These solar twisters are a combination of hot-flowing gas and tangled magnetic field lines, ultimately driven by nuclear reactions in the solar core. Giant super-tornados may also play a role in heating the sun's outer layer. Millions of them are going off every second across the sun, and collectively they heat the corona." "Despite being tiny by solar standards, each packs the wallop of a 10-megaton hydrogen bomb. "The explosions are called nanoflares because they have one-billionth the energy of a regular flare," Jim Klimchuk, a solar scientist at NASA's Goddard Space Flight Center (opens in new tab) in Maryland, said in a statement. Research suggests that tiny explosions known as nanoflares may help push the temperature up by providing sporadic bursts reaching up to 18 million F (10 million C). When you're roasting a marshmallow you move it closer to the fire to cook it, not farther away." "Things usually get cooler farther away from a hot source. "That's a bit of a puzzle," Jeff Brosius, a space scientist at Catholic University in Washington, D.C., and NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. Why the corona is up to 300 times hotter (opens in new tab) than the photosphere, despite being farther from the solar core, has remained a long-term mystery. As the gases cool, they become the solar wind. Temperatures in the sun's corona (opens in new tab) can get as high as 3.5 million degrees F (2 million degrees C). It appears as white streamers or plumes of ionized gas that flow outward into space. Like the chromosphere, the sun's corona can only be seen during a total solar eclipse (or with NASA's Solar Dynamics Observatory (opens in new tab)). The third layer of the sun's atmosphere is the corona.
(Image credit: NASA/SDO) (opens in new tab) “All of Solar Probe’s instruments are hidden behind the heat shield.The third layer of the sun's atmosphere is the corona. “It’s sort of like if you’re sampling the atmosphere here on Earth – you don’t need to point at a particular direction,” Dantzler said. The whole spacecraft is optimally designed to dissipate heat,” Dantzler told New Scientist.Īnd because the spacecraft will be embedded inside the corona, instruments don’t ever have to point directly at the Sun.
“It’s not your run-of-the-mill spacecraft. The side of the shield facing the Sun will heat up to 1400 ☌elsius (2600 ☏), while the instrument-carrying payload behind the shield will remain at room temperature, said Solar Probe project manager Andrew Dantzler. The heat shield technology is based on that used in Messenger, a NASA spacecraft that completed its first flyby of Mercury in January and that was also designed by engineers at APL. The mini-bus sized Solar Probe will be protected from the Sun’s fierce radiation by a disc-shaped, carbon-composite heat shield that will be 2.7 metres in diameter and about 15 centimetres thick. But scientists have only recently been able to design heat shields for such a spacecraft within NASA’s tight budgetary guidelines. The idea of studying the Sun at close range was first proposed by the US National Academy of Science in 1958.
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