- The Washington Times - Wednesday, August 11, 2004

Richard R. Fisher has studied the sun for almost 40 years. As director of the Sun-Earth Connection Division at NASA in Southwest, Mr. Fisher, who holds a doctorate in astrogeophysics, says a new field of science based on the behavior of the sun will form in coming years.

Similar to how oceanography blossomed after scientists better grasped how the ocean works, Mr. Fisher says, researchers are on the brink of understanding the system of the sun, such as what causes sunspots and solar winds. Once researchers know how the sun operates, they can better predict space weather and how it might affect the Earth or astronauts in interplanetary space travel.

“When sunspots change, they change everything in the solar system,” he says. “When there are a lot of sunspots, there are storms on the sun. Magnetic energy turns to radiation, and it emits charged particles. When that happens, the magnetic field of the Earth is charged by the magnetic field of the sun.”

Sunspots, dark spots on the sun with strong magnetic fields, are cooler than their surrounding areas. The eruptions associated with sunspots, called flares or coronal mass ejections, often interfere with communication and electrical systems on Earth, such as cellular phones, pagers and cable TV.

Scientists have not been able to pinpoint exactly why sunspots occur or when accompanying eruptions will take place. As they learn more about the sun, however, they expect that these questions will be answered.

In the next 10 years, several satellites will be launched to aid the National Oceanic and Atmospheric Administration in predicting space weather, says Chris St. Cyr, project scientist for a program named Living With a Star, which is run from Goddard Space Flight Center in Greenbelt. He holds a doctorate in astronomy.

“If you look back 50 years ago, there were rudimentary models of [the Earth’s] weather,” he says. “In the 1950s, no one ever believed the forecasts of the weatherman. Over the 1960s and 1970s, weather forecasts went from being a black art to being an applied science. … Our science with space weather is at an early stage. We’re just starting to get a handle on how to do a prediction.”

Correct judgments of upcoming space weather could help the economy, Mr. St. Cyr says. Along with Kevin Forbes, a professor of business and economics at Catholic University of America in Northeast, Mr. St. Cyr has written a paper that quantifies the effects of space weather on the electricity industry.

For the 19-month period from June 1, 2000, to December 31, 2001, the cost of the effects of space weather on the power grid for the Mid-Atlantic states was estimated at $100 million to $500 million.

The power grid is the network of transmission lines that moves power from generating plants to businesses and homes. Costs are incurred when space’s atmospheric conditions interfere with the transmission of electricity.

“When there are space-weather storms, it’s difficult for the power grid to transmit electricity,” he says. “If we knew how to predict space weather, you could maybe lessen the effects. … Similar to earthly weather, you can’t stop a hurricane, but having knowledge it’s coming can certainly help.”

Although the predictions aren’t always 100 percent accurate, Bill Murtagh, a space weather forecaster at NOAA’s Space Environment Center in Boulder, Colo., makes estimations of solar weather every day using satellites that orbit the Earth. He also gathers information from ground-based Air Force observatories.

At the end of July, along with other scientists, he spotted some of the biggest sunspots ever seen, which resulted in an impressive eruption, Mr. Murtagh says. Sunspots go through a cycle that maximizes every 11 years. Right now, the cycle is on a downward slope toward the minimum phase.

When he thinks there will be a large solar storm, he contacts NOAA’s clients, including major airlines, which won’t fly polar routes during heightened solar activity. Further, certain satellites need to be shut down or put in safe mode.

He says storms requiring such warnings happen about twice a year.

He looks at every layer of the sun, including the sunspots. Based on the structure of the sunspots, he can estimate how much energy is built up in the area, which tells how potent the sunspot is. He also tries to tell how likely sunspots will be to produce major flares or coronal mass ejections and how long it will take their ejections to reach Earth. Particles from flares can arrive in about 30 minutes, while particles from coronal mass ejections can take two to four days.

“The big area of concern today is Global Positioning System users,” he says. “The world is becoming so reliant on GPS in every sense. … [Space weather] interferes with the signal from the satellites. The degree of error would be in the tens of meters, but that’s critical for companies involving drilling and surveying requiring centimetric accuracy.”

As scientists research the sun in an effort to make weather predictions, they have been using helioseismology, which shows a three-dimensional picture of the sun, says Art Poland, research professor at George Mason University in Fairfax. Mr. Poland, who holds a doctorate in astrophysics, is a former project scientist for the Solar and Heliospheric Observatory, which is overseen by the European Space Agency and NASA.

The Solar and Heliospheric Observatory satellite hangs where the sun and Earth have equal gravity. Through the Michelson Doppler Imager on the device, scientists are able to measure the way sound waves travel and build an image of the interior of the sun, including the sunspots and the areas under them. The machine takes photos every three seconds. It also makes maps every 12 hours of the back side of the sun, which can give warning of upcoming sunspots.

Another aspect they have studied with the Solar Heliospheric Observatory is the solar atmosphere. At the center of the sun, it is 15 million degrees Kelvin. At the surface, it is 5,000 degrees Kelvin. Then, the temperature goes up to more than 1 million degrees Kelvin above the surface.

“We don’t understand the physical processes that make it do that,” he says. “Basic physics tells you the farther you are from the energy source, the cooler it gets, but if you look at the solar atmosphere, it should just keep on getting colder. We think there is convection going on just below the surface, which is the source of the energy in the outer layer of the sun.”

Although there are many unanswered questions about the sun, people shouldn’t worry about solar weather, including the effects of sunspots, says Barbara Thompson, a scientist at Goddard Space Center. She is working with the Solar Dynamics Observatory, which will be launched into space in 2008 with a Helioseismic and Magnetic Imager that will provide higher-resolution photos of the sun.

“Sunspots are more fun and interesting than anything,” she says. “They have been happening for thousands and thousands of years. … The sun hasn’t changed very drastically over the past couple centuries. It’s behaved pretty much the same.”



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