New York University Skip to Content Skip to Search Skip to Navigation Skip to Sub Navigation

Researchers Create “MRI” of the Sun’s Interior Motions

September 28, 2012

A team of scientists has created an “MRI” of the sun’s interior plasma motions, shedding light on how it transfers heat from its deep interior to its surface. The result, which appeared in the journal the Proceedings of the National Academy of Sciences, upends our understanding of how heat is transported outwards by the sun and challenges existing explanations of the formation of sun spots and magnetic field generation.

The work was conducted by researchers from NYU’s Courant Institute of Mathematical Sciences and its Department of Physics, Princeton University, the Max Planck Institute, and NASA.

The sun’s heat, generated by nuclear fusion in its core, is transported to the surface by convection in the outer third. However, our understanding of this process is largely theoretical—the sun is opaque, so convection cannot be directly observed. As a result, theories largely rest on what we know about fluid flow and then applying them to the sun, which is primarily composed of hydrogen, helium, and plasma.

Developing a more precise grasp of convection is vital to comprehending a range of phenomena, including the formation of sun spots, which have a lower temperature than the rest of the sun’s surface, and the sun’s magnetic field, which is created by its interior plasma motions.

In order to develop their “MRI” of the sun’s plasma flows, the researchers examined high-resolution images of the sun’s surface taken by the Helioseismic and Magnetic Imager (HMI) onboard NASA’s Solar Dynamics Observatory. Using a 16-million pixel camera, HMI measures motions on the sun’s surface caused by convection.

Once the scientists captured the precise movement waves on the sun’s surface, they were able to calculate its unseen plasma motions.

What they found significantly departed from existing theory—specifically, the speed of the sun’s plasma motions were approximately 100 times slower than scientists had previously projected.

“Our current theoretical understanding of magnetic field generation in the sun relies on these motions being of a certain magnitude,” explains Shravan Hanasoge, a research scholar at Princeton University and a visiting scholar at NYU’s Courant Institute of Mathematical Sciences. “These convective motions are currently believed to prop up large-scale circulations in the outer third of the sun that generate magnetic fields.”

“However, our results suggest that convective motions in the sun are nearly 100 times smaller than these current theoretical expectations,” continued Hanasoge, also a postdoctoral fellow at the Max Planck Institute in Katlenburg-Lindau, Germany. “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.”

The study’s other co-authors are Thomas Duvall, an astrophysicist at NASA, and Katepalli Sreenivasan, University Professor in NYU’s Department of Physics and Courant Institute. Sreenivasan is also senior vice provost for science and technology for the Global Network University at NYU and provost of Polytechnic Institute of NYU.

Type: Article

Researchers Create “MRI” of the Sun’s Interior Motions

Search News



NYU In the News

NYU Offers Financial Aid to Undocumented Students

The Wall Street Journal reported that NYU will begin offering scholarship aid to undocumented students for the school year beginning next September.

NYU Adopts Lean LaunchPad Program to Teach Entrepreneurship

Startup guru Steve Blank, in a Huffington Post blog, described how NYU adopted the Lean LaunchPad model to teach entrepreneurship to students and faculty at NYU.

Biology Professor Jane Carlton Examines Wastewater for the City’s Microbiome

The New York Times’ Science Times column “Well” profiled Biology Professor Jane Carlton and her research project to sequence microbiome of New York City by examining wastewater samples.

Steinhardt Professors Use a Play as Therapy

The New York Times wrote about a play written by Steinhardt Music Professor Robert Landy about the relationship between Adjunct Professor Cecilia Dintino, a clinical psychologist in the Drama Therapy Program, and a patient, former Broadway actress Jill Powell.

NYU Public Health Experts Urge Strengthening Local Health Systems to Combat Ebola

Dean Cheryl Healton of the Global Institute of Public Health and Public Health Professor Christopher Dickey wrote an op-ed in the Huffington Post saying international health agencies need to strengthen their presence in countries at the local level to prevent future ebola outbreaks.

NYU Footer