Explanation:
What do the sharpest views ever of Pluto show?
As the robotic New Horizons spacecraft moves into the outer
Solar System,
it is now sending back some of the highest resolution images from its
historic encounter with
Pluto in July.
Featured
here is one recently-received, high-resolution image.
On the left is
al-Idrisi Montes,
mountainous highlands thought composed primarily
of blocks of
solid
nitrogen.
A sharp transitional shoreline leads to the ice plains, on the right,
that compose part of the
heart-shaped feature known as
Sputnik
Planum.
Why the plains are textured with
ice pits
and segmented is currently unknown.
The image
was taken about 15 minutes before closest approach and shows an area
about 30 kilometers across.
The
New Horizons spacecraft is next scheduled
to fly past Kuiper Belt object
2014 MU 69
on New Year's Day 2019.
Explanation: A
crescent Moon and brilliant Venus met in predawn
skies on December 7, a
beautiful conjunction of planet
Earth's two brightest celestial beacons after the Sun.
Harder to see but
also
on the scene was Comet Catalina
(C/2013 US10).
The fainter comet clearly sporting two tails,
lunar night side, bright sunlit lunar crescent, and brilliant morning star,
are all recorded here by combining short and long exposures
of the same field of view.
Pointing down and right, Catalina's dust tail
tends to trail behind the comet's orbit.
Its ion tail, angled toward
the top left of the frame, is blowing away from the Sun.
Discovered in 2013, the new visitor from the
Oort cloud
was closest to the Sun on November 15 and is now outbound,
headed for its closest approach to Earth in mid-January.
The Brightest Spot on Ceres Image Credit: NASA,
JPL-Caltech,
UCLA,
MPS/DLR/IDA
Explanation: Dwarf planet Ceres
is the largest object in the Solar System's
main asteroid belt with a diameter of about 950 kilometers.
Exploring Ceres from orbit
since March, the Dawn spacecraft's camera has revealed about 130
or so
mysterious bright spots, mostly associated with impact craters
scattered around the small world's otherwise dark surface.
The brightest one
is near the center of the
90 kilometer wide Occator Crater, seen in this dramatic
false
color view combining near-infrared and visible light image data.
A
study now finds the bright spot's reflected
light properties are probably most consistent with
a type of magnesium sulfate called hexahydrite.
Of course, magnesium sulfate is also known to
Earth dwellers as epsom salt.
Haze reported inside Occator also suggests
the salty material could be left over as a mix of salt and water-ice
sublimates on the surface.
Since impacts would have exposed the material,
Ceres' numerous and widely scattered bright spots may indicate
the presence of a subsurface shell of ice-salt mix.
In mid-December,
Dawn will begin
taking observations from its closest Ceres mapping orbit.
Explanation: Venus now
appears as Earth's brilliant morning star, standing
in a line-up of planets above the
southeastern horizon before dawn.
For most, the silvery celestial
beacon rose predawn in a close pairing
with an old crescent Moon on Monday, December 7.
But also widely
seen from locations in North and Central
America, the lunar crescent
actually
occulted or passed in front of Venus
during Monday's daylight hours.
This time series follows the daytime approach of Moon and morning star
in clear blue skies from Phoenix, Arizona.
The progression of nine
sharp
telescopic snapshots, made between 9:30am and 9:35am local time,
runs from lower left to upper right, when Venus
winked out behind the
bright lunar limb.
Explanation:
This dance is to the death.
Along the way, as these two large galaxies duel, a
cosmic bridge of stars, gas, and dust currently stretches
over 75,000 light-years and joins them.
The bridge itself is strong evidence
that these two immense star systems have
passed close to each other
and experienced violent tides induced by
mutual
gravity.
As further evidence, the face-on spiral galaxy on
the right, also known as NGC 3808A,
exhibits many young blue star clusters produced in a burst
of star formation.
The twisted edge-on spiral on the left (NGC 3808B) seems to be wrapped
in the material bridging the galaxies and
surrounded by a curious
polar ring.
Together, the system is known as
Arp 87
and morphologically classified, technically, as
peculiar.
While such interactions are drawn out over billions of years, repeated
close passages
should ultimately result in the death of one galaxy in the sense that
only one galaxy will eventually result.
Although
this scenario
does look peculiar, galactic mergers are thought
to be common, with Arp 87 representing a stage in
this
inevitable process.
The Arp 87 pair are
about 300 million light-years
distant toward the constellation Leo.
The prominent edge-on spiral at the far left
appears to be a more distant background galaxy and
not involved in the on-going merger.
Explanation:
Comet Catalina is ready for its close-up.
The giant snowball from the outer Solar System, known formally as
C/2013 US10 (Catalina),
rounded the Sun last month and is now
headed for
its closest approach to Earth in January.
With the glow of the Moon now also out of the way,
morning observers in Earth's northern hemisphere are getting their best ever view of the new comet.
And Comet Catalina is
not disappointing.
Although not as bright as early predictions, the comet is sporting both
dust (lower left) and
ion (upper right)
tails,
making it an impressive object for binoculars and long-exposure cameras.
The featured image was taken last week from the
Canary Islands, off the northwest coast of
Africa.
Sky enthusiasts around the world will surely be
tracking the comet over the next few months to see how it evolves.
Kepler Orrery IV Video Credit &
Copyright:Ethan Kruse
(University of Washington)
Explanation: The exoplanet hunting Kepler
mission's total for candidate and
confirmed multiple
planet systems stands at 1,705 worlds in orbit around 685 distant stars.
Put
all of those exoplanet orbits on the same scale
and follow
their relative orbital motions to get
Kepler Orrery IV.
To make the planets visible, their sizes
aren't shown to scale.
But orbits of the planets in
the Solar
System (dashed lines)
are included to scale in the hypnotic video.
Of course, Kepler uses planetary transits to detect
exoplanets,
looking for a slight dimming of light
as the planet crosses in front of its star.
In the time compressed video,
Kepler's multiplanet system orbits are all oriented
to put observed transits at the three o'clock position.
The dervish-like movements highlight a stark contrast
between most Kepler-discovered exoplanetary systems and our own.
Planning
an interstellar vacation?
Be sure to check the scale at the upper left first.
The color code indicates a planet's estimated
equilibrium surface temperature
based on its orbit size and
parent star.
Explanation:
These clouds of gas and dust
drift through
rich star fields along the plane of our Milky Way Galaxy toward the
high flying constellation Cygnus.
Caught within the
telescopic
field of view are the
Soap Bubble (lower left) and the
Crescent Nebula (upper right).
Both were formed at a final phase in the life of a star.
Also known as NGC 6888,
the Crescent was shaped as its bright, central massive
Wolf-Rayet
star, WR 136, shed its outer envelope in
a strong stellar wind.
Burning through fuel at a prodigious rate, WR 136 is near the end of
a short life
that should finish in a spectacular
supernova explosion.
recently discovered Soap Bubble Nebula is likely a
planetary
nebula, the final shroud of a lower mass, long-lived, sun-like star
destined to become a slowly cooling white dwarf.
While both are some 5,000 light-years or so distant,
the larger Crescent Nebula is around 25 light-years across.
Explanation:
Saturn's icy moon Enceladus poses above the gas giant's
icy rings in this Cassini spacecraft image.
The dramatic scene
was captured on July 29,
while Cassini cruised just below the ring plane,
its cameras looking back in a nearly sunward direction
about 1 million kilometers from the moon's
bright crescent.
At 500 kilometers in diameter,
Enceladus is
a surprisingly active moon though,
its remarkable south polar geysers are visible venting
beyond a dark southern limb.
In fact,
data collected during Cassini's
flybys
and years of images have recently revealed the presence of a
global
ocean of liquid water beneath this moon's icy crust.
Demonstrating the
tantalizing
liquid layer's global extent, the careful
analysis indicates
surface and core are
not rigidly connected, with Enceladus rocking slightly back
and forth in its orbit.
Explanation:
The setting is San Francisco Bay, the time is sunset, and the bridge is the
Golden Gate.
What you are about
to see
is an unexpected double sunset ending with a rare
green flash.
Watch closely -- in the recorded time-lapse sequence,
unusually warm air created by bridge traffic refracts sunlight toward the Earth,
causing a superior image of the top of the Sun to form.
This image will disappear -- marking the first "sunset" -- only after the main image has dipped below the deck.
All the while,
boats pass in the foreground, cars pass over the bridge, and clouds
reflecting sunlight drift by in the distance.
The scene ends with Earth's turbulent
atmosphere
itself creating a path that only
higher-energy visible
sunlight can traverse, making the last glimpse of our home star appear to
flash green.
Explanation:
Rich in star clusters and nebulae, the ancient
constellation of the Charioteer
(Auriga)
rides high in northern winter night skies.
Composed from narrow and broadband filter data and
spanning nearly 8 Full Moons (4 degrees) on the sky,
this deep telescopic view shows off some of Auriga's celestial bounty.
The field includes emission region
IC 405 (top left) about 1,500
light-years distant.
Also known as the Flaming Star Nebula,
its red, convoluted clouds of glowing hydrogen gas are energized by hot
O-type star
AE Aurigae.
IC 410 (top right)
is significantly more distant, some 12,000 light-years away.
The star forming region is famous for its embedded young star cluster,
NGC 1893,
and tadpole-shaped clouds of dust and gas.
IC 417 and NGC 1931 at the lower right,
the Spider and the Fly, are also young star
clusters embedded in natal clouds that lie far beyond IC 405.
Star cluster NGC 1907
is near the bottom edge of the frame, just right of center.
The crowded field of view looks along the plane of our
Milky Way
galaxy, near the direction of the
galactic anticenter.
Explanation:
This huge swirling mass of stars, gas, and dust occurs near the center of a nearby spiral galaxy.
Gorgeous spiral
NGC 3521 is a mere 35 million light-years
distant, toward the
constellation Leo.
Spanning some 50,000
light-years, its central region is shown in
this dramatic image,
constructed from data from the
Hubble Space Telescope.
The close-up view highlights this galaxy's
characteristic multiple, patchy, irregular spiral arms laced with
dust and clusters of young, blue stars.
In contrast, many
other spirals exhibit grand, sweeping arms.
A relatively bright galaxy in planet Earth's sky,
NGC 3521 is
easily visible in small telescopes, but often overlooked by
amateur imagers in favor of other Leo spiral galaxies,
like M65 and M66.
Explanation:
They might look like trees on Mars, but they're not.
Groups of dark brown streaks have been photographed by the
Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost.
The above image was taken in 2008 April near the
North Pole of Mars.
At that time,
dark sand on the interior of
Martian sand
dunes
became more and more visible as the
spring Sun melted the lighter
carbon dioxide ice.
When occurring near the top of a dune,
dark sand may cascade down the dune leaving
dark surface streaks -- streaks that might appear at first to be
trees standing in front of the lighter regions, but cast no shadows.
Objects about 25 centimeters across are resolved on
this image spanning about one kilometer.
Close ups
of some parts of this image show billowing plumes
indicating that the sand slides were occurring even
while the image was being taken.
Explanation: Not a bright comet,
67P/Churyumov-Gerasimenko now sweeps slowly through
planet Earth's predawn skies near the line-up of
planets along the ecliptic.
Still, this composite of telescopic images follows the
comet's progress as it moves away from the Sun
beyond
the orbit of Mars,
from late September (left) through late November (far right).
Its faint but extensive
coma and tails
are viewed against
the colorful background of stars near the eastern edge of
the constellation Leo.
A year ago, before its perihelion passage,
the comet was less active, though.
Then the Rosetta
mission's lander Philae made its historic landing,
touching down
on the surface of the comet's nucleus.
