Sun More Violent Than Believed
December 9, 2013

IRIS Shows Parts Of The Sun More Violent Than We Thought

Lee Rannals for - Your Universe Online

NASA's newest solar observatory is showing the region located between the surface of the sun and its atmosphere is more violent than previously thought. The Interface Region Imaging Spectrograph (IRIS) spacecraft launched earlier this summer to study what is known as the interface region. For the past six months, IRIS has given scientists detailed images of this region, finding even more turbulence and complexity than expected.

"The quality of images and spectra we are receiving from IRIS is amazing," said Alan Title, IRIS principal investigator at Lockheed Martin in Palo Alto, California. "And we're getting this kind of quality from a smaller, less expensive mission, which took only 44 months to build."

IRIS’ observations open a new window into the dynamics of the low solar atmosphere that play a pivotal role in accelerating the solar wind and driving solar eruptive events. The spacecraft is able to capture both images and data on how much of any given wavelength of light is present. This data has shown the interface region is even more violent and turbulent than scientists imagined.

"We are seeing rich and unprecedented images of violent events in which gases are accelerated to very high velocities while being rapidly heated to hundreds of thousands of degrees," said Bart De Pontieu, lead IRIS scientist at Lockheed Martin. "These types of observations present significant challenges to current theoretical models."

There have been two particular types of events on the sun that have been interesting to scientists. One of these events, known as a solar prominence, leads to solar storms that can reach Earth. The second event, called spicules, are giant fountains of gas that shoot up from the sun’s surface at 150,000 miles per hour. Scientists say spicules play a role in distributing heat and energy in the sun’s atmosphere.

IRIS is allowing scientists to see how spicules evolve for the first time. They are finding with these observations that spicules are more complex than what existing theoretical models predicted.

"We see discrepancies between these observations and the models and that is great news for advancing knowledge," said Mats Carlsson, an astrophysicist at the University of Oslo in Norway. "By seeing something we don't understand we have a chance of learning something new."

IRIS scientists presented the mission’s early observations during a press conference at the American Geophysical Union meeting in San Francisco on Monday.