Scientists uncover evidence to explain Sun's hot outer atmosphere

Scientists have uncovered some of the strongest evidence to date to explain what made the Sun's outer atmosphere so much hotter than its surface, PTI reported.

According to researchers, the answer lay in nanoflares, the constant hammering of impulsive bursts of heating, none of which could be individually detected, which provided the mysterious extra heat.

The new observations come from only six minutes worth of data from one of NASA's least expensive type of missions, a sounding rocket, according to researchers.

The Sun's visible surface, known as the photosphere, has a temperature of around 6,000 Kelvins, while the corona regularly reached temperatures which were 300 times that high.

A number of theories had been suggested as to how the magnetic energy coursing through the corona was converted into the heat that raised the temperature.

The EUNIS rocket, short for Extreme Ultraviolet Normal Incidence Spectrograph, however, had a very sensitive version of an instrument called a spectrograph.

Spectrographs gather information about the amount of material present at a given temperature, by recording different wavelengths of light.

EUNIS reached up to 321 km above the ground on board a sounding rocket, a type of NASA mission that flew for only 15 minutes or so, and gathered around six minutes worth of observations from above the planet's air.

The probe scanned an active region of the sun which was the source of large solar flares and coronal mass ejections, China Topix reported.

According to Adrian Daw, EUNIS principal investigator, EUNIS  was a less expensive way of producing a robust science find.

The EUNIS mission offered a valuable test bed for new technology that might at a later date be flown on long-term space mission.

EUNIS would take flight again in 2016 where it would focus on different solar wavelengths that could spot the extremely high temperature materials like nanoflares.