Solar astronomers can now predict future sunspots. There should be a big one in a few days

The surface of the Sun is a turbulent dance of gravity, plasma and magnetic fields. Much like the weather on Earth, its behavior can seem unpredictable, but there are patterns to be found when you look closely.

The first model observed on the solar surface was that of sunspots. Sunspots were noticed by a few ancient astronomers, but they have been studied regularly since the 1600s. As astronomers counted the number of spots seen each year, they found that the Sun went through active years and quiet years. There is an 11-year cycle of high and low sunspot counts. There are other cycles as well, like the Gleisberg cycle, which lasts 80 to 90 years.

These patterns are similar to the tornado seasons of the US Midwest or the El Niño / La Niña cycles of the Pacific. These great patterns have a regularity that makes them easy to anticipate. But while it is relatively easy to predict sunspot cycles, predicting the appearance of an individual sunspot is not.

One of the challenges of sunspot prediction is that we cannot place sensors directly on the surface of the Sun. It is difficult to measure the magnetic fields that create sunspots. But astronomers have learned that the Sun can be studied using sound waves, and this technique is starting to allow them to predict individual sunspots.

One of the projects that studies the Sun in this way is the Global Oscillation Network Group (GONG). It is a collection of six solar telescopes that measure the movement of the Sun’s surface 24/7. The vibrations of the Sun’s surface are caused by sound waves moving inside the Sun. Studying the Sun in this way is known as helioseismology. Although it is primarily used to study the solar interior, sound waves are also affected by surface features such as sunspots, and recently the GONG team used this feature to predict one.

About a week ago, the GONG team noticed that the acoustic solar vibrations seemed to be disturbed by a feature on the other side of the Sun. They couldn’t see the feature, but it was consistent with that of a sunspot. So the team predicted that a cluster of sunspots could be visible from Earth around Thanksgiving. And it turned out they were right.

This type of prediction is extremely useful because large sunspots are often accompanied by other activities such as solar flares. Intense solar flares can disrupt modern satellites such as GPS and, in the most extreme cases, could threaten to collapse our power grid. Predicting these events several days in advance will give us time to mitigate their effects.

With further research, the GONG team and others may even be able to predict the appearance of sunspots before they form. It would give us well over a week to prepare for any threat of solar flares and give us all who use this technology a reason to breathe a little easier.

Reference: NSF National Solar Observatory Predicts Big Sunspot for Thanksgiving.