How's the Weather Up There?
In the spring of 1989, six million people in Canada, Sweden, and the United States lost electric power for up to nine hours thanks to stormy weathernot on Earth, but on the Sun. During particularly vigorous solar storms, billions of tons of plasma erupt from the Sun's gaseous outer layer (called the corona), speed toward Earth at hundreds of miles per second, and disrupt the Earth's magnetic field.
"Coronal mass ejections" constitute a poorly understood natural hazard of growing concern to the scientists at NSF's National Center for Atmospheric Research (NCAR). That's because they are associated with features on the Sun known as sunspots, whose activity follows an 11-year cycle. And not only is the most recent sunspot cycle expected to reach its maximum activity in the year 2000, but overall, these so-called "solar maximums" have become twice as powerful as they were in the early 1900s.
From 1980 to 1989, the NSF-funded Solar Maximum Mission
satellite collected the most detailed data yet on coronal mass
ejections. NCAR researchers used this data to develop a new
suite of observation tools that work in space and on the ground. For
example, a special electronic camera called CHIP (for "chromospheric
helium imaging photometer") perches on the volcanic flanks of
Hawaii's Mauna Loa and snaps highly detailed pictures of the solar
disk and corona every three minutes. These pictures are frequent
enough to provide scientists with a movie loop of ejections as they
develop and burst forth. Other satellite-borne instrumentssome
launched and retrieved by the space shuttle Discovery to escape
distortions caused by Earth's dusty atmospheremine the
sun's radiation for clues about its magnetic behavior. Along
with piecing together the basic science behind solar storms,
these instruments should help scientists do a better job of
predicting the next serious bout of bad space weather.