When you imagine satellite images, you probably see sharp photos of the Earth taken from orbit. But another technology used to image the planet, synthetic erture radar (SAR), is heating up following an increase in public and private satellite broadcasts. SAR satellites use radars, not cameras, to take snshots of the earth. Comparison of two SAR images taken at different times from the same position, a technique known as interferometric SAR (InSAR), can detect surface movements of only a few millimeters. Watch the video to learn how InSAR transforms earth science – and what to expect from the technology in the coming years.