This image shows the Martian terrain through the eyes of the Mars Exploration Rover Spirit's mini-thermal emission spectrometer, an instrument that detects the infrared light, or heat, emitted by objects. The different colored circles show a spectrum of soil and rock temperatures, with red representing warmer regions and blue, cooler. A warm and dusty depression similar to the one dubbed Sleepy Hollow stands out to the upper right. Scientists and engineers used this data to pinpoint features of interest, and to plot a safe course for the rover free of loose dust. The mini-thermal emission spectrometer data are superimposed on an image taken by the rover's panoramic camera.