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Solar flares are intense bursts of light and particles from the sun. While they can pose hazards for things like satellites, these flares are also beautiful, dramatic and incredibly hot. NPR's Nell Greenfieldboyce reports on just how high the temperatures can get.
NELL GREENFIELDBOYCE, BYLINE: The sun is hot - no duh - but how hot is it? Alexander Russell is with the University of St. Andrews in Scotland. He says different parts of the sun have different temperatures. The core is around 27 million degrees Fahrenheit. It's hotter than the surface, which is only around 10,000 degrees.
ALEXANDER RUSSELL: And then it actually starts to get hotter as you move out into the outer layer.
GREENFIELDBOYCE: That outer layer is the ghostly ring you see during a total solar eclipse. It can be over 2 million degrees. What Russell wanted to understand was the temperature of solar flares. These flares erupt when a sudden release of magnetic energy sends particles shooting out. There's two kinds of particles - electrons and ions. Telescopes looking at flares can measure the temperature of the electrons.
RUSSELL: And we've kind of just assumed, well, the ion temperature would be the same as the electron temperature.
GREENFIELDBOYCE: The trouble is, that doesn't seem to be true, at least not according to recent computer simulations and measurements in near-Earth space. They say that actually, ions can get way hotter than electrons. So Russell and his colleagues did some calculations, and they now say that solar flares could be more than six times hotter than previously known - over 100 million degrees Fahrenheit, maybe even up to 180 million.
RUSSELL: Which is kind of a crazy number.
GREENFIELDBOYCE: They've published their analysis in Astrophysical Journal Letters. One person who was happy to see it is James Drake. He's a physicist at the University of Maryland. He and his research partners have long been studying how magnetic energy gets dumped into particles like electrons and ions. He says the difference between the two has been overlooked when it comes to solar flares.
JAMES DRAKE: We've been confronting the solar physicists, telling them that even though they've measured in a lot of detail what's going on with the electrons, they're missing something big.
GREENFIELDBOYCE: He says adding this piece in should improve scientists' understanding of how solar flares and their associated phenomena actually work, which could help protect hardware like satellites and people like astronauts from these dangerous but awesome eruptions.
Nell Greenfieldboyce, NPR News.
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