Non-human intelligences on Earth?
Beyond the legacy program there is a broader question: how likely is it that non-human intelligences are present today on Earth or in its vicinity, or were in the past? These are different questions, with different evidence: here we keep them separate and give a declared estimate for each, with the reasoning behind it.
- Non-human intelligences present on Earth or in its vicinity in the last century, that is, at least some UAPs
- Non-human intelligences that arrived in the Solar System or on Earth at any time in its 4.5 billion years
- A non-human technological civilization that arose on Earth before ours (the “Silurian” hypothesis)
- Non-human intelligences living hidden on Earth today (the “cryptoterrestrial” hypothesis)
Data as of Nov 1, 2026 · version 1.2.8 · Data: nhi.json