What is the sea on the moon?

"The only way out of the dream,

Moonlight path from the earth ...

Moonlight like gravel,

Under the sea along the coast of Pat Nost. "

——Harin Martin, Sweden, "Moonlight Poems"

When you first read the word "Moon Sea", you may not help but think that it is the "ocean on the moon", like the blue star ball of the earth, it has a source of rush. But is this the fact?

Yuehai schematic diagram (original image image source: Bing Encyclopedia)

Is the sea of ​​moon?

Lunar Maria, although the name contains "sea", is not in fact, the name is not true, and the dripping water is not included. The surface layer of the moon is covered with rocks like the earth's basalt, the moon sea basalt.

After all, there is no water in the sea, and this naming that does not meet its geographical situation is because its appearance is similar to the ocean. Early observer, due to the limited astronomical equipment, could not clearly observe the details of the moon surface, so according to their understanding of the earth, guessing that the dark side on the moon was water -containing ocean. On the contrary, the relatively bright places are called Yuelu. In addition to the "sea" with the most watery area, there are also the so -called "Moon Lake", "Moon Bay", "Moon Marsh" and the waters on the earth.

Moon sea illustrations in the artist (Image source: Bing Encyclopedia)

Time of birth

Moon Hai formed 3.1 billion to 3.9 billion years ago. In addition to the meteorite pit that was more backward, these Moon Sea is the youngest geological unit on the surface of the moon and the main geographical unit on the surface of the moon. The total area of ​​the moon is 25%.

Generally, we believe that the following causes have the following causes: due to the impact of large foreign celestial bodies, the martial arts martial arts lava in the moon curtain is erupted and formed. In some cases, the eruption of lava will occur in two stages: first, the impact event itself causes eruption, and then the eruption caused by concurrent heating. Some Yuehai (or "basin") have a clear circular outline and the characteristics of huge impacts. Other basins like Donghai are multi -ring structures.

Regarding the uneven geographical distribution status of Yuehai, astronomers made assumptions: when the moon was first formed, it was completely in a state of fluid static balance, and the quality of the moon center shifted to the earth.

Moon map (image source: Bing Encyclopedia)

etymology

There are some shadows visible to the naked eye on the moon, which are particularly obvious around the full moon. These large areas of dark areas are the moon. The ancient Chinese had imagined it as a rabbit or cinnamon tree according to the shape of the shadow. The author's childhood watching the moon was no exception.

In 1608, the Dutch inventor Li Po Bal invented the world's first simple telescope. One year later, Galileo also produced telescopes on the basis of previously used to observe the starry sky. The first batch of scientists who observed the moon saw a huge dark area when using telescopes to observe the moon, and in 1647, Polish astronomer John Hepei stayed in the word Maria. At this point, the official name of Yuehai was born.

Yuehai schematic diagram (original image image source: Bing Encyclopedia)

Yuehai family member

The front of the moon (northern hemisphere) is the main distribution of Yuehai, and its area accounts for about half of the front of the moon. The back of the moon is only the three sea, the Moscow Sea, and the Zhihai.

There are 22 large moon sea on the moon, and when you stand on the earth and look up at the earth, a bright moon in the eyes contains 19 months. The area of ​​the middle of the moon is the storm, about 5 million square kilometers. In addition to the storm, Lenghai, Chenghai, Rich Hai, Dangerous Sea, Yunhai, etc. are also relatively large moon sea. The above names are named after ancient astronomers.

Please see what are the 22 members of Yuehai:

1. Mare Frigoris Cold Sea

2. MARE IMBRIUM

3. Oceanus Procellarum Storm

4. MARE COGNITUM knows the sea

5. MARE HUMORUM wet sea

6. MARE Serenitatis Chenghai

7. MARE Transquillitatis Quiet Sea

8. MARE CRISIUM

9. MARE FRCUNDITAS rich sea

10. MARE Nectaris

11. Mare Vaporum

12. MARE INSULARUM Island Sea

13. MARE NUBIUM Yunhai

14. MARE UNDARUM Langhai

15. Mare spumans bubble sea

16. MARE SMYTHII Smith Sea

17. MARE MOSCOVIENSE

18. MARE MAGINIS Jiehai

19. MARE Ingenii Zhihai

20. MARE HUMBOLDTIANUM

21. Mare Australe South China Sea

22. MARE ANGUIS's more specific location of the remote moon sea (image source: Zhihu)

In addition to "sea", there are five similar "lakes" that are similar to them -Menghu, Dead Lake, Xiahu, Qiuhu, and Chunhu. However, some lakes are larger than the sea. For example, Dream Lake, its area is 70,000 square kilometers, which is wider than the standard moon sea and other standard moon sea.

At the same time, Yuehai stretches to land and is distributed on the front. There are five in the bay: Luwan, Summer Bay, Central Bay, Hongwan, Meiyue Bay; and Marsh has three rotary marsh, epidemic, and Menguma. In fact, there is no difference between Marsh and Bay. The terrain of the moon and sea is generally low. Similar to the basin on the earth, the moon and the sea are 1-2 kilometers lower than the average level of the moon. At 6000 meters, the anti -photo rate of the moon is relatively low, so it looks darker.

Photos taken over the quiet sea before landing on the 11th of the Apollo spacecraft

(Image source: Baidu Encyclopedia)

Approach for the first time

On July 20, 1969, American astronauts Amsterrand and Oldling took Apollo Apolship 11 to become the first human beings to set foot on the moon. This is not only the first time that human beings have real contact with the moon, but also represent the first time we can see the true appearance of Yuehai.

The "Apollo" spacecraft in the United States has landed on the moon seas 6 times. In addition to the "Apollo-11" that has been carried on the moon, there is also the "Apollo-17" landing in Jinghai, "Apollo-12" Falling in the storm. The astronauts were wearing a astronal, walking on the "sea surface", and leaving a series of footprints of about 3 cm deep. They found that the dust on the moon was nearly gray slim powder, a bit like a charcoal dandruff with sticky.

American astronauts and human beings in history for the first time on the moon's footprints

(Image source: Baidu Encyclopedia)

Today, we already know that Yuehai does not contain water, it is just a low -lying plain with darker tones, but for historical reasons, people have always used this name to this day. Yue Hai not only provides the first batch of ancestors using telescope to provide observation and thinking space, but also has great value for modern astronomers who focus on studying the moon geology.

Original: Yang Yixiu

School countermeasures: Wang Jingyi, Wang Gong

Review: Wang Qingshan

Beautiful editor: Xu Yankun

Backstage: Hu Yongzheng

Reference materials:

1. Bonnie J. Buratti, in Encyclopedia of Physical Science and Technology (Third Edition), 2003, 2003

2. Baidu Encyclopedia, https://baike.baidu.com/item/ Yuehai, Apollo 11 (the first successful moon landing mission of human beings)

3. Beijing Astronomical Museum, what is Yuehai? How to form? -Be astronomical Q & A-Beijing Astronomical Museum (bjp.org.cn)

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Does not represent the position of the Institute of Physics of the Chinese Academy of Sciences

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Source: Murator Astronomy

Edit: Tibetan idiot

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