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SDO DESTROYS A SUNDOG:
The Solar Dynamics Observatory (SDO) lifted
off from Kennedy Space Center this morning at 10:23 am EST,
kicking off a 5-year mission to study the
variability of the sun. Moments after liftoff, SDO did
something that astonished and delighted observers. It flew
right through a bright, rainbow-colored sundog and destroyed
it. Click on the image to launch a 10 MB Quicktime video recorded
by13-year-old Anna Herbst of Bishop, California:
Sundogs are formed by ice crystals floating in cirrus clouds.
"When SDO's Atlas V rocket penetrated the cirrus, shock
waves went rippling through the cloud and destroyed the alignment
of the ice crystals," says atmospheric optics expert
Les Cowley. "This extinguished the sundog."
Play the movie
again and this time turn up the volume to hear the reaction
of the crowd when the waves hit the sundog. "I've never
seen anything like it," said Anna's friend and traveling
companion Amelia Phillips. "It was amazing!"
This was an auspicious beginning indeed for a mission designed
amaze. Once it reaches its final orbit, SDO will make IMAX-quality
movies of solar explosions and peer beneath the stellar surface
to see the sun's inner magnetic dynamo. No one has ever seen
anything like that either. Stay tuned for updates.
Sunspot 1045 is fading away, but sunspot 1046 is rapidly growing
to take its place as behemoth du jour. This 2-day
movie from the Solar and Heliospheric Observatory (SOHO) shows
the see-saw action:
Both sunspots pose a threat for isolated M-class
solar flares. According to NOAA, the total probability of
such an eruption in the next 24 hours is 30%. The chief effect
of M-flares on Earth is to ionize our planet's upper atmosphere.
This can alter the normal propagation of radio signals, boosting
some frequencies while suppressing others. Radio listeners
should be alert for blackouts
ionospheric disturbances (SIDs).
recent SIDs: from
Roberto Battaiola of Pantigliate, Milan, Italy; from
Rob Stammes of Lofoten, Norway.
Northern Lights Gallery
[previous Februarys: 2009,