Chapter 134: Extraterrestrial Life

"Spaceships could perform this yo-yo motion," Damour said, "but if you use your own fuel, you can escape the gravity of the wormhole" and explore the universe on the other side. However, friends on this side of the universe might have to wait billions of years to see you again, as the travel time through a wormhole would be incredibly long. Such delays make effective communication between the two sides nearly impossible. If microscopic wormholes could be discovered or constructed, this delay might be reduced to just a few seconds, according to Serodukin, potentially supporting two-way communication.

Stephen Hsu, a physicist at the University of Oregon in Eugene who researches black hole formation and wormhole properties, also believes that distinguishing between black holes and wormholes through observation is nearly impossible, at least with current technology.

"The most important characteristic of a black hole is the point of no return for objects falling into it, and this is something we currently cannot test," Hsu said.

However, it is not impossible that the celestial bodies currently identified as black holes are indeed black holes and not wormholes. There are many viable scenarios for black hole formation, such as the collapse of massive stars, but how wormholes are formed remains an unknown.

Wormholes might differ from macroscopic black holes in that they require exotic matter to maintain their stability, and whether such matter truly exists is still a mystery.

Serodukin believes that the formation of wormholes might be similar to that of black holes, such as originating from collapsing stars. In such scenarios, physicists generally assume a black hole is produced, but Serodukin argues that quantum effects might prevent the collapse from forming a black hole, resulting in a wormhole instead.

Serodukin claims this mechanism would be inevitable under a more complete physical theory—one that unifies gravity and quantum mechanics, which has long been the dream and goal of the physics community. If this theory is correct, then places where we previously assumed black holes would form might instead host wormholes.

This conjecture is not without a way to be tested; some physicists believe that future particle accelerator experiments will be able to produce microscopic black holes. These might emit calculable Hawking radiation, proving they are black holes rather than wormholes. But if Serodukin's conjecture is correct, the result would be a microscopic wormhole, which would not produce any radiation. "Through such a simple test, we could distinguish whether a black hole or a wormhole has been created."

Another advantage of wormholes is their ability to resolve the so-called black hole information paradox. The only thing black holes can release is Hawking radiation, but it is currently unclear how this radiation carries the original information of the objects that fell into the black hole. This chaotic effect conflicts with quantum mechanics, which forbids such loss of information.

"Theoretically, wormholes are much better than black holes because they do not involve information loss," Serodukin said. Since a wormhole has no event horizon, objects can exit it without needing to be converted into Hawking radiation, thus eliminating the problem of information loss.

"Class, study hard and consolidate your knowledge privately. Dismissed!" Professor Serodukin said.

"Goodbye, Professor!" the students replied. A large group of them then began to pack their things and exit the classroom in an orderly fashion. Such days had become the norm for this group of elite students selected from around the world.

A moment later, only Hua Feng, Yun Meng, and Bai Feng remained in the corridor, walking slowly toward the empty plaza below. The atmosphere was quiet, with the air permeated by the scent of everyone diligently cherishing their time for cultivation.

After a series of lessons, Hua Feng felt his knowledge base had been greatly updated. Although his level of understanding in various aspects still seemed to linger near that of the previous era, it was, fortunately, much better than it had been before.

Unknowingly, another month passed by in a flash. They had gradually become more accustomed to this high-intensity learning, often having little time for casual conversation. However, during the time after each class, they would engage in small-scale discussions about what they had just learned.

"Xiao Meng, you should be the one among us who understands wormhole-like time travel best. Back then, the Snow Lord used some method to send you to the present, allowing you to experience thousands of years of time as if you were born in this land," Hua Feng said, finding a stone bench to sit on. Yun Meng and Bai Feng sat down beside him.

"That's true, but I was young then, and I don't remember those events clearly. It just felt like a dream. All that remains in my mind are my father's instructions to me. Sigh! If I could, I really wouldn't want to have spent so much time in such an aimless way. Although I was happy for a while, it made my father bear too much alone." Recalling the past, Yun Meng felt a complex mix of emotions.

Seeing that the atmosphere had become heavy, Bai Feng quickly tried to break the awkwardness: "Alright, don't dwell on it. Compared to that, I am much more interested in alien life on our planet and in other places."

"The evolution of life is an extremely slow process, and the time it takes is comparable to the evolution of the sun. Fossil research has found that as early as 3.5 billion years ago, there was already a relatively advanced single-celled organism on Earth, called green algae."

"According to stellar evolution theory and the analysis of ancient rocks and meteoritic material on Earth, the formation of the sun and the Earth predates the appearance of these organisms by 1 to 1.5 billion years. It took about 5 billion years after the formation of the solar system for humans to appear on Earth," Bai Feng continued.

Hua Feng brought up a question he had been curious about since he was a child, and he immediately became interested: "Actually, I know a very vivid metaphor for this. Imagine compressing every 5 billion years into one 'year' at a simple ratio. Using this scale, one week is equivalent to 100 million years in real life, and one second is equivalent to 160 years. From the Big Bang to the birth of the solar system, about two years have passed. Earth was formed in January of the third year."

"In March and April, ancient single-celled organisms like blue-green algae appeared. After that, life evolved slowly but continuously. In September, the first large cells with nuclei appeared on Earth, and by late October, multicellular organisms likely existed. By the end of November, plants and animals had taken over most of the land, and the Earth became active. On December 18th, dinosaurs appeared; these arrogant, colossal beasts dominated the Earth for only one week."

"At 11:00 PM on New Year's Eve, Peking Man appeared; 10 minutes before midnight, Neanderthals appeared at the New Year's Eve party. Modern humans only appeared 5 minutes before the New Year, and recorded human history began only 30 seconds before midnight. Major events in modern life accelerated one after another in the final few seconds of the old year, and in the last second before midnight, the Earth's population tripled."

"Thus, it is clear that for most of the time since the Earth was born, it has been nurturing life, but only for a very small fraction of that time has life taken the form of higher organisms."

Yun Meng and Bai Feng looked at Hua Feng with admiration. Although they had come into contact with these things while in school, they were not things they were particularly interested in.

Hua Feng continued: "We have seen that the birth of intelligent life requires stars that can stably emit light and heat for at least 5 billion years. The lifespan of a star is closely related to its mass. The thermonuclear reactions of massive stars can only last for a few million years, which is far from enough for the evolution of life."

"Only stars with a mass similar to the sun are suitable candidates. There are about 100 billion such stars in the Milky Way, and excluding binary systems, there are about 40 billion single stars. Do all single stars have planets? Unfortunately, we know very little about other planetary systems, but we have gradually discovered through observation that some stars may have planets around them."

"Considering the objective existence of the solar system, and that even large planets have their own satellite systems—like Jupiter in our solar system—it is reasonable to be optimistic and assume that all single stars have planets. Having planets does not mean having life, let alone higher organisms. The key lies in the distance between the planet and its host star being just right; it cannot be too far or too near. Limited by our current understanding, we can only discuss life forms in environments similar to Earth, and in particular, we must assume the presence of liquid water."

"The solar system has eight planets, but the only one clearly in the so-called habitable zone where life can form is Earth. Venus and Mars are on the edge of this zone, and it has been verified that there is no life on their surfaces."

"For a planet to possess all the conditions necessary for life is truly rare. In our solar system, Earth is a unique lucky one. Detailed calculations show that among the 40 billion single stars mentioned, at most only one million have planets capable of allowing life to evolve to an advanced stage."

"Another limiting factor is that extraterrestrial life should have a similar chemical composition to life on Earth. Astronomical observations show that, with few exceptions, the distribution of chemical elements throughout the universe is quite uniform, so there is every reason to believe that the materials needed to form all organic molecules can be found on distant planets."

"In fact, many relatively complex organic molecules have already been discovered in many places. Therefore, it can be assumed that as long as life can theoretically form somewhere, it will indeed form. Thus, there could be one million planets in the Milky Way where life could be born, although the life on each planet would be at different stages of evolution."

The three of them unknowingly spent half an hour sitting together, talking about everything under the sun.