Global Ocean Suspected on Saturn's Enceladus
Image Credit:
Cassini Imaging Team,
SSI,
JPL,
ESA,
NASA
Explanation:
Do some surface features on Enceladus roll like a
conveyor belt?
A leading interpretation of
images taken of Saturn's
most explosive moon indicate that they do.
This form of asymmetric
tectonic activity, very unusual on Earth,
likely holds clues to the internal structure of
Enceladus,
which may contain subsurface seas where
life might be able to develop.
Pictured above is a composite of 28 images taken by the robotic
Cassini spacecraft in 2008 just after swooping by the
ice-spewing orb.
Inspection of these images show clear
tectonic displacements
where large portions of the surface all appear to
move all in one direction.
On the image right appears one of the most prominent tectonic divides:
Labtayt Sulci,
a canyon about one kilometer deep.
The small magnitude of Enceladus' wobble as it orbits Saturn might indicate damping by a globally extending
underground ocean layer.
A Prominence on the Sun
Image Credit &
Copyright:
Alan Friedman
(Averted Imagination)
Explanation:
This eerie landscape
of
incandescent plasma suspended in
looping and twisted magnetic fields stretched toward the
Sun's eastern horizon on September 16.
Captured through a backyard telescope
and narrowband filter in light from ionized hydrogen,
the scene reveals a gigantic prominence lofted above the solar limb.
Some 600,000 kilometers across, the magnetized plasma wall would
dwarf worlds of
the Solar System.
Ruling gas giant Jupiter can only boast a diameter of
143,000 kilometers or so, while
planet Earth's diameter is less than 13,000 kilometers.
Known as a hedgerow prominence for its appearance, the enormous
structure is far from stable though, and such large solar
prominences
often erupt.
A Plutonian Landscape
Image Credit:
NASA,
Johns Hopkins Univ./APL,
Southwest Research Institute
Explanation:
This shadowy landscape
of majestic mountains and icy plains
stretches toward the horizon of a small, distant world.
It was captured from a range of about 18,000 kilometers when
New Horizons
looked back toward Pluto,
15 minutes after the spacecraft's closest approach on July 14.
The dramatic, low-angle,
near-twilight
scene follows rugged mountains still popularly known as Norgay Montes from
foreground left, and Hillary Montes along the horizon,
giving way to smooth Sputnik Planum at right.
Layers of Pluto's tenuous atmosphere are also revealed
in the backlit view.
With a strangely familiar appearance, the frigid terrain likely
includes ices of nitrogen and carbon monoxide with
water-ice mountains rising up to 3,500 meters (11,000 feet).
That's comparable in height to the
majestic mountains of planet Earth.
This Plutonian landscape is 380 kilometers (230 miles) across.
Pickering's Triangle in the Veil
Image Credit &
Copyright:
J-P Metsävainio
(Astro Anarchy)
Explanation:
Chaotic in appearance,
these filaments of shocked, glowing gas break across
planet Earth's sky toward the constellation of Cygnus, as
part of the Veil
Nebula.
The Veil Nebula itself is a large
supernova remnant, an expanding
cloud born of the death explosion of a massive star.
Light from the original supernova explosion likely reached
Earth over 5,000 years ago.
Blasted out
in the cataclysmic event, the interstellar shock waves
plow through space sweeping up and exciting interstellar material.
The glowing filaments are really more like long ripples in a sheet seen
almost edge on, remarkably well separated into
the glow of ionized hydrogen and
sulfur atoms shown in red and green, and oxygen in blue hues.
Also known as the Cygnus Loop, the
Veil Nebula now spans
nearly 3 degrees or about 6 times the diameter of
the full Moon.
While that translates to over 70 light-years
at its estimated distance of 1,500 light-years, this field
of view spans less than one third that distance.
Identified as Pickering's Triangle
for a director of Harvard College Observatory
and cataloged as NGC 6979, the complex of filaments might be more
appropriately known as Williamina
Fleming's
Triangular Wisp.
Bright Spots Resolved in Occator Crater on Ceres
Image Credit:
NASA,
JPL-Caltech,
UCLA,
MPS/DLR/IDA
Explanation:
What created these bright spots on Ceres?
The spots were
first noted as the
robotic Dawn spacecraft approached
Ceres,
the largest object in the
asteroid belt, in February, with the expectation that
the mystery would soon be solved in higher resolution images.
However, even after Dawn arrived at Ceres in March, the
riddle remained.
Surprisingly, although images including the
featured
composite
taken in the last month do resolve many details inside
Occator crater, they do not resolve
the mystery.
Another recent clue is that a
faint haze develops over the crater's bright spots.
Dawn is scheduled to continue to spiral down toward
Ceres and scan the dwarf planet in
several new ways that, it is hoped,
will determine the chemical composition of the region and finally reveal the nature and history of the spots.
In several years, after running out of power,
Dawn will continue
to orbit Ceres indefinitely, becoming an artificial satellite and an
enduring monument to
human exploration.
A Spiral Aurora over Iceland
Image Credit & Copyright:
Davide Necchi
Explanation:
What's happened to the sky?
Aurora!
Captured late last month, this
aurora was noted by
Icelanders for its great brightness and quick development.
The
aurora resulted from a solar storm,
with high energy particles bursting out from the Sun and through a
crack in Earth's protective
magnetosphere
a few days later.
Although a spiral pattern can be discerned,
creative humans might imagine the complex glow as an atmospheric
apparition of any number
of
common
icons.
In the foreground of the featured image is the
Ölfusá River,
while the lights illuminate a bridge in
Selfoss City.
Just beyond the low clouds is a nearly full Moon.
The
liveliness of the Sun -- and the
resulting auroras on Earth -- is slowly diminishing as the Sun emerges from a
Solar maximum
of surface activity and
evolves towards
a historically more quite period in its 11-year cycle.
In fact, solar astronomers are
waiting to see if the
coming Solar
minimum will be as unusually quiet as the
last one, where sometimes months would go by with
no discernible sunspots or other active solar phenomena.
Pluto from above Cthulhu Regio
Image Credit:
NASA,
Johns Hopkins Univ./APL,
Southwest Research Inst.
Explanation:
New high resolution images of Pluto are starting to arrive from the outer Solar System.
The robotic
New Horizons spacecraft,
which zoomed by
Pluto in July,
has finished sending back some needed engineering data and is
now transmitting selections from its tremendous storehouse of
images of Pluto and its moons.
The
featured image,
a digital composite, details a
surprising terrain
filled with craters, plains, landscape of unknown character,
and landforms that resemble something on Earth but are quite unexpected
on Pluto.
The light area sprawling across the upper right has been dubbed
Sputnik Planum and is being studied for its unusual smoothness, while the dark cratered area just under the spacecraft is known as
Cthulhu Regio.
So far,
New Horizons has only shared a
few percent of the images and data it took during its Pluto flyby, but will
continue to send back new views
of the dwarf planet even as it glides outward toward even more distant explorations.
A Partial Solar Eclipse over Texas
Image Credit & Copyright:
Jimmy Westlake
(Colorado Mountain College) & Linda Westlake
Explanation:
It was a typical Texas sunset except that most of the Sun was missing.
The location of the missing piece of the Sun was not a mystery -- it was
behind the Moon.
Featured here is one of the
more interesting
images taken of a partial solar eclipse that occurred in 2012,
capturing a temporarily crescent Sun setting in a reddened sky behind
brush and a windmill.
The image was taken about 20 miles west of
Sundown,
Texas, USA, just after the
ring of fire effect was broken by the
Moon
moving away
from the center of the Sun.
Today a new
partial
solar
eclipse of the Sun will be visible from Earth.
Unfortunately for people who live in Texas, today's
eclipse
can only be seen from southern Africa and Antarctica.
ISS Double Transit
Image Credit &
Copyright:
Hartwig Luethen
Explanation:
Not once, but twice the
International Space Station
transits the Sun on consecutive
orbits of planet Earth
in this video frame composite.
The scene was captured
on August 22 from a single well-chosen location in Schmalenbeck,
Germany where the ISS created intersecting shadow paths only
around 7 kilometers wide.
Crossing the solar disk in a second or less,
the transits themselves were separated in time
by about 90 minutes, corresponding to the space station's orbital period.
While the large,
flare-producing
sunspot group below center, AR 2403, remained a
comfortable 150 million kilometers away, the distance between camera
and orbiting station was 656 kilometers for its first (upper) transit
and 915 kilometers for the second more central transit.
In sharp silhouette the ISS is noticeably
larger in angular size during the closer, first pass.
Of course, tomorrow the Moon will transit the Sun.
But even at well-chosen locations, its dark, central shadow
just misses the Earth's surface creating a
partial
solar eclipse.
Source -
NASA
