Rebecca Sato & Casey Kazan write on Daily Galaxy:
Are we the lone sentient life in the universe? So far, we have no evidence to the contrary, and yet the odds that not one single other planet has evolved intelligent life would appear, from a statistical standpoint, to be quite small. There are an estimated 250 billion (2.5 x 10¹¹) stars in the Milky Way alone, and over 70 sextillion (7 x 10²²) in the visible universe, and many of them are surrounded by multiple planets.
Meanwhile, our 4.5 billion-year old Solar System exists in a universe that is estimated to be between 13.5 and 14 billion years old. Experts believe that there could be advanced civilizations out there that have existed for 1.8 gigayears (one gigayear = one billion years).
The odds of there being only one single planet that evolved life among all that unfathomable vastness seems so incredible that it is all but completely irrational to believe. But then “where are they?” asked physicist Enrico Fermi while having lunch with his colleagues in 1950…