Why does the moon turn red during a total lunar eclipse?

Arab Weather - The moon is actually an opaque body that doesn't emit light of its own, but we see it illuminated because its surface reflects the sun's rays. During a total lunar eclipse, the Earth comes between the sun and the moon, blocking direct sunlight from the moon. Despite this, the moon doesn't plunge into complete darkness; instead, it glows a distinctive red or orange color. What's the reason behind this?

Total lunar eclipse: A blood moon graces the skies of the Arab world on this date.

Blood Moon and Rayleigh Scattering

The red color that covers the moon during a total eclipse has led many to call it a "blood moon." This color is due to a physical phenomenon known as Rayleigh scattering, which is the same phenomenon responsible for the blue color of the sky and the visible colors of sunrises and sunsets.

sunlight and the colors of the spectrum

Although sunlight appears white to the eye, it is actually composed of multiple colors called the visible spectrum, which can be seen in a rainbow. These colors differ in their wavelengths: red has longer wavelengths and lower frequencies, while blue and violet have shorter wavelengths and higher frequencies.

The role of the Earth's atmosphere

Earth's atmosphere is filled with air particles, dust, and water droplets. When sunlight penetrates this atmosphere, short-wavelength colors (blue and violet) are scattered more strongly, while long-wavelength colors (red and orange) pass through more easily.

During a total eclipse, sunlight refracts through Earth's atmosphere and bends around it, eventually reaching the moon's surface. Most of the short-wavelength colors are scattered away, while the red and orange colors reach the moon, giving it its famous glow.

Total lunar eclipse next Sunday, peaking on this date

A glimpse of the rare blue color

Sometimes a faint blue or turquoise band can be seen along the edges of the moon at the beginning or end of a total eclipse . This is caused by the ozone layer, which absorbs some of the red light and allows some of the blue light to pass through.

shades of red

The color of the moon during an eclipse is not constant; it may appear deep red or golden orange, depending on the state of Earth's atmosphere at that moment. The presence of dust, smoke, fog, or volcanic ash can make the color deeper and darker.