Scientists say most likely number of contactable
alien civilisations is 36. New calculations come up
with estimate for worlds capable of communicating
with others. Nicola Davis, The Guardian, June 15, 2020
[www.theguardian.com]

The paper is:

Tom Westby and Christopher J. Conselice, 2020,
The Astrobiological Copernican Weak and Strong
Limits for Intelligent Life. The Astrophysical Journal,
Volume 896, Number 1
[iopscience.iop.org]

Yours,

Paul H.

"The past is never dead. It's not even past."
William Faulkner, Act 1, Scene III, Requiem for a Nun (1951)