A translucent glass ball was found on the back of the moon. Does Chang'e also like to play with glass eggs?

Chang'e 4, the first human soft landing exploration mission on the far side of the moon, discovered several centimeter-sized translucent glass balls on the moon. What are these glass balls? What is the significance of their discovery? Let's take a look >>

Compiled by New Media Editor Lai Tianying

On February 17, a research team led by Dr. Xiao Zhiyong of Sun Yat-sen University published a Short Communication paper titled "Translucent glass globules on the Moon" in Science Bulletin 2022, Issue 4, reporting that the Yutu-2 lunar rover discovered transparent glass globules with a diameter of centimeters on the back of the moon. This is the first discovery of such glass beads in the world.

As soon as the news came out, netizens were discussing it hotly - "Are there glass beads on the back of the moon?" "Chang'e can also play marbles", "Who has such strong hands that can bounce marbles to the moon", "I wonder why the glass balls I played as a child are gone", "I have the qualifications to work on the moon because I can bounce marbles", "Chang'e said: My necklace broke and the beads were scattered all over the floor"...

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Uncovering the far side of the moon

Mysterious veil

On Earth, besides the Sun, the Moon is the largest and brightest celestial body that we can see with our naked eyes. As the Moon revolves around the Earth, the relative positions of the Sun, Earth and the Moon are constantly changing, which causes the illuminated part of the Moon to change as well, so we see the waxing and waning phases of the Moon.

▲The Moon and the Earth (Picture from Mars Science)

When the moon moves to the side away from the sun in its orbit, that is, when the earth is between the sun and the moon, a full moon will appear. At this time, we can see the round moon surface, and the moon looks like a bright white jade plate.

If you carefully observe and compare the full moons of each lunar month, you will find that the same scene appears every time the full moon appears. The black parts on the moon are the same, with "toad" and "jade rabbit". However, the moon is a sphere, and the moon itself rotates on its axis, so that the side of the moon facing the earth is always the same, so the other side of the moon, that is, the far side of the moon, is not visible from the earth.

▲Yutu-2 lunar rover (Photo from Tencent You Technology)

Although humans have launched many probes to explore the moon before, and even 12 astronauts have been to the lunar surface, they have all been to the front side of the moon. No probe has ever been to the back side of the moon. It was not until the beginning of 2019 that my country's Chang'e 4 successfully landed on the back side of the moon for the first time, and Yutu 2 followed suit.

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Where did the moon come from?

Transparent glass ball?

Yutu-2 has conducted a series of explorations on the far side of the moon and made many important discoveries. This time, it found several glass beads, some of which looked very round and transparent, which were out of place with the gray and barren lunar surface. So what are these glasses?

▲Glass balls found by the Yutu-2 lunar rover of the Chang'e-4 lunar mission (Image source: China Space Administration)

In fact, high-speed impacts are the main geological force that shapes the lunar surface and affects the lunar geological evolution. Under continuous impacts, the lunar surface is covered with a layer of lunar soil of varying thickness, forming glass spherical objects. Glass beads are an important component of lunar impact glass, formed by the condensation of vapors and condensation of melts. Like lunar volcanic glass beads, the diameter of lunar impact glass beads is mostly much smaller than 1 mm. Impact glass beads are the key carrier for inverting the composition of lunar soil materials and recording the impact history of the lunar surface.

The research team used the panoramic camera data on Yutu-2 to analyze the color, shape and production characteristics of these transparent glass balls. The study found that these glass balls are not the product of lunar volcanic activity or the direct landing of external impactors, but impact glass with special composition.

▲Moon glass balls collected by the Apollo mission (Photo credit: Lunar and Planetary Institute)

During the Apollo moon mission, American astronauts also collected some larger impact glass balls on the moon. The diameters of these balls could reach several centimeters. However, they were opaque black in color and often contained a large amount of debris and pores inside. The translucent glass balls discovered by Chang'e-2 are the first of their kind in the world.

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Small beads big world

The Moon's Big Secret

So what is the significance of the discovery of these glass beads? The study found that they are key information carriers recording the early impact history of the lunar highlands. For example, the formation process of these glass beads may be similar to that of tele-impact glass (commonly known as glass meteorites) widely distributed on Earth, which also shows that tele-impact glass is an inherent product of impact events on terrestrial bodies.

In addition, the ancient impact basins formed on the lunar highlands may have also formed a large number of such glass spheres, and their formation age is important information for inverting the early impact history of the inner solar system. Of course, the excavation and verification of these indicative significance requires the support of fine geochemical data.

When Apollo astronauts were on the moon, they were amazed at how conspicuous these centimeter-diameter glass balls were. The glass balls discovered by the Yutu-2 lunar rover are also very conspicuous, so future lunar exploration missions, especially those on the far side of the moon, will hopefully discover and return such samples. This discovery shows that lunar anorthosite is suitable for producing glass with good light transmission properties, and the construction of future lunar bases may consider using lunar anorthosite as a resource in situ.

▲Image of the "Yutu-2" rover landing on the moon, taken by the Chang'e-4 lander surveillance camera C (Photo from the People's Daily client)

We believe that with the advancement of science and technology, our exploration of the moon and even the universe will become more and more extensive, and we will discover many things that we cannot imagine now. Of course, the discovery of glass balls on the moon this time also shows that my country has taken a bigger step in the exploration of the universe. I hope that my country's science and technology will get better and better, and there will be more discoveries in more fields.

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(Information compiled from: The Paper, Sina.com, Mars Science, Sina Technology, NASA Space Enthusiasts, People's Information, Science China Magazine, Yangtze Evening News, etc.)

Produced by: Science Central Kitchen

Produced by: Beijing Science and Technology News | Beijing Science and Technology Media

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