INTRODUCTION
Are there aliens in our world? Or not? This is a question that has been asked to many people. Elon Musk, ISRO scientists and many others, there are many movies and conspiracy theories on this issue. Like this one about Area 51. And a month ago, there was big news on this issue. When a former US intelligence official said that the American government has recovered non-human biologics near a crash site. The existence of aliens has been also claimed by a former Israeli space security chief. The world’s greatest scientists have thought about this question as well. Are there aliens in our world or not? In this article we’d like to answer this question using the theories of these scientists. Many of you must have seen the movie Oppenheimer. Oppenheimer did make an atomic bomb. But he had a physicist with him without whose experiments, the bomb wouldn’t have been possible. His name was Enrico Fermi. On 2nd December, 1942, Fermi and his team made the world’s first nuclear reactor and conducted an experiment which resulted in the world’s first self-sustained nuclear chain reaction. As a result, America was able to make the world’s first atomic bomb. But Fermi is famous for one more thing. Fermi Paradox.
WHAT IS FERMI PARADOX?
In 1950, one day, Fermi and his team were going for lunch to the National Laboratory of New Mexico. They were accompanied by many great physicists who were working on the Manhattan Project. These four people were having fun and were discussing about cartoon in the New Yorker magazine. Basically, in 1950, a mystery came to light. Many trashcans were disappearing from New York. It was the same year when many people said that they had seen flying saucers in the sky. That’s why on May 20, 1950, the New Yorker published this cartoon. It combined both stories and showed that these flying saucers were taking away the dustbins in New York. During this discussion, Fermi asked his team a question. Where are the other people in the world? The phenomenon in question became famous as the Fermi Paradox. What does this paradox say? Our observable universe is 93 billion light-years wide. This means that if someone travels at the speed of light, it will take them 93 billion years to travel from one end of our universe to the other. Scientists estimate that there are 2 trillion galaxies in this universe. Each galaxy has about 100,000,000,000 stars. According to scientists, 1025 planets orbit around these stars. It’s hard to even guess 1025. So, when there are so many galaxies, stars, and planets in such a huge universe, can’t there be aliens on another planet? Despite this fact, if our universe is so big, why haven’t we found any aliens yet? This is Fermi Paradox. There is a possibility that there are aliens in our universe, but we haven’t found any evidence to prove it. This question has troubled many scientists. Fermi also believed that there can’t be life on every planet.
CONDITION REQUIRED FOR SUSTAIN LIFE
Life on a planet requires it to be located in the Goldilocks zone, also known as the Circumstellar Habitable Zone (CHZ). This zone is named after the story of Goldilocks and the Three Bears, where Goldilocks finds the perfect porridge that is neither too hot nor too cold. The Goldilocks zone is the region around a star where the temperature is just right for a planet to support life. Our Earth is situated in the Goldilocks zone of our solar system, approximately 150 million km away from the Sun. Astrophysicist Michael Hart’s computer model from 1978 showed that if the Earth was 1% farther or 5% closer to the Sun, our oceans would not be in liquid form. Each star has its own Goldilocks zone, which varies based on the size of the star. However, being in the habitable zone does not guarantee that a planet will have life. Other factors, such as the type of star the planet orbits and the level of solar activity, also play a role in determining the probability of life on a planet.
DRAKE EQUATION
A scientist calculated it. The formula shown in this image created by astronomer Frank Drake in 1961 to calculate the technically advanced civilizations in the Milky Way galaxy. This equation has 7 variables that tell us the possibility of our contact with an intelligent alien civilization. Now that we know the equation, we must also know the answer. But we don’t. The problem is that we don’t know the value of many variables in this equation. Scientists can estimate 3 variables correctly, but the 4 variables haven’t been estimated correctly. So, we have a Fermi Paradox, but no evidence. We have an equation but don’t know the value of the variables. So how can we say that there are aliens in our universe? Some scientists used Drake’s equation to prove this. They said, suppose ours the only planet with life in the universe. In Drake’s equation, ‘N’ is the number of technically advanced civilizations in the Milky Way galaxy. If n is equal to 1, what’s the probability that human civilization is the only civilization with an intelligent lifeform? The probability was 1 in 10 billion trillion. Adam Frank, a professor of physics and astronomy, who co-authored this paper, said that 1 in 10 billion trillion is a very small number. He said that he can’t believe that our civilization is the only intelligent civilization. There must be other civilizations that came before us. There are 3 reasons for this.
- There are many planets in the observable universe.
- Scientists have found life on Earth in such places where no one even expects it.
- Our universe is very old.
It’s very difficult to understand this, so let me give you an example. Let’s assume that the entire history of our universe is compressed in a year. The Big Bang that happened when our universe was created was the first second of 1st January. And today, when you’re watching this video, it’s the last second of that year. Now, in this one year, guess when humans came to be. 31st December, at 10.30 pm. At 11.33 pm, cooking started in our world. At 11.40 pm, clothes were invented. And at 11.48 pm, Homo sapiens emerged. So, in the last 12 minutes of the year, human civilization started. This will give you an idea of how old our universe is. The life that we know of developed in a very short period of time. So, the time that’s left, other life forms must have developed on other planets as well. If that’s the case, why haven’t we met alien life yet? Or why haven’t the aliens reached out to us?
WHY HAVEN’T WE FOUND ALIENS YET?
There are many theories about this. One theory says that for any civilization to develop so much so that they can communicate with each other, that civilization gets destroyed. The message that you see in image, was the message that humans sent to aliens on 16th November 1974. For this, we used the most powerful radio telescope of that time. This message was sent to the star system M13, which is in the Hercules constellation. M13 is about 21,000 light-years away i.e., if you travel at the speed of light, it will take you 21,000 years to reach M13. So, let’s assume that they received the message and replied the whole process will take 42,000 years. But will our civilization survive for 42,000 years? Paul Elrich, a scientist at Stanford, doesn’t agree with this. He says that our civilization is not sustainable. To maintain our lifestyle, we need 5 more Earths. He says that there are 8 billion people on Earth. Elrich says that these 8 billion people consume more resources than what’s available. Our Earth can regenerate resources to some extent. But our resource consumption is almost twice the amount of resources that Earth can regenerate. This means that there will come a time when all the Earth’s resources will be consumed. This is why our civilization is not sustainable. Scientists don’t just claim this about our civilization. They also claim this about other alien civilizations.
THE GREAT FILTER MODEL
This has been proven by the Great Filter Model. It states that a civilization needs to develop in order to contact another civilization. But before that happens, their civilization will be destroyed. Adam Frank, a professor of physics and astronomy, said through his research that there are 4 scenarios for the growth of a civilization.
1. The first scenario is called the die-off model. A planet’s population will grow so much that its environment will change drastically. Due to the change in the planet’s environment, almost 90% of the population will die. Even if a small part of the population survives, they won’t be able to use modern technology because the planet’s environment would’ve deteriorated.
2. The second scenario is called the sustainability model. According to this model, the growing population will reach a stable equilibrium so that the planet’s environment won’t change. And the civilization will be able to live in that environment.
3. The third scenario is called the collapse model. The population will grow so fast that the planet’s resources would run out. Immediately, the population will collapse.
4. The fourth and final model is called the collapse with resource change model. In this case, the planet will undergo a huge environmental change due to population growth. The population will decide to change their system. But that change won’t make any difference to the environment. People will still die.
Out of all these models, we’re in the 4th one. We know we’re making a mistake, but this realization came too late. That’s why scientists say that no civilization can live long enough to be able to contact other civilizations. This is called the great filter model. When several civilizations develop, most of them are destroyed after a certain time. The cause of destruction can be climate change. Or AI development. Or the decision that we don’t want more children in our society. If we want to establish contact with another civilization, we need to ensure that our civilization sustains. But even that will not guarantee our contact with the aliens. It’s because our universe is vast. And it continues to widen. This is why the distances between the galaxies continue to increase. Say you spot a planet that’s 10 billion light-years away. You picked up your spaceship and set out for that planet. But unfortunately, there’s not guarantee that you’ll reach that planet in 10 billion light-years. Because our universe is expanding faster than the speed of light. And this expansion isn’t consistent. The farther a galaxy is, the faster it’s moving away from us. Scientists say we will never be able to reach the galaxies that are 18 billion light-years away from us. But there’s another possibility.
CHEMICAL BIOSIGNATURE
Maybe we’re not looking for aliens properly. In today’s astrobiology research, we look for aliens using their chemical biosignatures. What are chemical biosignatures? In real life, we look at many plants and animals and judge whether they’re living or not in very unique ways. Sometimes, we look at a bird’s wings, an animal’s footprints, or a plant’s seeds floating in the air. All of these are called biosignatures. We don’t look at the entire plant or animal. We’re looking for the plant or animal’s signatures. Because life leaves chemical biosignatures in rocks, water, and the atmosphere. Similarly, biological molecules like lipids, carbohydrates, nucleic acids, and proteins can also be used as biosignatures. That’s why some scientists believe that if we find such biosignatures on other planets, we can say that maybe there are aliens there. But there’s a problem with this logic. It’s possible that alien life doesn’t depend on these same biosignatures. That’s why many scientists are wondering how to discover alien life on the basis of those biosignatures that we’re not using yet to find life. But it’s easier said than done. Because we only know one type of life. We haven’t seen life beyond that. But there’s another possibility that our civilization is truly alone in the entire universe. Drake’s equation predicts areas in our universe where life might exist. But that’s not a fact. Some scientists published a paper called Dissolving the Fermi Paradox where they said that according to our current astro-biological knowledge, there’s a 39-85% chance that we’re alone in this observable universe. Researchers aren’t saying that aliens don’t exist in our universe. They’re saying that according to our current knowledge, there’s a good chance that we’re alone in this universe.
ARE WE LIVING IN A COMPUTER SIMULATION?
But there’s one possibility that we might never be able to contact aliens, but they’ve already contacted us. And according to this contact, we’re in a computer simulation. The concept of computer simulation has been discussed in many books and movies, like Matrix. Nick Bostrom, a philosopher at Oxford University, argued that there’s a 20% chance that we’re living in a computer simulation. As if we’re characters in a computer game. Elon Musk also talked about this. The argument behind computer simulation theory is that in 1972, there were only basic computer games. In just a few years, these computer games have become very advanced. There’s a possibility that in 50 or 1000 years, we’ll be able to make such computer games that we won’t even know what a computer game is and what reality is. And there’s also a possibility that if our technology develops so much that we’ll be able to make such advanced computer games, then there’s also a possibility that we’re living in a computer game. Because it’s possible that before us, there was a civilization that was so advanced that they designed our world in a computer game. Computer scientist Rizwan Virk said that there are 10 stages of technology development. We’re currently in stage 5, where we’re talking about virtual reality and augmented reality. It’s possible that in 100 years, we’ll reach a point where we’ll be able to simulate reality. Humans have been in this world for 3 lakh years. So, in 3 lakh years, we’ve gone from basic development to rapid development. But our universe is 13.4 billion years old. So, if we’ve reached this point in 3 lakh years, it’s possible that some civilization has reached this point before us. That’s why Nick Bostrom says that the sooner we get closer to this technological development, it means that there are more chances that we’re in a simulated reality. And there’s an interesting consequence to this. If we’re in a simulated reality, there must be someone above us who made our game. That’s why this theory, which is very scientific, is very similar to many religions. Religions that say that there’s a God above us. Whatever it is, we should just hope that this person doesn’t lose the game.