The question we should be asking is: Why is space weather important now?
The increasing concern around space weather is not because the Sun is changing. Far from it. The Sun is our constant, reliable life-source and will be for a few billion more years. What is evolving, though, is our technological society. Dependency on our electronics, and a desire to take them for granted, is what forces us to study the Sun.
Although scientists continue to work tirelessly to predict the behavior of our violent neighbor, there is still much we do not know. Something we are familiar with, though, is the solar cycle: the Sun’s activity noticeably changes with a period of eleven years. During my career as a solar astronomer, I have seen three complete solar cycles. In each one of them, solar activity and its impact on Earth has become more and more noticeable in the media. This increased exposure by the public stems from social changes such as cell phones. These devices use signals from GPS satellites to find our current locations—and we love it when they help us find the restaurant a friend recommended to us. But GPS satellites and signals are impacted by the solar storms that hit our planet, making them less precise, and sometimes totally unreliable. While unfortunate, not finding the restaurant would be relatively inconsequential. However, GPS signals are also used for the exact timing of stock market transactions and for other mission critical activities. Even worse, our entire power grid can be impacted by solar storms in ways we are only now beginning to understand. An extreme solar event can bring down significant parts of our power distribution system for months. Thankfully, the last time the Sun produced an Earth-directed solar storm that wreaked such havoc occurred in 1859. At that time, the biggest issue was the telegraph system—the Victorian internet—that failed to work properly for days.
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Solar storms and their impact on our planet are collectively called Space Weather. The term is reminiscent of the more familiar terrestrial weather that provides reliable predictions for whether you’ll need an umbrella tomorrow. Achieving such accurate predictions has required decades of effort to understand the complex systems that influence weather across the globe. Cold, polar air flowing down from the north merging with warm, moist air from the Gulf of Mexico somewhere in the continental U.S. generates a winter blizzard. We now understand the physics that generate these blizzards and can predict them in advance, saving hundreds of lives and millions of dollars in property damage every year. In comparison, Space Weather is in its infancy. Even the basic ingredients are poorly understood or even completely unknown! Only some key components have been identified—most prominently the configurations of the Sun´s surface magnetism, which results in the occasional solar explosion.
One thing we do know is where our knowledge needs to improve. Characterizing the distribution of magnetic fields on the solar surface, and how their interactions lead to energetic explosions, is of paramount importance. But nature does not make it easy. Of the light we receive from the Sun, only about one part in ten thousand contains the valuable information. Even if the Sun looks bright to us, to our telescopes, the Sun is ten thousand times dimmer.
The NSF-funded Daniel K Inouye Solar Telescope, or DKIST, which the National Solar Observatory is building in Maui, will help transform our understanding of the violent physics of the Sun. When DKIST comes on-line in 2020, the National Solar Observatory (NSO) will be able to offer the scientific community the most capable facility ever designed to understand the microphysics of our local star.
While DKIST will transform our knowledge of the region near the Sun, further out into space we again become blind. With the vastness of space, there is just not enough material for telescopes to be able to pick up a reliable signal and our only option is to go there—close to the Sun—and take the measurements on-site. This is the objective of NASA’s upcoming satellite mission, Solar Probe Plus. Scheduled for launch in 2018, the probe will travel to within nine solar radii of the Sun’s surface. Combining observations from DKIST of the inner solar atmosphere and from the NASA mission mapping the external rarified Sun promises to bring the insight we need to take our understanding of Space Weather to the next level.
Is Space Weather important? This question does not have an absolute answer. What determined why Homo sapiens prevailed over Neanderthals had very little to do with Space Weather. But the nation that aspires to establish the first permanent base on the Moon or on Mars needs to be concerned about Space Weather. It is not clear yet whose nation this will be, but by building the DKIST and the Solar Probe, the USA will be better prepared to be that nation.
Valentin M. Pillet is the Director of the National Solar Observatory. Learn more about the potential danger of Space Weather in THE DARK SIDE OF THE SUN, premiering Saturday, February 11 at 10pm ET/PT on Discovery and Sunday, February 12 at 9pm ET/PT on Science Channel.
