Sun aims powerful flares at Earth

Top: Two large sunspot groups are visible in this image of the sun obtained by the Solar and Heliospheric Observatory (SOHO). Below: This SOHO image shows a large filament eruption that occurred February 26. The disk in the center is a mask that blocks out direct sunlight.

By Richard Stenger
CNN Interactive Staff Writer

March 1, 2000
Web posted at: 3:24 p.m. EST (2024 GMT)

(CNN) -- The sun should place the Earth squarely in its
sights this week as it aims its solar ray gun. Astronomers
tell terrestrial dwellers not to sweat it too much, despite
the fact that solar activity is approaching an 11-year peak.

Two large sunspots moving across the surface of the sun are
expected to directly face the Earth soon for up to several
days, according to solar scientists. Such sunspots often
herald powerful coronal mass ejections and solar flares,
space storms that can disrupt weather and electrical systems
on Earth.

Solar flares are the largest explosions in the solar system.
A typical one can release the energy equivalent of millions
of 100-megaton hydrogen bombs exploding at once.

Highly charged particles from large flares can overload power
grids and damage satellites. In 1989, one space storm knocked
out a major power plant in Canada, leaving millions without
power for hours.

Solar activity generally waxes and wanes during an 11-year
cycle and astronomers expect it to peak either this or next
year. But so far, the sun has produced only a "disappointing"
level of fireworks, said Joseph Gurman, a solar physicist who
analyzes data from the Solar and Heliospheric Observatory.

Coronal mass ejections are much more likely to produce
effects, Gurman said. Like flares, they send streams of highly
charged particles, but they also can emit a billion tons of
plasma, or ionized gas.

Fortunately the Earth's magnetosphere usually bears the brunt
of plasma particles. "If we were exposed to them, we
literally would be fried," Gurman said.