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Rogue plasma waves, rapidly flipping magnetic fields - these are some of the surprises that a NASA spacecraft has found near our sun. The Parker Solar Probe blasted off last year on a mission to get closer to the sun than ever before.
NPR's Nell Greenfieldboyce reports that some of what it's seen is so strange, researchers initially thought their instruments were broken.
NELL GREENFIELDBOYCE, BYLINE: The Parker Solar Probe was built to withstand the searing temperatures around the sun. It blasted off in August of 2018. Flybys of Venus help it adjust its orbit so that it gradually gets closer and closer to the sun. So far, it swung close by three times, coming about 15 million miles from the sun. That's a lot closer than the nearest planet, Mercury.
JUSTIN KASPER: The sun's already looking very different from what we've seen before.
GREENFIELDBOYCE: Justin Kasper is an astrophysicist at the University of Michigan. He says one of the biggest findings is something that could explain a long-standing mystery - why the sun's atmosphere is so much hotter than its surface.
KASPER: In apparent violation of, like - oh, I don't know - the second law of thermodynamics.
GREENFIELDBOYCE: He says it's just weird, like if you were walking away from a campfire and, instead of getting colder, the air got hotter.
KASPER: We have to identify some way that energy leaves the sun, travels out into space and then gets deposited.
GREENFIELDBOYCE: He says the Parker Solar Probe might have just found out how that happens. Close to the sun, there are strange features in a plasma called the solar wind, charged particles that are constantly streaming out into space.
KASPER: We'd see suddenly a spike in flow where, in just a couple seconds, the solar wind would start flowing 300,000 miles an hour faster.
GREENFIELDBOYCE: These spikes would only last a few seconds or minutes.
KASPER: But they nearly double the speed of the solar wind. And they're so violent, they actually flip the direction of the magnetic field in the solar wind around.
GREENFIELDBOYCE: The magnetic field kind of reverses itself and then straightens out again. Nicky Fox is director of NASA's Heliophysics Division and was previously the project scientist for the Parker Solar Probe.
NICOLA FOX: It's kind of like twisting, like, a rubber hose. It wants to continually straighten itself again. And so whatever is causing these features, as it is straightening out, it's giving out energy.
GREENFIELDBOYCE: She says all of this could explain what's heating up the sun's atmosphere.
FOX: And so to see the sort of smoking gun for our main questions of heating and acceleration of the solar wind was just an incredible thing.
GREENFIELDBOYCE: These results are reported in the journal Nature, along with plenty of others. For example, the solar wind rotates around the sun far faster than expected. And although the solar system can be a dusty place, it looks like the sun vaporizes or pushes out nearby dust.
FOX: We've actually found a dust-free region close to the sun, and that was first predicted back in 1929.
GREENFIELDBOYCE: The Parker Solar Probe was named after Eugene Parker, a superstar in studies of the sun, who first proposed the existence of the solar wind back in the 1950s. It's the first NASA mission named after a living person. Parker, who's now 92 years old, got to see the rocket launch that carried the probe into space. Fox visited him at his home in Chicago earlier this year.
FOX: I showed him a lot of the early science data, and he was very excited and very moved.
GREENFIELDBOYCE: The probe's next approach to the sun will come in January. Its closest approach will be in 2025, when it will come within 4 million miles of the sun's surface.
Nell Greenfieldboyce, NPR News.
(SOUNDBITE OF RAMIN DJAWADI'S "BLACK HOLE SUN")
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