In an effort to study the sun’s emission of high-energy X-rays, NASA is looking at the Earth’s closest star.

It goes without saying that the sun and black holes have very little in common. However, NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, which was launched in 2012 has been shifted to study the sun rather than the black holes for which it was designed.

NASA's Black Hole Telescope Turned To The Sun

NuSTAR is NASA’s only telescope array capable of studying black holes millions of light years away, but it also is perfect for observing X-rays produced by small solar flares called nanoflares inside the sun’s corona.

Mr. Smith goes to the sun

David Smith, of the University of California, Santa Cruz, approached NASA prior to the launch of the array hoping that NASA might observe something far closer to the Earth, the sun.

“At first I thought the whole idea was crazy,” said NuSTAR principal investigator Fiona Harrison of the California Institute of Technology in Pasadena, Calif. “Why would we have the most sensitive high energy X-ray telescope ever built, designed to peer deep into the universe, look at something in our own back yard?”

NuSTAR is ideal for study the sun, not something that all telescopes can do without they themselves being blinded. That is due to NuSTAR’s detection of high energy X-rays while blocking out the lower-energy X-rays.

Why is the sun’s corona so hot?

Smith and others in his field have long wondered why the sun’s corona is so damned hot when compared the surface of the sun. For those who have touched a lightbulb left on for hours, you notice that the surface is considerably hotter than the air around it, this is not the case with the sun’s corona which is indeed considerably hotter.

There are a couple of theories why this is the case and Smith is hoping to figure out which is more likely: the heating caused by coronal plasma or the effects caused by nanoflares that drives coronal heating.

“NuSTAR will give us a unique look at the sun, from the deepest to the highest parts of its atmosphere,” said Smith, who is also a member of the NuSTAR team. “NuSTAR will be exquisitely sensitive to the faintest X-ray activity happening in the solar atmosphere, and that includes possible nanoflares.”