A small National Aeronautics and Space Administration (NASA) satellite was set for launch Thursday on a mission to determine how the sun heats its atmosphere to millions of degrees, sending off rivers of particles that define the boundaries of the solar system. The study is significant because solar activity directly impacts Earth's climate and the space environment beyond the planet's atmosphere. Solar storms also can disable power grids, disrupt radio signals, and interfere with navigation, communication, and other satellites in orbit. Scientists long have wondered how the sun manages to release energy from its relatively cool 5,500-degree Celsius surface into an atmosphere that can reach up to 2.8 million degrees Celsius. Images and data relayed by the Interface Region Imaging Spectrograph (IRIS) telescope may finally provide some answers. The 1.2 meter, 204 kilogram telescope will observe the sun from 640 kilometers above Earth. "Every time we look at the sun in more detail, it opens up a new window for us," said IRIs program scientist Jeffrey Newmark.
