{"id":794335,"date":"2025-03-13T04:51:03","date_gmt":"2025-03-13T09:51:03","guid":{"rendered":"https:\/\/spaceweekly.com\/?p=794335"},"modified":"2025-03-13T04:51:03","modified_gmt":"2025-03-13T09:51:03","slug":"a-total-lunar-eclipse-looks-red-why","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=794335","title":{"rendered":"A total lunar eclipse looks red. Why?"},"content":{"rendered":"
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\nView at EarthSky Community Photos. | Kaitlin Moore took this image on November 8, 2022. Kaitlin wrote: \u201cThe image features the \u2018Beaver Blood Moon,\u2019 the world\u2019s last total lunar eclipse until 2025. The moon is positioned just over the top of the pine trees in a park in Madison, Wisconsin.\u201d Thank you, Kaitlin!<\/figcaption><\/figure>\n
Coming up \u2026 Total lunar eclipse of March 13-14<\/p>\n
During a lunar eclipse, you\u2019ll see the Earth\u2019s shadow creeping across the moon\u2019s face. The shadow appears dark, like a bite out of a cookie, until<\/em> the shadow completely covers the moon. Then, during the breathtaking time of totality, the shadow on the moon\u2019s face appears red, rusty orange or copper-colored. Why?<\/p>\n
2025 EarthSky lunar calendar is available now. A unique and beautiful poster-sized calendar with phases of the moon for every night of the year. Get yours today!<\/p>\n
Why a lunar eclipse looks red<\/h3>\n
The reason stems from the air we breathe. During a total lunar eclipse, the Earth lies directly between the sun and the moon. Earth casts its shadow on the moon as a result. If Earth didn\u2019t have an atmosphere, then, when the moon is entirely within Earth\u2019s shadow, the moon would appear black, perhaps even invisible.<\/p>\n
However, something much more subtle and beautiful actually happens, thanks to Earth\u2019s atmosphere.<\/p>\n
Earth\u2019s atmosphere extends about 50 miles (80 km) above Earth\u2019s surface. During a total lunar eclipse, with the moon submerged in Earth\u2019s shadow, there\u2019s a circular ring around Earth, the ring of our atmosphere. The sun\u2019s rays pass through this ring.<\/p>\n
Sunlight contains a range of frequencies<\/h3>\n
White sunlight consists of a range of different colors, or frequencies. As sunlight passes through our atmosphere, the green to violet portion of the light (electromagnetic) spectrum is, essentially, filtered out. This same effect, by the way, is why our sky is blue during the day. Meanwhile, the reddish portion of the spectrum is least affected.<\/p>\n
What\u2019s more, when this reddish light first enters our atmosphere, it\u2019s bent (refracted) toward the Earth\u2019s surface. And it\u2019s bent again when it exits on the other side of Earth. This double bending sends the reddish light onto the moon during a total lunar eclipse. It also explains why sunrises and sunsets look red.<\/p>\nView at EarthSky Community Photos. | Sergio Garcia Rill captured these lunar eclipse images on May 15-16, 2022, over the San Jacinto Monument in La Porte, Texas. He wrote: \u201cI took individual images at 850mm of the phases of the moon. And later I resized them (downsized), and re-arranged and overlaid with an HDR processed image of the monument, using Photoshop.\u201d Thank you, Sergio!<\/figcaption><\/figure>\n
The brightness and color of a lunar eclipse<\/h3>\n
Depending on the conditions of our atmosphere at the time of the eclipse (dust, humidity, smoke, temperature and so on can all make a difference), the surviving light illuminates the moon with a color that ranges from copper-colored to deep red. <\/p>\n
A moon in total eclipse never appears as bright as a full moon, but how dark it gets varies. The totally eclipsed moon was barely visible in December 1992, not long after the eruption of Mount Pinatubo in the Philippines, due to so much dust in Earth\u2019s atmosphere. <\/p>\n
All total lunar eclipses do not look alike<\/h3>\n
Can anyone know in advance how red or dark the moon will appear during a total lunar eclipse? Not really. Before an eclipse takes place, you\u2019ll hear people speculate about it. That uncertainty is part of the fun of eclipses, so enjoy! And watch for the red moon during a lunar eclipse.<\/p>\nView at EarthSky Community Photos. | Michael Hoag in eastern Kansas created this stunning composite of the lunar eclipse on May 15, 2022, and wrote: \u201cA composite of several photos. Nice seeing conditions for the eclipse. (The) front moved through dropping the humidity and clearing the skies.\u201d Thank you, Michael!<\/figcaption><\/figure>\nView at EarthSky Community Photos. | Shaun Tarpley in League City, Texas, captured this beautiful shot of the last total lunar eclipse on May 15, 2022, and wrote: \u201cThis image was taken from my backyard. The iOptron Skyguider Pro allowed me to take this 13-second image at roughly 700mm to bring out the detail in the moon and sky.\u201d Thank you, Shaun!<\/figcaption><\/figure>\n
What about that blue band?<\/h3>\n
Another color to watch for at the beginning and end of totality is a blue band of light along the limb of the moon. This blue band is light passing through our ozone layer \u2013 which absorbs red light \u2013 that allows blue light to come through. The blue band is frequently caught in photos but may be hard to see visually.<\/p>\nIn a lunar eclipse, the sun, Earth and moon line up, with the Earth in the middle. Image via NASA.<\/figcaption><\/figure>\n
Bottom line: Coming up \u2026 the total lunar eclipse of March 13-14, 2025. At maximum eclipse, the moon will look red. But why? Earth\u2019s atmosphere is the key.<\/p>\n
Coming up \u2026 Total lunar eclipse of March 13-14, 2025<\/p>\n
November 2022 lunar eclipse photos, via EarthSky\u2019s community<\/p>\n
Post your eclipse photo to EarthSky Community Photos<\/p>\n
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Deborah Byrd<\/h4>\n
View Articles\n <\/p><\/div>\n
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About the Author:<\/h6>\n
Our Editor-in-Chief Deborah Byrd works to keep all the astronomy balls in the air between EarthSky’s website, YouTube page and social media platforms. She’s the primary editor of our popular daily newsletter and a frequent host of EarthSky livestreams. Deborah created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Prior to that, she had worked for the University of Texas McDonald Observatory since 1976, and created and produced their Star Date radio series. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. In 2020, she won the Education Prize from the American Astronomical Society, the largest organization of professional astronomers in North America. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n
![\"Line](\"https:\/\/earthsky.org\/upl\/2022\/05\/Sergio-Garcia-Rill-LaPorte-Texas-May-15-2022.jpg\")
![\"Line](\"https:\/\/earthsky.org\/upl\/2022\/05\/Michael_Hoag_Eastern_Kansas_May15_2022.jpg\")
![\"Lunar](\"https:\/\/earthsky.org\/upl\/2022\/05\/Shaun-Tarpley-LeagueCity-Texas-May-15-2022.jpg\")
![\"Diagram](\"https:\/\/earthsky.org\/upl\/2018\/07\/eclipse-lunar-NASA-e1532689761309.jpg\")