Is there life out there?
The observable universe is about 90 billion light-years in diameter. There are at least one hundred billion galaxies, each with one hundred to one thousand billion stars. Recently, we’ve learned that planets are very common too. There are probably trillions and trillions of habitable planets in the universe. Which means, there should be lots of opportunities for life to develop and exist. But where is it? Shouldn’t the universe be teeming with spaceships?
Even if there are alien civilizations in other galaxies, There’s no way we’ll ever know about them. Basically, everything outside of our direct galactic neighbourhood, the so-called “Local Group”, is out of our reach forever, because of the rapid expansion of the universe. Even if we had spaceships travelling at the speed of light, it would literally take billions of years to reach these places, travelling through the dark expanse of space.
The Milky Way is our home galaxy. It contains up to four hundred billion stars. That’s a lot of stars, roughly ten thousand for every grain of sand on earth. There are about twenty billion sunlike stars in the Milky Way, and estimates suggest that a fifth of them have an earth-sized planet in its habitable zone, the area with conditions that enable life to exist. If only 0.1% of those planets harboured life, there would be one million planets with life in the milky way. If such a civilisation existed, There should be some sign.
What would such a civilization look like? There are three categories. A type one civilization could access the entire energy available on its planet. In case you are wondering, we are currently around zero point seven three on the scale, and we should reach type one sometime in the next couple hundred years. Type two would be a civilization capable of harnessing all the energy of its home star. This would require some serious science fiction, but it is doable in principle. Concepts like the Dyson Sphere, a giant complex surrounding the sun, would be conceivable. Type three is a civilization that controls its entire galaxy and its energy. An alien race this advanced would probably be godlike compared to Earth.
Where are all the aliens? This is the Fermi Paradox, and nobody has an answer to it. But we do have some ideas. Let’s talk about filters. A filter in this context represents a barrier that is really hard for life to overcome. There could be possible theories regarding this.
There are Great Filters and we’ve passed them. Maybe in the past, the Universe was way more hostile, and only recently, things have cooled down to make complex life possible. This would also mean that we may be unique, or at least one of the first, if not the first civilization in the entire Universe.
There are Great Filters and they are ahead of us. This one would be devastating. Maybe life on our level exists everywhere in the Universe, but it gets destroyed when it reaches a certain point, a point that lies ahead of us. If this is true, then we are closer to the end than the beginning of human existence.
Or, maybe there is an ancient type three civilization, that monitors the universe, and once a civilization is advanced enough, it gets eliminated, in an instant. Maybe there is something out there, that it would be better not to discover. There is no way for us to know.
One final thought, maybe we are alone. As of now, we have no evidence that there’s any life besides us. The universe appears to be desolate and lifeless. No one is sending any messages, no one is answering our calls. We may be completely alone, trapped on a tiny moist mud ball in an eternal Universe.
If we let life on this planet die, perhaps there would be no life left in the Universe. Life would be gone, maybe forever. If this is the case, we just have to venture to the stars and become the first Type Three civilization, To keep the delicate flame of life existing, and to spread it until the universe breathes its final breath, and vanishes into oblivion.
The universe is too beautiful not to be experienced by someone.
– PM Sayee Leshya