Fermi Paradox Theories

Alone

We are truly alone. In all the infinite galaxies, stars, and combinations of planets, we are solitary in our uniqueness.

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Space Travel Is Too hard

Some physical, astronomical, biological or engineering difficulty makes space travel infeasible.

Michael Hart - Quarterly Journal of the Royal Astronomical Society, Vol. 16, p.128

No Interest

They have chosen not to. A lack of interest, motivation or organization, political explanation.

Michael Hart - Quarterly Journal of the Royal Astronomical Society, Vol. 16, p.128

Time

Advanced civilizations are a more recent development in the universe. Their are civilizations capable of visiting us, but have not had time to reach us yet.

Michael Hart - Quarterly Journal of the Royal Astronomical Society, Vol. 16, p.128

We Missed It

They have come and gone, but humans were not here during that period to observe it.

Michael Hart - Quarterly Journal of the Royal Astronomical Society, Vol. 16, p.128

Life Is Too Fragile

Gaian bottleneck hypothesis

Life may be rare in the universe, not because it is difficult to get started, but because habitable environments are difficult to maintain during the first billion years.

Aditya Chopra - Astrobiology (2016)

Life Is Rare

Emergence bottleneck hypothesis

Humans Are The Smartest

Other civilizations exist, but they lack the advanced technology to make their presence known.

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Looking Time

Humans have only been looking for other signs of life for around 80 years. In the terms of a galactic time scale, that isn’t any time at all. We’ll find them, we just haven’t been looking very long.

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Too advanced

Other civilizations are all around us, but we lack the means to identify them, or communicate with them due to their advanced nature.

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They are already here

Another civilization is actively visiting us now. We are unaware.

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Too Far

There are many civilizations, but we are too far apart for meaningful two-way communication.

Webb, Stephen (2002). If the Universe Is Teeming with Aliens... Where Is Everybody?

Virtual Evolution

It has been suggested that some advanced beings may divest themselves of physical form, create massive artificial virtual environments, transfer themselves into these environments through mind uploading, and exist totally within virtual worlds, ignoring the external physical universe.

Bostrom, Nick (April 22, 2008). Where Are They?. MIT Technology Review.

We’re Isolated Intentionally

planetarium hypothesis / zoo hypothesis

Beyond a certain distance, the perceived universe is a simulated reality. This illusion, created by a Type III civilization capable of manipulating matter and energy on galactic scales, is intended to keep us in perpetual isolation. Our loneliness is engineered.

Baxter, Stephen, 2001, The Planetarium Hypothesis: A Resolution of the Fermi Paradox, Journal of the British Interplanetary Society, Vol. 54

Advanced civilizations are purposefully eliminated

There is an active force within the cosmos that actively seeks out and eliminates other civilizations.

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