Blade Runner sky
San Francisco residents woke up Wednesday to a world tinted a surreal orange. All across the Bay Area and other parts of the US West Coast, a layer of smoke from wildfires to the east sat above clear air coming in from the Pacific Ocean. Dust and smoke particles in that smoky layer scattered the sunlight, “the same effect that makes the sky blue and the evening red,” says Sam Trahan, a physicist with expertise in atmospheric physics and modeling. Both Rayleigh scattering, which most strongly affects short-wavelength light toward the blue end of the spectrum, and Mie scattering, which is not as dependent on wavelength, were at play in the effect. Despite the unsettling color, the air at ground level was relatively clean in most places. — Craig Bettenhausen
Photos by NatalieGrant, Adrienne Peña, Lindsey Anne, Kurt Texter, and David Gian-Cursio
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