What The Wandering Earth 2 didn’t say is here

The earth itself is not a hard rock, 40-70 kilometers below the earth’s crust is lava, which is somewhat similar to the structure of an egg. If you want to drive more than 10,000 engines, it will take only a hundred years to push the earth to "walk", and the engine will put pressure on the earth, which the earth cannot afford, and will break the shell of the "egg". And if the engine slowly accelerates and gradually reaches maximum power, the earth will be "wandering" for a longer time, or even thousands of years. During the "wandering" period, it is difficult to predict what will happen to the earth, what will happen to it, and what human civilization will experience.

If the solar crisis is imminent, how can human beings survive? As the only planet known to exist in the Milky Way, the earth is always "roasted" by the sun.

In five or six billion years, the sun is nearing the "end" of its life, and this "roasting" will become extremely deadly.

The recent blockbuster film "The Wandering Earth 2" unfolds against this backdrop of impending doom. In the film, humans try to find a chance to survive with the help of 10,000 giant planetary engines, quantum computers that understand everything, and towering space elevators.

So, in reality, will the sun eventually deal a fatal blow to the earth? Will the earth decline with the sun? Can planetary engines really push the earth to "wander"? To this end, the Science and Technology Daily reporter interviewed a number of scientific consultants, experts and scholars of "Wandering Earth 2" to interpret the hard core science about "Wandering Earth".

If the sun comes to an end, will the earth be spared?

The sun crisis had just appeared, and humans had joined hands to face it… The future depicted in "The Wandering Earth 2" was cruel but exciting.

The sun, a huge "fireball" about 150 million kilometers from the earth, is the largest celestial body in the solar system. About 4.60 billion years ago, about 26,000 light-years from the center of the Milky Way, the sun was formed by the collapse of a nebula under the influence of its own attractive force.

At present, the sun is in its prime, astronomically known as the main sequence stage, which lasts about 10 billion years. It brings light and energy to the earth, and is an essential factor in the origin of life. But sunspots, flares, and coronal mass ejections also often cause damage to human production and life.

However, the sun will eventually age, and the origin of "The Wandering Earth 2" is the rapid expansion and aging of the sun.

More than 90 per cent of stars in the Milky Way eventually become white dwarfs. At the end of their evolution, they devour nearby planets. As an "ordinary" star, the Sun also ends up as a white dwarf. Does this mean that the planets around the Sun, including the Earth, are destined to be devoured as well?

"If the planet is relatively close to the star, it is very likely to be swallowed by the star," Gou Lijun, a scientific advisor to The Wandering Earth 2 and a researcher at the National Astronomical Observatory of the Chinese Academy of Sciences, told Science and Technology Daily.

However, "being swallowed" is not the only destination for a planet. The sun will eventually experience an outburst of a planetary nebula and become a white dwarf. Around the white dwarf, the original planets may also exist.

With the improvement of human observation methods, astronomers have indeed discovered some planets orbiting white dwarfs around them.

On September 16, 2020, the international authoritative academic journal Nature published an article saying that a team of American scientists had for the first time published evidence of a Jupiter-sized planet orbiting a white dwarf. In addition, in February 2022, British astronomers discovered that a planet may also exist in the "habitable" zone near a white dwarf named WD1054-226, 117 light-years away from Earth.

Can the earth escape and avoid the "solar crisis"?

In 2078, the earth will encounter the "helium flash" crisis of the sun, which is the key to the human decision to "wander" in the movie.

The helium flash is a key link in the evolution of the sun, and it is also the moment of life and death when the earth accepts the sun’s "roast".

"The sun shines because the core of the sun is undergoing a nuclear reaction, where hydrogen is fused to form helium. This process will gradually consume hydrogen, which will then lead to the collapse of the sun’s core. At the same time, the envelope outside the sun’s core expands under high pressure." Chen Pengfei, a professor at the School of Astronomy and Space Sciences at Nanjing University, told reporters. "When the core of the sun, which is mainly composed of helium, gradually contracts, its temperature is also getting higher and higher. When the temperature reaches about 100 million degrees Celsius, the helium will be ignited, and a large amount of helium will complete the fusion reaction in a few minutes. The energy released is huge, and the light emitted will suddenly increase by about 50 times. This process is helium flash."

In more than five billion years, after the sun becomes a red giant, its surface temperature may drop from more than 5,700 degrees Celsius now to about 3,000 degrees Celsius, when the hydrogen in the sun’s core will be exhausted. "Helium flashes usually occur at the end of the evolution of red giants," said Liang Wenjie, a scientific consultant for Wandering Earth 2 and a researcher at the Institute of Physics of the Chinese Academy of Sciences. "In the red giant stage, the sun has expanded to Earth’s orbit, and the surface temperature reaches about 3,000 degrees Celsius, while the melting temperature of the earth’s rocks is below 2,000 degrees Celsius. Therefore, whether it is a temperature change in the red giant stage or a sudden explosion of helium flashes, the earth will melt."

If the survival crisis of the earth is inevitable in more than 5 billion years, can it be avoided in advance during the "expansion period" of the sun, change the orbit and find another place, and return to the original earth orbit after the helium flash and other crises are lifted?

Liang Wenjie believes that even if the solar crisis is lifted and the earth returns to its original orbit, it may not be of much significance to the earth, "because the sun has entered the aging period at that time, and the heat it provides should not be able to support the survival of life on earth. Jupiter, Saturn, Uranus, and Neptune in the solar system are all frozen planets due to their distance from the sun, and the temperature of the planet is minus one or two hundred degrees Celsius. If the earth wants to return to the sun to obtain energy, it will have to constantly correct its orbit and approach the sun, but in the end the’big fireball ‘of the sun will still be’extinguished’."

"Even if it is possible to temporarily’run away from home ‘and then return home, the earth needs to accelerate out of the original orbit and then slow down. The process of adjusting the speed will be very long, and it will consume huge energy on the earth, and the project will be huge. What’s more, the process of returning to the earth’s current orbit and approaching the sun also has risks," Liang Wenjie said.

And if you give up the sun and find other stars, you will also face greater challenges. Gou Lijun believes that if the earth chooses another "habitat" in the universe and chooses a new star to orbit, it means to "adapt" to a new planetary orbit. Then the speed, direction, energy, etc. of entering the orbit need to be accurately measured, and it is difficult for human existing technology to achieve planetary celestial bodies in the short term.

Would nuclear fusion be a better "wandering" solution?

In the film, humans tried to find life at the end of the world through the Mountain Moving Project, the Ark Project, the Monthly Project, and the Digital Life Project. In the end, tens of thousands of giant planetary engines became the hope to push the earth to start a "wandering journey".

Mr. Liang, who has advised on the film’s planetary and lunar engines, the physics of the month-by-month plan and the way the moon explodes, said: "Artistically, the’wandering ‘way of the earth in the film is a great imagination, but it is still difficult to achieve at the current level of science."

Liang Wenjie explained: "The earth itself is not a hard rock, 40-70 kilometers below the earth’s crust is lava, which is a bit similar to the structure of an egg. If you want to drive more than 10,000 engines, and it only takes a hundred years to push the earth to’walk ‘, the engine will put pressure on the earth, which is beyond the earth’s ability to bear, and will break the shell of the’egg’. And if the engine accelerates slowly and gradually reaches maximum power, the earth will be’wandering ‘for a longer time, even thousands of years. During the’wandering’ period, it is difficult to predict what will happen to the earth, what will happen to it, and what human civilization will experience."

"But if you consider the energy supply method, controlled nuclear fusion is worth looking forward to, although it still faces great technical challenges." Liang Wenjie introduced that nuclear fusion is in the case of high temperature, two atomic nuclei collide with each other, and eventually combine to form a new atomic nucleus, which can release huge energy. The key to this is to continuously export the energy produced by nuclear fusion for a long time. To achieve this, many technical problems need to be overcome.

However, even if the nuclear fusion of hydrogen could eventually be realized and provide a large amount of energy for humanity, the important raw materials for nuclear fusion, deuterium and tritium, were in low abundance in the earth’s seawater, and the reserves of helium-3, the raw material for nuclear fusion, were also extremely scarce. Therefore, based on the total amount of resources currently available to humans, the energy of nuclear fusion is still not enough to push the earth out of the solar system.

So, is it possible to "burn stones" like in "The Wandering Earth 2" and obtain energy through heavy nuclear fusion? Liang Wenjie said that heavy nuclear fusion refers to the use of heavier elements such as silicon and oxygen as fusion raw materials to obtain nuclear energy. Compared with light nuclear fusion using deuterium, tritium, and helium-3 as raw materials, heavy nuclear fusion is very inefficient in obtaining fusion energy. Although silicon and oxygen elements have a large proportion in the earth’s crust, in order to overcome the huge electrostatic repulsion between the nuclei of heavy elements and make them produce nuclear fusion reactions, higher temperatures and stronger pressures are required, and the reaction temperature even needs to reach billions of degrees Celsius, which greatly challenges the current scientific and technological capabilities of mankind.

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Are there wandering planets in the universe?

If one day, the earth had to embark on a "wandering" journey, would it be possible to encounter celestial bodies that "sympathize with each other" in the vast universe?

According to Gou Lijun, a scientific advisor of "Wandering Earth 2" and a researcher at the National Astronomical Observatory of the Chinese Academy of Sciences, there is a type of planet that does not orbit any star in the universe, namely the wandering planet. At present, humans have detected about 100 wandering planets, the larger ones are about ten times the size of Jupiter, and the smaller ones are close to the earth.

"According to the current understanding, there may be two ways for stray planets to form: one is that when they form, only the planets themselves. Another possibility is that the planet is’ejected ‘from the star system." For example, if a larger star is near the solar system, it is possible that under the action of attractive forces, the outermost planet of the solar system may deviate from its original orbit and eventually leave the solar system.

Liang Wenjie, a science adviser for "The Wandering Earth 2" and a researcher at the Institute of Physics of the Chinese Academy of Sciences, offered another hypothesis: Large stars experience a violent explosion at the end of their evolution, a supernova explosion, and eject a large amount of interstellar material. "Planets near the star may be ejected from their original orbits at this time and become wandering planets."

In recent years, with the improvement of observation technology, stray planets have been continuously discovered by humans. In August 2018, American scientists confirmed that a planet about 12 times the mass of Jupiter was wandering alone about 20 light-years away from the earth and was not attached to any star. It was the first stray planet discovered by radio telescopes.

In 2020, American and Polish astronomers wrote in the Astrophysical Journal Letters that they might have discovered the smallest known rogue planet, with a microscopic attractive force lens, that "weighs" about 10 percent of Earth.

"Wandering planets do not emit light, so it is difficult to detect them. They are often discovered due to an accidental event, so they are paid attention to by the detector for a very short time, which also leads to the current research on wandering planets is very limited." According to Gou Lijun, according to the current level of human technology, it is impossible to determine whether there is life on wandering planets.

Liang Wenjie analyzed that in addition to the elements that make up life, such as amino acids, carbon, hydrogen and other substances, the existence of life also requires a suitable temperature. "The evolution of the universe sometimes ejects some organic matter onto the star, and the survival of organic matter requires a suitable temperature. Wandering planets do not heat up, and there are no stars to provide heat for them, so they will continue to cool down until they reach the lowest temperature in the universe. Such low temperatures are difficult to breed life," Liang Wenjie said.

Source: Science and Technology Daily


Editor in charge: Feng Zheng

AITO Wenjie M5 Series Huawei Advanced Intelligent Driving Edition officially went on the market.

  AITO Wenjie M5 series Huawei advanced intelligent driving version has been officially launched recently, with 4 models, with the price ranging from 279,800 yuan to 309,800 yuan. This is also the first product equipped with HUAWEI ADS 2.0 advanced intelligent driving system.

  AITO Wujie M5 Intelligent Driving Edition was jointly designed by Celestial Motors and Huawei, with an acceleration of 4.4 seconds from zero to 100 kilometers. It is equipped with technologies such as HUAWEI DriveONE pure electric drive platform and HUAWEI DATS dynamic adaptive torque system, and realizes high-speed and high-order intelligent driving functions in urban areas without relying on high-precision maps. Under the urban road conditions, the M5 version of Zhijie can actively avoid all kinds of vehicles occupying the road and effectively deal with scenes such as "opening the door to kill" and "ghost probe". In the automatic parking scene, Wujie M5 Intelligent Driving Edition can handle more than 160 parking scenes, including dead-end road parking/parking, automatic vehicle parking, low-speed automatic parking, parking service assistance, etc., with a parking recognition rate as high as 96% and a parking success rate of 95%.

  In addition, a number of brand-new software and hardware technologies have also enabled the M5 Intelligent Driving Edition to realize "mobile whole house intelligence". Spatial audio technology combined with 19 units of professional-grade audio makes users feel as if they are at the performance site of the Grand Theatre. In the back row, HUAWEI MagLinkTM magic suction car interface realizes multi-device linkage, which makes the M5 Intelligent Driving Edition in the world become the exclusive study, game hall or conference room for users. The PC car-machine interconnection function makes the temporary office in the car more efficient, and the car-machine navigation can be carried out at the touch of the mobile phone.

  At the same time, the M9, the first full-size flagship SUV of AITO brand, also made a heavy appearance. The extended range version and pure electric version will be scheduled on April 17, and will be officially released in the fourth quarter of 2023. The estimated price range is 500,000-600,000 yuan. As a full-scale flagship SUV, Wenjie M9 provides 3-6 seats, all-aluminum chassis and air spring and CDC damping system as standard, which brings better ride comfort and safety. As the flagship product of Huawei’s deep empowerment, Wenjie M9 is fully equipped with Huawei smart car full-stack technology solutions, including Huawei megapixel smart headlights, HUAWEI AR-HUD, AI big model and other black technologies. (Reporter Li Zhiyong)

The chaos of the old scooter: the cottage "Lamborghini" sells well for 29 thousand.

  CCTV News:In recent years, many four-wheeled vehicles have appeared around us unconsciously, which look like cars and are one size smaller than cars, and the words "old scooter" are often marked in the prominent position of the car body. Sometimes these cars run parallel to motor vehicles, and sometimes they drive on sidewalks and bicycle lanes, and they walk freely through the streets and alleys of the city.

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△ At an intersection in Beijing, four-wheeled vehicles repeatedly violated regulations.

  So what exactly is this four-wheeled vehicle? Why can you drive on the road so willfully?

    The mystery of the life experience of "old scooter"

  During the visit, the reporter found that there are still many places to distribute this kind of car in Beijing. This kind of car is actually a low-speed four-wheel electric vehicle. It first came into the public eye as an "old scooter" around 2012, and the "old scooter" evolved from an electric wheelchair with a speed basically controlled below 10 kilometers per hour and belonging to medical devices.


△ "Old scooter" evolved from electric wheelchair.

  Around 2012, after continuous modification, the "old scooter" has been very close to ordinary motor vehicles, powered by electric energy, and the maximum speed can reach about 40 kilometers per hour.

  In the past few days, the reporter visited a number of dealers and found that the sales of this kind of car in recent years are quite amazing. According to a first-class dealer of a certain brand, he sold 1,600 cars a year. When it was hot, he had to queue up to buy a car and sell one, but his sales were not the most.


  According to rough statistics, in Beijing, there are at least ten primary dealers of a certain brand of electric vehicles with an annual sales volume of over 1,000 units, and there are several secondary distributors under each primary dealer; In addition to a few big brands of low-speed four-wheel electric vehicles, there are a large number of brand-name cars flooding the market. In recent years, low-speed four-wheel electric vehicles are growing at a high speed with an annual growth rate of tens of thousands in Beijing. The reason why it is still sold in the name of "old scooter" is that manufacturers and distributors have their own purposes.

   You can drive without a license? The treatment of scooter is very "special"

  Why can the so-called "old scooter" be sold so hot? The reporter consulted a number of dealers as buyers in Beijing, and all told reporters without exception: you can drive on the road without a license or a driver’s license! So is this the case? The reporter interviewed several car owners at random, and most car owners have not encountered inspection. A car owner who asked not to be named told reporters that if you want to buy a motor vehicle in Beijing, you must participate in the lottery, but you can’t shake it after several years, and finally you have no choice but to choose a low-speed four-wheel electric vehicle. In addition to not having to shake the license plate, car owners told reporters that the low cost of car use is also a major reason why they choose this kind of vehicle. First of all, the price of about 30,000 to 40,000 is close to the people. Secondly, the cost of running a hundred kilometers with full electricity is seven or eight yuan.


  According to the Road Traffic Safety Law and relevant regulations of Beijing, this kind of vehicle is recognized as a motor vehicle in Beijing. In the past two years, the traffic control department of Beijing has also strictly investigated the illegal behavior of such vehicles on the road, but in fact, except for the core sections such as Chang’ an Street, such vehicles are still popular in the city.

  In addition, in order to attract consumers, some dealers have also launched preferential activities to buy cars and send insurance. So what kind of insurance is this gift? China implements the compulsory motor vehicle third-party liability insurance system, in order to ensure the liability of the insured motor vehicle to compensate the victims for personal injury and property losses caused by road traffic accidents. The so-called third party liability insurance given by the dealer is not motor vehicle insurance, but actually a personal accident insurance, and once an accident occurs, the amount of compensation is very limited.

  There are no national standards for industries with different policies in different places.

  The reporter contacted a number of electric vehicle dealers in Beijing and conducted a test drive on a variety of low-speed four-wheel electric vehicles. It was found that the top speed of these electric vehicles can generally reach about 40 kilometers per hour. At present, the management standards for low-speed four-wheel electric vehicles are not uniform in different places. For example, in Shandong, Hebei, Henan, Sichuan and other places, such low-speed four-wheel electric vehicles can be licensed and can drive on the road, but in Beijing, Shanghai and other places, such vehicles are prohibited from illegally driving on the road.


  In China, domestic automobiles are certified by Announcement of Road Motor Vehicle Manufacturers and Products and China Compulsory Certification, that is, 3C certification. The public security traffic control department will take the Announcement of Road Motor Vehicle Manufacturers and Products regularly issued by the Ministry of Industry and Information Technology as the basis for the registration of such vehicles. But at present, no low-speed four-wheel electric vehicle has passed these two certifications, that is to say, the country has not recognized it as a motor vehicle.

  On the one hand, the speed of low-speed four-wheel electric vehicles far exceeds the national standard that the speed of "old scooter" is less than 10 kilometers per hour. On the other hand, low-speed four-wheel electric vehicles do not belong to the category of motor vehicles in theory. This means that the low-speed four-wheel electric vehicle is currently in the gray area between the "old scooter" and the motor vehicle.

  The cottage Lamborghini only sells for 29 thousand

  The reporter found through investigation that at present, most of these low-speed four-wheel electric vehicles on the market are produced in Shandong, Jiangsu, Hebei and other places. Among them, Shandong Province, as the "birthplace" of low-speed electric vehicles, ranks first in the country in terms of industrial scale. According to the data released by Shandong Automobile Industry Association, the output of low-speed electric vehicles in Shandong Province reached 347,000 in 2015, and the market of low-speed electric vehicles in Shandong Province maintained rapid growth for four consecutive years from 2012 to 2015, with a year-on-year increase. What about the production and sales there?

  Wucheng County, Dezhou City, located at the junction of Shandong and Hebei provinces, is famous for its automobile parts production. In recent years, Wucheng County has rapidly developed into the largest low-speed four-wheel electric vehicle manufacturing base in Shandong and even the whole country. On the grounds of talking about agency, the reporter contacted a manufacturer located in the old town of Wucheng County. From the county seat, less than 20 kilometers away, there are no fewer than 20 large and small electric vehicle manufacturers. Some manufacturers just sell cars in a facade room in front, and then set up a shed at the back to start making cars.


  Subsequently, the reporter came to the factory contacted in advance. As soon as he entered the factory, he saw a forklift truck being busy loading and delivering goods. Two workers in the workshop were installing an electric car that looked like a Ford Carnival. In order to show their strength, the sales manager also showed reporters a new model they are developing, which looks like Lamborghini and costs only 29 thousand.


  This low-speed electric car, which looks like a sports car, is a new product being developed by the manufacturer. The sales manager told the reporter that the car is currently in the debugging stage, and they can mass-produce it at any time if there is an order. For these manufacturers of low-speed four-wheel electric vehicles, batteries and other parts are ready-made, and the biggest research and development cost is the appearance of the vehicle.

  The production of "old scooter" is made of unqualified iron.

  In the workshops of many manufacturers visited by the reporter, there are all kinds of models such as Land Rover, Mercedes-Benz, BMW, Ford Carnival, etc., and the car bodies made of iron sheets occupy the mainstream of the market. According to the reporter’s visual inspection, the thickness of these iron sheets used to wrap the car bodies is no more than 2 mm, and no safety test has been done.


  The sales manager told the reporter that with the strength of their factory, it is not a problem to produce 20 cars a day. If the order quantity is large, they can also produce together with several small factories around them to ensure timely delivery. On the business license displayed by the manufacturer, the reporter found that this manufacturer does not have the relevant qualifications to produce four-wheeled electric vehicles. The reporter searched the registration data of dozens of electric vehicle enterprises in Wucheng County, including local first-class manufacturers such as Dexing, Weikerui and Xinaoyu, and found that the production and business scope of these automobile enterprises is only off-highway tourism sightseeing bus or indoor sightseeing bus, and does not include the R&D and production license of four-wheel electric vehicles. That is to say, these automobile enterprises all produce low-speed four-wheel electric vehicles with the qualification of producing sightseeing bus, and this phenomenon is also common in other parts of the country. 


  How to solve the chaos of the old scooter?

  On July 29th this year, Shandong Province issued an urgent investigation notice for low-speed electric vehicles, and investigation teams composed of departments such as letter, quality inspection, public security, industry and commerce went to all parts of Shandong Province to investigate the production and sales of low-speed electric vehicles, so as to provide a basis for formulating management opinions on low-speed electric vehicles in Shandong Province in the next step. And where should the low-speed four-wheel electric vehicle go next?

  Professor Shi Jing from Tsinghua University Transportation Research Institute said that relevant departments should make more efforts in management instead of simply banning it. He believes that to solve the management problem of low-speed four-wheel electric vehicles, one is to solve its safety problem, that is, to reduce the speed, and the other is to solve the order problem, which can be managed according to the motor vehicle number plate.

  In addition, the reporter learned from the National Standards Committee that the Ministry of Industry and Information Technology had submitted the national standard project "Technical Conditions for Four-wheel Low-speed Electric Passenger Cars" at the beginning of this year. In April this year, the National Standards Committee also solicited opinions on the project for the society and is currently organizing and handling the opinions received. In the next step, the General Administration of Quality Supervision, Inspection and Quarantine and the National Standards Committee will steadily promote the formulation of national standards, hoping to introduce relevant management regulations as soon as possible, so that the elderly scooter will no longer drive at will and reduce potential safety hazards.

Photo news | Immersed in the sea of spring flowers

▲ On February 20th, Baitang Garden, Tiaodunhe Park, Liangjiang New District, was full of beautiful plum blossoms.
It’s another year’s flower viewing season, and the beautiful plum flowers in Baitang Garden of Dunhe Park next to Kangzhuang Station of Rail Transit Line 6 are covered with branches. Citizens have invited friends and relatives to swim in this pink flower sea.
▲ On February 20th, Baitang Garden, Tiaodunhe Park, Liangjiang New District, citizens were enjoying themselves in the flower sea.
▲ On February 20th, in Baitang Garden, Tiaodunhe Park, Liangjiang New District, citizens punched in pink flowers and enjoyed the warm sunshine in spring.