Fermi's Paradox: The Lack Of Evidence For Alien Life
Humans are social creatures. We are evolutionarily designed to seek companionship, so it is no surprise that we have spent decades trying to figure out if there is another form of intelligent life somewhere in the cosmos that can communicate with us. So far, we have come up empty, which has left many scientists puzzled. After all, there are about ten trillion galaxies in the universe and each galaxy likely contains several trillion planets and planet-like structures. At some point during the universe’s fourteen billion year history, some of these planets were most likely the home of a communicative form of life. However, if these lifeforms ever sent out a signal to find out if anyone else was out there, then we seemed to have missed that signal.
Admittedly, humans have been searching for alien life for a relatively short amount time. We only seriously considered probing the cosmos at the end of the 1950s. Still, scientists are surprised at how little we have found. In the decades since the 1950s, we have searched through our own solar system and Mars and Europa look promising for less complex forms of life, but we have found nothing yet. We hope to find signs of intelligent life in places beyond our solar system, but every earth-like planet that we discover seems to be sending no signals our way.
Scientists definitely recognize that communicative lifeforms are not going to just appear. It took four billion years of evolution before humans showed up on our planet and it was an accident of natural selection that we have the desire to communicate with extraterrestrial life. Our current statistics still seem to suggest that ten trillion galaxies is a relatively large number of galaxies and that fourteen billion years is a relatively large number of years, which means the math says that we are not alone. However, the math also says that we should not have had to wait so long to figure out who else is sharing our universe. Therefore, there is definitely a good a chance that there are some factors that scientists are failing to consider when they do out the math. Perhaps Earth is actually a lot luckier than scientists believe.
People like to call Earth a Goldilocks Planet, meaning it is just the right distance from a star to contain water. It is neither too hot nor too cold, which allows for life to thrive here. In order to find intelligent lifeforms, we are going to have to find other Goldilocks Planets. The probability of finding another earth-like planets is actually high. In fact, if we confirm the existence of water on Mars, then Mars is also in the Goldilocks Zone. Additionally, planets are not the only astronomical body that can contain water. Moons sometimes have water as well. After all, Jupiter seems to have a moon that has water. Therefore, in our solar system alone, there are three structures that could theoretically sustain life. If our solar system has between one and three astronomical bodies in the Goldilocks Zone, then other solar systems probably have some Goldilocks Planets well.
Of course, water is not the only ingredient that a planet needs in order to support life. It also needs to have some of the building blocks of life, including things like carbon, amino acids, and possibly silicon. Like water, these building blocks seem relatively easy to come by on planets that are within the Goldilocks Zone. Many different objects in space seem to have plenty of organic molecules. In fact, scientists estimate that several billion planets across the universe possess all the appropriate characteristics.
With all the ingredients for life, a planet just needs to experience the right circumstances at the right time in order for the first single-celled organisms to evolve. Earth certainly got lucky. Many scientists believe that Mars and Europa could have gotten lucky too. There is a good chance that one of the billions of earth-like planets out there also got lucky. Once single-celled organisms evolve, all we have to do is wait a couple billion years for intelligent and communicative lifeforms to appear. It seems relatively simple and most scientists agree that it is. After all, if a planet is similar enough to Earth, then evolution should take its course in almost the same way as it did here. Of course, evolution relies heavily on chance, so some lifeforms will never evolve to look like humans. However, as long as there are enough instances of evolution taking place in the universe for a couple billion years, the laws of probability state that the evolution of intelligent and communicative lifeforms should occur in the more than one place.
However, it is possible that a couple billion years is actually a much longer amount of time than scientists think it is. Most planets survive longer than four billion years, but simply existing as an earth-like planet for billions of years is not enough for a planet to sustain intelligent life. The climate on the planet needs to be sufficiently stable. Here on Earth, the moon gifted us with a steady climate, but many planets are not fortunate enough to have a moon like ours. Our moon is a result of a massive cosmic collision between Earth and an astronomical body the size of Mars. This collision could have destroyed the Earth, but our planet managed to survive and all the cosmic debris from the impact coalesced and formed our moon, which rotates around our planet that just the right distance and speed to provide us with ideal weather conditions. There might be plenty of Goldilocks Planets out there, but only some of them will have a moon like ours, which definitely decreases the number of planets that show potential for intelligent life. To be sure, planets can, in theory, have a steady climate without having a perfect moon, but scientists should not take it for granted that any Goldilocks Planet can theoretically sustain intelligent life.
Additionally, scientists must also contend with the fact that technology might be dangerous in alien civilizations. After all, it is definitely dangerous for us. The technology required to communicate with extraterrestrial lifeforms is the same technology that could wipe out our entire species here on planet Earth. Scientific advancements can lead to great progress, but they can also lead to problems such as nuclear warfare and global warming. Therefore, There is a chance that, every time intelligent lifeforms get close to sending out signals through space, they end up destroying themselves before they get the chance. Humans may have been lucky enough to survive in the presence of advanced technology for a long enough time in order to start probing space. Other civilizations in the universe may not have been so fortunate.
At the moment, it looks like the chances of finding life is much lower than we think it is, but we only look for aliens that resemble life as we know it, meaning scientists might have been fooled into looking for life in all the wrong places. We look for planets with water, but maybe we share the universe with a form of life that does not rely on water. We believe intelligent life is likely to thrive with help from a consistent climate, but it is possible that intelligent life can find a way to evolve in places we assumed were too dangerous. Scientists do talk about life that is made from silicon and not carbon, but the notion of silicon-based life is about as creative as we have managed to get. However, maybe we need to get more creative. After all, scientists have been fooled before into believing that life could not survive in places where it actually thrived. For example, we used to think there could be no life at the bottom of the ocean, but we turned out to be wrong. No mathematician can calculate the probability of finding every conceivable and inconceivable form of intelligent life.
Therefore, in all likelihood, Earth is not unique. However, the current evidence suggests that it is definitely somewhat more unique than our math indicates. In order to figure out exactly how special Earth is, we are just going to have be a little bit patient and maybe a little bit creative. If we do find intelligent lifeforms one day, then we will be able to open the door to endless exciting possibilities about sharing technologies, languages, and ideas. If we do not find any communicative extraterrestrial life, then we will simply learn to develop a deeper appreciation for our planet because it seems to have beaten all the odds, even though we do not yet fully know what those odds are.