A new movie
from the Japanese Hinode spacecraft is one of the most detailed glimpses of a
solar flare ever made and has helped scientists see what's behind the colossal
eruption.
The striking
video, released this week, shows a major flare that lifted off
the Sun Dec. 13, 2006. The flare erupted from a sunspot catalogued as
number 930.
Sunspots
are cooler regions of the Sun's surface where magnetic energy caps the
superheated material below. Sometimes the cap unleashes a flare, similar to
soda exploding from a shaken can.
Hinode can
spot solar details as small as 90 miles wide, even though it's 93 million miles
from the Sun.
Other data
gathered by the spacecraft gave astronomers an unprecedented view of the
magnetic underpinnings of the flare.
"Solar flares are essentially
magnetic," said John Davis, NASA's project scientist for Hinode at the
Marshall Space Flight Center.
In the
maelstrom above a sunspot, lines of magnetic force are twisted and stretched
until the tension reaches a certain point--and then the whole thing explodes. A
rubber band provides a good analogy, Davis suggested in a NASA statement. Hold
one end in each hand, stretch it and twist until the band snaps.
Magnetic
fields behave a lot like rubber bands, and "Hinode was able to see the
twisting and stretching that preceded the Dec. 13th solar flare," Davis said.
The Dec. 13
flare was an X-3. All X-flares are major, with higher numbers indicated greater
releases of energy. This one created a coronal mass ejection (CME), or giant
expanding bubble of charged particles. The CME interacted with Earth's magnetic
field to produce Northern Lights as
far south as Arizona.
Hinode is
poised to help researchers unravel remaining mysteries about how solar flares
and storms work, but the Sun is
in a low period of activity in its 11-year cycle.
"The
kind of data we're getting from Hinode is just what we need to sort out how
flares work," Davis said. "All we need now is some more
explosions."
Some
forecasters expect the next peak in the solar cycle, due to begin ramping up in
a couple years, to be one of the strongest on record. Enhanced activity means
satellites and even power grids on Earth are at risk of electrical malfunction.
Hinode is joined by NASA's new 3-D STEREO spacecraft to provide better forecasting
ability than during past cycles.
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