Look carefully! The true color of the moon has been revealed

The lunar surface is composed of dark rocks such as anorthosite, a gray rock, and basalt. According to Christine Shupla of the Lunar and Planetary Institute, these gray rocks absorb small amounts of energy from across the spectrum and reflect a wide range of white light, giving the Moon its typical gray-white appearance.

However, the Earth's atmosphere plays a significant role in determining how this light appears. Evelyn Hesse of the University of Hertfordshire in England notes that light scattering processes in the atmosphere affect how we perceive the Moon's color. When the Moon is high in the sky, light travels a shorter distance, allowing all reflected light to reach the surface. However, when the Moon is near the horizon, it travels a longer distance through the atmosphere, causing blue light to be scattered, making the Moon appear orange.

This effect is more pronounced during a lunar eclipse. Shupla explains that during an eclipse, the Earth's shadow covers the Moon, and only light passing through the atmosphere reaches it. The atmosphere absorbs the blue light, leaving behind orange and red hues. This is why the Moon appears red during lunar eclipses, a phenomenon known as a "blood moon."

Pollutants, clouds, and dust in the atmosphere can also affect the Moon's color. Ash from volcanic eruptions scatters red light, making the Moon appear blue. Similarly, smoke from forest fires scatters blue light while leaving red light behind, making the Moon appear red.

THE TERM 'BLUE MOON' IS NOT ABOUT COLOR

However, the term "blue moon" doesn't actually refer to the Moon's color. It's typically given when there are two full moons in a calendar month, or the third of four full moons in a season. Most blue moons actually appear whitish.

The full moons in June typically appear honey-colored, giving rise to the term "honey moon." Shupla explains that this is also where the honeymoon vacation taken during this period comes from.

Refraction of moonlight—the bending of the light's path—can also create extraordinary colors. Hesse says that when the Moon is near the horizon, atmospheric refraction can cause the moonlight to appear green. This rare phenomenon lasts only a few seconds.

Sometimes, a rainbow ring can form around the Moon when ice crystals in the atmosphere refract the moon's light. Shupla explains that this phenomenon occurs when ice crystals refract light, similar to raindrops.

As a result, while the light reaching the Moon is white, it's difficult to precisely define its color due to optical interactions in the atmosphere. The most accurate description of the color of moonlight, Shupla says, would be "ephemeral."