Did scientists discover a star that emitted pi-approximating radiation?
March 12, 2010 8:27 AM Subscribe
"...he learned from a newsreel that scientists had discovered a dying star that emitted radiation on a wavelength whose value in megacycles approximated pi." Is this in reference to an actual finding, or is it just fiction? This appeared in Michael Chabon's The Amazing Adventures of Kavalier and Clay, which is set during World War II. Googling hasn't helped.
IANAAstronomer, nor have I read the book, but I very much doubt that such a finding would be meaningful or reported on its own for two reasons: one, lots of things 'approximate pi'. Two, frequency is a dimensional quantity, based on the length of a second: change the time base and you change the numerical value of the frequency. So such a coincidence really wouldn't signify anything.
posted by PMdixon at 8:56 AM on March 12, 2010 [2 favorites]
posted by PMdixon at 8:56 AM on March 12, 2010 [2 favorites]
It's not an actual finding, because the sentence doesn't make sense.
The problem is that 'wavelength' and 'cycles per second' are based on human concepts like the second and the meter. And then there's the word "approximated". So if one were to find, using local measuring concepts, that the numerical value of some cosmic phenomenon 'approximated' pi or any other number, this would be a coincidence and nothing more.
Add to that the wording in the text - the value of a wavelength is a distance measure, not representable in 'megacycles' - and the actual semantic content of the sentence closely approximates zero. That, I think, is a good indicator that the reference is fictional, or meaningless, or both.
posted by foobario at 8:58 AM on March 12, 2010
The problem is that 'wavelength' and 'cycles per second' are based on human concepts like the second and the meter. And then there's the word "approximated". So if one were to find, using local measuring concepts, that the numerical value of some cosmic phenomenon 'approximated' pi or any other number, this would be a coincidence and nothing more.
Add to that the wording in the text - the value of a wavelength is a distance measure, not representable in 'megacycles' - and the actual semantic content of the sentence closely approximates zero. That, I think, is a good indicator that the reference is fictional, or meaningless, or both.
posted by foobario at 8:58 AM on March 12, 2010
I'm skeptical. WWII would be very early in the history of radio telescopes - and 3 MHz would be in the HF band, a difficult band for ground-based astronomy because ionosophere effects are very strong. Given that, I think it's unlikely that anyone would even claim to be able to pick out the radio emissions of individual stars, and correlate them to episodes in stellar lifecycle.
posted by kickingtheground at 8:59 AM on March 12, 2010
posted by kickingtheground at 8:59 AM on March 12, 2010
I don't know about a star but asteroid number 3142 was discovered and named "kilopi" soon before WW2, in late 1937. It's a bit tenuous, but could this be an inspiration for the line?
Regardless, the line as stated doesn't make a lot of sense. Megacycles (now called megahertz) are a unit of frequency, not wavelength. Frequency and wavelength are directly related, but are not the same thing. Still, it's the kind of error that journalists make depressingly often when reporting on science, so it doesn't totally rule it out.
If it did happen, it would be a nice coincidence but not particularly significant. Frequency (cycles/second) is, obviously, dependant on the length of a second, which is an arbitrarily defined, man-made unit rather than being related to some fundamental property of the universe. So while pi is a special number, only people using our current definition of a second would agree that a given signal is at pi MHz. So a scientist might think it was a cool coincidence, but as it doesn't tell us anything important about the star or the wider universe, they probably wouldn't bother to report it except as an aside. Although, again, it is the kind of thing that journalists like to (wilfully?) misunderstand and blow out of all proportion. So it could still plausibly have been a real news story.
posted by metaBugs at 9:09 AM on March 12, 2010
Regardless, the line as stated doesn't make a lot of sense. Megacycles (now called megahertz) are a unit of frequency, not wavelength. Frequency and wavelength are directly related, but are not the same thing. Still, it's the kind of error that journalists make depressingly often when reporting on science, so it doesn't totally rule it out.
If it did happen, it would be a nice coincidence but not particularly significant. Frequency (cycles/second) is, obviously, dependant on the length of a second, which is an arbitrarily defined, man-made unit rather than being related to some fundamental property of the universe. So while pi is a special number, only people using our current definition of a second would agree that a given signal is at pi MHz. So a scientist might think it was a cool coincidence, but as it doesn't tell us anything important about the star or the wider universe, they probably wouldn't bother to report it except as an aside. Although, again, it is the kind of thing that journalists like to (wilfully?) misunderstand and blow out of all proportion. So it could still plausibly have been a real news story.
posted by metaBugs at 9:09 AM on March 12, 2010
I think it's a reference to Sagan's Contact. The Wikipedia article mentions it (SPOILERS) here (/SPOILERS).
posted by Jorus at 9:18 AM on March 12, 2010 [1 favorite]
posted by Jorus at 9:18 AM on March 12, 2010 [1 favorite]
As others have stated, both wavelength and frequency are based on arbitrary human constructs so any correspondence with pi would be presumed to be coincidental.
Wavelength is usually measured in meters which was originally defined as one ten-millionth of the distance from the equator to the north pole. This arbitrary number is a consequence of the choice of the base 10 number system, a preference for round numbers, and the size of the earth.
Frequency uses seconds which are related to both the speed of rotation of the earth and its speed of revolution about the sun. The Egyptians arbitrarily decided to divide the day and night into 12 hours and the Babylonians and Greeks decided to divide these into sub-units of 60.
So if any of these factors were to change, the whole thing falls apart and the number would be something other than pi -- diameter of the earth, use of the base 10 number system, speed of rotation of the earth, speed of revolution of the earth, choice of 12 hour day and choice of 60 sub-units.
The speed of the object with respect to the earth would also change the observed frequency so its inherent frequency would likely be different from pi at an arbitrary level of accuracy.
posted by JackFlash at 9:56 AM on March 12, 2010
Wavelength is usually measured in meters which was originally defined as one ten-millionth of the distance from the equator to the north pole. This arbitrary number is a consequence of the choice of the base 10 number system, a preference for round numbers, and the size of the earth.
Frequency uses seconds which are related to both the speed of rotation of the earth and its speed of revolution about the sun. The Egyptians arbitrarily decided to divide the day and night into 12 hours and the Babylonians and Greeks decided to divide these into sub-units of 60.
So if any of these factors were to change, the whole thing falls apart and the number would be something other than pi -- diameter of the earth, use of the base 10 number system, speed of rotation of the earth, speed of revolution of the earth, choice of 12 hour day and choice of 60 sub-units.
The speed of the object with respect to the earth would also change the observed frequency so its inherent frequency would likely be different from pi at an arbitrary level of accuracy.
posted by JackFlash at 9:56 AM on March 12, 2010
It's possible that Chabon knows something about astronomy and pulsars and is making an obscure in-joke based on "Pi" or simply that he saw an article about pulsar periodicity and was himself confused that they were talking about "pi" rather than "Pi" (which I think refers to initial rate of spin when it is changing).
posted by aught at 10:23 AM on March 12, 2010
posted by aught at 10:23 AM on March 12, 2010
Response by poster: Thanks for the replies. I will assume that Chabon was looking through old newspapers, looking for stories on interesting scientific discoveries, and came across an article that was misunderstood by the journalist or by himself.
posted by alligatorman at 11:08 AM on March 12, 2010
posted by alligatorman at 11:08 AM on March 12, 2010
But there are universal frequencies, it's just that you can't refer to them with Earth-based units and still have them remain universal. For example we refer to the Hydrogen line as 1.42 GHz and some other species might call it 421.4 boobooschmuz, but it's the same frequency and we would both know it well because it's a physical property of a common element. In Contact the aliens used that frequency times Pi (=4.46 GHz) as the carrier frequency of their message, and this is an example of a message incorporating Pi in a way that is not in any way specific to any Earth unit.
posted by Rhomboid at 11:25 AM on March 12, 2010 [2 favorites]
posted by Rhomboid at 11:25 AM on March 12, 2010 [2 favorites]
The problem is that 'wavelength' and 'cycles per second' are based on human concepts like the second and the meter. And then there's the word "approximated". So if one were to find, using local measuring concepts, that the numerical value of some cosmic phenomenon 'approximated' pi or any other number, this would be a coincidence and nothing more.
This is exactly it. Brilliant
posted by Ironmouth at 11:30 AM on March 12, 2010
This is exactly it. Brilliant
posted by Ironmouth at 11:30 AM on March 12, 2010
Yeah totally arbitrary. You'd have to know a lot about humans to know that a pattern like this could be perceived as a message, so it would be meaningless -- evidence of nothing -- for a star to have that behavior.
posted by grobstein at 11:34 AM on March 12, 2010
posted by grobstein at 11:34 AM on March 12, 2010
I will assume that Chabon was looking through old newspapers, looking for stories on interesting scientific discoveries, and came across an article that was misunderstood by the journalist or by himself.
I'd say it's roughly as likely that he thought up the idea himself and liked it enough to drop it in there. The book is pretty far down the fictionalized history rabbit-hole.
posted by Copronymus at 12:36 PM on March 12, 2010
I'd say it's roughly as likely that he thought up the idea himself and liked it enough to drop it in there. The book is pretty far down the fictionalized history rabbit-hole.
posted by Copronymus at 12:36 PM on March 12, 2010
It's really only the "megacycles" (=an arbitrary human unit) that break it. I'd vote "badly made up", since it's the design of a cosmic beacon (make something huge that every intelligent observer would notice and construe as the work of intelligent agents), but constructed so that only people whose time unit was based on a strange multiple of some obscure Cesium atom state's hyperfine structure split could decode it.
If I had to build this, I'd go for Planck units, or do something unit-independent like a series of closely spaced pulsars emitting at prime-number ratios. I'd also not choose Pi, because observers are much too likely to explain it away through some rotational or spherical symmetry effect.
posted by themel at 1:50 AM on March 13, 2010
If I had to build this, I'd go for Planck units, or do something unit-independent like a series of closely spaced pulsars emitting at prime-number ratios. I'd also not choose Pi, because observers are much too likely to explain it away through some rotational or spherical symmetry effect.
posted by themel at 1:50 AM on March 13, 2010
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posted by carsonb at 8:54 AM on March 12, 2010