The tool that has allowed scientists to learn about the characteristics of Earth and its layers through satellite imagery and data is Synthetic Aperture Radar (SAR). SAR is a form of radar utilized in remote sensing to create two-dimensional images or three-dimensional reconstructions of objects, such as the Earth's surface. It can penetrate through clouds and work in both day and night conditions, making it highly effective for studying various geological features, topography, and changes over time.
In addition to SAR, other satellite-based technologies like Lidar (Light Detection and Ranging), multispectral and hyperspectral imaging, and altimetry also contribute to our understanding of Earth's layers and surface characteristics by providing detailed data about topography, vegetation, and geological formations. These tools collectively enable scientists to analyze and monitor Earth’s environment, assisting in various fields such as geology, oceanography, and climate science.