The quantum sensor, which NASA has developed with Bay Area-based company AOSense, relies on some 100 million cesium atoms. The device launches the atoms inside a cylindrical column and times how quickly they fall. Atoms create an interference pattern of crests and troughs which vary based on how fast the atoms rise and fall. That can reveal tiny fluctuations in gravity.
This new sensor can detect a 1.5-centimeter change in sea level over an area the size of Hawaii’s Big Island. (Wired)