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Sun Lab

If you don't know much about the Sun, start in one of the three other sections of this Lab: Sun 101, Space Weather, or Technology & Discovery. The nine brief videos in these sections cover the basic science of the Sun and solar storms, and explain how this Lab uses a tool called the Helioviewer to bring you up-to-date images from some of NASA's best solar space telescopes.

But if you're ready to start exploring the Sun, use these guides to better understand solar cycles and the telltale signs of future solar storms. Or conduct your own investigation of the Sun's exciting and often unpredictable behavior—then share what you discover.

Solar Cycle

The centuries-old technique of counting sunspots is still one of the simplest and most reliable ways to estimate the level of solar activity.

A small number of sunspots signifies a quiet Sun, while many suggest high levels of activity and the potential for solar storms.

Now's your chance to use this method to see where the Sun is in the current solar cycle. Is activity increasing, decreasing, or staying the same? See for yourself.

To estimate sunspot number, simply count the total number of sunspot groups as well as the total number of individual sunspots in those groups. It might sound easy, but even experts come up with different estimates, and instruments and weather conditions vary widely. So, scientists use a "scaling factor"—k in the formula on the right—when calculating the official total. For our purposes, we'll assume k=1, so you can ignore it.

Where does one spot or group end and another begin? Take a look at the image on the right for clues and then try one yourself; we'll show you the official answer before you tackle a series of 5 dates on your own.

Let's do one for practice. To estimate sunspot number, count the total number of sunspot groups as well as the total number of individual spots in those groups. Use zooming and panning to get the best views for each count. And note that every sunspot is part of a group, even if it's a group of one.

After you submit your estimates, we'll show you an official count for comparison.

As you can see in the image on the right, the official estimate for this day was 4 sunspots groups, containing 12 individual spots, for an overall sunspot number of R=52. How did you do? Did you catch the one small sunspot in Group A? Were you able to distinguish the individual spots clustered together in Group B?

When you're ready, click "Next" to try a series of 5 more dates, and see if you can spot a trend in the solar cycle.

Count the number of sunspot groups and the number of individual spots within those groups. Enter those numbers into the spaces below and click submit to see how your estimate compares to the scientific estimate.
Count the number of sunspot groups and the number of individual spots within those groups. Enter those numbers into the spaces below and click submit to see how your estimate compares to the scientific estimate.
Count the number of sunspot groups and the number of individual spots within those groups. Enter those numbers into the spaces below and click submit to see how your estimate compares to the scientific estimate.
Count the number of sunspot groups and the number of individual spots within those groups. Enter those numbers into the spaces below and click submit to see how your estimate compares to the scientific estimate.
Count the number of sunspot groups and the number of individual spots within those groups. Enter those numbers into the spaces below and click submit to see how your estimate compares to the scientific estimate.
How do your estimates relate to the big picture of the solar cycle? As you can see, sunspot activity in 2011 was increasing, as the Sun marched closer to the next solar maximum. Based on the overall trend, when do you think that will be?

To find out what's happening now, use the Helioviewer to assess today's activity by clicking on "Open Investigation" below. But remember, a single snapshot can be misleading–the solar cycle is a average of activity over months and years, not days.

Or, take on the Storm Prediction challenge.
R   =   10 x
GROUPS
 +
SPOTS

  Sunspot Number (R)
 
Date
Your
Estimate
Scientific
Estimate
Apr 2011
  Sunspot Number (R)
 
Date
Your
Estimate
Scientific
Estimate
Dec 2010
Mar 2011
Jul 2011
Oct 2011
Jan 2012

How does your estimate compare to the scientific estimate? If it's different, why do you think this might be? Remember, even experts come up with different numbers, which is why R is a weighted average of counts from many different observers.

Next 1/5

Storm Prediction

No two sunspots are exactly alike. The differences between them can be classified based on characteristics such as size, complexity, and motion. More importantly, these characteristics can be used to predict a sunspot region's future behavior. Choose a scenario to see what active regions on the Sun can tell us about their potential to produce solar storms.

Next

Use the arrows to move both images forward or backward in time. Then, select the region you think is most likely to flare and cast your vote.

< 1/6 >

Region A (top)
Region B (bottom)
Vote
Open Investigation

Now is the time to put your powers of observation and scientific analysis—and the full power of the Helioviewer—to work. Think of a question that interests you and dive in… here are a few ideas to get you started.

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