The Observable Universe
Approximately, 90 Billion light years of diameter is the so called “observable universe” by us “Humans”. Among which, consist 100 Billion Galaxies with each 100 – 1000 Billion stars and Trillion Trillion Trillion Trillion planets in them. As us “The Earthlings” are at the center of this observable universe since we measured it from the Earth for us (So Obvious). But, shouldn’t there be so many opportunities for some living civilization to exist in this vast universe?
Are there any alien civilization?
Assume, even if there exist some alien civilization in other galaxies, there is no way we could know about them. Basically, everything outside our direct galactic neighborhood so called the “Local Group” is pretty much out of our reach forever because of the expansion of the universe. Even if we had a very very very fast spaceship, it would take Billions of years to reach out to nearest galaxy. So lets focus on our own galaxy “The Milky Way”.
Milky way consist approximately 400 Billion stars, that’s a lot of stars roughly 10,000 stars for every grain of sand on earth (wow). There are about 20 Billion “our sun-like” stars, out of which estimate suggest 1/5th of them have earth size planets with habitual zone. If 0.1% of those planets harbored life that would estimate 1 Million planets with life just in the milky way(again wow).
Milky way is 13 Billion years old. During it’s birth there couldn’t have been any habitable planets around due to continuous explosions. The first habitual planet could only be born after 1–2 Billion years after the birth of milky way. But our Earth is only 4 Billion old. Which means there might have been a lot of habitual planets before earth. Some of which could have been destroyed by now or one of them could have developed a space travelling civilization, But we would have noticed my now and we didn’t. Where are they?
What would such an alien civilization look like?
Based on our concepts there could exist three types of civilization.
- Type I Civilization
- Type II Civilization
- Type III Civilization
Type I Civilization
Such type of Civilization would be able to access whole energy available on it’s planet. If we consider ourselves on the scale to become a Type I Civilization, we stand around 0.73 from a scale 0–1. We could reach Type 1 civilization in the next couple of hundred years.
Type II Civilization
This would be a civilization capable to harnessing all of the energy of it’s home star. This would require some serious science fiction to able to achieve it. Theories/Concepts like “Dyson Sphere” a giant complex structure surrounding the sun to harness it’s energy sounds conceivable.
Type III Civilization
It’s a civilization which controls it’s whole galaxy and it’s whole energy. Such a civilization would probably be like god-like to us. To be such a civilization, one would require to colonize each and every part of the galaxy which would obviously take a lot of time.
If there were habitual planets before earth and might have sustained lifeforms and considerably had more time than we have, Where are all those lifeforms? They should probably be easy to spot right?
This brings us to The Fermi Paradox
The Fermi Paradox
We have no answer to the Fermi Paradox, The best we can do is “possible explanations.”
Explanation 1
There are no signs of higher (Type II and III) civilizations because there are no higher civilizations in existence. This maybe the case if something is obstructinng lifeforms to evolve. We call it “The Great Filter”
The Great Filter
The Great Filter theory says that at some point from pre-life to Type III intelligence, there’s a wall that all or nearly all attempts at life hit. There’s some stage in that long evolutionary process that is extremely unlikely or impossible for life to get beyond. That stage is The Great Filter. It turns out that when it comes to the fate of lifeforms, this question is very important. Depending on where The Great Filter occurs, we’re left with three possible realities: We’re rare, we’re first, or we’re doomed.
First Possibility (We’re Rare)
One hope we have is that The Great Filter is behind us, we managed to surpass it, which would mean it’s extremely rare for life to make it to our level of intelligence. This scenario would explain why there are no Type III Civilization, but it would also mean that we could be one of the few exceptions now that we’ve made it this far.
Second Possibility (We’re first)
If the Great Filter is not behind us, the one hope we have is that conditions in the universe are just recent for lifeform to exist, for the first time since the Big Bang, reaching a place that would allow intelligent life to develop. In that case, we and many other species may be on our way to super-intelligence, and it simply hasn’t happened yet. We happen to be here at the right time to become one of the first super-intelligent civilizations.
Third Possibility (We’re doomed)
If we’re neither rare nor early, We could conclude that The Great Filter must be in our future. This would suggest that life regularly evolves to where we are, but that something prevents life from going much further and reaching high intelligence in almost all cases and we’re unlikely to be an exception. Example:- Imagine inventing something which would revolutionize us and could take sci-fi to next level but instead ends up being our dooms day.
Explanation 2
Type II and III intelligent civilizations are out there and there are logical reasons why we might not have heard from them. Such logical possibilities are -
- First Possibility - Super-intelligent life could very well have already visited Earth, but before we were here.
- Second Possibility - The galaxy has been colonized, but we just live in some desolate rural area of the galaxy.
- Third Possibility - The entire concept of physical colonization is a hilariously backward concept to a more advanced species.
- Fourth Possibility - There are scary predator civilizations out there, and most intelligent life knows better than to broadcast any outgoing signals and advertise their location.
- Fifth Possibility - There’s only one instance of higher intelligent life, a “superpredator” civilization (like humans are here on Earth), that is far more advanced than everyone else and keeps it that way by exterminating any intelligent civilization once they get past a certain level.
- Sixth Possibility - There’s plenty of activity and noise out there, but our technology is too primitive and we’re listening for the wrong things.
- Seventh Possibility - We are receiving contact from other intelligent life, but the government is hiding it.
- Eight Possibility - Higher civilizations are aware of us and observing us (AKA the “Zoo Hypothesis”).
- Ninth Possibility - Higher civilizations are here, all around us. But we’re too primitive to perceive them.
- Tenth Possibility - We’re completely wrong about our reality.
Are we alone? still remains a Mystery. All we could have logical possibilities and hope if by some hypothesis there exist a Type II or III Civilization (should be friendly and non hostile),that could enlighten us.
Here’s a Video from Kurzgesagt – In a Nutshell explaining “The Fermi Paradox”.
