Chapter 1809 Pallas

&;!----&; Chapter 1809 Zhishen Star

Zhao Zhongyao drove the spacecraft and landed in the middle of this huge basin. When the spacecraft stopped on the ground, Zhao Zhongyao and Feifei saw a layer of sand on the ground outside.

‘Dad, why is this place like this, it’s different from other places. ’ Feifei looked at the sand-like thing outside and said.

Zhao Zhongyao looked at the situation outside and said, "This shows that this place has suffered serious resistance. This basin or pothole was formed due to an asteroid impact." It's just that the asteroid that hit Juno was also very large, and it directly knocked out part of Juno, and then left such a huge basin or pothole at the impact point. '

After hearing what his father said, Feifei knew what was going on. He looked at his father and said, "No wonder Juno has become a very irregular asteroid. It turns out that it was hit by another asteroid a long time ago. '

'Yes, many asteroids in space have collided with other asteroids. After all, the asteroid belt is relatively densely populated with asteroids. Due to the relatively high density of asteroids, their orbits will intersect each other. Therefore, they may collide with each other during the flight. ’ Zhao looked at his son and explained again.

After hearing what Zhao Zhongyao said, Feifei also understood what was going on. It's just that he still doesn't understand what the sand-like thing is outside.

'Dad, what are these sand-like things outside? Feifei looked at Zhao Zhongyao again and asked.

At this time, Zhao Zhongyao said again,'These things may have been formed by the dust generated when the impact slowly fell to the ground. Since this place is an impact crater, the dust gradually gathered in this impact crater. Thus, the sand-like things we see now are formed. '

After listening to his father's words, Feifei understood what these sand-like things were. He looked at his father again and said, 'Then are we still looking for amethyst gems here! Will there be amethyst gemstones on this Juno star? '

‘It’s unlikely, let’s go to another well-known asteroid to have a look! 'Zhao Zhongyao felt that it was unlikely that there would be amethyst gemstones on this Juno star, so he looked at his son and said this again.

‘Okay, then let’s go to Zhishen Star to have a look! ’ After hearing what his father said, Feifei wanted to go to Zhishen Star to have a look.

‘Let’s go, let’s set off to Pallas! ’ After Zhao Zhongyao heard what his son said, he drove the spaceship to Zhishen star again.

It's just that Pallas is hundreds of millions of kilometers away from Juno. If they want to fly to Pallas, they still have to fly for a while.

So, when flying to Zhishen Star, Feifei looked at Zhao Zhongyao again and said, "Dad, can you tell us about Zhishen Star first, so that we can learn more about this star?" Pallas has a general understanding. '

After hearing Feifei's words, Zhao Zhongyao said, "Humans don't know much about this Pallas, and it is difficult to see the shape of this asteroid through astronomical observations." There is relatively little information about this asteroid.

So, I don't know much about this Pallas star. However, I still know some knowledge about Pallas, so let me tell you about Pallas now! '

After finishing speaking, Zhao Zhongyao told everyone some of what he knew about this Zhishen star.

Pallas is the first asteroid discovered by humans after Ceres (the only dwarf planet in the asteroid belt). The estimated mass is % of the asteroid belt. Pallas has a diameter of 1,000 meters, slightly larger than Vesta, but its mass is 10% lighter than Vesta, so Pallas is the second heaviest asteroid in the asteroid belt. Pallas may be the largest irregular celestial body in the solar system (that is, its own gravity cannot make the appearance appear round), or it may be a remnant protoplanet.

Pallas is the third largest asteroid, similar in size to Vesta (not sure), but notable for its lower mass. Excluding trans-Neptunian objects, Pallas is the largest object in the Solar System whose surface has not been directly observed (with telescopes or probes). It may also be the largest irregular object in the solar system, that is, its own gravity is not strong enough to hold celestial bodies into a spherical shape.

Although Pallas is very large, as a celestial body in the middle of the asteroid belt, its orbit is quite inclined and its eccentricity is relatively large.

The results of photometry in recent years show that the inclination of Pallas's rotation axis is close to ° (the earth is only .°), which means that the length of sunshine in different regions on Pallas has strong seasonality. On the other hand, astronomers still don't agree on the direction of Pallas' rotation.

Through occultation and photometry methods, astronomers can indirectly infer the shape of Pallas. In addition, studies have pointed out that the spectral features of Pallas are similar to some carbonaceous chondrites.

Pallas' observational history has some noteworthy milestones: Pallas' occultations have been observed several times, and the event on 2, 2, 20, 20, 20, 20, 20, 20, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 21, 20, 20, 19, and 19, 2018 are the best observed of any asteroid occultation. An observer made this observation, carefully measuring the duration of the occultation, and assisting in the precise diameter measurement.

Observations in 2009 found that Pallas may have a satellite with a diameter of about one kilometer, but it was not confirmed. In 2000, the observations of the speckle interferometer reported that there was a large satellite with a diameter of 1,000 meters, but the existence of this satellite was later rejected. The mass of Pallas has been estimated from the surface of Pallas reflecting radar signals from spacecraft orbiting Mars, showing tiny perturbations affected by the orbit of Mars.

so far no

No telescope has ever observed features on Pallas' disk, and no spacecraft has ever probed Pallas. If the Dawn project to be carried out in the future can successfully detect Ceres and Vesta, it may extend the mission to Pallas later, but because of the high inclination of the orbit, it will be more difficult than detecting other asteroids.

After Zhao Zhongyao explained this knowledge, he looked at everyone and said, 'Because human beings don't know much about this Zhishen star. I also couldn't learn more about this Pallas star. And now we want to go to this Pallas star to see for ourselves. We want to see what this mysterious Pallas looks like. '

After hearing what his father said, Feifei also said, 'That's right, since human beings don't know much about this asteroid, we can go to this asteroid to have a look now. We can see it with our own eyes. '

‘Okay, let’s speed up and fly to Pallas! After Zhao Zhongyao finished speaking, he drove the spaceship to the mysterious Zhishen star again.

Soon, their spacecraft flew to a place hundreds of kilometers away from this Pallas star. From this place, you can fully see the shape of the entire Pallas.

The shape of the entire Pallas is a very irregular shape, and the outer color is relatively bright, basically yellow, with some black mixed in it.

Although the appearance of Pallas is not regular, judging from the appearance color, it still looks better than Vesta and Juno.

As soon as he saw the appearance of Pallas, Zhao Zhongyao said, "It turns out that this Pallas is really a huge carbonaceous grain meteorite, as human astronomers have guessed." '

Zhao Zhongyao said a professional term - carbonaceous chondrite. After hearing this, Feifei asked in puzzlement, 'Dad, what kind of meteorite is the carbonaceous chondrite you're talking about? '

After hearing what his son said, Zhao Zhongyao said, 'I still know a little about this carbonaceous chondrite. This kind of meteorite may be related to the origin of life on earth. '

‘Oh, it’s also related to the origin of life on Earth, so hurry up and tell me what this carbonaceous chondrite has to do with life on Earth. ’ After hearing what Dad said, Feifei became very curious.

‘Okay, let me explain first what is a carbonaceous chondrite. ' Next, Zhao Zhongyao explained to everyone what a carbonaceous chondrite is.

Carbonaceous chondrites are a type of chondrite rich in water and organic compounds, accounting for only about % of known meteorites. Its components are mainly silicates, oxides and sulfides. It has two minerals, olivine and serpentine, which are a major feature of it.

Carbonaceous chondrites are meteorites with special carbon-containing elements in the meteorite family. They are special because they have high scientific research value and practical significance.

They represent the evolutionary and causative matter of the most primitive solar system, solid matter that survived the early days of the formation of the solar nebula.

They preserve the condensation, evolution and genetic information of some solar nebulae, and their mineralogenesis and chemical material composition reflect the formation and evolution history of early solar nebula, planets, asteroids and stars.

Some features retained by carbonaceous chondrites during the hydrous alteration process are closely related to the low-temperature evolution of the early solar nebula. Therefore, carbonaceous chondrites are witnesses to the formation and evolution of the early solar nebula.

Carbonaceous chondrites of different chemical compositions represent the evolution products of different regions of the solar nebula. They are formed in different regions and at different distances from the sun, and their physical and chemical conditions will also change from oxidation to strong reduction.

In recent years, the academic community has discovered many different amino acids in some carbonaceous meteorites. These extraterrestrial amino acids are constantly being discovered, coupled with the study of some of their isotope changes and differences, and the study of these special interstellar matter, can be It has provided important clues to help us find extraterrestrial life and uncover the origin of life.

Carbonaceous chondrites, also known as C-type chondrites or "CCS", are relatively non-carbonaceous chondrites, and carbonaceous chondrites contain a certain amount of carbon in their rock facies, so they are named for their carbon content. Carbonaceous chondrites or carbonaceous meteorites.

Carbonaceous chondrites are members with a relatively high redox degree in the chondrite family. Because their chemical characteristics are also closest to the materials formed in the early days of the primitive sun and the solar nebula, carbonaceous chondrites are the most important for studying the origin of planets and stars in the solar system. Ideal specimen.

Due to the presence of volatile organic chemicals and water, it has not been subjected to severe (above °C) heating since its formation.

Carbonaceous chondrites are thought to best preserve the composition of the solar nebula that formed the solar system. Its components are mainly silicates, oxides and sulfides. It has two minerals, olivine and serpentine, which are a major feature of it.

Zhao Zhongyao looked at Feifei, Tiantian and Qu Yuqian, and told them some knowledge about carbonaceous chondrites.

After listening to what his father said, Feifei had a general understanding of the huge carbonaceous chondrite in front of him - Pallas.

Tian Tian still looked at this asteroid, which is more beautiful than Vesta and Juno, and said, 'Dad, now we can see the beauty of this asteroid. But I don't understand, why is this asteroid named Pallas? '

After hearing what his daughter said, Zhao Zhongyao smiled and said, 'Maybe it's because she looks better! Therefore, it is called Zhishenxing. '

After hearing what my father said every day, I was still very puzzled and said, 'Why, do you have to name it after Zhishen star because you are good-looking? '

'Because all good-looking women are smart! Therefore, this asteroid is also named after Athena, the goddess of wisdom in Western mythology.

Let's name it. Because it is named after the goddess of wisdom, it is called Zhishen star. Zhao Zhongyao looked at his daughter and explained.

After listening to my father's words every day, I have a clear understanding of why this Pallas star needs Pallas.

‘Dad, it’s really reasonable for you to say this. Such a beautiful asteroid should really be named after a goddess. ’ Said it again every day.

It's just that Zhao Zhongyao heard Tiantian's words, and said again,'I feel that this Pallas star, the reason why it is called Pallas, should have little to do with Athena. More importantly, such planets are closely related to intelligent life on earth. If it is Pallas, which named this asteroid because of this, it would be more appropriate. '

After hearing what my father said every day, I said inexplicably, 'Dad, why is this, why did you say that! '

Feifei also looked at his father and said, 'Dad, tell me, what does this Pallas have to do with life on our earth. '

After hearing what Feifei and Tiantian said, Zhao Zhongyao said, 'That's right, I feel that all the organic matter on our earth may come from these carbonaceous chondrites like Pallas. '

Feifei and Tiantian looked puzzled after hearing what their father said. Because they didn't understand what Dad meant by that. So Feifei asked again, 'Dad, why did you say that, and what basis do you have! '