This animation shows how the Sun's magnetic field becomes tangled as the Sun rotates.
Animation courtesy of SOHO (ESA & NASA).

Magnetic Field Lines Tangle as Sun Rotates

The Sun is not solid. It is a huge sphere of plasma, so it behaves like a gigantic ball of gas. Different parts of the Sun rotate at different rates. The Sun rotates more quickly at its equator than at its poles. This animation shows the different rate of rotation between the Sun's equator and its poles. At the start of the animation, magnetic field lines coming from the Sun are smooth and orderly. Over time, the Sun's differential rotation rates cause its magnetic field to become twisted and tangled.

The "tangles" in the magnetic field lines can produce very, very strong localized magnetic fields. Places where "ropes" of bundled field lines "break" the surface of the Sun are active regions where sunspots form. These active regions often generate solar "storms": solar flares and coronal mass ejections (CMEs).

When the Sun's magnetic field gets really twisted, there are lots of sunspots. Those times are the peaks of the 11-year sunspot cycle. There are lots of solar storms then. After a while, the Sun's "messy" magnetic field resets itself into a smoother, more orderly arrangement. Most sunspots go away. The cycle starts all over again. As the Sun spins and the smooth magnetic field gradually gets stretched, sunspots once again grow plentiful over the course of the next 11 or so years.

Each time the Sun resets with a new, smooth magnetic field, that field is reversed from the way it had just been. The Sun's North and South Magnetic Poles trade places. So it really takes about 22 years (two 11-year cycles) for the Sun's magnetic field to go through a complete cycle and end up back where it started.

Right-click (Windows) or Option-click (Mac) on any of the following links to download a copy of this video in QuickTime or MPEG formats: large (3.7 MB) QuickTime, small (919 KB) QuickTime, large (2 MB) MPEG, or small (714 KB) MPEG.

Last modified December 31, 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

News

Opportunities

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

Solid

Solid is one of the four common states of matter. The three others are gas, liquid, and plasma. There are also some other exotic states of matter that have been discovered in recent years. Unlike liquids...more

The Plasma State

Plasma is known as the fourth state of matter (the first three states being solid, liquid and gas).Matter in ordinary conditions on Earth has electrons that orbit around the atomic nucleus. The electrons...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

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

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

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

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

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