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Why are we feeling alone
Gliese 581 D planetary system
Are aliens smarter?
The Earth is typical and common. And revolves around Sun, a very common type star.. This universe is several times older than our Sun. It has billions of stars of various ages. Most of these stars have at least one planet. May be at least some of them were inhabited for millions of years before our solar system was even born. Vast stretches of time and space made it possible for evolution of more intelligent life everywhere.
Gliese 667 C - most habitable exoplanets
The billions of lives question
Why did not we find intelligent life or even life, so far? Are they there? Where are they? Are we alone? Why did not our telescopes find them?
Could we not announce our presence on earth here? Are we unable to find any intelligent aliens because they do not know we are here? Are we not intelligent enough to be contacted, communicated or related to? Are our astro-engineering skills enough to reach out the aliens in vast reaches of time and space?
Astronauts on Mars
Aliens are "humanly" too
Kepler mission experience reveals an interesting point. There are billions of . earth like planets with masses several times the size of earth. The energy of the sun is enough to sustain thousands of billions of humans. Other stars might be having even bigger potential with planets with much larger sizes than earth. Hence, our intelligent alien neighbors are most probably restricting to inhabiting within other planets of the same star systems. This makes it difficult for us to detect them.
confirmed exoplanets so far
Aliens too could be scary of space travel
Our assumption of intelligent aliens subconsciously assumes that that these civilizations are making intergalactic space travel and colonizing other habitable planets. That could be wrong as these aliens are probably wiser.
To expand as fast as humans imagine, they have to travel in space at the speed of light. There are limitations to this migration however best technology aliens adopt. Have they realized there is no future in such unlimited expansion? They may not be expanding population at a fast rate unlike us if they have true minds. Having a true mind is sign of evolution of advanced intelligence over billions of years.
Space travel has formidable dangers and risks. Any transport of life across space is possible only at a small fraction of the speed of light. Hence, it is too long to travel even to the nearest stars. The space is full of debris from asteroids and meteors. Aliens’ spacecraft too has great risk of collision with this debris. Even a collision with a small space particle results in as much damage as from nuclear bomb blast.
Conflict of differing eras and epochs
To announce our presence, we have to use limited bandwidth in the useful electromagnetic spectrum. By sharing it, we have to reduce the signal strength too so that transmissions on the same frequency do not interfere with one another. This signal reduction also means we are becoming invisible over vast distances in the galaxy. If advanced civilizations are also transmitting themselves using same technologies, they too get invisible within the mutual lifetimes of our civilizations for co ordination.
These aliens may have mightier technologies than humans have. But sending even a small spacecraft at a small fraction of the light requires huge energy input. And there is no guarantee for safe landing. Other stars’ planetary landscapes are varying and wide ranging. To send a small spacecraft the size of a small airliner at one-tenth the speed of light requires huge energy. And that doesn't ensure a safe a landing and home coming. It takes 10 million times as much energy to move a small space colony to another star as it takes to establish the same colony in the home system. And there is plenty of room at home.
Aliens may be passionate
These aliens are older civilizations than humans by millions of years. They may not want us to know they are there for reasons best known to them. They would have decided not to establish any contacts with humans. They were probably aware of our nuclear arsenal and the holocaust it already caused. They may not have necessity to establish contact with humans if they perceived us to be inferior. It will be up to them, not us, how and when some kind of detection or contact is made. They are probably studying us what we might someday become, or waiting for the right time to contact us. Or they are protecting themselves from our knowledge about them.
Travel against time
No conclusion is the conclusion on our lonely feeling
But we need not conclude we may feel alone for ever. Intelligent life would have already evolved themselves into thousands of years life spans. Even travelling at slow speeds in space, they may find it possible reaching out to humans. These intelligent beings would have started travel between small arms of our galaxy where it takes only a thousand light years or so. Even if they can’t travel more than 1/20 of speed of light, they or their automated spacecraft might reach within 20000 human years. Probably they visited humans already.
Radio communication is easier than interstellar travel. We may be unable to travel so much faster, better, and cheaper that we can visit a new star system but we can find visitors from galactic spaces. These civilizations if survived to a certain point, could easily become immortal. They probably learned how to avoid asteroids strikes, planetary catastrophes and other natural disasters. They probably learned to live peacefully within themselves.. They might have had a better understanding of nature as they are much ahead..
But we should not underestimate the practical interstellar travel. Doing even simple things in space is difficult, unforgiving, and exceedingly expensive. Antimatter rockets, beamed energy, interstellar ram jets, have severe problems. Known physics may never make it possible for humans visit Earth-like planets around other stars. Doing so would require "warp speed" and/or harnessing exotic phenomena such as wormholes or zero-point energy. We may visit Mars at the best. Humans may never become immortal even relatively more than today’s life spans. The expansion of the universe has accelerated. An accelerating universe would be the worst possible universe, both for the quality and quantity of life. All our knowledge, civilization, and culture will be easily forgotten.
We are not alone but may feel lonely for some more time to come.