The best reaches of the sun’s atmosphere are hundreds of times hotter than its surface, and a brand new study reveals that this mysterious heat discrepancy might be explained by weak but regular waves propagating within the region.
The “surface” of the sun — the photosphere, or sun’s visible part — is about 10,000 degrees Fahrenheit (5,500 degrees Celsius). Oddly, nonetheless, regardless that it’s farther away from the sun’s core, the uppermost a part of the sun’s atmosphere — referred to as the corona — is way hotter, usually reaching about 1.8 million to three.6 million degrees F (1 million to 2 million degrees C). Sometimes, coronal temperatures even reach as much as 72 million degrees F (40 million degrees C), in keeping with NASA.
The corona, which is made up of hot ionized gas called plasma, can be where extreme space weather events equivalent to solar flares originate. Nevertheless, it stays uncertain how the corona gets so hot.
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In the brand new study, researchers investigated common fluctuations related to the sun referred to as low amplitude decayless kink oscillations. These are fluctuations in coronal loops, or arch-like structures fabricated from plasma that start within the photosphere and extend into the lower corona. These waves are relatively weak, but don’t decay in strength over multiple cycles of fluctuation. As such, they might potentially supply a considerable amount of energy into the corona over time.
The scientists focused on the way in which through which these waves rippled either up and down, left and right, or at any angle in between, a property referred to as their polarization. The flexibility to investigate this aspect of the waves’ 3-D geometry could make clear their origins in addition to how much energy they’ve available. Nevertheless, scientists previously lacked a technique to examine these waves from multiple lines of sight and due to this fact detect the phenomena’s polarization.
In the brand new study, the researchers used data from the European Space Agency’s Solar Orbiter and NASA‘s Solar Dynamics Observatory to investigate the solar corona from multiple vantage points. They successfully detected a 4-minute decayless kink oscillation of a coronal loop.
The scientists found these waves nearly all vibrate in the identical direction. This means they’re “likely related to long-duration flows within the solar surface,” study co-author Valery Nakariakov, a solar physicist on the University of Warwick in Coventry, England, told Space.com.
This discovery suggests energy from the solar surface can reach the corona and warmth it. “Our finding provides essential information for answering the long-standing query of what heats the corona of the sun,” Nakariakov said.
The scientists detailed their findings online Sept. 12 within the journal Nature Communications.