Transient Lunar Phenomena, or TLP for short, are a poorly understood happening which occurs on (or perhaps in the atmosphere of) our Moon. They appear as brief glows, flashes of light, misty areas or shadows against the Moon’s disc.

For a very long time, these occurrences were consigned to the realms of pseudo-science, over-active imaginations and downright folly, it being a Well Known Fact that the Moon is completely inert. Of course, there was also a time when Science (with a capital S) scorned the idea of Ball Lightning, condemned the very notion that galaxies were islands of stars outside of our own Milky Way, and ridiculed those who claimed rocks might fall from the sky.

All of these are now known to exist (although Ball Lightning is itself still poorly understood), and we are also now aware that the Moon is not as geologically (or, to be precise, selenologically) dead as was once believed – we know that Moon-quakes occur and that the satellite has a very tenuous but detectable atmosphere, as well as a weak magnetic field.

As with many accounts of anomalous and sporadic phenomena, many years of eye-witness reports of TLP (including those by professional astronomers) have been relegated to the pages of publications dedicated to the mysteries of the unknown, and largely ignored by mainstream science.

Certain groups of scientists (amateur and professional alike) have, however, persisted in their study of this interesting area of Lunar astronomy. We have a group within the Liverpool Astronomical Society who maintain a keen interest, as do other astronomical societies, such as the British Astronomical Association, who have recently published an article in the March 2013 edition of their Lunar Section Circular, where on page 14, Jill Scambler investigates the idea that TLP may be related to Solar activity.

To quote Jill from the article:

In 1945 H. Percy Wilkins suggested that TLP activity may be tied to the sunspot cycle, occurring more frequently close to solar maximum. In 1966 Barbara Middlehurst performed a more detailed statistical analysis using monthly sunspot relative numbers and concluded that there was no correlation between sunspot activity and TLP, but instead that the distribution of events was “a random one superimposed on an asymmetric distribution of sunspot numbers”.
With a more complete dataset of TLP held by the ALPO (Association of Lunar and Planetary Observers) and BAA Lunar Sections, than was available in either of the past two studies, it is possible to check Wilkins’ claim again, and to examine other eras too covering 1700-2010

A very interesting article, and one that should remind us all that science is not only about cataloguing and quantifying what we know, but about embracing and understanding the unknown.

Full article on page 14 of Volume 50, Number 3, March 2013 edition of BAA Lunar Section Circular.
With thanks to Gerard Gilligan for forwarding the article to the LAS website.