Ridgeline Pleasures

CP 1919, for Cambridge Pulsar at right ascension 19 hours 19 minutes, was the first pulsar ever found. The detection happened in November 1967 at the Mullard Radio Astronomy Observatory outside Cambridge, on a field of around four thousand dipole antennas spread across roughly nine acres, built and run partly by hand. The pulses arrived once every 1.3373 seconds, sharper and more regular than anything astronomy had a name for. The formal modern designation is PSR B1919+21; the source lies in the constellation Vulpecula at a distance of around a thousand light-years, with a wide error bar. The star itself is indifferent to the figure.

For a few weeks, the discoverers labeled the signal LGM-1, for Little Green Men, because nothing natural was supposed to be that precise. Then more pulsars turned up. The mystery resolved into physics: a neutron star, the burnt-out core of a once-large sun, compressed to roughly the diameter of a city, spinning, with a magnetic field lashing radiation out from its poles in two narrow beams. One beam sweeps past the Earth on every rotation. We see a pulse. The pulsar itself is silent; the pulse is geometry.

The detection was made by Jocelyn Bell Burnell, then a graduate student under Antony Hewish, working through tens of feet of chart-recorder paper a night looking for scintillations. The 1974 Nobel Prize in Physics went to Hewish and to Martin Ryle. Bell Burnell was not included - an omission that has been written about, regretted, and refused to die ever since. She has, for her part, been gracious about it. In 2018 she received the Special Breakthrough Prize, three million dollars, and donated the entire sum to the Institute of Physics to fund the Bell Burnell Scholarship Fund - physics graduate studentships for women, ethnic minorities, refugees, and others underrepresented in the field.

Nine years after Craft's thesis, a guitarist in a young Manchester band came across the figure reproduced as Figure 6.7, page 111, of the 1977 Cambridge Encyclopaedia of Astronomy, in Manchester Central Library. (Some accounts credit a bandmate with the find instead; the guitarist's version is the more widely repeated one.) He brought it to the band's in-house designer. The designer inverted the image, black-on-white becoming white-on-black, despite the band's stated preference for the original orientation, and used it, alone, on the front cover of their first album. No title. No band name. No text of any kind. Just the stacked waveform of a star nobody could see, pressed into textured paper, embossed, and shipped on 15 June 1979.

The decision to leave the front bare was as much the work as the image. The record had to be flipped to be named. The album itself was recorded over three weekends at Strawberry Studios in Stockport that April, produced and engineered by a young Manchester production team known for spare, spatial mixes.

The band existed for four years. The lineup was a singer on voice, a guitarist on guitar and synthesizer, a bassist on a bass played high enough to function as melody, and a drummer on drums tuned and treated by their producer in ways the band themselves found maddening and could not, after that producer, replicate. They formed in 1976 in Salford under an earlier name, renamed themselves in early 1978, and released two studio albums, the one this piece is drawn from in 1979 and a second the following year, with a small handful of singles in between.

The singer died by suicide on 18 May 1980, age 23, hours before the band were due to fly to America for their first US tour. He had epilepsy, a difficult marriage, and a depression that the medication of the time was not equipped to treat. The remaining three regrouped under a new name, added a keyboardist, and went on for forty more years.

It is not customary to discuss the cover without discussing him. The cover came first, by eleven months. He saw it. He approved it. It would later be very difficult, for everyone, to look at it without him.

If you or someone you know is struggling, the International Association for Suicide Prevention maintains a directory of crisis lines: iasp.info/resources/Crisis_Centers

The image has not stayed where it was put. It is now possibly the most reproduced piece of graphic design from the second half of the twentieth century - bootlegged onto t-shirts, embroidered onto Supreme drops, tattooed onto forearms, restitched as Mickey Mouse ears, pixelated into Stranger Things merch, painted on the side of buildings in São Paulo and Tokyo and Manchester. The waveform has become unstuck from its source - most of the people wearing it have never heard the album, and a smaller fraction still know it began as a chart of a neutron star.

In statistics, meanwhile, the technique itself acquired a new name. The phrase joy plot was coined by Jenny Bryan in a tweet on 24 April 2017; Claus Wilke shortly afterward built the R package ggjoy, then renamed it ggridges in September 2017 after sustained discussion of the source, since the band's name traces back to a 1953 novella about Nazi concentration-camp sexual slavery, and of the discomfort that name carries when transplanted to a statistical method. The naming is now split: joy plot in informal use, ridgeline plot in respectable journals. Both names trace back, through the sleeve's designer, through the guitarist, through a Cambridge graduate student counting pulses on chart paper, to a star that doesn't know what we did with its rhythm.

In 2015, Scientific American's Jen Christiansen tracked the image back to Craft, interviewed him at length, and published the full provenance in a feature that closed a forty-year loop on a figure most readers had only ever seen on a t-shirt.

Ridgeline Pleasures is the cover taken at its word - pulled off the flat, given depth, allowed to breathe. The ridgelines on the default view are not procedural. Each of the eighty lines is a real consecutive pulse from CP 1919, traced from Craft's Figure 5.37: three hundred samples per pulse, the same data the album cover used, brought back to three dimensions and given a translucent skin. Some pulses are tall, some are short, some doubled, some shifted in arrival time. The differences are the point. A pulsar is regular; an individual pulse is not.

Tap audio and the page does what Bell Burnell did in 1967: it lets you hear the signal. Each row's peak triggers a soft sine ping at 1.337 s, CP 1919's actual rotation period, with a band-passed noise puff underneath for the sub-pulse fine-structure. A visible playhead sweeps the field in lockstep; you can see which pulse you're hearing. Underneath, a procedural loop sits in A minor at ~89.7 BPM: sine kick, a noise-burst snare run through reverb in that spare, spatial tradition, a high melodic bass line played high enough to function as its own voice, a sparse delay-rich arpeggio guitar line, and a slow filtered pad. None of it is a cover of that band's music. All of it is from the same neighborhood.

The instrument also reads seven other phenomena. The data row in the controls switches between Craft's real pulsar and four schematic siblings, cardiac and seismic and birdsong and solar, plus three more from very different domains: markets (intraday traces), prosody (lines of poetic stress), tonal (vertical scans of a horizon painting). Each dataset has its own music: the song follows the data, cross-fading to the new room over about two seconds. Switching dataset is also switching record.

Drag to orbit, all the way from looking down at the field to the album-cover vertical wall. Release and the drift resumes. The controls menu exposes amplitude, baseline lift, row spacing, line color, brightness, halo weight, skin opacity, pulse window (first / last / solo, so you can isolate one ridge or one decade of the stack), breath, rotation drift, time freeze, field of view, dolly, and a camera-preset row for the canonical orientations. The export panel writes the field as a welded OBJ mesh and a Rhino-readable .3dm with eighty degree-1 polylines, zipped together.

The classroom uses for this piece are why it exists in interrogable form rather than as a flat poster. Five overlapping demonstrations get used in critique.

One: data and image are not the same thing. The same eighty pulses can read as a stack of waveforms, as a translucent landscape, as a wireframe terrain, as a contour study, or as eighty isolated curves. Toggle skin and lines, push the row spacing, and watch the design move while the data does not.

Two: the figure is the dataset. Pull the pulse range down to a single pulse and read it like a sentence - the burst, the noise floor, the asymmetric trailing edge. Sweep through eighty of those sentences and you have begun reading the paragraph.

Three: a design decision is reversible. The designer inverted Craft's white-on-black to make black-on-white black-on-white again. We invert it back to white-on-black to read the original. The piece lets you swing between them with one click. The line color slider lets the next student try amber, or pulsar-blue, or anything else they want to defend.

Four: a famous image is somebody's PhD figure. Tilting the field to ninety degrees lifts the data off the page into a thing you could print in resin and put on a shelf. The export button writes the same lines as an OBJ mesh and a Rhino-readable polyline set; what was once an album cover is also a model, also a curve collection, also a teaching prop you bring to your next crit.

Five: provenance survives translation. Every transformation in this page is undoable, and every claim about the work is sourced in the panels above. The point is not to keep the data pristine. The point is to make the chain of decisions visible: Bell Burnell → Craft → the encyclopedia plate → the guitarist → the designer → Bryan → Wilke → you.