Dear visitor (if there is any) please note the following: The blog "Broken Radius" is hosted at Google Blogger's server. I can therefore not guarantee that your visit to the blog or any comment you write wont be recorded by the NSA. If you have any worries about this, you can visit instead my alternative blog Letters-to-a-Persian-Cat. This one is hosted at a European server which hopefully acknowledges visitors privacy.


No Dark Side of the Moon

Dear Michael,
The last full moon of 2013 was visible in the night between December 16th and 17th. This is a view over Parkers Piece in Cambridge, with the sky slightly claudy.

Although the moon is clearly masked here by some clouds, from a different view point (maybe only a few miles away) this might look completely different. Another blogger (in Sicily) made a very clear photo of the moon, I guess at the same night. But the confusion about the moons illumination (i.e. full moon or new moon) and its visibility (above horizon, below horizon, or masked by clouds) goes much further when people refer to the moons hemispheres relative to the earth. Because moons rotation around its axis is perfectly synchronous to its circulation around the earth, moon always faces the same side towards earth. With the exception of a slight deviation, we can therefore only see not much more than 50% of its surface. This is the hemisphere that always faces earth. The hemishere that faces away from earth was only photographed once the Russians succesfully launched the first man-made lunar orbiter in 1957. 

Man-kind of course was always fascinated by this "invisible" side of the moon, they perhaps assumed that someone dangerous is hiding there or something precious can be found there. The most weired idea was shown in the recent movie "Iron Sky", where Nazi refugees did not went to South America to hide after World War II, but occupied this averse side of the moon and there, as every evil breed,  proliferated and became strong enough to attack our democratic and liberal civilization in an awful attempt of revenge 70 years later .
And here (if you carefully listen to the voice at 33'') you have the indication of one of the biggest misunderstandings in our pop-culture when it comes to the two hemispheres of the moon.  When the Nazi kids are asked in a school lesson where they come from, they univocally shout "From the Dark Side of the Moon". This term "Dark Side of the Moon" became such a fixed term in pop-culture, that nobody questions its meaning any more. All the reviews for "Iron Sky" talked about the dark side of the moon, and it so nicely suits with the black Nazi outfit.
Before Iron Sky, there was another movie in the year 1990 by D. J. Webster, called "The Dark Side of the Moon", but was much less satirical.
Much earlier, the UK progressive rock band Pink Floyd called their most succesful album The Dark Side of the Moon. I guess they used the metaphorical dark (or invisible) side as a reference to the band founder and writer Syd Barret, who after leaving the band caused a creative crisis and left many unanswered questions. The video below is from a concert movie they produced a year earlier in Pompej.

The first time somebody wrote down the concept of a moons dark side was Mark Twain, in a collection of aphorisms he said „Every one is a moon, and has a dark side which he never shows to anybody.“

But despite this widespread usage of the phrase "Dark Side of the Moon", there is no area on our lunar neighbour that is permanently dark or bright. Each place on moon, whether its facing earth or not, experiences a regular day-night-intervall. The difference to earth, however, is that there are about 14 days uninterrupted sunlight followed by the same period of darkness.

This is to you and the New Year
Take Care


  1. This is too much publicity for such a bad movie.
    And yes, I took the photo in exactly the same night. A beautiful clear night it was here.

    Happy new year!

  2. Dear Michale, thanks for all the information. That is the nice quote by Mark Twain, coining the term "dark side of the moon". It also highlights the importance of recent lunar missions, in particular LRO that gave us detailed imagery of the so called dark side of the moon for the first time:

    Also, I like to understand your writing style better. Are you writing posts as correspondences between you and another person (Ghazal?)

  3. Hi Andreas, I did not watche the movie (yet), only became interested in it after reading some reviews about "Iron Sky". There they wrote again and again about a Dark Side of the Moon, which I am sure the writer assume was the reason for the Nazis beeing so pale. The biggest publicity, I think film producers did by starting a crowdfunding campaign for the production of "Iron Sky". This quickly hit the headlines of NYT, Huffington Post, New Yorker and many other newspapers. Without this new concept of raising money for a film project, "Iron Sky" would not have attracted more public attention than other B-movies.
    Best regards, Michael

  4. Hi Nargess, thanks a lot for the link. I like the idea of the NASA Lunar Reconnaissance Orbiter to "... return to the moon, enabling new discoveries and bringing the moon back into the public eye."
    For me as a very amateur sky-watcher, the moon is of course fascinating because one can see so many details and (moon phases, eclipses, structures on its surface). Sure, it does not provide us with energy, nor will it be a promising destination for a long-time colonization, but without its stabilising function on the earth' rotation life would perhaps never developed.
    Yes, I have to admit, that currently Ghazal is a fictional character. Initially the blog was a real conversation, but after a year or so the dialogues became more and more asymmetrical. So currently I simply try to imagine what this other person would comment or say, and write it down under her alias.
    best wishes, michael

  5. hi michael, the amphitheater in the pink-floyd video looks so much bigger than in my memories of our visit to pompej.
    take care

  6. Yes, you are right, maybe it is the special camera focus that makes it look so large in the concert film. But perhaps when we were there, we only saw it at night, illuminated only by the torch lamp of the Pompej custodian. The night changes everything, large becomes small, small turns into gigantic, spiders become monsters, and commn things turn into weired animals.
    Dont worry, my dear