When is the best time to see auroras? Where is the best place to go? And how do you photograph them? These questions and more are answered in a new book, Northern Lights - a Guide, by Pal Brekke & Fredrik Broms.
EDGE OF SPACE CHRISTMAS
CARDS: What do you give to the
sky watcher who has everything? How about a Christmas
card from the Edge of Space? For only $49.95, the
students of Earth
to Sky Calculus will fly your holiday greeting
or favorite picture to the top of Earth's atmosphere,
photograph it, and return the snapshot in time for
the holidays. It's a unique gift! The group has
previously flown cupcakes,
banners and telescopes.
This holiday magic is performed using suborbital
helium balloons. Contact Dr.
Tony Phillips for more information.
GEMINID METEOR SHOWER--IT'S
UNDERWAY: On Dec. 12th, NASA's
network of all-sky meteor cameras reported 23 Geminid
fireballs over the United States. This sharp uptick
in activity signals the official beginning of the
meteor shower. For the next 2 to 3 days, Earth
will pass through a stream of debris from rock
comet 3200 Phaethon, producing dozens of meteors
per hour flying out of the constellation Gemini.
"There is a nice show going on right now,"
says Bill Cooke, head of NASA's Meteoroid Environment
The multiple cameras of NASA's fireball
network are able to measure the orbits of Geminid
meteoroids. This plot shows the orbits of the 39
fireballs recorded so far this week:
Earth is the blue dot where all the
orbits intersect. The purple curve shows the path
of Geminid parent 3200 Phaethon.
Forecasters expect the shower to peak
on Dec. 13-14 when Earth passes through the busiest
part of Phaethon's debris stream. Peak rates could
reach 120 meteors per hour. However, glare from
the nearly-full Moon could reduce the number of
visible meteors 2- to 3-fold. Cooke advises looking
during the hours just before local sunrise on Saturday,
Dec. 14th. "At that time, the Moon will be
below the horizon, improving your chances of seeing
the show." [sky
You can listen to radar echoes from
the Geminids, unaffected by moonlight, on Space
Weather Radio. Also, tune into NASA's live
web chat about the Geminids on Friday the 13th
beginning at 11 pm EST.
Meteor Photo Gallery
NASA's Solar Dynamics Observatory is monitoring
a large coronal hole in the sun's northern hemisphere.
Shown here in an extreme ultraviolet photo taken
Dec. 11th, the UV-dark chasm overlies more than
500 billion square kilometers of solar terrain:
Coronal holes are places in the sun's
atmosphere where the magnetic field opens up and
allows solar wind to escape. A broad stream of solar
wind flowing from this particular coronal hole should
reach Earth on Dec. 15-17.
The last time a solar wind stream
blew past Earth, on Dec. 7th, the impact sparked
Northern Lights in the United States as far south
as Montana and Michigan. A repeat performance could
be in the offing. High-latitude sky watchers should
be alert for auroras early next week.
Aurora Photo Gallery
OVER ANTARCTICA: The season for
noctilucent clouds has begun in the southern hemisphere.
NASA's AIM spacecraft
is monitoring a vast bank of rippling electric-blue
NLCs blanketing almost all of Antarctica. This two
week movie chronicles the onset of the clouds in
late November and their rapid spread into December:
NLCs are Earth's highest clouds. Seeded
smoke," they form at the edge of space
83 km above Earth's surface. When sunlight hits
the tiny ice crystals that make up these clouds,
they glow electric blue.
NLCs appear during summer because
that is when water molecules are wafted up from
the lower atmosphere to mix with the meteor smoke.
That is also, ironically, the time when the upper
atmosphere is coldest, allowing the ice crystals
of NLCs to form.
In recent years NLCs have intensified.
Some researchers believe this is a sign of climate
change. One of the greenhouse gases that has become
more abundant in Earth's atmosphere since the 19th
century is methane. "When methane makes its
way into the upper atmosphere, it is oxidized by
a complex series of reactions to form water vapor,"
explains Hampton University Professor James Russell,
the principal investigator of AIM."This extra
water vapor is then available to grow ice crystals
Space Weather Photo Gallery
ISON Photo Gallery
Comet Photo Gallery
Every night, a network
all-sky cameras scans the skies above the United
States for meteoritic fireballs. Automated software
maintained by NASA's Meteoroid Environment Office
calculates their orbits, velocity, penetration depth
in Earth's atmosphere and many other characteristics.
Daily results are presented here on Spaceweather.com.
On Dec. 12, 2013, the network reported
(26 sporadics, 23 Geminids, 3 December
Monocerotids, 1 alpha Canis Majorid, 1 sigma Hydrid)
In this diagram of the inner solar
system, all of the fireball orbits intersect at
a single point--Earth. The orbits are color-coded
by velocity, from slow (red) to fast (blue). [Larger
Potentially Hazardous Asteroids (PHAs
are space rocks larger than approximately 100m that
can come closer to Earth than 0.05 AU. None of the
known PHAs is on a collision course with our planet,
although astronomers are finding new
all the time.
December 13, 2013 there were 1446
potentially hazardous asteroids.
Notes: LD means
"Lunar Distance." 1 LD = 384,401 km, the distance
between Earth and the Moon. 1 LD also equals 0.00256
AU. MAG is the visual magnitude of the asteroid on
the date of closest approach.
official U.S. government space weather bureau
first place to look for information about sundogs,
pillars, rainbows and related phenomena.
call it a "Hubble for the sun." SDO
is the most advanced solar observatory ever.
views of the sun from NASA's Solar and Terrestrial
and archival images of the Sun from SOHO.
the NOAA Space Environment Center
underlying science of space weather