NASA launches new telescope to solve sun heat mystery

[Nipuna]

About to stare at the sun (Image: Lockheed Martin/NASA)

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It's not usually a good idea to stare at the sun – unless you're a $181-million telescope, that is. NASA's Interface Region Imaging Spectrograph (IRIS) will be launched this week to probe an underappreciated aspect of the sun called the chromosphere – the region between the star's surface and its sizzling corona, the plasma layer that envelopes it.

Little is known about what happens in between. "IRIS will fill crucial gaps in our understanding of what role the interface region plays in powering the corona," said IRIS mission scientist Jeffrey Newmark.

On 26 June, an aircraft carrying a rocket with the telescope inside will launch from Vandenberg Air Force Base in California, and will release its payload 12 kilometres up. The rocket will then carry the telescope to its orbit 660 kilometres above the Earth.

IRIS has a higher resolution than previous observatories that have studied the chromosphere. It will track short-lived jets of plasma, which NASA hopes will help explain why the corona, at 1 million kelvin, is so much hotter than the surface, at a mere 6000 kelvin.

"How that happens is a mystery," says IRIS principal investigator Alan Title of Lockheed Martin's Advanced Technology Center in Palo Alto, California.