Shop Windows to the Universe

The Universe at Your Fingertips 2.0 DVD from the Astronomical Society of the Pacific is in our online store, filled with Earth and space science resources.

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

Journey Beneath a Sunspot

This movie takes us on an imaginary flight beneath the surface of the Sun. At the start, we are looking down at an active region on the photosphere. The photosphere is the visible "surface" of the Sun. Looping magnetic field lines are shown as silvery-white tubes. The magnetic field loops rise out of one sunspot and go back down in another. Sunspots are darker areas on the Sun's surface. Sunspots have very powerful magnetic fields that prevent hot plasma from flowing into them. This makes the sunspots cooler and darker than their surroundings.

Zooming in, our pretend flight takes us under the photosphere to the upper parts of the Sun's interior. Astronomers use 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 figure out what is going on underneath. On our imaginary flight, we see bundles of looping magnetic field lines rise from the depths and "break" the surface, creating sunspots at the photosphere.

As we once again rise above the surface, we see one loop of a magnetic flux "rope" narrow and then get "pinched off". This is called magnetic reconnection. Like an overstretched rubber band that snaps, magnetic reconnection releases lots of energy. This movie shows the energy release producing a solar flare - a sudden brightening of the photosphere below. It also creates a coronal mass ejection (CME) - a swarm of energetic particles that blasts upward 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:

Traveling Nitrogen Classroom Activity Kit

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 colder than the areas around them. A large sunspot might have a temperature of about...more

Sunspots and Magnetic Fields

Sunspots are caused by very strong magnetic fields on the Sun. The best way to think about the very complicated process of sunspot formation is to think of magnetic "ropes" breaking through the visible...more

The Magnetic Field

The force of magnetism causes material to point along the direction the magnetic force points. As shown in the diagram to the left, the force of magnetism is illustrated by lines, which represent the force....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 by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF