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SOLAR ACTIVITY: NASA's
STEREO spacecraft and the Solar and Heliospheric Observatory
(SOHO) are monitoring an active region about to emerge over
the sun's southeastern limb: image.
Readers with solar
telescopes are encouraged to keep an eye on the region
for signs of a possible sunspot.
MYSTERY OF THE MISSING
PLUMES: NASA scientists are grappling with
a mystery. What did the debris go? Last Friday morning, Oct.
9th, the water-seeking LCROSS spacecraft and its Centaur booster
rocket crashed into the floor of crater Cabeus near the Moon's
south pole, on time and on target. But the debris plumes that
were supposed to issue from the impacts failed to materialize.
Consider this image recorded 15 seconds after the Centaur
impact by the Palomar Observatory's 200-inch Hale telescope:
Click
to view a 12-minute mpg movie.
Cabeus crater is located in the center, behind
the large bright mountain. Plumes of shattered spacecraft
and lunar soil should have emerged into sunlight from the
shadows, but even Palomar's sensitive adaptive optics system
registered nothing.
The absence of debris plumes does not mean LCROSS
was a failure. On the contrary, by offering up the unexpected,
LCROSS is teaching us something new about the lunar surface
and the products of lunar impacts. That makes it, by definition,
a successful experiment. All that remains is to figure out
what the new information is. Researchers will be
announcing their findings in the days and weeks ahead. Stay
tuned.
BLINDING FIREBALL:
On Friday night Sept. 25th, at approximately
9:03 pm EDT, an asteroid the size of a child's tricycle hit
Earth just above Lake Ontario. It was a lucky
strike, right in the middle of a network of seven all-sky
cameras operated by the University of Western Ontario (UWO).
The disintegrating asteroid produced a blinding fireball 100
times brighter than a full Moon. Click on the image to view
a movie from the Hamilton, Ontario, station:
The asteroid exploded in flight, producing strong low-frequency
sound waves in the atmosphere. Analysis of infrasound
records along with video from the seven camera stations
lead researchers to believe that fragments of the asteroid
could have reached the ground. "This bright fireball
was large enough to have dropped meteorites in a
region south of Grimsby on the Niagara Peninsula, providing
masses that may total as much as several kilograms," according
to a UWO press release.
Researchers at Western Ontario are interested in hearing
from anyone within 10 km of Grimsby who may have witnessed
or recorded the fireball, seen or heard unusual events at
the time, or who may have found possible fragments of the
freshly fallen meteorite. Meteorite-hunting tips and more
video may be found here.
Sept.
2009 Aurora Gallery
[previous Septembers: 2008, 2007, 2006, 2005, 2004, 2002, 2001]
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