Reflections on the 2024 Eclipse

Do popular science articles on solar eclipses overlook the fact that the majority of viewers go for the subjective experience?

Don’t get me wrong, communicating the astronomy and physics of eclipses is hugely important – as is recognising the remarkable coincidence of the moon’s diameter and distance from Earth resulting in an angular size of 1/2 degree, which is exactly the same as the sun’s angular size from Earth – but we shouldn’t forget that viewing an eclipse is also a human experience which should not, and cannot, be limited to our scientific understanding of the phenomenon. One enhances the other, and we should celebrate the experiential alongside the analytical.

Relaxing in a hammock overlooking a semi-rural valley south of Mexico City, it’s surprisingly hard to believe I was in the desert town of Durango less than a week ago, witnessing the recent North American eclipse that cast a 185 km-wide band of totality stretching from Mazatlán on Mexico’s Pacific Coast to Nova Scotia on Canada’s Eastern Seaboard

You’ve probably read several articles on the science of eclipses, and seen countless telescopic photos of the April 8th eclipse, but nearly every article I’ve read – no matter how well-researched – gets three important things wrong.

The first error is that totality (the period when the sun’s disk is entirely covered by the moon from the point of view of an observer on Earth) is frequently described as “total” or “near total” darkness. It is nothing of the sort, and if it seems pitch dark, it’s only because your eyes are still adjusting to the sudden drop in luminance. Totality is an uncanny twilight, and you can see as clearly in totality as you can under a full moon. Unlike moonlight, however, the light of an eclipse isn’t cold, blue, and flat. If pressed, I’d say it has an ethereal, silvery quality, like the white light of burning magnesium but without the harsh shadow.

The second error is that photographs of the eclipse unfailingly show an ink-black sky with the black disk of the moon ringed by the corona (the outer atmosphere of the sun in which temperatures can exceed 1 million degrees kelvin, compared to less than 6,000 K in the core). But the sky is not black during an eclipse, it’s blue. The issue here is that human eyes and brain can cope with a much wider range of brightnesses than any camera, be it digital or analogue. In order not to over-expose the delicate corona, cameras underexpose the sky, but the human vision system copes much better with this wide dynamic range, and we see the sky as midnight blue. Clouds (so rarely present in professional eclipse photos) stand out white against the ink-blue sky.

The final, and perhaps most egregious, error is that few, if any, scientific articles talk about what it’s *like* to witness a total solar eclipse, focusing – as they must do – on what’s going on and what to look out for. So let me tell you, that above all else, watching an eclipse is an emotional experience. People gasp, people cheer, many people cry. It is a profound and magical experience. In this sense, it is also very much a shared experience.

I’ve been fortunate to experience two stunning eclipses with totalities lasting almost 4 and 7 minutes (let’s forget the 1999 European eclipse, hidden behind exactly 2 minutes of cloud). My first, in nature, was a shared experience with hundreds of strangers in the shadow of ancient Toltec ruins. In Durango we stood in the town square, where the municipality had set up several telescopes and a huge viewing screen, but in the end it was again an intensely personal experienced shared in awe with hundreds of strangers bound by a common purpose. There’s a good reason that rational people become eclipse chasers, going to great lengths to stand for another few minutes in the shadow of totality; there really is no other experience like it.

The periods either side of totality are marked by strange twilight and even stranger shadows. If you’re lucky enough to be on a hill overlooking flat ground, you can see in the final few seconds before totality the moon’s shadow rushing towards you at around 2,000 kph. During totality animals change their behaviour. Some fall silent, while others begin making their nocturnal sounds. Some roost or hide, others just stop still.

The eclipsed sun is simply glorious. While the sky is inky blue, the moon’s disk is utterly black – so black, in fact, that it appears to writhe with a bizarrely incandescent blackness. Your eyes can play tricks on you as they cope with the darkness of the moon and the shimmering corona that surrounds it, punctuated, if you’re very lucky, by solar prominences visible to the naked eye as tiny orange loops. No wonder many ancient civilisations imagined a giant snake or jackal eating the sun, or some demon fighting with the forces of light during an eclipse.

I think we do a disservice to our ancestors if we assume the only reason they perceived eclipses as originating in the realms of magic and mythology was the they didn’t understand them scientifically. The Mayans were excellent astronomers and could predict both lunar and solar eclipses, yet they still experienced them as magical, mystical phenomena. We may not share their worldview, and we have all the resources of modern science at our fingertips, but that should not prevent us embracing the absolute wonder of such scientifically explicable phenomena. Indeed, it should enhance it.