By Madhulika Guhathakurta, a solar physicist at NASA and Daniel N. Baker, the director of the Laboratory for Atmospheric and Space Physics at the University of Colorado. These views are their own (THE NEW YORK TIMES, 17/06/11):
Lately, the Sun has been behaving a bit strangely. In 2008 and 2009, it showed the least surface activity in nearly a century. Solar flare activity stopped cold and weeks and months went by without any sunspots, or areas of intense magnetism. Quiet spells are normal for the Sun, but researchers alive today had never seen anything like that two-year hibernation.
Now that the Sun is approaching the peak of its magnetic cycle, when solar storms — blasts of electrically charged magnetic clouds — are most likely to occur, no one can predict how it will behave. Will solar activity continue to be sluggish, or will solar storms rage with renewed vigor?
Luckily, policy makers are paying attention to space weather. Late last month, President Obama and the British prime minister David Cameron announced that the United States and Britain will work together to create “a fully operational global space weather warning system.” And just last week, the United Nations pledged to upgrade its space weather forecasts.
But most people have never heard of space weather, which is a problem, because both high and low solar activity have serious effects on life on Earth.
Modern society depends on a variety of technologies that are susceptible to the extremes of space weather. Spectacular explosions on the Sun’s surface produce solar storms of intense magnetism and radiation. These events can disrupt the operation of power grids, railway signaling, magnetic surveying and drilling for oil and gas. Magnetic storms also heat the upper atmosphere, changing its density and composition and disrupting radio communications and GPS units. The storms’ charged particles can be a hazard to the health of astronauts and passengers on high altitude flights.
Severe storms in 1989 and 2003 caused blackouts in Canada and Sweden. In 1859, a solar super storm sparked fires in telegraph offices. Such storms are predicted every century or so, and perhaps we’re overdue. According to a 2008 National Academies report, a once-in-a-century solar storm could cause the financial damage of 20 Hurricane Katrinas.
A quiet Sun causes its own problems. During the two-year quiet spell, our upper atmosphere, normally heated and inflated by the Sun’s extreme ultraviolet radiation, cooled off and shrank. This altered the propagation of GPS signals and slowed the rate of decay of space debris in low Earth orbit. In addition, the cosmic rays that are normally pushed out to the fringes of the solar system by solar explosions instead surged around Earth, threatening astronauts and satellites with unusually high levels of radiation.
The more we know about solar activity, the better we can protect ourselves. The Sun is surrounded by a fleet of spacecraft that can see sunspots forming, flares crackling and a solar storm about 30 minutes before it hits Earth. NASA and the National Science Foundation have also developed sophisticated models to predict where solar storms will go once they leave the Sun, akin to National Weather Service programs that track hurricanes and tornadoes on Earth. Thanks to these sentries, it is increasingly difficult for the Sun to take us by surprise.
If alerted, Internet server hubs, telecommunications centers and financial institutions can prepare for disruptions and power plant operators can disconnect transformers.
But what good are space weather alerts if people don’t understand them and won’t react to them? Consider the following: If anyone should be familiar with the risks of space weather, it’s a pilot. During solar storms, transpolar flights are routinely diverted because the storms can disrupt the planes’ communications equipment. And yet a space weather forecaster we know at the National Oceanic and Atmospheric Administration often tells a story of a conversation he had with a pilot:
Pilot: “What do you do for a living?”
Forecaster: “I forecast space weather.”
Pilot: “Really? What’s that?”
The point of the story is to highlight how far the scientific community and the government have to go to raise awareness about space weather and its effects.
With the sun waking up, trans-Atlantic cooperation comes at just the right time. Let us hope it is only the beginning of a worldwide effort to forecast and understand space weather.
Fuente: Bitácora Almendrón. Tribuna Libre © Miguel Moliné Escalona