INTRODUCTION
Throughout most of human history, people believed that our world was unique. With the emergence of philosophy and science, we discovered that Earth is just one of eight planets orbiting our sun. It took us a considerable amount of time to realize that there are other galaxies out there and that the twinkling lights in the sky are actually other Suns with their own orbiting worlds, potentially capable of hosting alien life. Initially, we were unaware of any planets beyond our solar system because we hadn’t yet been able to detect them. Even though we may have speculated that we weren’t special, we lacked the knowledge to support this notion. However, in the early 1990s, we began the ability to detect planets, and to date, we have identified well over three thousand. Our missions, such as the Kepler telescope, have been dedicated to the detection of thousands of planets. Consequently, the current understanding is that almost every star in the sky is likely to have planets orbiting around it, which is truly remarkable. When you gaze at the stars on a clear night, it’s feasible to imagine that there are solar systems surrounding each one. This realization allows us to ponder on the potential number of Earth-like planets that may exist in the Milky Way galaxy, which amounts to approximately 20 billion. This would mean there is a rocky planet at the right distance from its star, possibly with the right conditions to support liquid water on the surface. In the solar system, we refer to this region as the habitable zone. In the habitable zone, there are three planets: Venus, Mars, and Earth. Venus is situated closer to the Sun, while Mars is further away. All three planets are believed to have had water on their surfaces, making them potentially habitable.
LIFE ON MARS
The search for life on Mars continues, with the discovery of life on the planet being one of the most significant potential breakthroughs in human history. However, if life does exist on Mars, it is largely anticipated to be microbial in nature. The discovery of multicellular life, such as plants or animals, would be even more impactful and could reshape our understanding of the universe. Fortunately, there is a celestial body within our solar system that may be capable of hosting such life forms: Jupiter‘s moon Europa.
LIFE ON EUROPA (JUPITER’S MOON)
NASA is currently preparing for the Europa Clipper Mission, scheduled for launch in October 2024 and expected to arrive in 2030. The mission’s current plan is to carry out four years of scientific observations at Europa. This moon displays strong evidence of an ocean of liquid water beneath its icy crust, making it a prime candidate for exploration in the hopes of discovering signs of extraterrestrial life. Given the difficulty, if not impossibility, of sending space probes to find evidence of alien life with our current technology, the best approach is to focus on listening for radio signals or directing telescopes at the locations of exoplanets to search for potential biosignatures. The most intriguing form of alien life is undoubtedly intelligent life. Based on our current rate of technological advancement, it is estimated that a civilization could potentially colonize our entire galaxy within 10 million years. However, this leads to the perplexing question: if this is the case, where are they? This concept, known as the Fermi Paradox.
THE FERMI PARADOX
Named after the Italian physicist Enrico Fermi, who posed the simple question of the absence of evidence of extraterrestrial civilizations despite the vast number of planets, stars, and time available for complex life to emerge in our galaxy. The perplexing part of this conundrum lies in the fact that, on one hand, the history of life on Earth suggests that the emergence of life is a lengthy and seemingly unlikely process. On the other side, there’s a vast amount of land available, and if we consider the possibilities for our civilization, we are rapidly progressing towards becoming a space-faring society. In the next thousand years, assuming we don’t cause our own demise or make foolish decisions, it’s highly likely that we’ll have a presence on Mars, the moon, and possibly even take our initial steps towards the stars. Fast forward a million years, and if we manage to survive, we should have evolved into a spacefaring civilization. Considering that the galaxy has existed for around 12 to 13 billion years, it wouldn’t take many civilizations that developed earlier than us in the span of a million years – or even a billion years – to be beyond our current level of advancement. This leads some to speculate that perhaps there is a finite lifespan for all civilizations, that they may self-destruct, or fail to become a spacefaring society.
THE GREAT FILTER
The Fermi Paradox may be resolved by the concept of the great filter, which suggests that there is a specific barrier in the development of life that makes detectable extraterrestrial life very rare. This barrier could prevent the evolution of intelligent life, possibly due to self-destruction. By developing telescopes that can detect techno signatures, we may gain insights into the great filter. If planets with techno signatures are common, it may indicate that the great filter is in the past. Conversely, if techno signatures are absent despite finding common life, it may suggest that the great filter lies in the future. Another intriguing hypothesis proposes that advanced extraterrestrial species may transition into machine intelligence and lose interest in colonizing the galaxy. The zoo hypothesis, favored by UFO enthusiasts, suggests that we are being secretly observed. Lastly, the grim solution to the Fermi Paradox is that we may be the first civilization and will become extinct long before any others emerge in our galaxy.
THE ORIGIN OF LIFE
When speaking with astronomers, it’s fascinating to hear that they estimate there are around 20 billion potentially Earth-like planets in our galaxy. The assumption is that there must be life in many places, but this is only a guess because no evidence of life has been found elsewhere. However, based on Earth’s history, we know that life began shortly after the planet formed, around 3.8 billion years ago, when the oceans formed. This suggests that the origin of life on a planet could be highly probable under the right conditions, based on what we observe on Earth. Another important aspect is the emergence of complex life. Evidence of complex multicellular organisms on Earth dates back around 600 million years, within the last billion years. It took approximately a third of the age of the Universe on Earth to transition from the origin of life to the emergence of complex life. This transition occurred when the star was stable, the planet’s orbit was stable, and there were fewer asteroid impacts. As we know that, development of complex life may require billions of years to progress from the origin of life to intelligent organisms. The emergence of eukaryotic cells, which constitute all complex life on Earth, appears to be a rare event. This type of cell likely originated from a bacterium entering and surviving within another type of cell called an archaeon, giving rise to the complexity of life we see today. Observing these processes that led to our existence leads me to consider the possibility that Earth is exceptionally unique. We argue that Earth may be the only planet in our galaxy where cognitive life exists. If we, as the only planet in the Milky Way with conscious beings, were to cease to exist, meaning and consciousness may be lost in a galaxy containing 400 billion stars. Just imagine if we were to initiate a nuclear war – the potential extinction of meaning in an entire galaxy.
CONCLUSION
The Fermi Paradox highlights the apparent contradiction between the high probability of the existence of extraterrestrial civilizations and the absence of any evidence or communication. Fermi Paradox also suggests that given the billions of stars and potentially habitable planets, we should have detected intelligent life, yet no such signs or encounters have taken place. One possible explanation for the Fermi Paradox is that advanced civilizations might be uncommon or have short lifespans, which could account for the lack of communication. Ultimately, the Fermi Paradox prompts us to question humanity’s position in the universe and consider whether life beyond Earth exists but remains undetected due to immense cosmic distances or technological limitations.