 The Cosmic Ray Soil Moisture Observing System, COSMOS, is a new method for measuring area average soil moisture at the hectometer horizontal scale. It uses cosmic rays to measure the amount of soil moisture present in the soil. The cosmic rays interact with the hydrogen atoms in the soil, which are mostly found in soil water, and emit neutrons that can be measured by a stationary cosmic ray probe. These neutrons are then mixed instantly in the atmosphere and their density is inversely correlated with soil moisture. COSMOS has deployed more than 50 of the planned 500 probes, with most of them located in the United States. The data collected by these probes is processed and disseminated to the public. This article was authored by Msrita, W.J. Shuttleworth, Exxon, and others.