The corrosive and obscuring volcanic ash has grounded airplanes all across South America and even in Australia, but the tiny dust and glass particles are also responsible for an optical effect that has lead to spectacular sunsets and sunrises filled with bright gold, fiery orange, and blood red hues around the globe.
"The wavelength of light coming from the sun is being diffracted differently, and that's what causes the visual effect that we see," explained Jay Miller, a volcanologist at Texas A&M University.
The transformed light can range across the color spectrum, but it's usually a dark color, because less sunlight penetrates the atmosphere as a result of the ash cover.
"The two most important things [with respect to] to the variation in hues that we see are how much ash and how high in the atmosphere it gets," Miller said. "A bunch of ash hugging the ground would just make it dark."
Photograph by Patricio Rodriguez, Reuters
Under a Blood Red Sky
A plume of ash rises high into the atmosphere and tints the sky blood red above Chile's Puyehue volcano in this June 5 photograph.
Many sky-watchers reported that the eclipsed moon appeared rusty orange or blood red. This type of color transformation isn't uncommon during eclipses, because dust and gas in the Earth's atmosphere can filter blue wavelengths from the sun's rays, but ash particles from the Chilean eruptions could have helped enhance the effect for this particular eclipse. (Find out how the lunar eclipse worked.)
"I would assume there was some impact," Miller said. "Anytime there's a large amount of ash in the atmosphere, we have reports of this type of phenomenon."
Photograph by Carlos Gutierrez, Reuters
Wisps of volcanic ash float across the setting sun, which appears to have been leached of all its color in this photo taken from Buenos Aires, Argentina, on June 13. Ash from the Puyehue eruption continues to plague the capital city of Argentina, grounding airplanes and shutting down airports.
Dormant for decades, the volcano erupted again on June 4 and lofted an ash cloud more than six miles (ten kilometers) into the atmosphere.
That might seem impressive, but eruptions have been known to launch ash more than 19 miles (30 kilometers) into the air, Miller said.