When sunlight disappears across a narrow swath of southern Africa on June 21, hoards of tourists, astronomy enthusiasts and researchers will view the only total solar eclipse of 2001 as either a scientifically revealing or spiritually moving moment or both.

In any case, it's a nearly 5-minute-long moment. That's how long the Moon will block out the entire disk of the Sun, offering a rare opportunity to study aspects of our favorite star that are still mysterious.

This eclipse coincides with a peak in an 11-year cycle of solar activity, a time when the Sun spews far more gas and charged particles into space than normal. Sunspots are more common, and the Sun's outer atmosphere, called the corona, takes on a different look.

A total solar eclipse is one of the grandest flukes in the cosmos. At its current distance from Earth, the Moon is exactly the right size to completely -- but only barely -- block the Sun from our view when a host of orbital coincidences come together.

But for many who have seen an eclipse, the event is beyond science, and even beyond words.

"It is very hard to describe in words the feeling of witnessing an eclipse," Stolovy says, echoing the thoughts of other astronomers by adding that the experience is "deeply emotional and exciting ... and spiritual, too."

She says the beauty is derived from the glimmering corona surrounding "a black hole" in the sky. That would be the Moon.

"We are forced to acknowledge that we as humans cannot control everything -- the Sun, Earth and Moon will persist in their celestial dance regardless of what we mortals do."

Stolovy will watch the eclipse along with 80 other people on a private farm just south of Chisamba, Zambia. This will be her third trek to watch the Moon block out the Sun. It is unlikely it will top her 1998 experience, when on a cruise to see an eclipse from the Caribbean she met the man who is now her husband.

Why does she keep chasing something she's seen before?

"It's hard to top meeting one's husband at an eclipse as a reason to become an eclipse chaser," she points out, but she adds that every eclipse is different, both in how the Sun looks and in terms of the setting. Africa will provide a unique chance to possible see how animals react to the event.

In previous eclipses, scientists have learned that animals can be fooled by the sudden darkness and begin to settle in for sleep, and nocturnal animals sometimes poke their heads out to prepare for a night of foraging.

The behavior of scientists changes during an eclipse, too. Before modern optics and satellites, solar eclipses provided one of the most significant methods for studying the Sun and a handful of other phenomenon.

For example, Albert Einstein had predicted that gravity would bend the light of a more distant star as it passed by the Sun, Stolovy notes. Arthur Eddington found the first observational evidence for this in 1919, on an expedition to Brazil, by measuring the deflection of starlight during a total solar eclipse.

And so the June 21 eclipse provides another opportunity to see the Sun in a different light, or lack thereof. The Sun's corona is normally not visible from Earth because it is outshined by the star's photosphere.

But in a total eclipse, the photosphere is blocked and scientists can study the corona.

Jay Pasachoff, director of the Hopkins Observatory at Williams College in Massachusetts, will try to take advantage of the eclipse to further his research. Pasachoff will lead a group of 11 students and four scientists to Zambia. He and colleagues are trying to figure out why the Sun's outermost atmosphere is heated to 4 million degrees Fahrenheit, while the surface of the Sun is only around 11,000 degrees.

Pasachoff's team worked on a technique to study this phenomenon in a 1999 eclipse, combining their ground-based images with pictures taken from space-based observatories. The images were released last month.