A Giant Squid in the Flying Bat
Image Credit &
Copyright:
Steve
Cannistra
(StarryWonders)
Explanation:
Very faint but also very large on planet Earth's sky, a
giant Squid Nebula cataloged as Ou4, and Sh2-129 also known as the
Flying Bat Nebula, are both caught in this scene
toward the royal constellation Cepheus.
Composed with
a total of 20 hours of broadband and narrowband data,
the telescopic field of view is almost 4 degrees or 8 Full Moons across.
Discovered in 2011 by
French astro-imager
Nicolas
Outters, the Squid Nebula's alluring
bipolar shape
is distinguished here
by the telltale blue-green
emission from
doubly ionized oxygen atoms.
Though apparently completely surrounded by the reddish hydrogen
emission region Sh2-129, the true distance and nature
of the Squid Nebula have been difficult to determine.
Still, a
recent investigation
suggests Ou4 really does lie
within Sh2-129
some 2,300 light-years away.
Consistent with that scenario, Ou4 would represent a spectacular
outflow driven by HR8119, a
triple
system of hot, massive stars seen near the center of the nebula.
If so, the truly giant
Squid Nebula
would physically be nearly 50 light-years across.
NGC 4372 and the Dark Doodad
Image Credit &
Copyright:
Marco Lorenzi
Explanation:
The delightful Dark Doodad Nebula drifts
through southern skies,
a tantalizing target for binoculars in the constellation
Musca, The Fly.
The dusty cosmic cloud
is seen against rich starfields just south of the
prominent
Coalsack Nebula and the Southern Cross.
Stretching for about 3 degrees across this scene
the Dark Doodad
is punctuated at its southern tip (lower left) by globular star cluster
NGC 4372.
Of course NGC 4372 roams the halo of
our Milky Way Galaxy,
a background object some 20,000 light-years away and only
by chance along our line-of-sight to the Dark Doodad.
The Dark Doodad's well defined silhouette belongs to the
Musca molecular
cloud, but its better known alliterative moniker was first
coined by
astro-imager and writer
Dennis di Cicco in 1986 while
observing Comet Halley from the Australian outback.
The Dark Doodad is around 700 light-years distant
and over 30 light-years long.
NGC 1316: After Galaxies Collide
Image Credit & Copyright:
Damian Peach/SEN
Explanation:
Astronomers turn detectives when trying to
figure out the cause of startling sights like
NGC 1316.
Their investigation indicates that
NGC 1316
is an enormous
elliptical galaxy
that started, about 100 million years ago, to devour a smaller
spiral galaxy neighbor,
NGC 1317, just above it.
Supporting evidence includes the dark
dust lanes
characteristic of a
spiral galaxy,
and faint swirls and shells of stars and gas visible in this
wide and deep image.
One thing that
remains unexplained is the unusually small
globular star clusters,
seen as faint dots on the image.
Most
elliptical galaxies have
more and brighter globular clusters than
NGC 1316.
Yet the observed
globulars are too old to have been
created by the recent
spiral collision.
One hypothesis is that these
globulars
survive from an even earlier galaxy that was subsumed into
NGC 1316.
Another surprising attribute of
NGC 1316,
also known as Fornax A, is its
giant lobes of gas that glow brightly in
radio waves.
Distorted Green Flash Sunset over Italy
Image Credit & Copyright:
Paolo Lazzarotti
Explanation:
This was one strange sunset.
For one thing, the
typically round Sun appeared distorted, geometrically, and
multiply layered.
For another, some of these layers appeared unusually green.
The
Sun,
of course, was just fine -- its odd appearance was caused entirely by its
light refracting in the Earth's atmosphere.
When layers of the Earth's atmosphere are unusually warm, layers of the Sun may
appear distorted or even seen multiple times.
The effect is most
strong nearest sunrise and sunset when terrestrial
inversion layers
occupy distinct
altitudes above the horizon.
Different colors
of the Sun may also become deflected by significantly different amounts, so that the uppermost
superior image may appear
momentarily green -- a phenomenon known as a
green flash.
The featured image was taken in February from
Porto Venere,
Italy, with
San Pietro church
situated in the foreground.
The Shark Nebula
Image Credit & Copyright:
Maurice Toet
Explanation:
There is no sea on Earth large enough to contain the Shark nebula.
This
predator
apparition poses us no danger, though, as it is composed only of interstellar gas and
dust.
Dark dust like that
featured here
is somewhat like cigarette smoke and
created
in the cool atmospheres of giant
stars.
After being expelled with gas and
gravitationally recondensing, massive stars may
carve intricate structures into their birth cloud using their high energy light and fast
stellar winds as sculpting tools.
The heat they generate evaporates the murky
molecular cloud as well as causing ambient hydrogen gas to disperse and glow red.
During disintegration, we humans can enjoy
imagining these
great clouds as
common icons, like we do for
water clouds
on Earth.
Including
smaller dust nebulae such as Lynds Dark Nebula 1235 and Van den Bergh 149 & 150, the
Shark nebula spans about 15 light years and lies about 650
light years away toward the constellation of the King of Aethiopia
(
Cepheus).
Earthrise
Image Credit:
Apollo 8,
NASA
Explanation:
What's that rising over the edge of the Moon?
Earth.
About 47 years ago, in December of 1968, the
Apollo 8 crew flew from the
Earth to the
Moon and back again.
Frank Borman,
James Lovell, and
William Anders were launched atop a
Saturn
V rocket on December 21,
circled the Moon ten times in their command module,
and returned to Earth on December 27.
The
Apollo 8
mission's impressive list of firsts includes: the first humans to journey to the
Earth's Moon,
the first to fly using the
Saturn V
rocket,
and the first
to
photograph the Earth from deep space.
As the Apollo 8 command module rounded the
farside of the Moon,
the crew could look toward the
lunar horizon and see the Earth appear
to rise, due to their spacecraft's orbital motion.
Their
famous picture of a distant blue Earth
above the Moon's limb
was a marvelous gift to the world.
Atlas V Rising
Image Credit &
Copyright:
Mike Deep
Explanation:
Early morning risers along Florida's Space Coast, planet Earth,
were treated to a launch spectacle
on September 2nd.
Before dawn an Atlas V rocket rose into still dark skies carrying
a US Navy communications satellite from Cape Canaveral Air Force
Station into Earth orbit.
This minutes
long exposure follows the rocket's arc
climbing eastward over the Atlantic.
As
the rocket rises above Earth's shadow,
its fiery trail becomes an eerie,
noctilucent
exhaust plume glinting in sunlight.
Of course, the short, bright startrail just above the cloud bank is
Venus rising, now appearing in planet Earth's skies as
the brilliant morning star.
Milky Way with Airglow Australis
Image Credit &
Copyright:
Yuri Beletsky
(Carnegie
Las Campanas Observatory)
Explanation:
After sunset on September 1, an exceptionally
intense, reddish airglow flooded this Chilean winter night skyscape.
Above a sea of clouds and flanking the
celestial Milky Way, the airglow seems to ripple and flow
across the northern horizon in
atmospheric waves.
Originating at an altitude similar to aurorae,
the luminous airglow is instead
due
to chemiluminescence, the
production of light through chemical excitation.
Commonly captured with a greenish tinge by sensitive
digital cameras, this reddish airglow emission is
from OH molecules and oxygen atoms at extremely low densities
and has often been present in
southern hemisphere nights during the last few years.
On this night it was visible to the eye, but seen without color.
Antares and the
central Milky Way
lie near the top, with bright star Arcturus at left.
Straddling the Milky Way close to the horizon are Vega, Deneb,
and Altair, known in northern nights as the
stars of the Summer Triangle.
Arp 159 and NGC 4725
Image Credit &
Copyright:
Stephen Leshin
Explanation:
Pointy stars and peculiar galaxies span
this cosmic snapshot,
a telescopic view toward the well-groomed constellation
Coma Berenices.
Bright enough to show off diffraction
spikes,
the stars are in the foreground of the scene, well within our
own Milky Way.
But the two prominent galaxies lie far beyond our own, some
41 million light-years distant.
Also known as NGC 4747, the smaller distorted galaxy at
left is the
159th entry
in the Arp Atlas of Peculiar Galaxies, with extensive tidal tails
indicative of strong gravitational interactions
in its past.
At about a 100,000 light-years across, its likely companion on the right
is the much larger NGC 4725.
At first glance
NGC 4725 appears to be a normal spiral galaxy,
its central region dominated by the yellowish light of
cool, older stars giving way to younger
hot blue star clusters along dusty spiral outskirts.
Still, NGC 4725 does look a little odd with only
one main spiral arm.
The Flare and the Galaxy
Image Credit & Copyright:
Martin Mark
Explanation:
Is this person throwing a lightning bolt?
No.
Despite appearances, this person is actually pointing in the direction of a bright
Iridium flare,
a momentary reflection of sunlight off of a
communications satellite in orbit around the Earth.
As the
Iridium satellite orbits,
reflective antennas became aligned between the observer and the Sun to create a
flash brighter than any star in the night sky.
Iridium
flares typically last several seconds, longer than most meteors.
Also unlike meteors, the
flares are symmetric and
predictable.
The featured
flare
involved Iridium satellite 15 and occurred over southern
Estonia last week.
In this
well-planned image, a spectacular night sky appears in the background, complete with the
central band of our
Milky Way Galaxy running vertically up the image center.
Distant Neutrinos Detected Below Antarctic Ice
Image Credit:
IceCube Collaboration,
U. Wisconsin,
NSF
Explanation:
From where do these neutrinos come?
The
IceCube Neutrino Observatory
near the South Pole of the Earth has begun to detect
nearly invisible particles of very high energy.
Although these rarely-interacting
neutrinos pass through
much of the Earth just before being detected, where they started remains a mystery.
Pictured here
is IceCube's Antarctic lab accompanied by a cartoon depicting
long strands of detectors frozen into the crystal clear ice below.
Candidate origins for these cosmic neutrinos include the violent surroundings of supermassive
black holes at the centers of distant galaxies, and tremendous stellar explosions culminating in
supernovas and
gamma ray bursts far across the universe.
As
IceCube detects increasingly more high energy
neutrinos,
correlations with known objects may resolve this cosmic conundrum -- or we may never know.
Source -
NASA
