Blood RED SKY
IN CHINA
Contents
<p>On the evening of 7 May 2022, residents of Zhoushan — a port city on an archipelago off the coast of Zhejiang province in eastern China — looked up to find the entire sky glowing a deep, arterial red. Within hours the images were everywhere. On Weibo, China’s answer to Twitter, the hashtag drew more than 150 million views as people compared the scene to a horror film and asked, only half-jokingly, whether the world was ending. It was not. The cause turned out to be considerably more mundane than the apocalypse, though no less curious once you understand the physics involved.</p>
<h2 id="what-actually-turned-the-sky-red">What actually turned the sky red</h2><div class="ad-unit ad-in-article" aria-label="Advertisement">
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<p>The explanation came quickly, and from an unexpected source. China Aquatic Products Zhoushan Marine Fisheries Company confirmed that a vessel harvesting Pacific saury — a slim, silvery fish caught at night — had been working offshore. Saury boats are floodlit with hundreds of powerful red-tinted LED lamps, because the fish are drawn towards light, and the coloured glow attracts them more effectively while disturbing them less than white light. Massed together on the water at night, those lamps throw an extraordinary amount of red illumination upward.</p>
<p>The weather did the rest. Zhoushan that evening was overcast with a fine drizzle. The local meteorological bureau explained that when the air is heavy with moisture, it forms aerosols — tiny suspended droplets that refract and scatter light. The red glare from the fishing lamps struck this damp, particle-laden air and spread across the low cloud, smearing the whole sky in crimson. It was, in effect, an enormous natural projection screen catching the reflected light of a fishing fleet. Meteorologists were careful to rule out solar or geomagnetic activity, and there was no pollution event, no fire, and certainly no omen.</p>
<p>The detail that made the explanation convincing was how localised the phenomenon was. The red glow hung over the harbour and the water’s edge, precisely where the boats were working and where the moist sea air was thickest, rather than spreading evenly over the whole city as a genuine atmospheric event would. Photographs taken from slightly different vantage points showed the intensity fading with distance from the coast — exactly what you would expect from a bright point source scattered through low cloud, and exactly what you would not expect from a solar or geomagnetic cause, which would tint the sky across a far wider area. That geographic fingerprint, more than any single expert quote, is what settled the matter.</p>
<h2 id="why-red-skies-have-always-frightened-us">Why red skies have always frightened us</h2>
<p>The panic in Zhoushan was thoroughly modern in its delivery — screenshots, video clips, viral speculation — but the underlying fear is old. A blood-coloured sky reads as a warning at a level beneath conscious thought, and the historical record is full of moments where unusual sky colours were taken as portents. The most spectacular documented case followed the eruption of Krakatoa in the Sunda Strait on 27 August 1883, one of the most violent volcanic events in recorded history. The blast hurled so much ash and sulphur dioxide into the upper atmosphere that sunsets around the planet turned lurid shades of red and orange for months.</p>
<p>Those Krakatoa skies left a mark on art and science alike. In London, fire brigades were reportedly called out on several occasions by people convinced the intense red glow on the horizon signalled a distant blaze. The painter William Ascroft made hundreds of pastel sketches of the sky over the Thames during that period, creating an unintended scientific record of the fading aerosol veil. Many scholars have argued that the swirling, blood-orange sky in Edvard Munch’s <em>The Scream</em>, painted in 1893, was inspired by the Krakatoa afterglows Munch witnessed a decade earlier; Munch himself wrote of walking at sunset when “the sky turned as red as blood.” Whether or not that specific link holds, the episode shows how deeply a coloured sky can imprint itself on the people who see it.</p>
<h2 id="the-science-of-a-scattered-sky">The science of a scattered sky</h2><div class="ad-unit ad-in-article" aria-label="Advertisement">
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<p>The colours of the sky are almost entirely a story about how light of different wavelengths interacts with what floats in the air. Blue light has a short wavelength and scatters easily off the molecules of the atmosphere, which is why a clear daytime sky is blue. At sunrise and sunset, sunlight travels a longer, shallower path through the atmosphere; the blue is scattered away before it reaches your eye, leaving the longer-wavelength reds and oranges to dominate. Add extra particles — volcanic ash, desert dust, wildfire smoke — and that reddening intensifies, because larger particles scatter and absorb light in ways that favour the red end of the spectrum.</p>
<p>Zhoushan simply added a human light source to this equation. Instead of the sun reddened by a long atmospheric path, the city had a fleet of red lamps whose light was scattered by drizzle and cloud. The result looked supernatural precisely because the brain expects sky colour to come from the sun, not from a boat. Once the light source is identified, the eeriness dissolves into ordinary optics. The same physics that paints a red sunset painted the Zhoushan sky — only the lamp had changed.</p>
<h2 id="when-the-sky-misbehaves-elsewhere">When the sky misbehaves elsewhere</h2>
<p>Zhoushan is far from alone. Similar reddening had been reported over Chinese waters before, when saury and squid fleets lit up coastal skies. Beyond fishing lamps, dramatic red and orange skies have descended on major cities within living memory for reasons rooted in dust and smoke. On 16 October 2017, the remnants of Hurricane Ophelia dragged Saharan dust and smoke from Iberian wildfires across the British Isles, turning the sun a deep red and casting an unsettling yellow-brown pall over London and much of England; the phenomenon trended online under a wave of half-serious end-times jokes. In September 2020, wildfires along the west coast of the United States turned the sky over San Francisco a dense orange at midday, a colour so wrong that streetlights switched on and residents described it as apocalyptic. Bushfire smoke has done the same to Sydney’s skies during Australia’s worst fire seasons.</p>
<p>The pattern repeats: an unusual concentration of particles, an unusual angle or source of light, and a population reaching instinctively for the language of doom. What changes is only the trigger. The atmosphere, thin and easily coloured, remains the same delicate screen it has always been.</p>
<p>It is worth pausing on how thin that screen actually is. If the Earth were the size of an apple, the layer of air responsible for nearly all of this colouring would be shallower than the apple’s skin. Everything — the blue of noon, the red of sunset, the crimson panic over Zhoushan — happens in that sliver. A change in what floats within it, whether saury lamps and drizzle or Saharan dust hauled north by a dying hurricane, is enough to repaint the entire dome overhead. That fragility is easy to forget on a clear day, and easy to mistake for menace on a strange one.</p>
<h2 id="fun-facts">Fun facts</h2>
<ul>
<li>The Zhoushan images racked up more than 150 million views on Weibo within hours, making a fishing fleet briefly one of China’s most-discussed topics.</li>
<li>Pacific saury boats use red-tinted lamps deliberately: the fish are attracted to the light, and red reportedly disturbs them less than white light while still drawing them to the nets.</li>
<li>After the 1883 Krakatoa eruption, London fire crews were called out to “fires” on the horizon that were actually the volcanic afterglow reddening the evening sky.</li>
<li>Edvard Munch described a sunset sky that “turned as red as blood” before painting <em>The Scream</em> — an image many researchers tie to the Krakatoa afterglows.</li>
<li>The orange midday sky over San Francisco in September 2020 was dark enough that automatic streetlights and car headlights switched on at noon.</li>
</ul>
<h2 id="a-closing-reflection">A closing reflection</h2>
<p>What is striking about the Zhoushan sky is not that people were frightened, but how quickly the fear was resolved once the light source had a name. The gap between terror and understanding was a single fact: a boat, some lamps, a little drizzle. That gap is where rumour breeds, and it closes only at the speed information can travel and be trusted. The same optics that unsettle us at night over a Chinese harbour delight us at dusk over any ordinary horizon — the same scattered light, read one way as beauty and another way as warning. If there is a lesson in a red sky, it is that the atmosphere is a screen we are constantly, unknowingly, painting on, and that the difference between an omen and a curiosity is usually just knowing who is holding the lamp. For a gentler version of the sky putting on a show, the shifting colours of the <a href="/story/chasing-the-northern-lights-aurora-borealis-uncovered/">aurora over the polar regions</a> run on the same principle of light meeting particles, and the way a whole city can turn its gaze skyward is worth marking on <a href="/specialdate/international-day-of-light/">International Day of Light</a>.</p>
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