The Jovian Infrared Auroral Mapper (JIRAM) will study Jupiter’s atmosphere in and around the auroras, learning more about the interactions between the auroras, the magnetic field and the magnetosphere. JIRAM will be able to probe the atmosphere down to 50 to 70 kilometers (30 to 45 miles) below the cloud tops, where the pressure is five to seven times greater than at Earth’s sea level. JIRAM consists of a camera and spectrometer, which splits light into its component wavelengths, like a prism. The camera will take pictures in infrared light, which is heat radiation with wavelengths of two to five microns (millionths of a meter) – three to seven times longer than visible wavelengths. In particular, the instrument will snap photos of auroras at a wavelength of 3.4 microns – the wavelength of light emitted by excited hydrogen ions in the polar regions. Methane in the atmosphere absorbs light at this same wavelength, darkening the atmosphere behind the auroras. In front of a darkened background, the auroras stand out even more brightly. The instrument will also try to learn about the structure and origin of voids in Jupiter’s atmosphere called hot spots. These spots – like the one the Galileo probe happened to have dropped into in 1995 – are windows into the depths of Jupiter’s atmosphere. By measuring the heat radiating from Jupiter’s atmosphere, JIRAM can determine how water- containing clouds circulate under the surface. It turns out that this sort of motion – called convection, in which hot gas rises and cool gas sinks – reveals the amount of water in these clouds. Certain gases in the atmosphere – methane, water, ammonia and phosphine, in particular – absorb certain wavelengths of infrared light. When the spectrometer measures the infrared rainbow emitted by Jupiter, the wavelengths of light absorbed by those gases would be missing. The missing wavelengths indicate the chemical composition of the atmosphere. JIRAM was developed by the Italian National Institute for Astrophysics and funded by the Italian Space Agency.