Is the moon actually black?

Lunar soil refers to the soil unique to the moon. Studies have found that there are natural mineral particles such as iron, gold, silver, lead, zinc, copper, antimony, and rhenium in the lunar soil.

I was lucky enough to see lunar soil with my own eyes some time ago. In the laboratory of Professor Yang Wei of the Institute of Geology and Geophysics of the Chinese Academy of Sciences, I saw for the first time the "bulk" lunar soil poured out of a bottle.

My first reaction was: it’s too dark.

Under natural lighting conditions, the lunar soil samples look darker than the earth soil we see every day, and even look a bit like fine coal slag. To the naked eye, they seem darker than the videos or pictures we have seen before. This is very different from the gray lunar soil we remember, and even more different from the bright white color of the moon in the night sky.

On February 22, 2021, the lunar soil from the National Museum of China's collection No. GB93484 arrived at the museum.
(Image source: Baidu Encyclopedia)

The reason why it looks so black is that the albedo of the lunar soil is actually very low. Specifically, as for the lunar soil you see, spectral experiments later found that the albedo of the lunar soil is only 0.1, which means that only a little more than 10% of the light is reflected.

(Photo source: National Museum)

In fact, the moon is one of the dimmest objects in the solar system. I once saw someone use asphalt to describe how "dark" the moon is - it is said that the albedo of old asphalt roads is actually not much different from that of the moon.

(Photo source: NetEase - Fun Exploration)

So, from a slightly far-fetched perspective, can we say that the moon is actually black? After all, we have seen a small piece of black lunar soil.

China Science Expo

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