The Solar Dynamics Observatory (SDO) is designed to help us understand the Sun's influence on Earth and Near-Earth space by studying the solar atmosphere on small scales of space and time and in many wavelengths simultaneously.
SDO's goal is to understand, driving towards a predictive capability, the solar variations that influence life on Earth and humanity's technological systems by determining how the Sun's magnetic field is generated and structured as well as how this stored magnetic energy is converted and released into the heliosphere and geospace in the form of solar wind, energetic particles, and variations in the solar irradiance.
SDO has three major instruments: The Helioseismic and Magnetic Imager (HMI), the Atmospheric Imaging Assembly (AIA), and the Extreme-ultraviolet Variability Experiment (EVE).
HMI observes the full disk of the Sun's surface; the photosphere. It takes remarkably high-definition images at a rate of an image per second. For the next five years, HMI will observe every sunspot and will model the flow of plasma beneath them, to a depth of 12,000 miles.
AIA observes the Sun's outermost atmosphere, the corona. It takes high-resolution images in multiple wavelengths of light which correspond to different temperatures in a 2 million-degree Celsius range. Along with data from other solar observatories, AIA will help astronomers better understand the physics that drives the activity in the corona by watching erupting filaments and prominences to see how the temperature, structure, and mass change as they lift off the surface, into the atmosphere, and out into space.
EVE measures the variability in the solar irradiance in the extreme-ultraviolet. When eruptions like flares occur on the Sun and eventually reach Earth, they dump high-energy radiation and particles which shapes the Earth's ionosphere and causes "space weather." EVE aims to help astronomers understand why there is solar irradiance variability as well as allow astronomers to more accurately predict when eruptions and irradiance variability will occur.