Why Study Sunspot Complexity?

Hello citizen scientists! As leader of the Sunspotter science team, it is my job to welcome you to the project. If you would like to learn something about solar activity, and what makes the Sun such an interesting system to study, then I’m sure you will enjoy following this blog. And, as the project develops, we will keep you up to date on what we are learning from your classifications.

I am a solar astrophysicist and have spent the last few years investigating what makes sunspots tick. Sunspots are like animals – they are born, they grow and change, and then slowly they decay and fade away, leaving barely a trace (the trace they leave is important, but I’ll explain that in a future blog post). They live for a couple of weeks, and although their lives are short, from time to time they release the most powerful (in energy per time) events in the solar system: solar flares. It is my job to study the evolution of sunspots to determine when and why they release flares, in an effort to predict them; much like a weather forecaster on Earth, I try to forecast space weather. This is important work because adverse space weather resulting from solar flares can jeopardise our GPS system, affect the health of our astronauts, inhibit long range radio communications,  endanger our power grid, and the list goes on…

A sunspot group seen in visible light.

A sunspot group seen in visible light. Courtesy of SDO/HMI.

If you have already tried a few classifications, you may have noticed that the images of sunspots shown do not look like a dark spot on a bright Sun, they look more like a mix of black and white on a gray background. This is because they are maps of the sunspot magnetic fields (a.k.a., magnetograms). Magnetic fields are what make the Sun and especially sunspots (where the strongest magnetic fields are) so interesting.

A magnetic field map (magnetogram) of a sunspot group.

A magnetic field map (magnetogram) of a sunspot group. Courtesy of SDO/HMI.

We use computer programs to automatically track sunspots and calculate their various physical properties. For example, we determine the area they cover on the Sun’s surface, their maximum magnetic field values, their total magnetic flux (magnetic field times area) and so on. We have found that the properties most likely to help us predict the future occurrence of eruptions are related to the line(s) separating the black and white areas of the magnetogram, known as a polarity separation line. For example, a sunspot group is much more likely to flare if it has a long line separating the white and black areas, rather than a short one.

It is also known that the more complex a sunspot group is, the more likely it is to flare. Thus, we seek to reliably measure the complexity of sunspot groups. And this is where you come in … and where computers fail, since they cannot yet determine the complexity of an image in a meaningful way. Humans on the other hand, have a pretty easy time of indicating which is the more complex of a pair of images. Scientists have been trying (pretty unsuccessfully) to come up with a way to represent the complexity of sunspot groups for a long time. The Sunspotter project might just be the golden ticket!

So, please help us reliably measure the complexity of our sunspot group images. The results of this project could lead to significant advances in our ability to predict flares. This is only phase 1 … stay tuned for more!


About Dr. Paul A. Higgins

I am a postdoctoral research fellow in the Astrophysics Research Group at Trinity College Dublin in Ireland. Currently I am a visiting researcher at LMSAL in Palo Alto, CA. I am investigating the causes of solar eruptions. To do this I use image processing and data mining techniques to study the evolution of sunspot groups as they are born, cross the solar disk, producing flares and coronal mass ejections, and then quietly decay and fade away.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: