"Human beings are so smart, why don't they travel the universe?" Yin Fat joked.

Liao Jiayi also smiled: "Yin Shao, you are asking the right person, I once heard a friend who is engaged in this research talk about this, I will tell you the answer, what is the reason." After finishing speaking, he filled another bowl of blood swallow porridge and drank it in a big gulp.

"Jiayi, let's just put on a score, hurry up, everyone is waiting for you to solve your doubts!" Yin Yuting glanced at her.

Liao Jiayi put down the dishes and chopsticks in her hand, took a few napkins in the carton on the dining table, wiped her mouth, and then said slowly: "Since the birth of human civilization, the exploration of the vast universe has almost never stopped, and the concept of "cosmic speed" is a standard for the speed of human spacecraft launched by scientists. Only when the spacecraft reaches a certain fast enough speed can it get rid of the gravitational constraints of some celestial bodies, and at present, human beings have proposed 6 different cosmic speeds according to the "galaxy level" discovered, and theoretically reach the fastest "6th cosmic speed", and they can fly out of the universe. Speaking the last sentence, Liao Jiayi deliberately screamed her voice.

Everyone grinned and shook their heads when they heard this.

Wu Lang shook his head and smiled, but did not speak.

Liao Jiayi took another bowl of blood swallow porridge, drank it in a big gulp, and after drinking, put down the dishes and chopsticks in her hand, took a few napkins in the carton on the dining table, wiped her mouth, and then said slowly: "First of all, the most basic "first cosmic speed", and it is also the slowest speed needed to launch artificial satellites on our earth, and it is also the fastest orbiting speed In mid-air, of course, this speed can only make people float in mid-air, and if you want to completely break free from the shackles of the earth and "go to the sky" with a light jump, you need to reach the "second cosmic speed", that is, 11.2 km/s. ”

"Of course, even if it can reach the second cosmic velocity and get rid of the shackles of the earth, the objects are still in the solar system, and they will be subject to the gravitational pull of the sun, and the mass of the sun accounts for about 99.8% of the total mass of the solar system, and the gravitational field generated is also very huge. If you want to break free from the gravitational pull of the sun and fly out of the solar system, you need to reach the "third cosmic velocity", which is 16.7 km/s. ”

After Liao Jiayi finished speaking, she was about to get up again to serve the blood swallow porridge, and Yin Fatzi snatched the bowl in her hand: "Dr. Liao, you can solve our doubts, I will do such a trivial thing." He said that he quickly served her porridge and put it in front of him.

Liao Jiayi nodded and smiled at Yin Fat, and said, "The above three cosmic speeds are already the current limit of human science and technology. Today, our fastest spacecraft can only reach a speed close to 70 km/s, and it is accelerated by the gravitational pull of other planets, and this number is still a long way from the "fourth cosmic velocity" that flies out of the Milky Way: according to human estimation of the total mass of the Milky Way, the fourth cosmic velocity is about 110 to 120 km/s. It may take some time for humanity to reach the 4th cosmic velocity. ”

As for the "5th cosmic velocity", it is the speed of escaping the galaxy structure at a higher level of the Milky Way, that is, the "local galaxy cluster", which is a collection of galaxies within a range of the universe, including our own galaxy, all revolve around the center of the local galaxy cluster, with a radius of about 5 million light years. According to human calculations, the speed of the fifth universe is about 1500 to 2250 km/s, and the more advanced galaxy level than this galaxy cluster is the "local supergroup of galaxies" with a radius of about 100 million light years, and it needs to reach the "6th cosmic speed" out of its gravity, and scientists calculate that this speed is infinitely close to the speed of light, that is, human beings need to achieve the speed of light in order to truly travel in the universe. ”

After hearing this, everyone did not speak for a long time, and they all lowered their heads, not knowing what they were thinking.

Wu Lang looked at everyone and smiled: "Let's just talk, why make it so heavy and solemn, human beings completely understand their own bodies, I think the most important thing is at the moment." ”

"Xiao Langlang, what do you mean by that?" asked Fat Yin, handing him a cigarette.

Wu Lang took the cigarette, lit it, took a deep breath, slowly exhaled the smoke in his mouth, and then said slowly: "When people are on the verge of death, their brains are still working, and they can clearly realize everything that is happening around them. Tell me why?"

"Xiao Langlang, look at what you said, we have to know, we will become a doctor, how can it be your turn?"

Shang Minjie said softly: "There are still many debates among medical experts about what happens when humans die, unconfirmed records show that some patients who "come back from the dead" have seen bright lights or flashes, there is evidence that the "deceased" can even hear themselves being declared dead by doctors, and a new study shows that when the human heart stops beating and the human body fails, consciousness is still functioning. This means that for a short time after death, the brain is still working, and the person is equivalent to being "trapped" inside his own corpse. ”

"Wow, I've heard of this for the first time, Xiao Wen, tell me more about it, what's the situation?" Liao Jiayi said in surprise.

Wu Lang, Yin Yuting, Yin Fat, and Xin Ying also showed curious expressions and looked at Shang Minjie.

Shang Minjie nodded and smiled: "There are scientists abroad who are studying many cases of cardiac arrest in Europe and the United States, hoping to reveal the mystery of whether there is consciousness after death. They found that people in the early stages of death, may still have some form of consciousness, such as some cardiac arrest survivors who wake up and can accurately describe everything that happens around them during the period when the heart stops beating, such as the work of doctors and nurses, and conversations between others, in another scientific experiment, neurologists successfully recovered the function of some brain cells and molecules in the pig brain, which was previously widely believed that the brain is very sensitive to changes in oxygen levels and disruption of blood flow, and brain cells will die in large numbers a few hours after the body dies, but the study showed that the brain that has died has died, there are still living cells that can be removed and cultured in a petri dish, suggesting that the brain is likely to be resurrected after death. ”

"One team has developed a system called the "ex vivo brain", which consists of three parts, pumping a synthetic solution at 37°C into the brain in a manner similar to cardiac perfusion, a perfusion device that mimics an organ and pumps the solution, and a surgical technique to isolate the brain. The researchers obtained 32 pig brains that had been dead for four hours from the slaughterhouse, perfused with the solution for six hours, and compared them with the unperfused brains. ”

Wu Lang and everyone were attentive, listening intently to Shang Minjie's explanation, and there was only a cigarette holder with a long cigarette ash hanging in Yin Fatzi's hand, and he didn't notice it.

"The results show that brain tissue and cellular structures are preserved, cell mortality is reduced, and some molecular and cellular functions are being restored, including glial and vascular responses to stimuli, as well as spontaneous synaptic activity and active metabolism. Of course, no normal brain function or consciousness was found in the resuscitated pig brains. Scientists say that not only is it not the goal of the study to "resurrect" the brain, but if any signs of whole-brain activity are found, the study will be terminated immediately to prevent consciousness from being detected, and if humans are used as test subjects, and some kind of consciousness is induced from the dead brain, there will be a series of ethical and moral problems, so the experiment can only be performed on animals at present. ”