Shop Windows to the Universe

Learn about planets outside our solar system through Exoplanets and Alien Solar Systems by Tahir Yaqoob, Ph.D., a book in our online store book collection.

Animation courtesy of NASA/Walt Feimer, Max-Q Digital.

Journey Beneath a Sunspot

This animation takes us on a fanciful flight beneath the surface of the Sun. At the start, we are looking down at an active region on the photosphere, the visible "surface" of the Sun. Looping magnetic field lines, shown as silvery-white tubes, rise out of one sunspot and descend back into another. Sunspots are darker areas on the Sun's surface where extremely powerful magnetic fields inhibit the inflow of hot plasma, making the sunspots somewhat cooler and dimmer than their surroundings.

Zooming in, our make-believe flight takes us beneath the surface of the photosphere to the upper reaches of the Sun's interior. Starting in the 1960s, solar astronomers have used a technique called helioseismology to study the interior of the Sun. By observing the motion of pressure waves on the Sun's surface, they can infer properties of the solar interior beneath. On our imaginary flight, we see clusters of looping magnetic field lines rise from the depths and "break" the surface, creating sunspots at the photosphere.

Rising once again above the surface, we see one loop of a magnetic flux "rope" narrow and then get "pinched off" in a process called magnetic reconnection. Like an overstretched rubber band that snaps, this reconnection process releases lots of energy. This animation shows this energy release producing a solar flare - a sudden local brightening of the photosphere below - and a coronal mass ejection (CME) - a swarm of energetic particles blasting off into space.

Right-click (Windows) or Option-click (Mac) on one of the following links to download a copy of this video in either the QuickTime (6.1 MB) or MPEG (5.9 MB) format.

Last modified December 30, 2009 by Randy Russell.

Shop Windows to the Universe Science Store!

Cool It! is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store.

Windows to the Universe Community



You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Active Regions on the Sun

An active region on the Sun is an area with an especially strong magnetic field. Sunspots frequently form in active regions. Active regions appear bright in X-ray and ultraviolet images. Solar activity,...more

The Photosphere - the "Surface" of the Sun

Most of the energy we receive from the Sun is the visible (white) light emitted from the photosphere. The photosphere is one of the coolest regions of the Sun (6000 K), so only a small fraction (0.1%)...more

The Sun's Magnetic Field

The Sun has a very large and very complex magnetic field. The magnetic field at an average place on the Sun is around 1 Gauss, about twice as strong as the average field on the surface of Earth (around...more


Sunspots are dark, planet-sized regions that appear on the "surface" of the Sun. Sunspots are "dark" because they are cooler than their surroundings. A large sunspot might have a central temperature of...more

Sunspots and Magnetic Fields

Sunspots are caused by extremely strong, localized magnetic fields on the Sun. "Jet streams" of plasma that form deep within the Sun's convective zone produce powerful magnetic fields. When these loops...more

The Magnetic Field

The force of magnetism causes material to point along the direction the magnetic force points. This property implies that the force of magnetism has a direction. As shown in the diagram to the left, the...more

Particle Radiation

One main type of radiation, particle radiation, is the result of subatomic particles hurtling at tremendous speeds. Protons, cosmic rays, and alpha and beta particles are some of the most common types...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA