLPs typically cover a space of a few kilometers and last for several minutes.Ĭrotts has uncovered a strong statistical relationship between TLPs and so-called outgassing events on the lunar surface. Yet explanations of why they occur and even their reality as true lunar phenomena have been hotly debated. Transient Lunar Phenomena (TLPs), in which the lunar surface reportedly changes in brightness, blurriness or color, have been photographed and observed by thousands of astronomers over the centuries. Credit: Columbia UniversityĬolumbia astronomy professor Arlin Crotts thinks he has solved a 400-year-old mystery: the origin of strange optical flashes often reported as appearing on the moon’s surface. The TLP is the small, bright spot in the center of the image. Image of TLP taken in 1953, courtesy of Columbia’s Department of Astronomy. that are almost vertically above them, and that release of gases through poorly consolidated soils at an early stage of the Moon’s history may have led to the formation of at least some of the craters on the Moon.Astronomer Offers New Theory Into 400-year-old Lunar Mystery It appears likely that channels produced by the outrush of gases from the interior of the Moon are associated with the sites of the h.f.t. and the epicentres of the deep moonquakes at levels of about 800-1000 km below the surface. The present paper considers some of the implications of the correlations between the two classes of sites and between the l.t.p. site and the depths are given by Nakamura et al. Most of the epicentres are within 5° of at least one l.t.p. About 300 sites for the latter and about 17 shallow moonquake epicentres have been recorded. The positions of the epicentres of the recently discovered, high-frequency teleseismic (h.f.t.), shallow moonquakes have been compared with those of the surface phenomena known as lunar transient phenomena (l.t.p.).

Lunar transient phenomena