There are more than 100 billion galaxies in the observable universe. And there may be billions more outside the observable universe that we can’t see.
You might know that there are more than 500 billion planets in our galaxy, Milky Way alone. Out of these, more than 10 billion could be similar to earth. All these galaxies & planets, but we have not yet discovered any alien life forms yet. But let us assume that we find any alien life outside earth? What if SpaceX or NASA finds out alien life on other planets?
How would that affect our civilization on earth? Would you consider that bad news for us?
We, humans started searching for alien life from the 19th century. We are yet to encounter alien life. But if we find one, that would probably affect us badly. Alien life may range from simple bacteria to species more advanced than us.
Why do we think that there could be an alien life outside the earth? Mostly because the universe is huge. We can’t be the only life in the universe. It is highly plausible that there is alien life somewhere.
You would ask, what is up with this logic. This logic is based on the Copernican principle. Named after the scientist Nicolaus Copernicus, the principle states that the earth and the sun are not observers in the universe, nor are they better or worse than other planets or stars. Everything that applies to other planets also applies to Earth and that includes life.
You might have heard about “Habitable Zones”. It’s an orbital region around a star in which an Earth-like planet can possess water on its surface and possibly support life. We have already discovered billions of earth-like planets, but very few have been found in these zones which meet the criteria for life.
This is with the assumption that solvent water is the necessity for life on Earth.
What if the aliens visit us? It would not look like the invasions we have seen in various sci-fi movies. I don’t think they will blast their advanced weapons at humans. Let’s hope not.
Even if they attack us, that would not concern us. As by the time alien life finds us, we would already be on our way to self-destruction. All because of the Great Filter. You would ask why?
Probability suggests that there should exist an alien life somewhere in the universe, but we don’t know exactly how far. If they existed, wouldn’t we have seen some signs till now? But we have not. The universe seems endlessly empty.
This is the contradiction that has been confusing scientists ever since we realized that the Universe is very very huge. Scientists call it the Fermi paradox. It suggests that all species in the universe go through the same evolutionary path, no matter where they are from.
Let’s check out the step by step evolution of the planet or life.
It starts with the development of life. It started anywhere in the Universe with the right star system and a planet that has the required right conditions.
Next, the organic compounds assemble themselves into self-replicating patterns and then evolve into complex multi-cell organisms. These organisms evolve to become the species with the big brain, that takes over their own planet and change it as per their need. In the case of Earth, we, Humans are these evolved species.
Then comes the space colonization. Space colonization comes due to various reasons like curiosity to explore, find answers to scientific questions, survival due to overpopulation, or the conquest of the solar systems. Whatever is the reason of space colonization, all civilization will end up trying to colonize space.
There could be alien species that may have been around for millions of years longer than us. But they still have not visited the Earth. It seems that something is making it very hard for species to colonize their galaxy, maybe even impossible. Maybe, it’s the Great Filter, that might wipe out all of humanity.
Great filter is something that is dangerous, something that happens to every civilization that is advanced enough to go beyond their home planet. We have not yet met other life forms, hence we can safely hypothesize that the Great Filter didn’t wipe us out. We could also be the first civilization to safely pass the great filter and reach this level of technology.
Just because we have not yet received any proof, that doesn’t mean that alien doesn’t exist or never existed. There is a chance that there is another alien civilization that is trying to colonize their home galaxy, or even on their way to destroy Earth. But as they have never shown up nor that we received any signal from them, it could mean that something has destroyed their civilization before they could travel through space.
It is highly improbable that we will find anyone as advanced as our species. If there was even one alien civilization that is more advanced than us, we would have known it by now. The best we can hope if seeing bacteria on planets like Mars or multicellular animals in the oceans of Europa.
The worst thing that could happen to us is to find the ancient ruins of an advanced alien civilization. Because if they didn’t get past the Great filter, neither will we. The only difference would be that they are long gone and we are on our way to self-destruction.
The best thing to find is the more advanced alien life, as it would mean that we’re behind the Great filter. Maybe that filter starts once the species take control over their own planet. It could be the nuclear wars, AI destroying the humans or genetic experiments gone wrong, we don’t know. If it happened to a dead alien civilization, it might probably happen to us too.
Though the alien life sounds more exciting than anything else, it would be better for us the Universe is totally clean. This would increase our chance to discover new planets and terraform to make it habitable.