Water on The Moon, I. Historical Overview

TL;DR

This paper reviews the historical evolution of scientific understanding regarding the presence of water on the Moon, highlighting early beliefs of dryness and recent discoveries suggesting possible water-related phenomena since 2007.

Contribution

It provides a comprehensive historical overview of lunar water research, emphasizing recent paradigm shifts and lesser-known aspects of lunar water studies.

Findings

Early astronomers believed the Moon was dry and airless.

Measurements in 1892 indicated extremely low atmospheric pressure on the Moon.

Since 2007, new evidence has challenged previous assumptions about lunar dryness.

Abstract

By mid-19th century, astronomers strongly suspected that the Moon was largely dry and airless, based on the absence of any observable weather. In 1892, William H. Pickering made a series of careful occultation measurements that allowed him to conclude that the lunar surface's atmospheric pressure was less than 1/4000th of Earth's. Any number of strange ideas arose to contradict this. Respectable scientists realized that significant amounts of water on the Moon's surface would rapidly sublime into the vacuum. Since 2007, however, the field has started another revolution in thought, and we describe this, including some lesser known aspects.