Caramel corn or the sun?

Credit: NSO/AURA/NSF

The new pictures from NSF’s Inouye Solar Telescope confirm that the sun is made of caramel corn, right? Well, not quite.

Though the likeness is uncanny, the sun is more complex than that. What you see in the solar telescope pictures is called hot plasma, a scorching gas that’s boiling toward the sun’s surface in a process called convection.

The individual “kernels,” called granules, are formed by physics inside the sun. To put it briefly, hotter plasma rises and cooler plasma sinks. You can see the same process here on Earth in a pot of boiling water. Hot liquid at the bottom rises to the surface and pushes cooler liquid aside. Eventually the cooler liquid sinks, then rises again as it’s reheated.  In the sun’s case, the furnace powering the heat is its core.  

Rising kernels, or granules, are formed inside the sun, where plasma is hot and bright. Cooler material at the surface looks darker as it’s pushed downward, leaving dark channels between the granules.

Credit: NSO/AURA/NSF

The top 125,000 miles of the sun are roiling with convection, which produces granules that, though they look like small popcorn kernels, are hundreds of miles wide –- close to the area of Texas.  

Although they may look like caramel corn, their color is far from golden. Astronomical cameras take black-and-white pictures through filters that isolate specific colors of light. Scientists then use computer image processing to add colors and reveal gradients to bring out the most interesting features.

Here the image was taken at a wavelength that, when perceived by the human eye, looks like a shade of red. Additional techniques were used to reduce what researchers call “noise,” or interference; these enhance the image’s contrast and color depth, and bring out subtle details.

Next time you order popcorn at the movies, imagine each kernel as a granule on the sun.  Luckily for Earthlings, our granules aren’t made of hot plasma.