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QUIET
SUN: Solar activity is very low.
Only one small sunspot group (AR1241) is crossing
the visible face of the sun, and it poses no threat
for strong flares.
ASTEROID
FLYBY: Asteroid 2011 MD is flying
past Earth today, Monday June 27th. At closest approach
around 1:00 p.m. EDT the ~10-meter
space rock was only 12,000 kilometers (7,500 miles)
above the planet's surface. NASA analysts said there
was no
chance it would strike Earth, and indeed it
didn't.
Astronomers around the world are monitoring the
object as it flies by. Using a remotely-controled
telescope in Cerro Tololo, Chile, Joe Pollock of
Appalachian State University obtained this light
curve:
"Asteroid 2001 MD appears to be rotating with
a 23.3 or 11.6 minute period," notes Pollock.
After closest approach to Earth, the spinning asteroid
will recede through the zone of geosynchronous satellites.
The chances of a collision with a satellite or manmade
space junk are extremely small, albeit not zero.
Stay tuned for updates.
flyby movies and images: from
Marco Langbroek of Sierra Stars Obs., California;
from
Efrain Morales Rivera of Aguadilla, Puerto Rico;
from
Nick Howes of Siding Spring Australia; from
Rafael Ferrando of the Observatory Pla d'Arguines
in Segorbe, Spain; from
Libor Vyskocil of the Observatory Upice in the
Czech Republic; from
Nick James of Chelmsford, UK; from
Rolando Ligustri of Talmassons Observatory,
Italy
ELECTRIC
BLUE STORKS: Electric-blue noctilucent
clouds are rippling over Europe this week. In Poland,
that means sky watchers should be alert for the
silhouettes of storks:
Marek Nikodem of Szubin, Poland, caught this specimen
backlit by night-shining clouds on June 26th. "Each
year in late spring-early summer, thousands of storks
(Ciconia ciconia) arrive in Poland for
nesting," he says. "Their arrival coincides
with the summer onset of noctilucent clouds. Whenever
young storks are born in the heavens, we can admire
the NLCs!"
Noctilucent clouds form at the very top of Earth's
atmosphere, at the edge of space itself where meteoroids
can seed the formation of tiny ice crystals. When
summer sunlight strikes these crystals--voila!--the
sky glows electric blue. High-latitude observers
should look for these strange
clouds just after sunset or before sunrise;
observing tips may be found in the 2009
NLC gallery.
more images: from
Ivo Dinsbergs of Riga, Latvia; from
John Houghton of Newtown Linford, Leicestershire;
from
Aurimas Dirse of Vilnius, Lithuania; from
Barbara Grudzinska of Warsaw, Poland; from
Richard Fleet of Pewsey Vale, Wiltshire, England;
June
2011 Aurora Gallery
[Aurora alerts: text,
voice]
[previous Junes: 2010,
2008, 2001]
June
15th Lunar Eclipse Gallery
