Fired up sun creates dazzling light show

Scientists spot cannibalizing eruptions

larger   Aurora last week over Valkeakoski, Finland

By Richard Stenger
CNN

(CNN) -- Exhibiting its most agitated behavior in a decade, the sun has become rife with violent storms and explosive flares, spurring some of the most spectacular auroras in years.

The sun recently sent a powerful energy burst in the direction of Earth, which could trigger dazzling aurora displays over nighttime skies on Friday and Saturday, NASA astronomers said.

Having reached the peak of an 11-year cycle, the sun is experiencing an epidemic of sunspots. Scientists identified almost 300 of the peculiar storms on the surface of the sun in late March, including active region 9393.

GALLERY These pictures were taken between March 20 and 24 in Fairbanks, Alaska, by Jan Curtis with The Alaska Climate Research Center Click here enter the gallery   RESOURCES Click here for more aurora pictures NOTE: Opens in new window

The largest sunspot in ten years, it covers a surface area 13 times larger than Earth. It can be seen without magnification through pinhole projectors and certain types of solar filters. Astronomers warn sky watchers not to look at the sun with the naked eye.

Sunspots can herald powerful solar flares and coronal mass ejections (CMEs), which spew billions of tons of ionized gas and particles into the solar system.

Directed toward Earth, such blasts can distort Earth's magnetic field, producing in extreme latitudes colorful nocturnal sky displays known as auroras, or the Northern and Southern Lights.

People in Alaska have witnessed some of the best auroras in years, after a CME struck the magnetosphere last week, according to spaceweather.com, a NASA-affiliated Web site.

larger   This aurora was photographed near the University of Oulu in Finland on March 19, 2001

They were also memorable in Finland.

"The most intense phases of that display were simply unbelievable! For a few minutes it was so bright that the dark evening almost turned into day," said Tom Eklund, who photographed the auroras.

The heightened solar activity could produce a steady stream of spectacular auroras for months, according to astronomers.

Solar eruptions can also trigger magnetic storms around our planet, damaging electrical and communications systems in orbit and on the ground.

Such outbursts sometimes take bizarre twists and turns before reaching the planet. Fast solar eruptions can overtake and consume their slower predecessors, scientists announced this week.

They discovered the so-called "cannibal coronal mass ejections" by studying radio and visual measurements from two different NASA satellites.

The collisions can change the speed of the eruptions and may prolong the duration of magnetic storms over Earth.

"Coronal mass ejection cannibalism is the most violent form of interaction between CMEs," said Natchimuthuk Gopalswamy of NASA's Goddard Space Flight Center.

This image sequence is a computer animation that illustrates one coronal mass ejection gobbling another in an act of cannibalism

"This happens when a slow moving CME is expelled before a fast one. The fast one simply gobbles up the slow one," he said.

Young stars rock their cradle in Hubble pic
March 28, 2001
Venus creates twilight spectacle
February 22, 2001
Sun flips magnetic field
February 16, 2001
Solar energy offers relief to power crisis
February 1, 2001
Another strong solar flare heads toward Earth
July 14, 2000

NASA's Goddard Space Flight Center
SpaceWeather.com
SpaceWeather.com's Aurora Gallery
Jan Curtis' images of the aurora
Jouni Jussila's Aurora Page
Tom Eklund's Aurora Page

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