Chapter 135: Discovery and Crisis

Before aliens were discovered in Australia, reports of extraterrestrials frequently appeared in the news. Many claimed to have seen UFOs or even aliens themselves, often providing various photographs as "proof." Are these claims true or false? Do aliens really exist?

According to those who claim to have encountered them, these extraterrestrials are mostly described as short, humanoid creatures with large, round heads, narrow, slit-like mouths, and skin-tight suits.

Others are enthusiastic about searching for traces of aliens left in ancient times. They argue that the circular masks on figures in Sahara Desert murals, the megalithic structures of Easter Island and South America, and inexplicable prehistoric marvels like the pyramids are all linked to extraterrestrials. Some scholars even suggest that humanity are descendants of aliens, or that certain human ethnic groups, such as the Maya, are the product of interbreeding between aliens and humans. However, these remain mere conjectures and hypotheses, most of which lack sufficient evidence.

Scientists have proposed various bold and seemingly bizarre scenarios regarding the existence of aliens. Yet, who can blame human imagination? Perhaps these fantasies will one day become observable realities. If we feel encouraged by the large number of one million and assume finding aliens will be easy, we might be celebrating too soon.

For extraterrestrial advanced life to be meaningful, we must be able to establish contact. As far as human understanding goes, radio signals are the only viable means of communication. Therefore, we must further investigate how many planets are inhabited by civilizations capable of transmitting such signals.

If they had been sending such signals since their inception, there should be one million planets currently broadcasting. But in reality, humanity did not possess this capability until just over a century ago, let alone earlier forms of life. Furthermore, life forms whose technology has been destroyed or who have perished themselves would not be doing so.

Let us not forget that around the same time humanity gained the ability to transmit radio signals, we also developed large-scale nuclear weapons capable of annihilating all life on Earth. Could aliens have been destroyed by their own insane warmongers? This possibility cannot be entirely ruled out.

Let us once again be optimistic and assume that aliens have the capacity and wisdom to solve the problems we worry about, and suppose they have lived in an environment of peace and prosperity for one million years. With highly advanced science and technology and abundant resources, they would surely have the motivation and the means to invest heavily in significant, pioneering research, including attempts to contact their peers in the external world. They would have been sending powerful radio signals into space without interruption for a million years.

In this scenario, only a small fraction of the one million aforementioned planets would be broadcasting at any given time—a ratio of one million years to four billion years, or 0.025%. This means only 250 planets are currently sending signals. If they were evenly distributed across the Milky Way, the distance between neighboring planets would be approximately 4,600 light-years. It would take 4,600 years for human signals to reach the nearest aliens.

If they received the signal and replied immediately, we would have to wait another 9,200 years to receive their response! The targets of Project Ozma were only a dozen light-years away, making that approach of little significance. To make such a project meaningful, we must monitor every sun-like single star within a 4,600-light-year radius for meaningful signals.

To be more practical, consider that human history only spans 4,000 recorded years. If aliens only possess the capability to transmit radio signals for a 4,000-year window, then today, only one planet might be broadcasting! Consequently, there would be at most one other civilization in the entire Milky Way sending signals, making all our efforts to listen with radio telescopes a completely futile endeavor.

Readers may feel deeply disappointed by this conclusion. How much might the actual situation differ from these estimates? There are many uncertainties in the discussion above. Does every star have planets? Can life only emerge in environments like Earth's? Furthermore, we do not know how long an intelligent species can survive—can they survive indefinitely? These questions will likely remain unanswered for a long time.

However, did primitive humans ever imagine today’s large passenger jets, color television, high-speed computers, or moon landings? As long as humanity can continue to live in peace and prosperity, the development of science will gradually answer these questions. For now, even if aliens exist, we are temporarily unable to communicate with them effectively. Therefore, linking UFOs to extraterrestrial spacecraft is likely unreliable.

Some scientists believe that the reason aliens have not yet arrived on Earth is that they were killed by gamma-ray bursts before they could reach us.

Dr. James Annis of the Fermi National Accelerator Laboratory in Illinois states that the reason aliens have not yet arrived is that our galaxy has only recently provided the conditions for life to thrive in space.

Annis explains that until a few hundred million years ago, our galaxy was frequently bombarded by gamma-ray bursts caused by stellar collisions and black holes releasing massive amounts of lethal radiation. Only as these collisions became rare did it become possible for extraterrestrial life to emerge and travel from their home planets to distant regions.

Annis hopes that the theory he proposed in the British weekly *New Scientist* will resolve one of the most famous debates regarding the existence of extraterrestrial life: the Fermi Paradox. This paradox is named after the Italian-born physicist and Nobel laureate Enrico Fermi. It is said that Fermi proposed this paradox in the 1950s; its core point is: If aliens truly exist, where are they?

This question is persuasive because it is based on two facts about our galaxy: first, the Milky Way is very old, approximately 10 billion years; second, the galaxy’s diameter is only about 100,000 light-years. Therefore, even if aliens could only travel through space at one-thousandth the speed of light, they would only need about 100 million years to cross the entire galaxy—a time frame far shorter than the age of the universe. So, where are they?

Fermi clearly took this reasoning as evidence that aliens do not exist at all. Now, Annis claims to have found a loophole in Fermi's inference: aliens very likely exist, but it is only recently that the cycle of gamma-ray bursts has lengthened, providing them with sufficient time gaps for interstellar travel.

British scientist Paul Davies has discussed the "panspermia" hypothesis, suggesting that extraterrestrial intelligence does not necessarily need to travel in person. Instead, highly intelligent robots could carry biological seeds (stored in absolute zero environments) on spacecraft to propagate life and colonize other worlds. This would bypass the obstacles of interstellar travel, such as cosmic gamma rays, the staggering energy required for near-light-speed travel, and the limitations of biological lifespans.

As long as sufficient energy is available for the journey, this "panspermia" method could be realized. Reasoning from this, over the vast timeline of the universe, highly intelligent life should be present on almost all habitable planets, engaging in extensive interstellar communication, including with Earth. Yet, the fact remains that Earth has not received any information from extraterrestrial life, leading some scientists to conclude that the reason aliens haven't appeared is simply that they do not exist.

Thus, scientists have yet to reach a consensus or provide definitive proof for or against the existence of extraterrestrial life. Nevertheless, the study of aliens is no longer just science fiction; it has become an important subject in a promising interdisciplinary field: astrobiology.

The study of aliens is also a matter of statistics. According to scientific observations, there are approximately 100,000,000,000 stars in the Milky Way, and about 100,000,000,000 galaxies in the entire universe. If we assume the probability of life emerging is 1 in 1,000,000,000,000, there would still be 100,000,000 planets where life could appear.

Many believe that space-time travel is impossible, given that interstellar distances are measured in light-years. Yet, they overlook a point: in the mid-19th century, scientists believed 55 km/h was the absolute limit of human speed. Today, we have long since left the speed of sound behind, and it took us a mere 200 years to do so. Why, then, could some race on one of those 100,000,000 potentially life-bearing planets not have surpassed human intelligence and invented or mastered the method of interstellar travel?

Could they, for instance, use the application of antimatter to reach Earth? Although scientists have long debated the existence of black holes—as they cannot be observed by conventional telescopes—the vast majority of astronomers believe the results from radio telescopes, concluding that such celestial bodies, which can even absorb light, do indeed exist.

Hua Feng understood that many people still do not know what form or attitude those potentially harmful aliens might take when they descend upon Earth in large numbers, but those extraterrestrial "vanguard" scouts in Australia have already demonstrated one possibility that humanity had only previously imagined.