The Fermi Paradox

By Luke Davis

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Are we the only living things in the entire universe? There are about 20 billion sun-like stars in the milky way. Estimates tell us that about ⅕ of them have an Earth sized planet in their habitable zone. If only 0.1% of these planets harbored life, there would be 1 million planets with life in the milky way.  So you would guess, given this information, that we would be in contact with loads of alien planets. If there are millions, if not billions of planets that can sustain life in the milky way, and these other life forms have had much more time than us to develop…where are they? Our solar system should be teeming with aliens, spaceships and civilizations. This is called the fermi paradox. To find the solution to this problem, first we need to establish the difference between a galaxy and the universe. A galaxy is a system of millions or billions of stars. The Milky Way is our galaxy. Now, the universe is all existing matter and space as a whole; the cosmos. Everything. The universe is thought to be at least 10 billion light years in diameter and contains a vast number of galaxies, though it is constantly expanding. So even if there are civilizations in other galaxies, we’ll never know about them. Everything outside our direct galactic neighborhood (called the local group) is pretty much out of reach forever. Because of the expansion of the universe, even if we had spaceships going really, really, really fast, it would take billions of years to get out. (more information about the local group here)


So, what are some solutions to this problem?


  • Filters. A filter is a barrier that is really hard for life to overcome. We have passed many already, but there are definitely more to come. Nuclear war, climate change, and other problems we cannot even fathom now.
  • The past. Things could have been much more hostile and dangerous before, and only recently have become bearable. Maybe we are the first civilization?
  • Humans have not been around for that long. We’ve only been intelligent, communicating humans for about 250,000 years. We could just be late for the party and we just missed all the grand alien civilizations that came before us.
  • Differences. There’s no reason to think that aliens are like us at all. They could have no hearing or sight, so our messages to them would be lost in the abyss of space. They could not even function by our logic or science, or just be spectators, watching. So even if we did meet them, we would probably be too different to communicate in any meaningful way anyway. Different organisms have different needs and thoughts. Some beings’ only job is to survive and breed, so to even the smartest of them, doing anything other than their job would make no sense to them.


One major hold back of all these solutions is that we have no idea where the limits of technology and science are. We could be nearing the end of makeable machines, or nowhere near it. The thing is, we really don’t know…anything. We have no other civilization to base thoughts off, or any context.


And one last thought: maybe we are alone. There is no evidence to suggest that there is any life beyond earth. We are trapped on a lonely mudball, with nothing but dark, empty space all around us. If we let life on earth die, maybe that’s the end, and there will be no life left in the universe for the rest of…forever. The universe is too beautiful to not be experienced by anyone. All the more reason to savor it while you can.


“Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.”

― Arthur C. Clarke




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The Fermi Paradox