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Today is the last part of the space travel trilogy.
In 2019, the professional journal “Journal of Astronautics” published a conception of pushing the sun into the universe. It is quite rigorous, and people can’t help but want to behave like this and make a comment on the same grand conception of “Wandering Earth”.
First, correct your attitude and flatter yourself. Liu is a very good science fiction writer. His works have a magnificent vision and profound humanity, especially “Three Body”, sincerely recommend! However, sci-fi writers belong to writers, who do not pursue scientific rigor. The monk can barely be regarded as a popular science writer. Looking at the loopholes in sci-fi masterpieces, it will inevitably be itchy to fix the storyline from a purely scientific perspective.
Helium flashes from the sun
First of all, this big background: the sun will suddenly explode, and the earth must wander.
The research on stellar evolution is relatively mature, and the fate of the sun is basically determined by the fortune teller. Without external factors, it is difficult for accidents to occur. Such a major event of the sun’s helium flash is naturally already on the schedule.
The evolution of the sun on the Hero map
Helium flash is probably like this:
Stars use gravitational force to twist hydrogen into helium and rely on fusion to maintain balance. However, as hydrogen continues to be consumed and helium continues to accumulate, problems arise. Because the inside of the star is only sufficient for hydrogen fusion, but not for helium fusion, the fusion reaction gradually weakens and the core volume begins to shrink.
As soon as the volume shrinks, the internal pressure increases, and the helium piled in the center is compressed into a degenerate state. This degenerate state is the key to helium flash. It can be understood that the electrons are compressed to no place to move, like a super pressure cooker.
If the mass of the star is less than 0.8 times the mass of the sun, then this pressure cooker will always be like this, commonly known as a white dwarf, because the composition is helium, also called a helium white dwarf.
If the mass of the star is higher than 2.0 times the mass of the sun, the internal pressure is sufficient to twist helium atoms into carbon atoms before turning into a pressure cooker. Once helium fusion takes place in advance and the energy is replenished, the star will stop shrinking, and this round of helium flash will be avoided. After several years, continue to challenge the next round of carbon flash. If the challenge fails, it will become a carbon-white dwarf star. The famous masonry star is such a star.
If the mass of the star is between 0.8 and 2.0 times the mass of the sun, it will be troublesome. Before turning into a pressure cooker, the internal pressure is not enough to cause helium fusion. After turning into a pressure cooker, the internal pressure can continue to press Blast this pressure cooker.
The moment the pressure cooker was detonated, helium fusion was ignited. This uncontrolled reaction was violent and short-lived, which was called “helium flash.”
Judging from the mass of the sun, it is obvious that helium flash cannot be avoided, but helium flash is not something that people on earth need to worry about. Because the helium flash occurs at the end of the red giant phase, before the helium flash, the 1 billion-year red giant phase has turned the earth yellow.
In short, using helium flash as a reason to wander the earth is not scientific enough.
murder the sun
If the sun is good, the motivation to wander the earth will not exist, so the sun must be annihilated. But unfortunately, murdering the sun is a very tricky thing.
Scene 1: Exoplanet breaks into the solar system
Even if the eight planets collide with the sun together, they just splash a few small prominences, which is a disaster for mankind and scratches the sun. As for throwing hydrogen bombs, don’t be ashamed. The sun itself is a super large hydrogen bomb, and it didn’t even blow itself up. If you have to throw something on the sun to destroy the sun, you have to throw in at least one star, and star collisions can be predicted N years in advance, there is no suddenness, this way will not work.
Scene 2: Massive supernova explosion
It is indeed a good reason to avoid supernova explosions, but it is obviously not more reasonable to push the earth than to push the sun. For specific methods, please refer to the previous article“Dyson Ball”, this way is also unworkable.
Scene 3: Aliens
How about being lazy and letting aliens destroy the sun? Then there is no need to wander around. After such a big beam, people must cut the grass and roots, and this way will not work.
By the way, the principle of using light particles to strike a star in the novel is: accelerate a small ball to close to the speed of light. According to the relativity effect, the mass of the small ball can be increased to a fraction of that of the star, which is equivalent to two The stars collided, destroying the target star.
This principle is of course no problem, but the theory of relativity also tells us that the kinetic energy of a ball with a constant star quality is also a constant star, and it also conforms to the law of conservation of mass and energy. In other words, to increase the mass of the ball to a constant star level, the energy of the constant star level is needed to accelerate. Where does this energy come from?
To be honest, within the existing theory, the earth wants to wander outside the solar system,There really is no good reason. However, if the existing theory goes one step further, there is a good opportunity.
At the end of the evolution of a massive star, it will be forced into a point by gravity and become a black hole. In other words, strong gravity means black holes. According to the theory of relativity, gravity and acceleration are equivalent, and acceleration can also do things that gravity can do.
We cannot create strong gravitation, but we can create strong acceleration, such as the moment when high-speed particles collide. The speed of the colliding particles drops sharply from nearly the speed of light, which is an astronomical acceleration. Strong acceleration is likely to mean black holes.
So this story can be written like this:
After human beings mastered nuclear fusion, they built a super super collider around the sun, accelerating the particles to an infinitely close to the speed of light, and accidentally crashed several particles into black holes. The existing theory believes that this mini black hole with a diameter far less than 1 nanometer will decay into various particles through Hawking radiation in a very short time.
However, please pay attention, but whether Hawking radiation is reliable or not, the consensus of scientists is: it has yet to be verified!
Therefore, we have room for reverie: Assuming that the mini black hole can exist stably, and can continuously absorb various radiations, gradually grow, and it is expected to start devouring the solar system in 400 years.
Finally, we have a reason to take the earth to wander.
I don’t know the true face of the earth, only because I am in the crust
The arrangement on the sun side is almost done, let’s look at the earth side next.
Humankind’s research on the structure of the earth mainly uses seismic waves. There are not many deterministic conclusions at present, only some general judgments. The earth is crust, upper mantle, lower mantle, outer core and inner core in order from the outside to the inside.
The thickness of the crust ranges from a few kilometers to tens of kilometers, with an average of 17 kilometers, accounting for only 0.4% of the earth’s mass.
This 0.4% is the entire range of human activities on the earth so far. Seven continents and four oceans, rivers and mountains, animals and plants, and 2 million years of human history are all in this 0.4%, so many people subconsciously regard this 0.4% as the whole of the earth.
For example, the following picture of the dehydration of the earth, which has been widely circulated, was shocked and not questioned at first glance. But looking back, The average depth of the Pacific Ocean is only 4 kilometers, and the diameter of the earth is 12,000 kilometers. Even if the water is drained, and even Mount Everest is counted, the earth is definitely smoother than a basketball.
The real structure of the earth sounds a little panic…
The theory of plate tectonics divides the thin crust into six major plates, the Asia-Europe plate, the African plate, the American plate, the Antarctic plate, the Indian Ocean plate, the Pacific plate, and many small plates, all of which float in the asthenosphere. on.
The so-called asthenosphere, as the name implies, high temperature and high pressure make the material here flow slowly in a semi-viscous state, located between 60 and 250 kilometers underground, in the middle and upper part of the mantle. Although the asthenosphere is not a liquid, it has a certain degree of fluidity, and even has convective motion like the atmosphere, so our six large slices can move on it. This is an important basis for the theory of continental drift.
By the way, the Earth is the only planet known to be suitable for the theory of plate tectonics. It is said that this is a necessary condition for the evolution of life, because plate movement brings abundant geological activities, such as volcanic earthquakes. Promote the carbon cycle.
Including the asthenosphere, 33 kilometers to 2,900 kilometers underground belong to the mantle. The composition is mainly silicate, metal oxide, etc., accounting for 68% of the earth’s mass, which largely determines the nature of the earth. This geological activity has a decisive influence.
According to the difference of seismic wave propagation, the mantle is divided into upper mantle and lower mantle. The lower the temperature, the higher the temperature and the greater the pressure. The pressure of the lower mantle can reach 1.3 million atmospheres, which is equivalent to 1,000 times the working pressure of the world’s largest forging machine. The density of being beaten by such a big guy every day can be imagined.
Because of the high temperature, although the mantle is solid, it has a semi-fluid plasticity like asphalt. That’s right, asphalt can flow, and unbelieving little friends can search for the asphalt drip experiment that has lasted for almost a hundred years.
So, if you continue to press the American continent and push the earth, the thin continental plates will either be crushed or pushed into the mantle. It’s like a big truck and an asphalt road. It doesn’t matter if you run a few times occasionally. If you run for many years, the asphalt road will definitely be pressed out of the pit.
The 2900 kilometers to 4700 kilometers further in is a liquid outer core. Although it is a liquid, the pressure is 1.5 to 3 million atmospheres. This is about to catch up with the central pressure of an ordinary atomic bomb. Said that simply relying on the shock wave of the atomic bomb explosion may not be able to make waves in this pool of water…
After another 400 kilometers of transition layer, the inner core is 1,200 kilometers in diameter. The inner core is mainly an iron-nickel alloy. Because the pressure exceeds 3.5 million atmospheres, it can remain solid at a temperature of five to six thousand degrees.
The inner and outer nuclei occupies 31.5% of the earth’s mass, which is a monster!
By the way, studying the structure of the earth is mainly to analyze the difference between the transverse and longitudinal waves of seismic waves propagating in different materials, plus the aids of gravity and electromagnetic fields. This accuracy is not as accurate as the old Chinese medicine. So these conclusions, Just take a look.
Transform the Earth
Such a structure is obviously not conducive to our promotion of the earth and must be changed. The key to the transformation is to make the asthenosphere in the upper mantle firmer. The whole project is divided into three steps.
The first step is to modify and strengthen.
The upper mantle is a complex mixture. Therefore, the modified silicate with high density and high melting point can be melted and poured into the upper mantle to squeeze out impurities with lower melting points. But just the plateau mountains and rivers on our ground, it’s not enough to fill up the asthenosphere, and this thing might not be done on earth.
As the saying goes, look up at the moon, look down at your hometown, look up at the moon, and think about the mantle. The main components of the moon are silicates and various metal oxides, which can be used as modified raw materials and poured into the mantle after melting. Anyway, when pushing the earth away, sooner or later, we have to get rid of the obstructive moon, it is better to turn it into ashes and take it away. If the moon is not enough, you can go to Mars and plan again. It will definitely be enough.
Of course, after the moon melts and disappears, the movement of the earth is not small. After all, the two brothers have been together for billions of years, so we must deal with it in advance.
The second step is to cool down.
After the silicate is modified, the upper mantle can be solidified into a hard solid when the temperature is lowered a little bit. The stress is controlled during cooling, similar to the principle of tempered glass, which can appropriately enhance the compressive strength of the mantle.
However, the earth has been cooling for 4.6 billion years and it is still hot. Is there any way to quickly cool it down?
Hot rod technology is not a novelty. When the Qinghai-Tibet Railway was built in permafrost regions, in order to prevent the permafrost from melting and damaging the roadbed, hot rod technology was used to transfer heat from the ground to the atmosphere. in.
The magical hot rod is actually a hollow tube with a heat conducting liquid added to it, one end is inserted into the ground, and the other is exposed on the ground. When the temperature of the frozen soil rises, the liquid at the bottom of the pipe vaporizes and rises. When the top meets cold and liquefies to release heat, it flows back to the bottom, and so on, reducing the temperature of frozen soil.
This principle transfers heat very quickly, and it is also applied in other fields. The monk was almost stunned when he first met!
After the temperature of the mantle drops, the heat from the core will accelerate to the outside. To calculate the temperature distribution after the earth is stabilized, you need to use “Mathematical Methods”. This course is one of the four books of university physics. Look at the thermal differential equation in spherical coordinates:
The monk looked at the formula and guessed it. Assuming that the asthenosphere is completely solidified, the overall temperature of the earth drops by 50 degrees, and the heat released is equivalent to 100 billion tons of standard coal. (This data really depends on guessing, the calculation is too complicated.)
The third step is recycling + heat dissipation.
If so much heat is dissipated directly into the atmosphere, the earth will become a steamer. Geothermal energy is a good thing and cannot be wasted. You have to find a good place. For example, it takes 40 billion tons of coal to melt the moon, plus transportation and wasted energy… it is estimated to be almost the same.
However, according to the second law of thermodynamics, heat cannot be completely converted into useful work by absorbing heat from a single heat source. Therefore, the heat in the atmosphere will inevitably increase, and these must be taken to space.
Many people think that the space is so cold that it must be easy to dissipate heat, but don’t forget the nature of temperature. The vacuum environment does not transfer heat, and the heat can only be dissipated in the form of radiation.
For example, on the International Space Station, there are solar panels standing upright, which are very familiar, and white panels standing horizontally, right? This is a heat sink specially designed to dissipate heat. The heat is carried to these boards and then released into space in the form of infrared rays.
When the planetary engine is turned on, heat dissipation becomes a top priority. For this reason, the monk thought of a good idea with one stone and three birds: Build a stack of heat sinks at an altitude of 50 kilometers, and put the entire The earth’s atmosphere is wrapped and sealed. It has three functions:
First, heat dissipation, if the area is not enough, it can continue to extend upward.