Couldn't find element LayerAd

Error finding content

Sunspots and Magnetic Fields - Windows to the Universe

Shop Windows to the Universe

Earth Science Rocks! Select one of our four cool NESTA t-shirts from our online store, and express your love of Earth and space science!
Sunspots come in pairs with opposite magnetic polarity. If we could bury a giant horseshoe magnet beneath the surface of the Sun, it would produce a magnetic field similar to that generated by a sunspot pair.
Click on image for full size
Windows to the Universe original artwork by Randy Russell using an image from NASA's TRACE (Transition Region and Coronal Explorer) spacecraft.

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 surface (photosphere) of the Sun. Where the rope comes up from the solar surface is one sunspot and where the rope plunges into photosphere is another sunspot.

As you can see in the picture to the left, one sunspot has North magnetic polarity and one sunspot has South magnetic polarity.

Scientists believe the differential rotation of the Sun is the underlying cause of the magnetic ropes on the Sun. Since the gaseous sphere of the Sun rotates more quickly at its equator than at its poles, the Sun's overall magnetic field becomes distorted and twisted over time. The twisted field lines eventually come through the photosphere, showing their presence as sunspots.

When the tangled fields reach a "breaking point", like a rubber band that snaps when wound too tight, huge bursts of energy are released as the field lines reconnect. This can lead to solar flares and Coronal Mass Ejections (CMEs).

Last modified January 19, 2010 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:

Cool It! Game

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

Sunspots

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

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

The Solar Corona

Rising above the Sun's chromosphere , the temperature jumps sharply from a few tens of thousands of kelvins to as much as a few million kelvins in the Sun's outer atmosphere, the solar corona. Understanding...more

Solar Eclipses Were not Always Enjoyed

Eclipses have been watched for centuries, but it was only recently that we understood what really occurs. Eclipses have always been fascinating to watch, but they weren't always welcome. For many years,...more

Solar Eclipses

An eclipse of the Sun occurs when the Earth passes through the Moon's shadow. A total eclipse of the Sun takes place only during a new moon, when the Moon is directly between the Sun and the Earth. When...more

Helmet Streamers and the Magnetic Structure of the Corona

The gas in the solar corona is at very high temperatures (typically 1-2 million kelvins in most regions) so it is almost completely in a plasma state (made up of charged particles, mostly protons and electrons)....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