The Milky Way stretches across the Chajnantor plateau in Chile’s Atacama Desert, home of the Atacama Large Millimetre/submillimetre Array, in this European Southern Observatory photo. Image: ESO/P. Horálek
The Fermi Paradox, named after the Italian physicist Enrico Fermi, refers to an apparent contradiction: the expectation that intelligent life must be commonplace in a galaxy with billions of solar systems and the complete lack of observational evidence. Discussing UFOs and the prospects of alien civilisations in 1950, Fermi reportedly summed up the contradiction with the observation “but where are they?” Or words to that effect.
Researchers at the University of Nottingham may have come up with an explanation. Using the Earth-Sun system as a model for the chemistry, temperature and other conditions that gave rise to intelligent life – humanity – over similar timescales, they calculate there should be about three dozen communicating civilisations across the galaxy.
“There should be at least a few dozen active civilisations in our galaxy under the assumption that it takes 5 billion years for intelligent life to form on other planets, as on Earth,” said Nottingham astrophysics professor Christopher Conselice. “The idea is looking at evolution, but on a cosmic scale. We call this calculation ...