Scientists have long puzzled over why the surface of the sun is cooler than its corona, the outer hazy atmosphere visible during a solar eclipse. Now thanks to a five-minute observation by a small, but very high-resolution ultraviolet telescope they have some answers.
Even before the July 2012 launch of the High-resolution Coronal Imager, nicknamed Hi-C, scientists suspected that magnetic fields on the sun were responsible for ramping up its energy, resulting in a flaring corona that can reach 7 million degrees Fahrenheit, compared to a visible solar surface temperature of about 10,000 degrees.
Hi-C, which was launched aboard a suborbital rocket to study the sun without interference from Earth's atmosphere, revealed interwoven magnetic fields braided like hair. When the braids relaxed, they released energy.
"I had no idea we would see structures like that in the corona. Seeing these braids was very new to me," astrophysicist Jonathan Cirtain with NASA's Marshall Space Flight Center in Huntsville, Ala., told Discovery News.