By GREG DIXON
Curious question for the day: if a tree falls in a forest and there's no celebrity there to hear it, did it fall?
The answer, if tonight's TV3 documentary Abba's Biggest Secret (9.30pm) is any sort of measure, is apparently no.
At face value, the show's title suggests that this hour-long programme will reveal, after an investigation of the late 70s pop band, some only-just-discovered titbit about the band, say that they didn't write their own songs or that they're all (as is popular over at TV3) aliens.
Instead, what viewers will find tonight is a story which has absolutely nothing to do with the group - as a group - at all.
Which is also why this British-made documentary has two titles: the one above (which was used when it screened on Britain's Channel 5 in March) and Norway's Nazi Secret, the title for its March-April screenings on two other channels, Canada History and UK History Channel.
It is the second title which is closer to describing the "secret" revealed.
In large part the documentary traces the effect on Norway of the Nazis' plan during the 1930s and 1940s to create a race of Aryan supermen through a programme the regime called Lebensborn (literally, life fount).
This large scale eugenics experiment, which was principally supported by the SS, sought to produce "racially pure" children by encouraging SS men to breed with German women (wives or not) of good Aryan, or Nordic, stock.
After the German invasion of Norway in 1940, the Nazis decided to include that country in the Lebensborn programme because Norwegians were considered by Nazi racial fanatics to be a pure Nordic-Aryan people.
During the war, around 10,000 children were born to Norwegian mothers as a result of relationships with German soldiers. In the postwar period, once the fathers had been booted back to Germany, these mothers - considered collaborators - and their offspring were subjected to sometimes appalling treatment by their fellow Norwegians.
All these children were treated as traitors and/or potential fascists by their fellow citizens and hundreds were even put into mental institutions immediately after the war.
Through the courts, a small number have sought compensation from the Norwegian Government for their treatment and although the case was lost, the Government has agreed, in principle, that something should be done.
Now all this is appalling, yes. But what has all this to do with Abba, a 1970s Swedish pop group?
Well, it turns out (though it was first reported in 1977) that one of its singers, Frida Lyngstad (the brunette one), was one of these children.
Unfortunately, a rather glaring hole for the makers is that Lyngstad - and she is fortunate in this - did not suffer at any length at the hands of Norwegian postwar intolerance.
Increasingly horrified by Norway's attitude to the children of German fathers, Frida's mother moved them both to Sweden soon after the war ended.
Which means Frida - who isn't even interviewed in the documentary - grew up without the stigma of being a Lebensborn child and went on to you know what.
So why exactly, I hear you asking, is this documentary called Abba's Biggest Secret?
It seems, on television, history without a celebrity is like that tree falling in the forest.