The question is, “Are We Really Alone?”. A universe is a vast place. However, we humans will only ever experience a tiny fragment of all it offers. Within our own little spheres, we plan theories about that which we can see and that which we cannot. But, perhaps you might think a most impractical thought to get lost thinking about is–extraterrestrials.
Have you ever come across an article or video of a mysterious UFO sighting online? Or have you ever found yourself alone with a ghost? In fact, the chances of the first happening are not very slim. Although this is the age of information, not all that you see or hear is legitimate. In fact, some UFO spotters will go to immense lengths to hold their position that they have established contact. To this date, however, no one has produced obvious evidence of extraterrestrial life on earth or elsewhere. Causes of absurd claims over UFO sightings could be anything from fame to money or other incentives. Perhaps some even just like to believe that they’re special or get a kick out of fooling the public.
Are We Really Alone?
The question of “Are we really alone?” has baffled us for ages. It has little to do with alien sightings or UFOs. It is rather more of a scientifically posed question. The question is roughly like–given the vast expanse of the universe, what is the probability that there is intelligent life outside of Earth?
When you hear that question “Are we really alone?”, what is your innate response? Whether you had thought about it previously, now that you think about it, you feel- the vast extent of the universe–it is a likely possibility, don’t you? You must have heard already that there are billions of galaxies with an unimaginable number of planets. What are the chances of intelligent life showing up on any single one of them? It is a splendid chance.
But here is what makes this question (Are we really alone, Are we not?) so difficult to answer–there is a second follow-up question if your answer was a No–Well, then where are all the aliens? Seriously, where are they? Hundreds of thousands of years of humans and billions of years of life on earth and we are yet to contact extraterrestrial life. One would think aliens would have developed the level of technology required to make contact by now. Yet, they are nowhere for us to see.
I proudly introduce you to–The Fermi Paradox, named after physicist Enrico Fermi. It states, “If there are millions to billions of planets likely to flourish life, and those probable alien races have had considerably more time than humans AND considering with generation spaceships we could colonize the whole Milky Way galaxy in a couple of million years–where are all the aliens?” Whew, that’s a mouthful, isn’t it? Let me break it down into its parts.
The Milky way isn’t the only galaxy, there are billions of others. For the argument, we consider only our observable universe.
Likeliness of Life:
Earth is one of approximately 400,000,000,000 (400 billion) planets in the Milky Way. Like earth, there are billions of other planets in the Milky Way. There are also approximately 20 billion sun-like stars in our galaxy. I take it you know about habitable zones, the places within a solar system where habitable conditions prevail. The likeliness of over a million habitable planets in the Milky Way galaxy is considerably high. Hence, those planets in other habitable zones are also likely to host life.
Age of Earth:
Earth is about 4.5 billion years old. That is not ancient compared to the Milky Way galaxy. So, before Earth was born, millions of habitable planets had already likely been born. If life had sprouted there, it would have had considerably more time to develop than that on Earth. Therefore, it is also likely those races would have become space-traveling before Earth was even born.
A generation spaceship is conceptual which can house life forms like humans spanning several generations, even thousands of years. With such vessels, it would be possible to colonize the Milky Way within a couple million years.
The Big Question, “Where Are They?”
Our imaginary friends would have reached us by now (and probably overtaken us)! So where are they?
Earlier, we talked about intelligent life. What do we mean by intelligent life, and how do we quantify intelligence?
Again the question arise “Are we Really Alone, Are We Not?”
There are three categories of what our imaginary super civilization might look like:
A type-1 civilization could harness all of its home planet’s energy. We should become such a civilization in a couple of hundred years.
A type-2 civilization could harness all of its home star’s energy.
A type-3 civilization would be the boss of its entire galaxy and all of its energy.
Now you must be curious to know the “Why” of this paradox. And the answer is–filters. Filters are significant barriers which can thwart life from flourishing. There are two possibilities regarding filters:
The pleasant reality: There are filters, obstacles which can cause mass extinction of a species or life in a place. But we are past them now. Flourishing of intelligent life is more complex than we thought, and we’ve had to overcome certain difficult obstacles to get to this point.
The grim reality: Filters exist. We must have encountered none yet. Perhaps it will be nuclear fallout or lack of food production which will cause the end of life on Earth.
Each reality comes with a fresh set of implications from the other. The pleasant reality implies that other alien life could have never got past the filters we have successfully overcome; and because of this, we see no sign of other intelligent life. The awful reality implies that tougher times are ahead of us, which other species have passed and have faced obliteration. Some have theorized that there is a star killer of sorts, of a type-3 civilization member, which destroys civilizations as soon as they become too intelligent. Others think it could be because of malfunctioning technology that all life eventually must vanish.
Regardless, we took so many assumptions, remember? And we can only hope for the best as little of the universe is visible and even less do we understand it.
In conclusion, I’d like to say–the only way to search for intelligent life outside of Earth is for us to become that much intelligent first. So why don’t we focus on ourselves and not the likeliness of other intelligent species?