Twenty-one, uncontrollable changes

  Before class that day, Fang Jixin received a letter from his professor.

  A letter from abroad, from America.

  Fang Ji's oral expression is not good, but his writing is fine.

  This is an invitation letter.

  Fang Jixin is a student majoring in Applied Physics of the Department of Physics.

  And he majored in nuclear fusion.

  Nuclear fusion is the process by which atomic nuclei combine to form a heavier nucleus, releasing energy in the process. It is the process that powers the sun and other stars.

  A huge amount of energy is stored in the atomic nucleus, and changes to the nucleus (from one type of nucleus to another) often release this energy.

  If a heavy atomic nucleus changes into a light one, it is called nuclear fission, such as an atomic bomb explosion.

  If it is changed from a light atomic nucleus to a heavy atomic nucleus, it is called nuclear fusion, such as the energy source of the sun's light and heat.

  Compared with nuclear fission, nuclear fusion will hardly bring radioactive pollution and other environmental problems. Its raw materials can be directly extracted from deuterium in seawater, which is almost inexhaustible, making it an ideal energy source.

  Humans have already achieved uncontrolled nuclear fusion, such as the explosion of hydrogen bombs. However, in order for energy to be effectively utilized by humans, it is necessary to reasonably control the speed and scale of nuclear fusion, achieving sustained and stable energy output. Scientists are working hard to study how to control nuclear fusion, but there is still a long way to go.

  Currently, there are mainly several controllable nuclear fusion methods:

  Acoustic Nuclear Fusion

  Laser-induced inertial confinement fusion

  Tokamak

  People can't yet achieve controlled nuclear fusion, mainly because the conditions required for nuclear fusion are extremely stringent.

  Nuclear fusion requires a temperature of 100 million degrees to proceed, so it is also called thermonuclear reaction.

  It's imaginable that no material can withstand a high temperature of 100 million degrees. Moreover, there are many unimaginable difficulties to overcome.

  Despite many difficulties, people have made gratifying progress through continuous research.

  Scientists have designed many ingenious methods, such as using powerful magnetic fields to confine reactions and powerful lasers to heat atoms.

  The earliest notable method is the "Tokamak" type magnetic confinement method. It uses a strong magnetic field generated by a strong electric current to confine the plasma in a very small range to achieve the above three conditions. Although it has approached success under laboratory conditions, it still falls far short of industrial application.

  At current technological levels, establishing a Tokamak-type nuclear fusion device would require tens of billions of dollars.

  Another approach to achieving nuclear fusion is inertial confinement.

  Inertial confinement fusion involves compressing a small pellet of fuel, typically a mixture of deuterium and tritium, to incredibly high densities with an extremely powerful laser or particle beam.

  Uniformly injecting laser beams or particle beams from the outside, the sphere evaporates outward due to energy absorption, and under its reaction force, the inner layer of the sphere is compressed inward (the reaction force is a kind of inertial force, which relies on it to constrain the gas, so it is called inertial confinement). Just like the jet engine gas is sprayed backward to propel the aircraft forward, the gas inside the small ball is compressed and the pressure rises, accompanied by a sharp increase in temperature.

  When the temperature reaches the required ignition temperature (which requires tens of billions of degrees), the gas inside the sphere explodes and produces a large amount of heat energy.

  This explosive process takes a very short time, only several picoseconds (1 picosecond equals one trillionth of a second).

  If such explosions occur three or four times per second and continue uninterruptedly, the energy released is equivalent to that of a power station of megawatt class.

  In principle, it's that simple. However, the power achievable with present-day laser or particle beams is still several tens to hundreds of times short of what is needed, and other technical problems make inertial confinement fusion a hope rather than a reality.

  Although the realization of controlled thermonuclear fusion still has a long and arduous road ahead, its beautiful prospect is attracting scientists from all over the world to strive for it. It can be predicted that people will eventually master the method of controlling nuclear fusion, making nuclear fusion serve humanity.

  However, while the prospect of controlled nuclear fusion is wonderful, its consequences are difficult to predict.

  Xu Fulong had just finished cultivating the fifth layer and was preparing to charge towards the sixth layer when he felt a strange change in his body.

  The fear caused by this change made him stop reading and correcting for a while.

  Rather than saying that he forcibly sealed the Dragon's Absorption Technique, it would be better to say that he wanted to live like a normal person, without being startled by his own superhuman abilities, and not being frightened by the side effects produced by his own changes.

  After practicing the fifth layer, he found that every time he operated on his own, the objects around him would produce a slight tilt in front of him, which ordinary people could not perceive.

  Some tiny things that are invisible to the naked eye will drill into their own bodies. They can't control it at all.

  His body is like a vacuum cleaner.

  Although the gravitational and repulsive forces of Long Xugu are growing synchronously, after reaching the sixth layer, the balance of the forces appears to be unequal.

  This change is not good.

  Any qigong practice is a balance of energy during cultivation. Longxi Gong should be no exception.

  What's wrong? He hasn't figured it out yet, and being adventurous isn't his style. He might as well take advantage of this time to stop for a while and wait until he understands before practicing again.

  This trouble reminded him and made him more careful in his learning process.

  What to do with and how to control the waste generated after nuclear fusion reaction.

  In the universe, there is a kind of celestial body with extremely high density called black hole.

  Its density is extremely high, objects near it are bound by its gravity (just like humans on Earth can't fly away), and no matter how fast they move, they cannot escape.

  For the earth, flying at the second cosmic velocity can escape the earth, but for a black hole, its second cosmic velocity is so great that it exceeds the speed of light, so even light cannot get out, and the light shot in does not reflect back, our eyes can't see anything, just a piece of black.

  The process of producing black holes is similar to the process of producing neutron stars;

  The core of a star collapses rapidly under its own weight, causing a massive explosion.

  When all matter in the core is converted into neutrons, the collapse process stops immediately and compresses into a dense star.

  But in the case of a black hole, where the mass of the stellar core is so great that the collapse continues indefinitely, the neutrons themselves are crushed out of existence by their own gravity, leaving behind a density of matter that is almost unimaginable.

  Anything that gets too close to it gets sucked in, and a black hole becomes like a cosmic vacuum cleaner.

  The thermonuclear reaction has exhausted the fuel (hydrogen) in the core, and the energy produced by the core is no longer abundant.

  It no longer had enough strength to bear the weight of its massive shell.

  So under the crushing weight of the outer shell, the core begins to shrink until it finally forms a small volume and high-density star body that can balance with pressure again.

  A massive hydrogen bomb could provide such conditions: physicist John Wheeler once calculated that if all the deuterium in the oceans of the world were gathered together and ignited, it would produce a black hole.

  Will human activities create artificial mini black holes?

  Based on one's own insight and learned guidance.

  Fang Lizhi elaborated on his views in a classroom assignment, which caught the attention of the substitute professor. After obtaining his consent, the professor made some minor revisions to the original text and sent it to Nature magazine.

  I didn't expect it would actually be published.

  In fact, it's not that Fang Jinxin's proposition and naming are particularly new. On the contrary, many nuclear physicists have made their own inferences and hypotheses about this phenomenon in their works, even including precise calculation results.

  Fang Jixin's unique charm and attraction to editors lies in his combination of physical changes from his qigong practice with theoretical physics, linking the physiological universe within him to the external world universe, a very enticing perspective!

  And also drew attention from relevant parties in the United States.

  They originally wanted to invite Fang Jixin for academic exchange, but after investigation, they found that the other party was still a student, so they changed their decision and directly sent an invitation, hoping he could go abroad to study.

  Full scholarship for studying abroad.

  Fang Jixin did not expect that a small stone he had inadvertently thrown would cause such a big commotion.

  The school is considering whether to let people go.

  Publishing a paper in a world-class scientific journal is difficult even for an old professor who has worked in a research position for many years, let alone a sophomore student.

  People like this won't stay in the country, are they going to let Americans poach them or what?!

  The school has its own considerations...

  The head of the National Security Bureau is also hesitant, weighing the pros and cons.

  Fang Jixin himself is also facing a choice.

  To go or not to go, that's the question!