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ASTRONOMY NIGHT AT
THE WHITE HOUSE: Tonight, Oct. 7th, President
Barack Obama will host a
star party for middle school students on the South Lawn of the
White House. Selected amateur astronomers will be on hand to show
guests the moons of Jupiter and point out a brilliant Iridium flare.
That's about all you can see from the light-polluted skies of Washington
DC, but for many attendees, it'll be the experience of a lifetime.
Tune into whitehouse.gov
for a live webcast.
LUNAR IMPACT:
NASA's LCROSS spacecraft and its Centaur booster rocket will hit
the Moon on Friday morning, Oct. 9th, at approximately 4:30 a.m.
PDT (11:30 UT). The spectacular double-impact will be broadcast
live on NASA TV. Can't wait? Click
on the image below to watch a computer-generated preview (11 MB
Quicktime):
The impacts are designed to unearth frozen water from
the cold and shadowy floor of crater Cabeus near the lunar south
pole. Moon water is valuable stuff. It costs about $30,000 to rocket
a liter of water from Earth to the Moon. If NASA could find water
already on the Moon, it would save a lot of money for future thirsty
colonists. H2O also can be split into O2 for
breathing and H2 for rocket fuel.
Evidence of water will be sought in two plumes of
debris that billow out of Cabeus. The Hubble Space Telescope, NASA's
Lunar Reconnaisance Orbiter, and several great telescopes on Earth
will monitor the plumes for spectral signs of water (H2O)
or water fragments (OH). Mission scientists say the plumes might
also be visible in backyard telescopes with apertures of at least
10 inches. US observers west of the Mississippi River are favored
with darkness and a good view of the Moon when the spacecraft strike.
Browse the links below for observing tips:
ITALIAN GLORY: Yesterday,
photographers Andrea Alessandrini and Paolo Candy were flying over
Italy's Tirrenum Sea when they looked out the window of their airplane
and saw this:
It was a
glory--"one of the prettiest I've ever seen," says
Candy. And that means something because he's written a
book on the subject.
Glories are rings of light around your shadow. They
are caused by sunlight reflected backwards from water droplets in
clouds. Exactly how backscattering produces the colorful rings is
a mystery
involving surface waves and multiple reflections within individual
droplets. Each sighting is a puzzle--all the more reason to seek
them out.
"Glories are often seen from aircraft,"
notes atmospheric optics expert Les Cowley. "Get a seat opposite
the sun and watch them ring the aircraft's shadow." Airplanes
are not absolutely required, however. All you really need is a high
perch and moist clouds. Look for glories on mountains
and hillsides, in sea
fog, and even indoors.
more images: from
Stephen Thompson flying over St Eustatius in the Dutch Caribbean
Sept.
2009 Aurora Gallery
[previous Septembers: 2008,
2007,
2006, 2005,
2004, 2002,
2001]
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the Sunspot Cycle |
