Lunar eclipse photographed on September 7, 2025.
A lunar eclipse occurs when Earth passes between the Sun and Moon, casting its shadow on the lunar surface. During totality, the Moon exhibits a characteristic reddish coloration due to Rayleigh scattering in Earth’s atmosphere. Shorter blue wavelengths are scattered away by atmospheric particles, while longer red wavelengths are refracted through the atmosphere and illuminate the lunar surface - the same optical process responsible for red sunsets.
During partial phases, observers may notice a subtle blue-violet fringe at the shadow’s boundary. This phenomenon results from selective absorption by Earth’s stratospheric ozone layer, which filters out red and yellow wavelengths while allowing blue and violet light to refract around our planet’s limb. The varying intensity and hue of eclipse colors depend on atmospheric conditions, including dust content, water vapor, and aerosol distribution along Earth’s terminator.