Scientists Spot 'Tsunami' on the Sun
Pastor Dale Morgan
Scientists Spot 'Tsunami' on the Sun*
By Robert Roy Britt
Senior Science Writer
posted: 08 December 2006
02:05 pm ET
A major flare on the Sun earlier this week generated what scientists are
calling a solar tsunami.
The tsunami-like shock wave, formally called a Moreton wave, rolled
across the hot surface, destroying two visible filaments of cool gas on
opposite sides of the visible face of the Sun.
Astronomers using a prototype of a new solar telescope in New Mexico
recorded the action.
"These large scale 'blast' waves occur infrequently, however, are very
powerful," said K. S. Balasubramaniam of the National Solar Observatory
(NSO) in Sunspot, NM, "They quickly propagate in a matter of minutes
covering the whole Sun, sweeping away filamentary material."
It is unusual to see such an event from a ground-based observatory,
Balasubramaniam said. And it was also unusual that it occurred near
solar minimum, when the Sun is at its least active during an 11-year cycle.
But solar activity can come at any time. Flares like this one are
spawned by sunspots, which are dark, cool regions that cap magnetic
activity below. When the caps pop, colossal doses of superheated matter
and radiation are unleashed.
Sunspot 929 began kicking up flares Tuesday, when a major X-9 event was
detected by a space-based observatory.
When another flare erupted Wednesday, the NSO's Optical Solar Patrol
Network (OSPAN) was watching.
A shock wave propagated like the splash from a rock thrown into a pond.
This was seen as a brightening from compressed and heated hydrogen gas.
Astronomers enhanced the contrast of the images to bring out the detail,
and they created an animation of the event.
Later, the shock wave swept across two dark filaments widely seprated on
the solar surface, and they disappeared for a few minutes. Scientists
are unsure whether the filaments were blown off or were compressed so
they were temporarily invisible, according to an NSO statement.
Forecasters say there is a 40 percent chance of more major flares
through this weekend. Skywatchers in Alaska, Canada and the very
northernmost United States should be on the lookout for colorful
Northern Lights generated by the space storminess.