There is a mysterious area just above the sun’s surface called the interface region. This region, which is only 3,000 to 6,000 miles thick, is constantly experiencing movement of heat and energy. This energy helps heat the corona, the upper layer of the atmosphere, to temperatures of 1 million kelvins (approximately 1.8 million Fahrenheit). That makes this part of space nearly a thousand times hotter than the surface of the sun.
NASA’s IRIS Mission has been announced to study exactly how that energy travels through this area. IRIS stands for Interface Region Imaging Spectograph and is set to launch on June 26, 2013, from California’s Vandenberg Air Force Base.
Studying this particular area of space is important because the energy that flows through the interface region has an effect on many aspects of near-Earth space. For example, only a fraction of the energy there leaks through, but that fraction actually drives the solar wind, creating a constant stream of particles that flows out into the entire solar system. This region is also the source of most of the sun’s ultraviolet emissions, which impacts near-Earth space and Earth’s climate.
Joe Davila, IRIS project scientist at Goddard Space Flight Center in Maryland, said, “IRIS will extend our observations of the sun to a region that has historically been difficult to study. Understanding the interface region better improves our understanding of the whole corona and, in turn, how it affects our solar system.”
IRIS is tailored to provide high-resolution images and can capture data on about one percent of the sun at any given time. Although these images will be small, IRIS will still be able to see a lot of detail in those images, as small as 150 miles across. Velocity, temperature and density information will be provided by IRIS’ spectograph, which can show details about many wavelengths of light at once. Analysis of this can provide key information about how heat and energy moves through the region.
IRIS also has highly advanced computing skills to assist in interpreting the data it collects.
“When you observe the interface region, there is no intuitive approach to understanding the light’s path from the sun’s surface and that’s been a major stumbling block,” said Bart De Pontieu, the IRIS science leed at Lockheed Martin. “We’re trying to understand something that’s hidden in a fog — but now, thanks to the enormous advance of computers and sophisticated numerical models, the fog is lifting.”
IRIS will take flight to the skies using a Pegasus XL rocket, carried aloft by an Orbital Sciences L-1011 aircraft from Vandenberg. After it has been deployed, it will spread its solar panels, which measure about 12 feet across. IRIS will then move in a polar orbit in synchronicity with the sun, traveling around Earth.