## Where are the extraterrestrials? Fermi’s paradox, diversity and the origin of life

Delicate Arch at night; credit: Astronomy.com

Where are the extraterrestrial civilizations? (Fermi’s paradox) Updated 1 February 2024 (c) 2024

Introduction

In 1950, while having lunch with colleagues Edward Teller and Herbert York, who were chatting about a recent cartoon in the New Yorker depicting aliens, physicist Enrico Fermi suddenly blurted out, “Where is everybody?,” a question now known as Fermi’s paradox. This article presents background on Fermi’s paradox, explains why many of the proposed solutions are NOT viable, and mentions a few promising new results and directions.

Behind Fermi’s question was this line of reasoning: (a) Given the

## PiDay 2022 crossword puzzle

So soon? Yes, it is that time of year again — PiDay, namely Mar 14 (from 3/14 in North American date notation) is less than two weeks away. Continuing a long tradition on the Math Scholar blog, we present a custom-constructed crossword puzzle to commemorate the occasion.

This year’s puzzle commemorates a well-known pi-related theorem, one of the most beautiful facts in mathematics, which was originally discovered in the 18th century. The theorem is stated, in full, in the completed puzzle (see clues 20A, 30A and 44A).

My spouse and one daughter, who solved the puzzle, agreed that in terms

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