A Super-Technicolor World
The colors that we see in the world around us provide more information than would be available in a black-and-white world. An orange is easy to distinguish from a grapefruit because of color. Red and yellow leaves on trees signal the transition from summer to fall. It is because of the interaction of light and matter that we see objects in different colors. If we could see the world in infrared colors, we would discover even more details.
The Interaction of Light and Matter
When matter is exposed to the electrical and magnetic components of light, the atoms and molecules within it are affected. The chlorophyll molecules in plants absorb UV and most visible wavelengths, but reflect green and near-IR light. The minerals in rocks absorb and reflect thermal IR light of different wavelengths (colors) depending on the composition of each mineral. Because every mineral absorbs and reflects thermal IR differently, each has its own spectral signature in these wavelengths. If our eyes could see thermal IR light, every mineral would have a unique color. This is also true of the gas molecules in the atmosphere and frozen molecules in ice. The TES instrument views Mars with thermal IR detecting "eyes". This means that we can identify what minerals are on its surface, what gases are in its atmosphere, and what ices are at the poles. To learn how we measure thermal IR energy, read on.
