A team of researchers from NYU’s Courant Institute of Mathematical Sciences and its Department of Physics, Princeton University, the Max Planck Institute, and NASA have created an “MRI” of the sun’s interior motions.
Looking for Some Hot Stuff
The sun’s inner core creates heat through a process called nuclear fusion. The heat moves to the outer surface of the sun through convection. Since the sun is opaque, not much has been learned about how the process works. Scientists have had to rely on studies of fluid models and then try to apply those observations to the sun.
The sun is primarily composed of hydrogen, helium, and plasma. Plasma according to Princeton’s website is “a fourth state of matter distinct from solid or liquid or gas and present in stars and fusion reactors; a gas becomes a plasma when it is heated until the atoms lose all their electrons, leaving a highly electrified collection of nuclei and free electrons”. It is also the primary contributor to the sun’s magnetic fields. This study sought to grasp a better understanding of phenomenon such as sun spots and magnetic fields. A fantastic NASA video showing activity on the surface of the sun is embedded below.
Smile! Say Cheese
To get their “MRI” the researchers relied on NASA’s Solar Dynamics Observatory to get a high definition picture of the sun’s surface. The Helioseismic and Magnetic Imager measures the effects of convection on the sun’s surface using a 16 million pixel camera. No hiding any sun spots or blemishes with a camera like that!
The end result of the research showed that many of our assumptions about the sun were incorrect. Current theory about the sun’s magnetic field rely on assumptions about the speed and magnitude of the sun’s inner motions. According to an NYU press release, study author Shravan Hanasoge, an associate research scholar in geosciences at Princeton University and a visiting scholar at NYU’s Courant Institute of Mathematical Sciences said, “our results suggest that convective motions in the Sun are nearly 100 times smaller than these current theoretical expectations” Hanasoge continued saying “If these motions are indeed that slow in the Sun, then the most widely accepted theory concerning the generation of solar magnetic field is broken, leaving us with no compelling theory to explain its generation of magnetic fields and the need to overhaul our understanding of the physics of the Sun’s interior.”
As so often happens in science, further research sometimes opens more questions and challenges the theories of the day. This research has been published in the Proceedings of the National Academy of Sciences.