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GEMINID METEOR SHOWER:
The annual Geminid meteor shower peaks on
Dec. 13th and Dec. 14th when Earth passes through a stream of debris
from extinct comet 3200 Phaethon. Bright
moonlight will reduce the number of visible meteors from the
usual 100/hr to only 20/hr or so. That's still a nice show. For
best results, watch the sky starting 10 pm local time on Saturday
night (Dec 13th) until dawn on Sunday morning (Dec. 14th). [live
updates] [photo]
SOMETHING NEW:
Spaceweather.com is broadcasting a live audio stream from the Air
Force Space Surveillance Radar in Texas. When a Geminid meteor passes
over the facility, the radar echo sounds like
this. Our experimental system can support 1000 simultaneous
listeners. Give
it a try; feedback
welcomed.
GOODBYE PERIGEE MOON:
Last night's full Moon was the biggest of
the year, a "perigee
moon" 14% wider and 30% brighter than lesser full Moons
earlier in 2008. "We really didn't think we would notice the
difference, but it did look bigger than usual!" says Raquel
S. of Cocoa, Florida. "My whole family just watched in
awe."
It's gone now, though. Elias
Chasiotis photographed it this morning setting behind a hillside
in Markopoulo, Greece:
Good-bye, perigee Moon!
In case you missed the show, another perigee full
Moon is coming on Jan. 10, 2009. Just as last night's full Moon
was the biggest of 2008, the Jan. 10th full Moon will be the biggest
of 2009. Mark your calendar.
more images: from
John Stetson of Sebago Lake, Maine; from
Larry Fischer of Topeka, Kansas; from
Kevin Witman of Cochranville, Pennsylvania; from
Glenn Johnson of Tallahassee Florida; from
Bill Bradley of West Hempstead, New York; from
Anthony Ayiomamitis of Athens, Greece; from
Carl Bernhardt of Riverside, California; from
Paulo Neiva of Praia da Aguda, Portugal; from
Bill Davis of Albuquerque, New Mexico; from
Michael Prokosch of Huntsville, Texas; from
Mariusz Lemiecha of Warsaw, Poland; from
Oscar Martín Mesonero of Salamanca, Spain; from
Doug Zubenel of De Soto, Kansas;
NEW ICE HALOES:
Ice haloes are normally found high in the sky among frosty clouds.
But lately researchers in Finland have been making their own halos
near the ground. They do it by shining halogen lamps into the air
downwind of snow-making machines:
Marko Riikonen of Rovaniemi, Finland, created these fantastic "angel
wings" on November 5, 2008. It's more than just a pretty
picture; the wings represent a serious attempt to discover new haloes
and to understand old ones.
Atmospheric optics expert Les Cowley explains: "Early researchers
had to rely on chance sightings of rare
displays to unravel the mysteries of ice halos. Later on they
journeyed to Polar Regions and especially the South
Pole where halos are at their finest. They explained the halos
well using models of geometrically perfect crystals aligned in just
a few ways in the sky. But mysteries remain. For instance, rare
Lowitz arcs
refuse to be fully understood, while perfect crystals cannot explain
new arcs like Moilanen's
or the elliptical
halos."
"Now researchers in Finland have new lamps and tools. Working
at night they use halogen
beams to light the high-quality crystals found a mile or more
downwind of ski-slope snow guns. It’s almost (but not quite!) a
laboratory where the crystals can be collected, examined and compared
with the halos they make. Careful lamp and camera placement lets
the 'sun' be raised or lowered and even halos normally invisible
beneath our feet can be projected
into the dark sky. In just one night a few days ago Marko Riikonen
captured several new
halos. Marko Mikkilä is even experimenting with a home-made
'Halogun.'"
"The new methods are starting to teach us that nature is richer
than we thought. There are new halos galore, some from crystals
with special shapes and others needing particular orientations.
Will the new tools ‘clean up’ halo research or remove their mystery?
More likely, they will reveal yet more puzzles. But at the same
time greater understanding will be gained which will enhance the
beauty and enchantment of the halos we all see from that 'old lamp'
– the sun."
Great
Conjunction Photo Gallery
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