Solar Radiation and Climate Experiment Solar Radiation and Climate Experiment The Solar Radiation and Climate Experiment (SORCE) is a NASA-sponsored satellite mission that measures incoming X-ray, ultraviolet, visible, near-infrared, and total solar radiation. These measurements specifically address long-term climate change, natural variability and enhanced climate prediction, and atmospheric ozone and UV-B radiation. These measurements are critical to studies of the Sun, its effect on our Earth system and its influence on humankind. The SORCE spacecraft launched on January 25, 2003 on a Pegasus XL launch vehicle to provide NASA's Earth Science Enterprise (ESE) with precise measurements of solar radiation. SORCE measures the Sun's output using
Kirchhoff's law of thermal radiation law. This law turned out to be inconsistent yielding the ultraviolet catastrophe. The correct form of the law was found by Max Planck in 1900, assuming quantized emission of radiation, and is termed Planck's law. This marks the advent of quantum mechanics. In a blackbody enclosure that contains electromagnetic radiation with a certain amount of energy at thermodynamic equilibrium, this "photon gas" will have a Planck distribution of energies. One may suppose a second system, a cavity with walls that are opaque, rigid, and not perfectly reflective to any wavelength, to be brought into connection, through an optical filter, with