Thousands of years ago, observers noticed an unusual phenomenon on the Sun which challenged their understanding of the cosmos. Today, astronomers are still studying sunspots to learn about the workings of the Sun. I’m Jim Metzner, and this is the Pulse of the Planet.
“Sunspots were first observed in the B.C. time period by naked eye observations in China and in Europe. But it wasnâ€™t until the telescope was invented in the early 1600s, that people really began to study sunspots.”
Aimee Norton is a scientist at the High Altitude Observatory at the National Center for Atmospheric Research in Boulder, Colorado.
“In the early 1600s, Aristotle’s view of the cosmos was still the predominant view. And that is that the cosmos was unchanging and ideal. So it was very difficult for scientists of that time to understand that there could be changing spots on the surface of the Sun. So, many people thought that they were moons, or that they were planets that were passing in front of the Sun and casting a dark shadow. Galileo actually watched closely enough to figure out that sunspots were part of the Sun.”
Sunspots give us a direct indication of the energy output of the Sun.
“A sunspot is a region of intense magnetic field that you see on the solar surface. Itâ€™s seen as a darker region because itâ€™s cooler than the surrounding solar surface. The magnetic field actually keeps it cooler. There is a correlation between the magnetic fields of the sun and the output of energy of the Sun. The Sun emits more energy when thereâ€™s more sunspots on the Sun.”
A typical sunspot is about the size of the Earth, although a large sunspot could fit five to ten Earths inside of it.
We’ll hear more about sunspots in future programs. Pulse of the Planet is made possible by the National Science Foundation. I’m Jim Metzner.