Shadows and Eclipses12

In the summer of 1968 I went wandering in Provence, a left-over sun-shrunken scrap of the Roman Empire. From the village of Saint-Rémy, which once sheltered Van Gogh’s anguish, I crossed the stony hills called Les Alpilles. There were ‘no smoking’ notices among the grotesque wind-racked pine trees, for the atmosphere was explosive, heavy with resinous exudations. Then I descended to the sun-smitten streets of Arles, where I found a museum, which I entered for the sake of shade. It had, I read in my guidebook, been founded by Mistral, the nineteenth-century poet who wrote the dying Provençal language and culture back into life. His very name – borrowed from the occasional biting north wind that comes avalanching down mountain slopes in the Rhône valley – proposed the opposite of the unmerciful sun.

The shadowy and dusty interior came close to my idea of the perfect museum. It was so crammed with exhibits that my mental records of them have strangled each other, all except that of one cryptic item: a hen’s egg with a shallow indentation on one side, in the shape of a circle from which a few broad grooves radiated. The notice beside it was terse: ‘Egg laid during an eclipse.’ This object appealed to me as the ideal museum piece, the mysterious deposition of a culture, the condensate of intricate eclipses that occur when the moon, the earth and the sun are aligned, or nearly so. If the earth lies between the sun and the moon, the earth casts its shadow on the moon. If the moon is between the earth and the sun, the moon casts its shadow on the earth. In the first case, the face of the moon visible from the earth is fully illuminated apart from the area shaded from the sun by the earth. That is why eclipses of the moon occur at full moon. In the second case, the face of the moon visible from earth is turned away from the sun and is in shadow; hence, eclipses of the sun occur at new moon. During a new moon eclipse, to an observer situated on the part of the earth’s surface overshadowed by the moon, the latter appears as a black disc moving across the face of the sun and obscuring it in full or in part. By coincidence the apparent sizes of sun and moon as seen from the earth are roughly the same, and so it is possible for the moon to hide the sun completely for a brief time. Since the moon’s orbit round the earth is not quite circular but elliptical, the distance between the two varies cyclically, as does the apparent size of the moon’s disc. If an eclipse of the sun occurs when the moon is at its apogee or greatest distance from the earth, and therefore its apparent size is at its minimum, it cannot totally obscure the sun, and may appear as a black disc with a rim of fire.

What would it be like to observe these phenomena from one side, say from some other planet? Light in general is invisible unless it falls on a retina, either directly from its source or by reflection from an illuminated surface; light rays passing in front of the eye do not interfere with those entering the eye. Since the space in which the sun and its planets pursue their courses is empty apart from extremely tenuous dust clouds, the sun’s rays are reflected only from such surfaces as that of the moon and the earth. Astronomical shadows, therefore, are only seen by contrast with illuminated surfaces; they do not show up in empty space as dark bands or shafts as shadows do in misty air. So for the extraterrestrial observer introduced above, the shadow of the moon is only visible during a solar eclipse, when it shows up as a dark circle on the otherwise illuminated surface of the earth. Similarly, the shadow of the earth is only visible during a lunar eclipse, when it appears as a dark area on the otherwise illuminated surface of the moon. If another body such as an asteroid were to pass behind the moon, relatively to the sun, the extraterrestrial would see it as a dot, shining by reflection of sunlight, that winks out as it enters the zone from which the moon blocks off the sun’s rays. This zone comprises the actual shadow of the moon, visible by contrast on the surface of the earth during eclipses, plus its potential shadow made up of all the points at which its shadow would be visible if there were a surface there for it to inscribe itself on.

As a potentially reflective object I cannot enter the moon’s zone of potential shadow without actualizing part of it as shadow on my own surface. This fact of physics precludes me from seeing my unshadowed self by the absent light of a lunar eclipse. Full moon and new moon are such by virtue of the collapse into a line of the triangle formed by earth, sun and moon; eclipses are the mark of the most complete and perfect of such compressions of space. If it were possible to interfere with geometry, I could hold open such a triangle and slip through it into the zone of potentiality, either that of the earth or that of the moon. In these impossible circumstances I, as a sun-maddened, or let me say a sun-warmed creature, would see my own shadow from the inside, as it were. Suppose I were on the nocturnal side of the earth during a solar eclipse, looking down a hole passing through the centre of the earth to what would be, if it were not for the interruption of the sun’s rays by the moon, its daylight side; then I, no, I mean to say, if I were on the diurnal side of the earth and looking through it by means of such a hole as described, during a lunar eclipse, I would see on the shadowed moon the image of the hole, illuminated, and within that frame my own shadow. To be absolutely accurate and comprehensive about this thought-experiment, I should admit that it would require telescopic eyes, for my shadow and the image of the illuminated window around it would occupy an almost infinitesimally small portion of the distant moon’s dark face. Nevertheless, the principle stands, I believe.

The geometry of the triangle mentioned above calls for elucidation. In the case of an impending lunar eclipse the earth marks the vertex of the triangle opposite its longest side, which is under varying tension as the earth moves into perfect alignment with the sun and the moon, passes through this position and proceeds into space on the other side of the triangle’s longest side, or since all these positions are relative to each other perhaps it would be clearer to say that as the moon pursues its orbit around the earth and the earth its orbit around the sun, the latter approaches, attains to and abandons a position on an extension of the earth/moon side of the celestial triangle. Were it not for the impermeability of the vacuum to sound, this growth and release of tension might be heard as a musical note like that of a harp string, and indeed I believe this to be the origin of the Pythagorean theory of celestial harmony. I should have written, above, that the extension of the earth/moon line sweeps through space and approaches, etc., the sun, instead of the other way round. The outcome is the same, of course: the emission of an inaudible note in the Harmony of the Spheres. To one who has ears for such sublimities I recommend a study of the interactions of the shadows actual and potential described above and the sides and vertices of the imaginary but musical celestial triangle. But how can I convey the subtleties of this tenuous matter? Am I stable enough to pick my way without tripping through the tangles of, triangles of, sound unheard and shadow unseen?

The half-moon is of course exempt from eclipse. At six o’clock of an equinoctial evening it perches on the chimneypot of the old schoolteacher’s cottage with its flat side exactly vertical, single silver breast of the night, a cup spilling half the stars there are conversely does the warp and weft of sublunary and transundance Sunwise transident spidersweb cohere sufficiently to keep me aloft for long enough to let me observe the inwork of creation the invisible ink of creation from above or from outside its all-inclusive tenuities or am I at risk of falling falling falling falling Icarus into a sea of error and contradiction and inexactitudes and approximents to truth but a miss is as bad as a mile where all that counts is all that counts is all that counts perhaps to start agon again an agon with the simplest condsiderialities such as the diffention of an ecl As this: Eclipses occur when the moon, the earth and the sun are aligned, or nearly so if the earth lies between the sun and the moon, the earth casts its shadow on the moon if the moon is between the earth and the sun the moon casts its shadow on the earth in the first case the face of the moon visible from the earth is fully illuminated apart from the area shaded from the sun by the earth. I suspect error in all this, or terror. Slivered in the moon’s eclipse was my birth triangle, a a a a beginning of lifelong hesitation too slow a a a a beginning of lifelong hesitation too slow for heaven when the sun shines on its own shadow from inside, so much so that, when M and I holidayed in Provence many years later, I insisted we visit the museum of the time-lain egg. But I found the place much changed. The corridors had been cleared of what the act of clearance itself would have defined as clutter. Despite curtains drawn over the windows, the air was hot and stagnant. The attendants – three or four young women – seemed to be not so much wearing as crammed into Provençal costumes, stifling complications of aprons, skirts, petticoats, scarves and bonnets. One of them, evidently a new recruit, was being trained to pace the galleries; she was already bored and frustrated, on the verge of hysterics. As blindly angry as a wasp against glass, she marched the length of a central aisle, turned with a stamp of a foot and marched back again, her expression almost audibly crying, ‘That was a stupid waste of effort.’ To avoid a situation that looked as if it might open like a carnivorous flower into a screaming row, we took to the minor aisles and bent our attention to the highly polished vitrines. Their contents were spaciously laid out, with every item clearly and informatively labelled. Identification, classification, order reigned. Despite the heat I felt a chill wind descending from the heights of rationality. But of the egg of the eclipse there was no sign. If it had hatched in the meantime surely a stuffed cockatrice would have been on show. But we knew without consulting the attendants or whatever senior curator might have been disinterred from some distant office that the egg had been purged, as being too bizarrely folkloric. Of course nobody in authority there could have known that for twenty years it had eclipsed the whole of Provence in the mind of a wanderer.