NASA eyeballs solar heat bombs, mini-tornadoes and nanoflares on Sun
Astro boffins probe fiery star's hidden depths
NASA scientists have unveiled data that they believe shows how the Sun's energy moves from the surface of the star at the centre of our Solar System through its fiery atmosphere.
In a series of papers published in the latest issue of Science magazine, the astro boffins presented their findings from the US space agency's Interface Region Imaging Spectrograph (IRIS), which was launched into orbit last year.
"This set of research really delivers on the promise of IRIS, which has been looking at a region of the Sun with a level of detail that has never been done before," said Bart De Pontieu, the project's science lead at Palo Alto, California-based Lockheed Martin.
"The results focus on a lot of things that have been puzzling for a long time and they also offer some complete surprises."
The researchers claim to have uncovered a number of "clues" about what heats the interface region, dubbed the corona, which – as NASA explained – is sandwiched between the solar surface and its outer atmosphere.
All the energy to power the Sun's incredible output passes through the corona first.
Scientists at the Gottingen, Germany-based Max Planck Institute for Solar System Research observed what they described as "big surprises" using the IRIS data.
They spotted heat pockets of 200,000 F, much lower down in the solar atmosphere than expected. The boffins names the pockets bombs due to their short, sharp energy release.
"These unexpected results will likely lead to a reassessment of other phenomena in the low solar atmosphere," said IRIS principal investigator Alan Title.
Elsewhere, researchers pored over other aspects of the data to see if IRIS revealed more surprises within the Sun. Mini-tornadoes swirling at up to 12 miles per second were spotted throughout the interface region just above the Sun's surface, known as the chromosphere.
"These twisting motions are often associated with heating to hundreds of thousands of degrees," De Pontieu said.
Scientists, in another paper revealing results of the IRIS data, found "ubiquitous nanoflares throughout the corona."
"Nanoflares have long been associated with coronal heating," Title said.
"With this research we can show the properties of these high energy electrons and how they affect the interface region – the area where the bulk of solar atmospheric heating is known to occur."
NASA noted that the research would help scientists also understand how high-speed electrons occur in other stars. ®