The Fermi Paradox
The universe is ancient, enormous, and full of ordinary stars much like ours. So where is everybody?
1950 (Fermi's remark), 1975 (Hart's argument)22 min read
American astrophysics
Michael H. Hart
1932
Astrophysicist whose 1975 paper in the Quarterly Journal of the Royal Astronomical Society gave the first rigorous form of the modern argument: starting from plausible colonisation speeds, the Galaxy should have been settled long ago, so the absence of extraterrestrials on Earth is itself evidence about their existence. He also did early work on the habitable zones of planetary systems.