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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.

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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