First Light, False Colour

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Stories from the end of representation.

Business Day, 14 January 2020. Image gallery.

In the beautiful |Xam mythologies of the night sky, the stars of the northern Karoo are imagined as close-at-hand, familiar beings who sing and speak: ‘I grew up listening to the stars’, in the words of |Han≠kass’o: ‘The stars say: “Tsau! Tsau!”. Now this place of ancient human habitation, rock art and archaeological sites is becoming a portal to the early universe as astronomers reshape and rewire the landscape to listen in a different way. The Square Kilometre Array (SKA) will one day be largest, most complex scientific instrument ever built. Already, the precursor MeerKAT is among the most powerful radio telescopes in the world. But will we understand what we are seeing?

‘Of course, you know the universe isn’t really that colour?’

While finishing my doctorate, I lived in a flat full of engineers and scientists. An astrophysicist called Giorgos and I would sit at opposite ends of a long dining room table, writing up our respective PhDs: mine on literature, his on black holes. Giorgos took great pleasure in pointing out basic scientific truths and generally revealing how ignorant know-all humanities types are about life, the universe and just about everything. I had been marvelling at some of the images from the Hubble Space Telescope (HST): the vast dust spires of M16, the Eagle Nebula; the Ring Nebula M57 in Lyra, dubbed ‘The Eye of God’; the ultra-long exposure of the Hubble Deep Field, stretching the instrument to its limits, the blackness speckled with a riot of colourful galaxies.

‘Most of it isn’t any colour at all’, Giorgos went on, ‘Strictly speaking.’

It came as a bit of a shock to me: that the Hubble pictures which adorn so many calendars and desktop backgrounds are actually ‘false colour’ images, regarded by many scientists as a necessary but rather kitsch public relations exercise. Their palettes, cropping, orientations, even the ‘lens flare’ of cross-shaped diffraction spokes that one can see on especially bright galaxies in the Hubble Deep Field – all of these are aesthetic decisions and additions made by those processing the grayscale digital images actually captured by the Hubble cameras (these can be accessed online and are in some ways more austerely beautiful than the gaudy, colourised versions).

In her 2012 book Picturing the Cosmos, Elizabeth Kessler points out the similarities between the famous Eagle Nebula (nicknamed ‘The Pillars of Creation’) and 19th-century paintings of the American West. The Hubble pictures and Romantic landscapes share towering spires and vertical orientations; desert colours of sienna and ochre; dramatic lighting, high contrast, and a sense of boundlessness. Tracing a history of how optical astronomy has often been drawn to remote, arid landscapes in search of darker, clearer skies, Kessler suggests that the distant cosmos has often been constructed as a grand interstellar landscape, and one that corresponds to pre-existing, earthly notions of the sublime. Hence the uncanny mix of otherworldliness and familiarity that the Hubble Heritage images seem to hold.

If scientists are often imagined as going boldly towards new frontiers of knowledge, then humanities types might suggest (from the other side of the dining room table) that we always remake the radically unknown partly in terms of the already known. This is something that reaches absurdist heights when looking at the 1756 star chart of the French astronomer Nicolas Louis de Lacaille, who visited the Cape in the 18th century and named many of the constellations of the southern hemisphere after his own scientific instruments. Among the Telescope, the Compass and the Easel, one can also find Mons Mensa: Table Mountain, its white tablecloth provided by one of the two dwarf galaxies orbiting the Milky Way. To the European observers who looked to astronomy as a prime means of oceanic navigation, these came to be known as Magellanic Clouds. To Muslim chroniclers of the heavens like Ibn Qutaybah and Al-Sufi, they were cows (al-Baqari). To the ancestors of Yamaji and other Aboriginal communities living near the SKA site in Western Australia, they were emu eggs. And to the |Xam peoples whose heartland overlapped so closely with what is now the SKA core site in the northern Cape, they were a family of steenbokke. Tables, easels, galaxies (from the same root that gives ‘lactic’: milky), eggs, antelopes, wood ash thrown into the sky – the cosmos can be seen both as a scientific object and a multi-dimensional archive of the humanities: a vast repository of narrative, picturing, pattern-recognition, myth and metaphor.

Ever since Giorgos’s astronomy lessons, I have tended to regard any strenuously majestic images of the cosmos with a little more scepticism. To what extent are we seeing projections of our own all-too-human desires, myths and aesthetics into the farthest reaches of space? And so when an image of a black hole was released earlier this year amid much fanfare, I found myself wondering: what exactly are we looking at here? I mean I didn’t do a PhD on them, but aren’t black holes precisely the things that light can’t escape? Another crushingly ignorant question which he had to set me right on via Skype, explaining things (long-sufferingly) from first principles.

What the layperson calls ‘light’ is the form of radiation in which our sun puts out much of its energy, and which (in the circular logic of organic evolution) the eyes of living creatures on earth have become most sensitive to. Yet what is visible to humans and other animals constitutes only a tiny portion of the electromagnetic spectrum, which ranges from lethal gamma and X-rays (very short wavelength, very high energy) to the faintest of radar waves and microwaves (very long wavelength, very low energy). The latter are the immensely faint signals that radio telescopes strain to detect, waves that have been travelling for as long as it has been possible for them to travel, the aftershocks of the Big Bang itself.

For astronomers, then, light is less about vision than measurable energy: ‘a series of numeric values that corresponds to wavelength or intensity’, writes Kessler, ‘attributes that the naked eye may or may not discern and never with the precision of an instrument’. Even within the Hubble images, radiation in the infrared and the ultraviolet bands (those wavelengths lying just to either side of the rainbow) has been read off via different instruments and layered into in a final image where what is ‘real’ is no longer defined by human senses. In this sense, the common caption ‘false colour’ in popular astronomy publications is misleading (I finally got Giorgos’s point) since the phenomena they signal do not exist as colours at all. The palettes are visual codes assigned to represent physical properties underlying the properties in an image (intensity, energy or chemical composition, for example) and which function as tools for making structure visible. Many astronomical images are perhaps something closer to conceptual art than photography or figurative representation. These are graphics better understood as the layering of disparate and painstakingly derived orders of information: visual artefacts that (particularly when stripped of the scales and axes required in scientific publication) hover ambiguously between picture and data, metaphor and map.

Moving from optical to radio astronomy, the whole question of what it means to picture the universe becomes still more complex. Consider a journey from Cape Town’s old Observatory to the core site of the Square Kilometre Array radio telescope in the northern Cape, where a vast astronomy reserve has been decreed, so that the MeerKAT dishes are undisturbed by cell phone signals, petrol engines and all the other electromagnetic clutter of modernity.

Beginning at the Observatory that the Cape Town suburb is named after, one can take a tour of the gloriously steampunkish 1897 McClean’s Telescope, which peeks out of a domed cupola. Someone pulls a lever and the entire floor of the room rises up, hydraulically, allowing you to put your eye to the eye-piece. When I did so, there was Saturn. It was the first time I had ever seen it for real: ringed as promised, greyish, greenish and scratchy like something from an old news reel or a film by Georges Méliès at the dawn of cinema.

If you take the trip to Sutherland, the Karoo town where the South African Astronomical Observatory moved in the 20th century to escape light pollution, you can visit the South African Large Telescope. As the biggest optical instrument in the southern hemisphere, SALT is sensitive enough (your guide might tell you) to detect a match being struck on the moon. Like a big compound eye, its hexagonal mirrors collect and collate as much light as possible from the night sky: a process that a non-specialist can easily understand and identify with. Yet to move further north from Sutherland to the MeerKAT array near Carnarvon requires a shift in one’s understanding of what a telescope is: both an aid for greater seeing, but also an instrument for imaging the unseeable.

‘With a radio telescope there is no eyepiece’, as SKA cosmologist Roy Maartens puts it, and the dishes observe all day. Operated remotely from a control room in Cape Town, the 64 antennae at the Losberg core site draw down numbers from the cosmos, amassing astronomical quantities of data that must then be correlated, cleaned and ‘piped’ to the city for further processing. In this business park HQ (so different to the classical facades of the old Royal Observatory just across the Liesbeeck River), ‘Sleep Rooms’ allow for the telescope controllers to recover after sessions spent remotely guiding the dishes. Those working on imaging use a mathematical operation known as the Fourier transform is to ‘translate’ the immense streams of radio data into visual renditions of immensely distant phenomena – pulsars; radio galaxies with energy spewing from supermassive black holes at their centre; ‘relic radiation’ of an early universe – that in no way correspond with what the human eye would be able to see.

In 2016, astronomers released MeerKAT’s ‘First Light’ image, the term for a telescope’s public debut. In a patch of sky representing 0.01% of the celestial sphere, the instrument detected 1300 galaxies where only 70 were known before. The New York Times called it ‘the first taste of the ultimate cosmic feast to come’. In July 2018, the completed MeerKAT array was trained on the supermassive black hole at the centre of our Milky Way galaxy, a region shrouded by dust, impenetrable to optical instruments. MeerKAT’s image was aglow with supernova remnants and gaseous filaments. These images, along with a more recent, hyper-blue press release of vast radio ‘bubbles’ in the Milky Way, are mysterious and arresting. But for many of its observations, the SKA will be looking at (or listening for) immensely distant celestial objects, right back to the emergence of the first star-producing regions at the dawn of the universe, the so-called Epoch of Reionisation. These are domains where vast radio galaxies do not resolve into much more than pixelated blurs, reminiscent (as with many radio astronomical images) of infrared or thermal mapping. Even when magnified, they have the feel of low-res graphics, or pictures still being rendered.

When I visited the SKA core site in the northern Karoo, the first sign of the project was the new fibre optic cabling strung up on old roadside electricity poles, leading our tour party onward into the dry, shallow hills. Engineers must inspect this new-old infrastructure regularly, ensuring that sociable weaver colonies do not make their enormous, haystack-like nests on the pylons in a way that might disrupt the crucial data pipeline. Feral horses and sheep within the core site were also causing problems, apparently, and so too the jackal populations now able to move freely between adjoining farms and a space functioning as a de facto nature reserve. The Karoo Astronomy Advantage Area is a curious superposition of cutting-edge technology and incipient wilderness, or even re-wilding.

In his 1756 star chart, Lacaille quite literally saw his own telescopes embedded in the night sky. Yet for contemporary radio astronomy, which deals with such faint radiation, much of the work is to identify and subtract the noise produced by the physical structures and properties of one’s own instruments. The Array will be attuned to celestial radio power that is ‘a million times fainter than a cell phone signal’ or, in another of the gimmicky metaphors that scientists fall back when speaking to someone unversed in the language of mathematics, ‘the equivalent a smartphone on Pluto’. Scientists and engineers must tease out images from the barrage of unwanted electromagnetic radiation, both ‘natural’ and anthropogenic, that is always present even in a radio quiet zone: solar flares; ‘spill over’ radiation absorbed and then released by the earth; Kulula flights passing overhead – these are the electromagnetic clouds, spikes and pings that must be filtered out.

‘It’s like trying to hear someone whispering to you in a club’, said Bradley Frank of South African Radio Astronomy Observatory (SARAO), and then added: ‘Like someone whispering the lottery numbers to you in a dub-step club.’

In a world in which radio quiet has become a scarce resource, the SKA core site was chosen for its distance from the petrol engines, mobile phones, lighting and countless other technologies that produce radio interference. It is a space relatively free of the electromagnetic noise of modernity, and yet also full of petroglyphs and stone tool middens: remnants of a different kind of modernity, in the archaeological sense, and which testify to an enormous time depth of human occupation. The long human history in the region is distantly registered in the richness and beauty of the star lore related by |Xam individuals in the 19th-century. As such it is a portal reaching deep into both the earthly and cosmic past. It is a place where mind-bendingly different scales, temporalities and histories ‘touch’ each other, and a project that is hard to bring into words or images, or to justify in conventional socio-economic terms.

The final SKA may come to speak in a somewhat different visual language to that of optical telescopes like Hubble or SALT. But perhaps some of the most intriguing visuals produced by contemporary astronomy are not those that have been cropped and translated into the recognisable and over-worked register of the sublime, the pretty, or the kitsch; but rather those operate, as James Elkins writes in Six Stories from the End of Representation at ‘the ill-defined borders shared by abstraction, competing naturalisms, and conceptual art’. He calls for observers from the humanities to become more literate in visual-scientific registers that are not narrowly literal or figurative; to extend the idea of what is interesting beyond conventional aesthetic categories; and to develop a taste of images that are in some sense impossible:

‘The images I am interested in show us things that we can’t possibly be seeing: things so far away, so faint, so large or soft or bright that they couldn’t possibly be contained in the rectangular frame of a picture – and yet they are. They are pictures of objects that literally don’t exist – that couldn’t exist as they are pictured – but somehow do.’