SPACE

3-D Images to Illuminate Sun’s Secrets

A pair of NASA spacecraft have recorded the first 3-D images of the sun, giving scientists and space weather experts a much-improved ability to monitor and predict solar storms that can disrupt communications satellites, interfere with widely-used GPS systems, and knock out electrical power grids.

The two spacecraft, NASA’s Solar Terrestrial Relations Observatory (STEREO), both orbit the sun, one positioned slightly ahead of the Earth and the other slightly behind. Their offset position, much like the position of human eyes, gives STEREO depth perception, letting the spacecraft produce 3-D images via the onboard telescopes and imaging systems.

“The improvement with STEREO’s 3-D view is like going from a regular X-ray to a 3-D CAT scan in the medical field,” said Dr. Michael Kaiser, STEREO Project scientist at NASA’s Goddard Space Flight Center.

Cool and Useful

The 3-D images of the sun are not only interesting to look at; they’re also meant to give scientists a better understanding of the sun’s properties. STEREO is designed to improve space weather forecasts, which will in turn help people protect and manage various technologies. There are several kinds of solar weather patterns, which come in cycles.

“The sun has an 11-year cycle with increased levels of solar activity during the four- to five-year-long solar maximum period. It is possible for the sun to produce a large solar radiation storm during eight or nine of the years during the cycle,” Ron Zwickl, deputy director of the Space Environment Center (SEC).

The SEC works with the National Weather Service, which is a branch of the U.S. National Oceanic and Atmospheric Administration (NOAA). The SEC provides space weather alerts and warnings to government and industry in the U.S.

“The large radiation storms, called the S scale in the NOAA Space Weather Scales, occur infrequently with only a few per year. Geomagnetic storms, the G scale, can cause problems with electronics for spacecraft and for electric power systems,” Zwickl explained. “If geomagnetic storms could be ‘better predicted,’ we could considerably reduce the impact on electric power grids, essentially eliminating any failure due to geomagnetic storms.”

NOAA is currently arranging an international partnership of ground systems to receive a real-time signal stream from STEREO, enabling organizations to study solar weather and provide better forecasts.

Brewing Storms

Even though we are in the low point of the 11-year solar cycle, our sun produced strong solar flares in December of last year.

“We’ve been working our way down toward solar minimum, and we may be in it now or just out of it — it’s hard to tell exactly until we’re out of it,” Chris Balch, lead forecaster for SEC, told TechNewsWorld. “We had a real busy two weeks in December … and we are pretty close to minimum, so that was surprising.”

There are three primary sun space-weather phenomena: radio blackouts, solar radiation storms, and geomagnetic storms.

Radio blackouts primarily affect long-distance high-frequency transmissions, which tend to be used by the military, the north and south poles, and aircraft that need to send signals over the horizon of the earth.

Solar radiation storms can affect electronics and spacecraft and pose a danger to astronauts in space, who may need to move into safer areas of spacecrafts or space stations during the outbursts.

Geomagnetic storms come from strong surges of solar wind and are often associated with Coronal Mass Ejections (CMEs), which are eruptions of electronically charged gas, called plasma, that erupt from the sun’s atmosphere.

A CME cloud can contain billions of tons of plasma and move at a million miles per hour, NASA says. In addition, a CME cloud is laced with magnetic fields and can smash into our planet’s magnetic field. If the CME magnetic fields have the proper orientation, they dump energy and particles into Earth’s magnetic field, causing magnetic storms.

The Northern Lights

“The most well-known manifestation of magnetic storms is the aurora borealis, and the same time that’s going on, you have currents running in the upper atmosphere, and that can induce a current on the ground,” Balch said. “This causes problems for electric companies because it introduces current into power lines.”

In addition, the storms can interfere with increasingly popular Global Positioning System (GPS) systems and devices. Many automobile drivers currently use GPS systems to navigate through cities, and while a service disruption might prove annoying, GPS is also being used to drive unmanned harvesting equipment on America’s farms.

Who knows — as we enter the next active solar cycle, some farmers may need to pay attention to space weather in addition to their local forecasts.

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