Because this basin is very large, with a diameter of 2,000 kilometers and a depth of 12 kilometers. From a high altitude, it looks like someone deliberately dug a big pit in Antarctica.

Feifei looked at the big pit on the monitor, and he was very happy. After all, what he wanted to see was the Aitken Basin.

'Dad, it seems that we can only appreciate the Aite Basin from this height. If we fly below, we won't be able to see anything.' Feifei thought, since this

If it was pitch black inside the Aitken Basin, then their UFO spaceship would not be able to see anything when it flew into the basin.

After listening to Feifei's words, Zhao Zhongyao said again, "Speaking of this Aitken Basin, there is indeed nothing good to see. However, there is a relatively large impact crater in this basin, which is more beautiful."

of.'

‘Ah! There is an impact crater in this basin. What does that impact crater have to do with this basin?’ Feifei said again.

‘This impact crater has nothing to do with the Great Basin itself. The Aitken Basin is a very old and huge impact crater. It may have been created by a huge asteroid colliding with the moon more than three billion years ago.

The impact crater in this basin is relatively young. But when it was created, we have to go down below to detect it to know.' Zhao Zhongyao said.

After hearing what his father said, Feifei said, 'Then let's go and have a look! I want to know what the impact crater looks like.'

'Don't be anxious, just listen to me talk about this impact crater!' Zhao Zhongyao felt that it would be better to tell his son about this impact crater first. This would allow Feifei to have a better understanding of this impact crater.

Have a general understanding of impact craters.

‘Okay, let’s first listen to dad talk about this impact crater!’ Feifei looked at his dad at this time and said.

'Okay, let me tell you about this Antarctic impact crater. The crater is located in the Aitken Basin. The eye-catching impact craters distributed around the ring include Shoemaker crater, Haworth crater, De Gerlach

crater, svi

Droop Crater, Slater Crater, Faustini Crater; and a little further away, the larger crater Amundsen, located on the eastern half of the front side of the moon, was named after two early Antarctic explorers.

and Scott Crater.

Shackleton Crater has a diameter of 20.92 kilometers and a depth of about 4.2 kilometers. The moon's rotation axis is located only a few kilometers away from the center point in Shackleton Crater. From the Earth, only sand on rough, rugged highlands can be seen.

At the edge of Kelton Crater, the crater wall is slightly protruding from the lunar surface, and the outer slope is slightly eroded by impact, but there is no obvious intertwined crater wall. Viewed from the earth at a viewing angle of 50–90°, the slope of the crater outer wall is about 1.5

°.

Since the moon's orbit is only tilted 5° from the ecliptic, the interior of the crater is in permanent darkness, but the wall peaks at the mouth of the crater are almost constantly exposed to sunlight, and the time exposed to the sun accounts for about the total lunar orbital period.

80-90%. The continuously illuminated mountain range is also known as Everlasting Peak, a title that has existed since the 20th century.

Japan's Moon Goddess probe used the reflection of the crater wall to image the shadow area inside the crater. The interior of the crater is composed of a uniform inner wall with a slope of 30° and a crater bottom with a diameter of 6.6 kilometers, with a small number of scattered

Small craters no more than a few hundred meters in diameter.

The bottom of the crater is covered with a layer of undulating mound-like structure about 300-400 meters thick, with a central peak height of about 200 meters. The permanent darkness keeps the temperature at the bottom of the Antarctic crater below 100K for a long time. According to Shackleton

As for the crater, the measured average temperature is about 90K, while the bottom of the crater is as low as 88K.

Under these conditions, it is estimated that the loss rate of any water ice will be only 10-10 meters/second. All water molecules arriving here with the impacting comet will be frozen on or below the surface of the crater floor. Lunar Prospector Probe

Measured data show that the hydrogen content in the crater is much higher than the general level on the lunar surface, which indicates that water ice may exist. However, the albedo of the crater bottom is consistent with that of the far side of the moon, indicating that the crater bottom is not exposed.

of surface ice.

From the earth, the crater is located on the southern edge of the moon, making observation difficult. Until the advent of orbiting spacecraft, no detailed map of the lunar polar regions and the back side had been mapped. The Shackleton crater is completely located in a vast

, one of the largest known impact craters in the solar system - the Antarctic-Aitken Basin.

The basin is more than 12 kilometers deep, and its detection may provide useful information about the moon's interior. The neutron spectrometer on the Lunar Prospector probe detected neutrons near the moon's north and south poles, including in the Shackleton Crater.

High concentrations of hydrogen. At the end of the mission in July 1999, the probe impacted near Shoemaker Crater, hoping to detect water molecules in the dust emitted by the impact through telescopes on Earth.

However, no water molecules were detected in this impact, which may indicate that hydrogen does not exist in the form of hydrates, or that there is no ice at the impact site; or, the impact may not be deep enough to break through the surface layer of debris and release it.

A certain amount of water molecules are produced. Judging from the images of the edge of the crater taken by radars and satellites on Earth, its appearance is relatively complete, very much like a young crater that has not been eroded by subsequent impacts.

This may mean that its inner wall is relatively steep, which will cause inconvenience for unmanned probes to visit the moon. In addition, it is possible that the crater formed itself and a sufficient amount of volatiles has not accumulated at the bottom of the crater.

However, the craters around it are quite old and may contain significant hydrogen in the form of water ice.

Radar studies before and after the Lunar Prospector mission showed that the reflection characteristics of the inner wall of Shackleton Crater are similar to those of some craters exposed to sunlight, especially around it, where there appears to be a large amount of sputter coverage.

This suggests that its radar reflection characteristics are the result of a rough surface, rather than ice. This is consistent with previous radar data from the Clementine spacecraft.

However, this explanation has not yet gained unanimous recognition in the scientific community. Radar images with a wavelength of 13 centimeters show that there is no evidence of a water ice layer in the crater.

This time we went to the Shackleton Crater for detection, just to see if there is water ice at the bottom of the crater. Although we have carried out a series of detections of this crater on Earth before, but that

After all, it is an indirect detection, not a direct detection. This time, we have to go to the Shackleton crater to have a look in person.'

Zhao Zhongyao looked at Feifei and then talked about the Shackleton impact crater. After hearing this, Feifei became very curious about the impact crater.

‘Dad, let’s go over and have a look!’ Feifei heard what his father said about the Shaslton impact crater and wanted to go over there and have a look.

'Okay, let's set off!' After Zhao Zhongyao told his son about the Shackleton Impact Crater, he drove the UFO spacecraft towards the Shackleton Impact Crater located at the center of the Antarctic.

.

Soon, the UFO spacecraft flew over the impact crater. The UFO spacecraft is now one thousand meters above the impact crater. At this height, the overall shape of the Shackleton impact crater can be seen completely.

This is a huge bowl-shaped impact crater. It is surrounded by steep peaks and there is a low-lying area in the middle. Since sunlight cannot shine into the low-lying area of ​​this impact crater, the entire low-lying area is always in darkness.

.Now no one knows what is in this low-lying area.

Although the entire Aitken Basin is in darkness, the edge of Shackleton's impact crater is indeed very bright. Because the edge of this impact crater towers over the entire Aitken Basin.

.

Although most of the Aitken Basin is dark, the area around the Shackleton crater is indeed extremely bright because sunlight can shine on the mountain peaks on these edges.

In this way, from a close distance, the Shackleton impact crater is really amazing. Because the entire impact crater cannot be seen from other places. The only place that can be seen is from this impact crater.

On the edge, how can this not make people feel amazing?

Since sunlight propagates in straight lines in space and does not scatter. Therefore, when looking at the Shackleton Crater from the surface of the moon, it feels like a phantom appearing in the void. After all, everything around it is

It's dark, and only the ring of peaks is bright. It certainly looks very magical.

"Dad, this impact crater looks amazing!" Feifei couldn't help but marveled at the strange scene in front of him.

Tiantian and Qu Yuqian also saw the strange scene in front of them. They also widened their eyes and looked at the circular impact crater under the spacecraft in amazement. Looking at the circle of bright mountain peaks, they both felt

Very magical.

'Of course, otherwise why would we come to see it!' Zhao Zhongyao also said with some surprise as he looked at the wonderful scene in front of him.

'Then let's go down there and take a look now! I really want to know what kind of magical things are in this impact crater.'

Feifei feels that since this impact crater looks very magical from a high altitude, then there might be many magical things inside this impact crater.

‘There must be something magical in a wonderful scene, and I also think that there must be something magical in this magical impact crater.’ Zhao Zhongyao also thought the same as Feifei.

‘Dad, let’s hurry up and have a look inside this impact crater!’ Feifei was a little anxious and wanted to hurry up and have a look inside this impact crater.

After Tiantian and Qu Yuqian heard Feifei's words, they also looked at Zhao Zhongyao. They wanted him to quickly drive the UFO spaceship to take a look inside this magical impact crater.

But at this time, Zhao Zhongyao looked at everyone and said, 'Don't worry, we need to land the UFO spacecraft on an edge mountain to take a look.'

When Feifei heard this, he didn't understand. He looked at his father and asked, 'Dad, why do you have to land on the edge of the mountain? You can just fly directly into the impact crater.'

'We need to first detect the formation time of the rim peaks of this impact crater. We need to see whether this impact crater was formed at the same time as the Aitken impact crater. Or is this impact crater a very young impact crater?

'

Zhao Zhongyao now wants to figure this out. Although they have detected this crater before, at that time they only indirectly detected the age of the crater by launching detectors.

The method at that time was very inaccurate. After all, it is very inconvenient to remotely control detectors on the earth. Samples obtained by detectors are difficult to be universal. They are often collected from places where it is easier for detectors to collect.

Some rocks collected. These rocks may not be the rocks formed when this impact crater hit the moon. Therefore, we now need to collect more rocks from the impact rim peak and conduct some tests. Only in this way,

Only in this way can we have more reliable data.

After listening to her father's words, Feifei of course agreed with her father to go to the edge of the Shackleton crater to have a look.

‘Okay then! Let’s go to these peaks first and take a look at the scenery!’ Feifei looked at her father and said.

At this time, Tiantian seemed relatively happy. Seeing that Feifei was unhappy, she also said, "Brother, let's go to the top of the mountain to see how nice it would be. There is sunlight that can shine on the mountain top. It will definitely be more fun than going to the impact crater."

.'

‘Okay, let’s go to the edge peaks first.’ After listening to Tiantian’s words, Feifei became very interested in these edge peaks.

Qu Yuqian didn't say anything now. As the mother of Feifei and Tiantian, she went out to play this time purely to accompany the two children. She would never argue with the two children. As long as the two children were willing to go there

She will agree to play.

Zhao Zhongyao saw that both children were willing to go to these edge peaks first. He then piloted the flying saucer spaceship and flew towards Shackleton's edge peaks.

Because just now Zhao Zhongyao was driving the flying saucer spacecraft to hover a thousand meters above the Shackleton impact crater. Now he only needs to drive the flying saucer spacecraft and land on one of the edge peaks of the impact crater.

So, Zhao Zhongyao drove the flying saucer spacecraft towards the impact crater. Soon, he was driving the flying saucer spacecraft and flew over a mountain on the edge of the mountain.

What Zhao Zhongyao and the others saw just now from a high altitude was just the appearance of the entire impact crater. It seemed that the impact crater was not very big. But when they really flew to the top of a mountain in the impact crater, they felt the impact crater.
Chapter completed!