A Blue-Banded Blood Moon on September 7, 2025
A truly captivating celestial event graced our skies on September 7, 2025: a 'blood moon' lunar eclipse, distinguished by an unusual and striking blue band.
This incredible image, credited to the 立川高校天文気象部, highlights a phenomenon that sparks both awe and scientific curiosity.
Understanding the Blue Band
The question on many minds is: what causes this ethereal blue band to traverse the Moon during an eclipse? While the red hue of a 'blood moon' is a familiar sight, caused by sunlight refracting through Earth's atmosphere and scattering away blue light (much like a sunset), the blue band is a rarer occurrence.
The blue band is essentially sunlight that has passed high through Earth's atmosphere, specifically through layers where ozone is more prevalent. Ozone absorbs red light more effectively than blue light, allowing the blue wavelengths to pass through and illuminate this part of the Moon. This process is akin to how a prism splits light, revealing its constituent colors.
It's important to note that the featured image, captured from Norman, Oklahoma, was processed using HDR techniques to enhance these subtle colors. While the blue band is a real atmospheric effect, its visibility can vary, and digital processing can further accentuate its presence.
A Moment of Scientific Wonder
This event serves as a beautiful reminder of the complex interplay between celestial bodies and our own planet's atmosphere. The clarity of this image allows us to appreciate the intricate ways light behaves, painting our night sky with breathtaking spectacles. It's a testament to the power of observation and the ongoing quest to understand the universe around us.
This phenomenon offers a clear visual demonstration of scientific principles, even prompting humorous, albeit misguided, discussions about the shape of our Earth in some online forums!
