I recall attending a talk by science writer Simon Singh in which amongst other fascinating things, he explained that Katie Melua, the jazz/blues singer and songwriter, had a single “Nine Million Bicycles” where the lyrics were as follows:
We are 12 billion light years from the edge,
that’s a guess, no one can ever say it’s true,
but I know that I will always be with you.
OK, here you go, here is the full song …
- Firstly, we know that the universe is 13.79 billion years old and so 12 billion is simply not right at all.
- Secondly, that’s not a guess, but rather is evidence-based, because measurements of the cosmic background radiation give the cooling time of the universe since the Big Bang, and also measurements of the expansion rate of the universe can be used to calculate its approximate age by extrapolating backwards in time. While there is an agreed bit of wiggle room of 37 million years, it is all way beyond a guess and is indeed an actual measurement.
So the story is that Simon wrote about this in The Guardian, and when Katie read the article she decided to re-record her 2005 hit song, and even invited Mr Singh to meet her in the studio when she did so.
The new version of the lyrics went like this:
We are 13.7 billion light-years from the edge of the observable universe,
that’s a good estimate with well-defined error bars,
and with the available information, I predict that I will always be with you.
Oh and here is a clip in which Michael Shermer plays the above modified version during his TED talk …
The problem is that while the age of the universe may indeed by 13.7 billion years, that is not the radius of the universe.
The easily forgotten fact is that space itself has been expanding over time, so it is not 13.7 billion light years to the edge, but is instead a lot further – 46 billion light years.
The Khan academy has a video that explains why it is like this …
So will she yet again re-record?
Actually no, there is no need, it is perhaps best to stick with the original because the song itself is not a scientific statement, but rather is a poetical expression of an emotion and not literal statement of fact, anything other that the original does not work and breaks the meter/rhythm.
So why the re-work in 2005? Well because it was not just a bit of fun, but was also good publicity for both Katie’s song, and also Simon’s book.