Thursday, June 20, 2013

Astrophysical Meme: Jocelyn Bell Burnell's Pulsar, Little Green Men, Joy Division, and Beautiful Data

In November, 1967, Jocelyn Bell (Burnell) was just a graduate student when she discovered the first radio pulsar (or pulsating star), a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. This radiation (light in the radio frequency band) can only be observed when the star is point towards us; so, like the light from a distant lighthouse, it appears to pulse at a precise frequency. She had been working with her supervisor Antony Hewish and others to construct a radio telescope to study quasars (quasi-stellar objects which emit radio waves). She noted some "scruff" on her chart-recorder, and then that the pulses were incredibly regular, occurring every 1.337 seconds. Hewish was initially scornful and insisted the regular pulses must be noise from a human made source. He first dubbed this object, emitting with such regularity 'LGM 1' for "Little Green Men 1", a playful joke about their uncertainty about what could emit radiation so regularly - obviously it could only be a communication from extraterrestrials hahaha! Only after she found other such sources, in different places with different frequencies, were her colleagues convinced and this lead to the development of the pulsar model. It is now known PSR B1919+21.

The 1968 paper announcing this discovery in Nature has five authors, lead by Hewish, followed by Jocelyn Bell. In 1974, Hewish won the Nobel Prize for this discovery, along with fellow radioastronomer Marlin Ryle). Jocelyn Bell was not included as it was assumed that the "senior man" was responsible for the work. This was controversial and has been condemned by many leading astronomers like Fred Hoyle )(who with Thomas Gold was first able to explain the signals as due to a rapidly rotating neutron star). Jocelyn Bell Burnell herself has stated she was not upset. Bell Burnell has a great career and won many honours after her impressive start, but her exclusion from the Nobel win, based on her own research strikes me and many others as one of the more blatant and egregious examples of gender bias in the selection of Nobel prize recipients.

Not only the discovery, but the presentation of the data is impressive and elegant. The diagram above (from the Cambridge Encyclopaedia of Astronomy) shows superimposed images of successive pulses. Stripped down to their essential information like sparklines (chart lines without annotation or axes, but drawn of course to a common scale) so their regularity really stands out, and they can be easily compared and contrasted. If you are used to looking at time series, you'll know that since they can be easily superimposed and the pulses line up, that the frequency is quite regular. The diagram is downright eloquent, and would warm Edward Tufte's heart. It appeared even earlier in the January 1971 edition of Scientific American article “The Nature of Pulsars” by Jeramiah P. Ostriker (shown above on pale blue) and 1974 graphic design book on data visualisation ‘Graphis Diagrams’(via Gia's Blog).

From there, the image began a sort of life of its own. The British rock band Joy Division included the image from the Cambridge Encyclopaedia of Astronomy in a folder of reference material for their 1979 album Unknown Pleasures submitted to Peter Saville, who designed the album cover- iconic in white on black, it's the pulsar data graphically on a square field (at left). It of course appeared as art, without explanation of its source. The beauty of the image itself, as well as the devotion of fans of the enigmatic album, lead to it propagating as a meme to this day. Peter Saville himself gives a great explanation of the life of this diagram in this video.

Data Visualization Reinterpreted by VISUALIZED from VISUALIZED on Vimeo.

Consider how the image has propagated, from tattoos
via Gia's Blog and tattoo by dodie

to sculpture
[unkn0wn pleaSures 1919] by Marvin Bratke, Lasercut Sculpture 40x40cm, wood/acrylic glass

to food
Brock Davis

through fashion (both consciously of its original source, and more tongue-in-check critique of our contemporary cult of images disconnected from their source - though ironically, I'm pretty sure the tee shirt was designed by someone who thought kids today should know Unknown Pleasures, rather than radioastronomy).

PULSAR 1919 SKIRT by lovelysally

Graphic artist Adam J. Kurtz has created this humorous t-shirt via laughing squid

We've arrived at something interesting to look at on tumblr, without reference to Joy Division or pulsars, an enigmatic but captivating image with an unknown source... an unknown pleasure if you will.

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