Mountain heights across the country are about to change. Gravity is to blame
A national system that defines where things are across the country will get a complete overhaul
The official locations and sizes of America's mountains, valleys, forests, and waters, or at least their measurements, are about to experience a major overhaul. Researchers at the National Oceanic and Atmospheric Administration (NOAA) are in the final stages of completing a comprehensive update to the National Spatial Reference System (NSRS), the framework that defines where things are and their orientation in space for the United States and its territories.
The new system, currently in beta testing, is scheduled to be finalized early in 2027. Kevin Ahlgren, a geodesist with the National Geodetic Survey (NGS), part of NOAA managing the transition, explains that every latitude, longitude, and height across the country will experience a slight change. The alterations, which may shift measurements by up to around six feet, are a result of actual environmental changes like ice melt and advancements in technology and science since the last update in 1986.
Key to the NSRS's vertical component is gravity, which varies across the Earth's surface. Scientists have long known that gravity is not consistent everywhere, and the geoid—a theoretical model depicting these variations—serves as a reference point. Researchers have used direct measurements, readings from the ground, and data from space to create a new gravitational picture, which helps define the invisible "sea level" from which heights are measured in the NSRS.
As a result of the new system, elevation above sea level will see the smallest shift in the Southeast, while the extent of changes will increase toward the north and west, potentially lowering the official height of geographic features by approximately six feet in Alaska. These updated coordinates and heights will be utilized by all federal agencies and projects, as well as GPS devices and mapping programs used by the general public.
While mountain peaks and floodplains will not physically change, the new system better aligns our mode of measuring the world with our experiences of it.
Written by urgent.news from Scientific American's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
