The end goal is to help us understand solar variations that influence life on Earth by determining how the Sun's magnetic field is generated and structured and 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.
The movie recorded on April 19th spans four hours of actual time and almost 50,000 miles of linear space. "It's huge," says Karel Schrijver of Lockheed Martin's Solar and Astrophysics Lab, who is leading the analysis - the entire planet Earth could fit between the plasma streamers with room to spare. I feel wee little next to that.
Magnetic filament on April 19th. The black hair-like object is a speck of dust on the CCD camera, not Mayans about to invade or anything crazy. Credit: SDO/AIA.
Schrijver told NASA's Tony Philips the coronal rain has long been a mystery that appears to have been solved. It's no surprise that plasma would fall back to the Sun like rain, given its immense gravity, but the question was why it falls so slow. "The rain appears to be buoyed by a 'cushion' of hot gas," said Schrijver. "Previous observatories couldn't see it, but it is there."
SDO contains an array of ultraviolet telescopes called the Atmospheric Imaging Assembly (AIA), so it can measure the temperature of gas in the sun's atmosphere. Coronal rain turns out to be relatively cool, they say, only 60,000 K(!) but as it falls it is supported by an underlying cushion of much hotter material, between 1,000,000 and 2,200,000 K.
Color-coded temperature movie of the eruption. Red and oranges are cooler, 60,000 - 80,000K, while blues and greens are hot: 1,000,000-2,200,000K). A speck of dust is on the CCD camera. Credit: SDO/AIA
The specs on SDO is that it is a sun-pointing semi-autonomous spacecraft that will allow nearly continuous observations of the Sun with a data downlink rate of 130 Mbps. SDO is 4.5 meters high, over 2 meters on each side and weighs 3,100 kg with fuel. SDO's inclined geosynchronous orbit was chosen to allow continuous observations of the Sun and enable its (exceptionally) high data rate through the use of a dedicated ground station.
SDO's orbit is located on the outer reaches of the Earth's radiation belt, where radiation can be quite high, so additional shielding was added to the instruments and electronics to reduce the problems caused by exposure to radiation - that Space Weather effect, the very thing SDO is designed to study.
More: Solar Dynamics Observatory home page