A tiny spacecraft with its gaze trained on the sun has observed the strongest solar flare since it launched into orbit last summer, NASA announced.
NASA's sun-watching IRIS observatory captured an amazing video of the mid-level solar flare on Jan. 28 while observing a magnetically active region on the sun.
The IRIS spacecraft ( the name is short for Interface Region Imaging Spectrograph) is on a mission to study the mysteries of our nearest star, including the forces behind the huge eruptions known as solar flares. These solar events occur when the twisted magnetic field lines of the sun cross and reconnect, causing explosions with the force millions of hydrogen bombs that send X-rays and light streaming into space. Sometimes, the resulting radiation storms are powerful enough to trigger radio blackouts on Earth. [Photos: NASA's IRIS Sun Observatory Mission in Space]
In recent months, more powerful solar flares have burst on the sun than the one IRIS saw, including an X1.2-class solar event on Jan. 7 that delayed a private cargo mission to the International Space Station. IRIS, however, only peeks at 1 percent of our star at a time.
But this up-close view means IRIS can make out features as small as 150 miles (240 km) across. It also gives IRIS an unprecedented look at the chromosphere, the layer of the sun's lower atmosphere just above the surface. The chromosphere regulates the flow of energy and material traveling from the sun's surface out into space, NASA officials say.
The spectrograph aboard IRIS can distinguish individual wavelengths of light, which in turn correspond to different temperatures, velocities and densities of solar material. Since the spectrograph was aimed at the heart of this flare when it hit its peak, the data obtained could help scientists understand how flares work, according to NASA.
The $120 million IRIS mission launched aboard an Orbital Sciences Corp. Pegasus XL rocket from Vandenberg Air Force Base in California on June 27, 2013. The spacecraft belongs to NASA's Small Explorer program, which puts a budget cap of $120 million on each mission.
The probe weighs 400 pounds (181 kilograms) and measures just 7 by 12 feet (2.1 by 3.7 m) with its solar panels extended. IRIS circles Earth in a polar orbit that takes it over the equator at the same local time each day.