DURHAM, N.H. -- Few celestial events move scientists out of their labs and onto exotic locales, but that's
where researchers will be headed Feb. 26, when a total solar eclipse makes its dazzling debut. Prime viewing:
the tropical paradises of the Caribbean.|
To scientists, however, the trip will be anything but a vacation, says Joseph Hollweg, University of New Hampshire professor of physics. "They'll probably be flying in one day, and flying out the next," says Hollweg, who will be staying in Durham this time around.
Locally, New Hampshire residents will see a partial eclipse from 12:45 to 2:05 p.m. Thursday, Feb. 26.
Hollweg, who works in the UNH Institute for the Study of Earth, Ocean and Space, directs the Space Science Center's Solar Terrestrial Theory Group, which works to unlock the mysteries of the Sun, solar wind and cosmic rays. A total solar eclipse -- caused when the moon passes between the Earth and the Sun -- is especially interesting, says Hollweg.
A firsthand look provides information on the solar atmosphere, the hot, ionized gas or plasma hovering above the surface of the Sun. One of the regions of the atmosphere being studied is the relatively thin chromosphere, says Hollweg. "It's visible briefly during the eclipse as a thin, red-emitting layer, hence the 'chrom' in its name," he explains.
The other region of interest is the corona, the white halo surrounding the Sun and the source of the solar wind, the continual outflow of plasma from the Sun. "The Earth is immersed in the solar wind," says Hollweg, "which affects our magnetic environment, causing phenomena like the Northern and Southern Lights. Its influence on the Earth is one very important reason we study the corona and solar wind."
One of the major riddles facing Hollweg and others is why the chromosphere and corona are hotter than the Sun's surface. "There's some heating process at work, but we don't know what it is. Everyone agrees that solar magnetism is crucially involved, but no one is sure how," Hollweg explains.
So how can actually looking at an eclipse help solve the riddle? Hollweg points out that energy must enter the corona from lower levels, so scientists have to examine the low levels in the chromosphere and corona, "and that's best done at eclipses." Researchers can "make" artificial eclipses using ground- or space-based telescopes, but they are unable to see the low corona and chromosphere.
The Feb. 26 eclipse will offer scientists the best viewing since the total eclipse in 1991, which Hollweg saw from Costa Rica. Scientists will have 3 minutes' view of the total phase of the eclipse.
As always, Hollweg and other experts warn it is harmful to the human eye to watch even a partial solar eclipse. A safe way to view the event is to watch the Sun's image projected onto a piece of paper. Poke a small hole in an index card with a pencil point and hold a second card two to three feet behind it. The hole will project a small, inverted image of the eclipse just like the real Sun in the sky.
For those who keep track: the next total solar eclipse visible in the Western Hemisphere will occur in the year 2017. The next best thing, a total lunar eclipse, is expected Jan. 20, 2000.
EDITORS, NEWS DIRECTORS:
Prof. Hollweg is available to comment on the eclipse. His office number is 862-3869.
Contact: Carmelle Druchniak, 603-862-1462