> "Halley's Comet last returned in 1986, and the next return will be in mid-2061."

At the time of its return in 1986, Halley's Comet became the first comet on Earth to be observed in detail by a spacecraft, providing first-hand information on the structure of the comet's nucleus and the mechanisms of comet emanation and tail formation.

These observations support some long-held assumptions about the structure of comets, in particular Fred? HP's "dirty snowball" model correctly assumes that Halley's Comet is a mixture of volatile ice – such as water, carbon dioxide, and ammonia – and dust.

The Chinese's record of Halley's Comet can be traced back to the Yin Shang era.

"King Wu fell, the east and the year, to the water and water, to the head and fall. The comet came out, and the Yin people were given its handle. From time to time, there are comets, and the handle is in the east, and you can sweep the people of the west! (Huainanzi?) Soldier Training)

According to Zhang Yuzhe's calculations, this is the record of the return of Halley's Comet in 1057 BC. A more accurate record of Halley's Comet is in 613 BC (the 14th year of the Spring and Autumn Lu Wen Dynasty) "In the seventh month of autumn, a star entered the Beidou." ("The Left Biography of the Spring and Autumn Period?") The Fourteenth Year of Lu Wengong)

This is the world's first definitive record of Halley's Comet. From 240 BC (the seventh year of the Warring States Qin Shi Huang), every return of Halley's Comet was recorded in China.

Records of Halley's Comet are sometimes detailed. One of the most detailed records is in 12 BC (the first year of the Han Yuan Dynasty) "July Xinwei, there are stars in the east well, practice the five princes, out of He Shubei rate Xuanyuan, Taiwei, the day after tomorrow more than six degrees, the morning out of the east." On the thirteenth, the evening saw the west, committed the second concubine, the long autumn, the fight, the fill, and the bee flames ran through the purple palace. After the fire, it reached the Tianhe River, except for the domain of the queen of the concubine. Nan Death Degree Guilty Big Horn, Seti. To the heavenly market and according to the festival Xu Xing, Yan into the city, ten years and then go west; On the fifty-sixth day, he was in ambush with the dragon. (The Book of Han?) Chronicles of the Five Elements).

Halley's comet's nucleus is an ugly, dirty one. It looks more like a roasted potato than a shelled peanut.

Its epidermis is full of cracks, wrinkles and scars, and its dirt and blackness are unimaginable. It is 16 kilometers at its longest point, about 8.2 kilometers at its widest point and 7.5 kilometers at its thickest point, with a mass of about 300 billion tons and a volume of about 500 cubic kilometers.

Halley's comet's nucleus is very dense: about 1 g/cm3, indicating that it is porous, probably because most of the dust is left behind after the ice sublimation.

The surface of Halley's Comet is darker than soot, which allows it to absorb a lot of solar radiation and make the temperature 30~100°C. There are at least 5~7 places on the surface of the comet nucleus that are constantly throwing dust and gases outward.

The composition of the comet nucleus is mainly water ice, accounting for 70%, and the other components are carbon monoxide (10~15%), carbon dioxide, carbon oxides, hydrocyanic acid, etc.

The density of the whole comet nucleus is 10~40% of that of water ice, so it is just a very loose snowdrift.

Deep in the nucleus of the comet is primordial material and volatile ice, surrounded by a water-ice envelope containing silicates and hydrocarbons, and the outermost layer is a honeycomb-like refractory carbonaceous layer. ”

Hearing that Zhang Binhui kept emphasizing that Halley's Comet was a dirty snowball, Yuan Yuanzi was not satisfied, she had just made a wish to it? Looking at its white figure and long comet tail, Yuan Yuanzi definitely did not accept this point of view.

"Are your earthlings' observations accurate? Did they make it to the comet? ”

Zhang Binhui scratched his head: "Then no, we didn't have that ability at that time." ”

"That's right", Yuan Yuanzi was proud: "As the saying goes, hearing is false, seeing is believing, the things you said are all analyzed by the earth's scientists, which is very unrealistic."

If you want to prove what Halley's Comet looks like, the most accurate way is to land on it so you can see it with your own eyes. ”

Speaking of this, Yuan Yuanzi's tone became soft, and she stretched her head over: "Brother Hui, I still have a spaceship here, I believe it is not very difficult to go up."

Since there is no war now, why don't we go up and have a look? Standing on a meteor and making a wish, wow, it's impossible to think about it. ”

The more she talked, the more excited Yuan Yuanzi became, this little girl had always been an optimist, and stars were already popping up in her eyes.

Zhang Binhui smiled and stretched out his hand to habitually pat her face, but when that hand was only halfway out, he was suddenly stunned.

Halley's Comet, spaceship, ice, is this a hint?

After waiting for a long time, he didn't see Brother Hui's hand stretched out, Yuan Yuanzi turned his head, and unexpectedly found Zhang Binhui sitting there, looking at the sky with two eyes stunned, looking at the famous comet.

"Brother Hui, what's wrong with you, are you okay?"

Yuan Yuanzi shook Zhang Binhui, and Zhang Binhui bounced violently.

I saw him scream excitedly, and then hugged Yuan Yuanzi in his arms: "Wow, I thought of it, I finally thought of a way."

Yuanzi, you're such a genius, you're the lucky star of our squad, I've finally found that patch! ”

A minute later, the tribal leaders reassembled, and everyone was dumbfounded.

"What? Brother Hui, are you going to shoot down that comet? Did I hear me right? ”

Zhang Binhui nodded very seriously: "All of you heard it right, this is exactly my plan, one of the only feasible ways at present."

Shoot down Halley's Comet and let it crash into us, thus destroying all the xenomorphs that have gathered here. ”

Pangu's face turned white, he always believed that Zhang Binhui would think of a way, but he didn't expect him to be whimsical.

Shoot down a celestial body, oh my god, will humans still exist here?

Zhang Binhui sighed, and then said the reason why he made this terrible plan:

"Uncle Pangu, do you remember what we argued about? I told you that this is the pre-era era of our later generations, and that humanity was all gone.

After you, the temperature of the Earth dropped dramatically, and there were Quaternary glaciers here, and most of the Earth's northern hemisphere continental shelf was frozen.

This time the climate change is very drastic, and I have never understood this reason, which is unreasonable!

But now it seems that I finally understand that this is the helpless thing, the final choice of us human beings.

The aliens must be exterminated, or we humans will die out under their claws, they do not belong to our planet, and the time patch effect will definitely appear.

Now, the Xenomorphs are starting to gather, our weapons are gone, and Halley's Comet is here.

It is not impossible to hit the planet with a comet to achieve the goal of destroying the aliens, which the Human Alliance has done on other planets.

All of this has been described very clearly: that is, we hit the Earth with a comet, and the Earth was covered with a large amount of snow and ice, and the Earth entered the Quaternary glacial period.

The alien has been wiped out, and the human civilization of our ancient times has also disappeared, this is the choice of time, our inevitable fate! ”