Google Earth Engine combines a multi-petabyte catalog of satellite imagery and geospatial datasets with planetary-scale analysis capabilities and makes it available for scientists, researchers, and developers to detect changes, map trends, and quantify differences on the Earth's surface.
Remote sensing is the science and art of obtaining information about an object or feature without physically coming in contact with that. In remote sensing, electromagnetic radiation reflected or emitted by the targets are recorded using sensors located away from the targets. The energy recorded at the sensors are analyzed to identify the target features and to interpret their properties. Basic understanding of the characteristics of the electromagnetic radiation and their interactions with the atmosphere and surface features is essential for better analysis and interpretation of the remote sensing data.