Today in the history of astronomy, the Moon goes dark – and red.
The same aerosols that made sunsets spectacular after the eruption of El Chichon in 1982 also affected the color and shading of the July 6 lunar eclipse. Credit: Neil M. Wyatt/Wikimedia Commons
- The July 6, 1982, lunar eclipse lasted 1 hour, 45 minutes, and 44 seconds.
- The eclipse was visible across several continents.
- Volcanic aerosols from El Chichón affected the eclipse’s appearance.
- The Moon appeared unusually dark, especially in its upper half.
The total lunar eclipse of July 6, 1982, was the longest lunar eclipse of the 20th century, with totality lasting 1 hour 45 minutes 44 seconds. Visible across Australia, the Pacific, the Americas, and western Africa, the eclipse was dramatically impacted by the March-April 1982 eruption of El Chichón volcano, in Mexico. A volcanic eruption injects sulfur dioxide and water vapor into the stratosphere, creating a haze of sulfuric acid. Such a cloud can persist for years, filtering sunlight, impacting surface temperatures, reducing solar radiation, and creating unusually brilliantly colored sunrises and sunsets. During the lunar eclipse of 1982, it also gave the Moon a distinct appearance: the top and middle were darker, while the bottom was shaded in red. The noticeably blacker appearance of the Moon’s upper half suggested that volcanic aerosols were more present in the Northern Hemisphere.
