Into Unscientific Chapter 156

  Chapter 156 Myths from Beyond (6.6K)

  Astronomy enthusiasts should know.

  The so-called supernova explosion.

  Refers to a violent explosion that some stars will experience when they are near the end of their evolution.

  These explosions are extremely bright, and the burst of electromagnetic radiation during the process can often light up the entire galaxy in which they are located.

   And it can last for weeks to months before it gradually decays and becomes invisible.

  During this period.

  The energy radiated by a supernova can even be comparable to the sum of the energy radiated by the sun in its lifetime.

But on the other hand.

  Supernova explosion is an extremely dazzling spectacle in the universe, magnificent, beautiful and fascinating.

  But for humans, this is actually a risky thing.

   During the explosion, a supernova will release a large amount of gamma rays, which radiate into the earth's atmosphere at the speed of light.

  Gamma rays trigger a special chemical reaction after contact with the atmosphere:

  They convert nitrogen molecules into nitrogen oxides.

  This consumes the protective umbrella of life on earth, that is, the ozone layer.

  As a result, life on earth is directly exposed to harmful radiation such as solar wind and cosmic rays.

  For example, there have been five mass extinction events in the history of life on earth, and the Ordovician mass extinction ranks second.

  The Ordovician mass extinction occurred 440 million years ago, which led to the extinction of 85% of the earth's species at that time, and later triggered an ice age.

   And in 2005.

  NASA and the University of Kansas jointly released a research report.

  The report believes that this mass extinction event is likely to be a tragedy caused by a gammray burst released by a supernova.

  The situation restored according to the model.

  The whole process may have lasted only ten seconds, but it destroyed half of the Earth's ozone layer.

  Finally, the sun's ultraviolet rays attacked the earth, resulting in the death of a large number of organisms on the surface, thus causing the mass extinction of organisms. (doi.org/10.1099/ijs.0.02503-0)

Incidentally.

  Currently, Betelgeuse is more discussed in the astronomical circle. Recently, its photometry data is not normal, and it may produce a supernova explosion.

   But due to the distance, this thing will not have any effect on the creatures on the earth.

   After all, radiation also needs to talk about the basic laws of physics.

   Except Betelgeuse.

  Another star that may overexplode is WR102 in Sagittarius.

  It is a very rare oxygen-rich Wolf-Rayet star. According to the existing model deduction, the star has exploded with high probability.

   Inferred from distance.

  As long as you live 1500-2000 years longer, you should be able to see this beautiful scenery, not too difficult

all in all.

  In the past two thousand years, there have been eight supernova explosions observed by humans.

   There are also many of the most:

  For example, the earliest supernova record is SN185, which was seen by local astronomers in 185 AD.

   Another example is that the brightest supernova on record is SN1006.

  Supernovae SN1572 and SN1604 are the last two Milky Way supernovae observed with the naked eye, which have a significant impact on the development of European astronomy.

  Because they are used to disprove the Aristotelian universe that is constant beyond the moon and planets, they are benchmark discoveries.

   Wait until the age of the telescope.

  Humans have observed SN1885A, SN1987A and SN2006gy successively.

Of course.

   Saw this.

   Students who failed in mathematics should have discovered a problem:

  There are eight supernova explosions, why only seven are mentioned above?

   Exactly.

  The remaining supernova explosion was the superexplosion of the Crab Nebula that Lao Su personally experienced in 1054 AD.

at the same time.

   It is also the most widely observed supernova explosion in human history.

  It is about 6,500 light-years away from the earth, which means that the scene we see now happened 6,500 years ago.

  Analysis of historical records shows that.

  The supernova explosion time that produces the Crab Nebula is in April or early May, and when it is the brightest in July, the apparent magnitude rises to between -7 and -4.5.

   That is, during that time, it is brighter than any object in the night sky except the Moon.

   This spectacle even lasted until the 21st century:

  The Crab Nebula at that time was in the visible light region, and there were still a large number of elliptical filamentous structures surrounding the diffuse blue core area.

   Up to 6 arc minutes long and 4 arc minutes wide.

   is one of the celestial bodies with the largest apparent diameter.

Of course.

   is also the most beautiful celestial body. (If you are interested, you can search it. It is really beautiful. Friends who have the opportunity to go to Shanghai can buy a planetarium ticket for 60, which is definitely worth it)

  However, compared to observing the moon for the first time, Xu Yun did not do it himself this time.

   Instead, let Lao Su try it himself.

Again.

  Teaching people how to fish is worse than giving them fish. If you just blindly instill knowledge, everything will return to its original state after you leave.

   "Yes, yes, turn the finderscope first, wait, pass it."

   "Crosshair is further up"

  Looking at Lao Su who was tinkering with the equipment, Xu Yun seemed very patient.

  After all, compared with those rare readers in his previous life, Lao Su is simply a learning model.

after awhile.

   Seeing that Old Su's tune was almost ready, Xu Yun asked:

   "Master, do you know the location of Bisu?"

  Old Su nodded without much hesitation this time, and said:

   "Bi Su, one of the twenty-eight mansions, the fifth mansion of the Western White Tiger.

  In the star map written by the old man, the position of this star is marked. "

   Bisu, also known as Bi Yuewu.

  It is composed of eight stars, and it is one of the ancient Chinese star officials.

  The origin of Bisu is actually very simple:

  Its eight stars are combined together, which is very similar to a "Y" shape. The ancients believed that its appearance is very similar to a long-handled tool "Bi" used to capture small animals.

   So it was passed on, so it was named Bisu.

Of course.

   There is another more intuitive icon—have you seen the fork of Runtu?

  Yes, that stuff.

  In modern astronomy, Hyades is located in the constellation Taurus, adjacent to the Pleiades.

   Among them, Aldebaran has a diameter of about 53 million kilometers, which is 38 times the diameter of the sun, and its brightness is extremely conspicuous.

   On October 19, 2005, there was also an astronomical spectacle in which Aldebaran and the moon competed for brightness.

  At that time, in many small places, you could still see many 'profiteers' who set up binoculars on the street to trick children into looking at the stars, and they charged ten yuan a time.

   Nowadays, many bigwigs in the circle who drive an off-road vehicle and pull hundreds of thousands or millions of astronomical telescopes, many of them rely on that method to complete their primitive accumulation.

  The line of sight returns to the original place.

  As the person who is most familiar with the star map in the contemporary era, Lao Su quickly locked the area where Bi Su was located after receiving Xu Yun's guidance.

  Xu Yunjian said and continued:

   "Master, if the villain remembers correctly, the supernova is in the northeast of Bisu"

  Old Su heard the words and quickly locked his eyes on the finderscope, twisted the screw, and continued to calibrate.

  Looking at Lao Su who was gradually familiar with the operation, Xu Yun really wanted to say to those classmates in his previous life, "Look at Lao Su".

Of course.

   At that time, those Sao readers will most likely cut off the starting combat power list, and in turn, Aite will make a counter-kill-"Look at the eagle!".

  Damn tentacle monsters.jpg.

that's it.

after awhile.

  Old Su's expression was shocked suddenly, and he waved towards Xu Yun with his left hand:

   "Xiao Wang, let's take a look, this star. Or is this object the Crab Nebula?"

  Xu Yun hurried forward.

  I saw this moment.

  In the field of view of the finder mirror in front of Lao Su, a small white light group with high brightness can be vaguely seen.

  Xu Yun was very familiar with the shape of this light group, so he nodded immediately:

   "Yes, this is the Crab Nebula."

  Old Su was overjoyed when he heard the words, and immediately became motivated, and quickly followed the operation taught by Xu Yun to perform the final focus.

   Half an hour later.

  Old Su suddenly gave a slight surprise and said:

   "Huh? Xiao Wang, isn't it?"

  Xu Yun winked at him:

   "Master, what's wrong?"

  Old Su glanced at him, pointed to the picture in the eyepiece and said:

   "Why is there no planet in this light cluster? It seems to be shining like a cloud of mist?"

  In fact, friends who know the Crab Nebula should know it.

   At the inner core of the Crab Nebula, there is a pulsar with a diameter of 20 kilometers.

  However, due to the accuracy of the equipment, Lao Su obviously couldn't see too much of the internal situation—even the Hubble Telescope had to expose for more than 24 hours.

   Therefore, Lao Su can only judge the stars according to the intensity of the luminous body, and thus conclude that there are no planets in the entire nebula.

  Xu Yun was silent for a moment when he heard the words, and instead of directly explaining, he said to Old Su:

   "Sir, have you ever seen fireworks?"

  Old Su stroked his beard, nodded and said:

   "Of course."

  Fireworks appeared during the Sui and Tang Dynasties, and became popular in the Song Dynasty. They are relatively common now.

  For example, Ling Zhen, the "Booming Thunder" in "Water Margin".

  In addition to supervising the production of firearms, he also shouldered the responsibility of making fireworks, and Bianjing would also set off some fireworks on holidays.

  Xu Yun paused, then asked again:

   "May I ask my lord, what happens to the fireworks after they fly high into the sky?"

  Old Su thought for a moment, folded the five fingers of his left hand, and made a gesture of exploding:

   "First it rises to a certain height, then explodes suddenly, the light shines like daylight in an instant, and then it turns into ashes and so on!"

  Old Su was talking, and suddenly realized something.

   Raised his head suddenly, fixed his gaze on Xu Yun:

   "Xiao Wang, you mean. Fifty years ago, old man, the white light seen in Bianjing was the scene where the guest star exploded?"

  Xu Yun nodded emphatically, affirming:

"good."

  Old Su's pupils shrank suddenly.

   stars

exploded?

   What can be seen now is only the afterglow that has not yet dissipated?

  Old Su's chest heaved and heaved a few times, then he took a deep breath and asked:

   "Xiao Wang, how does that star compare to the earth?"

  Xu Yun thought for a while and replied:

   "In terms of quality, at least three million times more."

   Well known.

  The sun cannot become a black hole or a neutron star due to insufficient mass.

  It is at the end of the star, and eventually it can only become a red giant first, and then a white dwarf.

   Only stars with more than eight times the mass of the sun will first expand into red supergiants and then explode into supernovae.

  Finally become a black hole or a neutron star.

Of course.

   There are also cases where white dwarfs eventually turn into neutron stars, which is relatively rare.

  Considering that many people do not understand how terrifying neutron stars are, here is a number that is more intuitive than density:

  The diameter of a neutron star is generally about ten kilometers, but the speed can be as high as hundreds of revolutions per second.

   Exactly.

   Every second, not every minute.

   That is, the moment you blink.

  The neutron star with the fastest rotation speed discovered so far is called PSRJ1748-2446ad.

   Don't look at it looks like a serial number, it's actually terrifying to death:

  The diameter is 20 kilometers, and the rotation speed is as high as 716 cycles per second.

  You can make up your own brains for the specific screen, so I won't repeat them.

all in all.

  The protostar of the Crab Nebula can produce supernova explosions, which means that its mass is at least 8 times that of the sun.

  The mass of the sun is 330,000 times that of the earth, so it is conservatively estimated that the mass of the protostar of the Crab Nebula is more than 3 million times that of the earth.

   Gollum—

  Hearing this number, Wang Yue on the side couldn't help swallowing heavily.

  As a general who has been fighting on the Western Front for a long time, he still has a lot of contact with the number 'million'.

  For example, how many thousands of soldiers, how many catties of grain and grass, and how many tens of thousands of copper coins, etc.

  A star with a mass three million times that of the Earth

   Three million times

  According to Xu Yun's statement.

  The area of ​​Bianjing is only one-fifth of that of the Song Dynasty (the territory of the Song Dynasty is small), and the area of ​​the Great Song Dynasty is only one-twentieth of the continent where it is located

  Mom.

  Wang Yue suddenly realized that his brain seemed to be a bit insufficient.

   In fact, it's not just Wang Yue.

  When everyone present heard this number, their brains almost shut down for a while.

   After regaining consciousness.

  Everyone made a consistent action at the same time:

   looked up at Xinghe.

   A little over a week ago.

  Xu Yun deduced the mass of the earth through the Cavendish torsion balance experiment with the assistance of Lao Jia and others:

   is about 6 times ten to the 24th power.

   And three million times that number.

  Looking at the vast universe, Lao Su suddenly felt a sense of fear that he had never felt before:

  Under this galaxy, human beings are really too small

   Right now.

   Zhang Shuye, who had never spoken, couldn't bear it any longer. He cupped his hands at Xu Yun:

   "My lord, if according to what you said, in the endless starry sky where the earth and the earth are, is there life in other planets?"

  Xu Yun was silent for a moment, then shook his head in confusion:

   "Sorry, the grassroots don't know about this."

  Different from those who pretended to be stupid before, Xu Yun told the truth this time.

   Extraterrestrial life.

   This is a very controversial topic in the 21st century.

  Among them there are philosophical and scientific ones.

  It's like it's hard for Old Su to truly understand the concept of 3.3 million times the mass of the earth.

  The human beings of later generations are not Lao Su at another stage?

   But Xu Yun himself.

   holds a positive attitude towards extraterrestrial life.

   That is to say, the earth is not alone, it's just that human beings have not yet come into contact with it.

  Even if he put aside the rebirth and mysterious aura, he still wouldn't change his opinion.

  After all, the universe is too vast.

  In the known universe, hundreds of billions of galaxies have been observed, and the Milky Way is just a very common galaxy.

  In the Milky Way, the number of stars is as many as hundreds of billions.

  The sun is just a very ordinary star.

  There are 3000 trillion stars in the entire universe, who can guarantee that there is no other life or even civilization outside the earth? (doi.org/10.1038%2Fnature0957, data from "nature")

all in all.

   Today's observations brought a psychological and conceptual impact to everyone present, which was too great, so the atmosphere was a bit dull.

   And just when Lao Su was about to relax the atmosphere.

  Xiao Li on the side suddenly let out a light sigh, pointed in the direction of Beidou, and said in surprise:

   "Look over there, there are stars!"

   Hearing what Xiao Li said.

  All the people present turned their heads immediately, and all looked towards the north.

   Sure enough.

   At the corner of the sky, there is a long tail slowly flying south.

   Exactly.

  Star Bo, refers to the comet.

   This is a common name for comets in ancient China. In addition, there are peng stars and long stars.

  Firstly, it comes from the record of Lu Wengong's fourteenth year in "Spring and Autumn":

   "In autumn and July, there are stars entering the Big Dipper."

   However, the name of Xingbo seems to be very elegant, but in ancient China, the meaning of comet is not very good.

  The folks mostly call it the broom star and the disaster star, thinking that it will bring disasters.

  Even a relatively rational person like Lao Su couldn't help frowning when he saw the comet.

   But what he didn't notice was.

  Among a crowd of frowning, dignified and even vaguely frightened people.

  Facing the comet, Xu Yun heaved a sigh of relief.

   Good guy.

   Finally waiting for you.

   Exactly.

   This comet is one of Xu Yun's core goals this time!

  Its number is called 109P/Swift-Tuttle, and it returns once every 130 years on average. It is not a particularly famous comet.

   Xu Yun remembers it not by deriving the date, but by memory:

  He is a native of Hu Qing from Fujian Province. There is a famous person in his hometown named Cai Boyu, who is also one of the rare historical figures in his hometown.

  Xu Yun used to play around in front of Cai Bozu's stele when he was a child, so he remembered clearly that Cai Bozu died on August 4th, 1100 AD.

   And according to epitaph records.

  A comet passed by the night before Cai Bozhen's death, and it was later combined with Cai Bozhen's death.

   After entering the University of Science and Technology, Xu Yun made a special trip to check the information of this comet and determined its origin.

  The two impressions are strengthened, and I can't forget it even if I want to.

   But if you care, you don't care.

  109P/Swift-Tuttle is not a particularly famous comet, so it is difficult to observe the nucleus and coma structure through a telescope.

  Combined with its fast speed, there is not much time to adjust the base of the telescope, so Xu Yun gave up the idea of ​​observing it.

  He just stood with the crowd on the high platform on the mountainside, watching the comet go away from afar.

   In a quarter of an hour.

  The comet disappeared in the south.

  Xu Yun turned around slowly and looked at the capital of Song Dynasty not far away.

   Looking at the brightly lit Bianjing City, the corner of his mouth gradually raised an arc:

  Xiao Zhao and others are out of Beijing to watch the stars tonight, presumably an artist is also paying attention here.

   That is to say.

  He should have seen the comet streak across the sky with his own eyes.

   "The next thing is up to you, don't let me down."

   "Rye Erguotou."

Note:

  For the sake of all-night coding, give me a monthly pass, woo woo woo.

   Went to bed at 6.6k all night

  (end of this chapter)

Chapter end