(via APOD: 2011 August 8 - Seasonal Dark Streaks on Mars)
‘What is causing these dark streaks on Mars? A leading hypothesis is flowing — but quickly evaporating — water. The streaks, visible in dark brown near the image center, appear in the Martian spring and summer but fade in the winter months, only to reappear again the next summer. These are not the first markings on Mars that have been interpreted as showing the effects of running water, but they are the first to add the clue of a seasonal dependence. The above picture, taken in May, digitally combines several images from the the HiRISE instrument on the Mars Reconnaissance Orbiter (MRO). The image is color-enhanced and depicts a slope inside Newton crater in a mid-southern region of Mars. The streaks bolster evidence that water exists just below the Martian surface in several locations, and therefore fuels speculation that Mars might harbor some sort of water-dependent life. Future observations with robotic spacecraft orbiting Mars, such as MRO, Mars Express, andMars Odyssey will continue to monitor the situation and possibly confirm — or refute — the exciting flowing water hypothesis.’
APOD: 2011 August 7 - MyCn18: An Hourglass Planetary Nebula
The sands of time are running out for the central star of this hourglass-shaped planetary nebula. With its nuclear fuel exhausted, this brief, spectacular, closing phase of a Sun-like star’s life occurs as its outer layers are ejected - its core becoming a cooling, fading white dwarf. In 1995, astronomers used the Hubble Space Telescope (HST) to make a series of images of planetary nebulae, including the one above. Here, delicate rings of colorful glowing gas (nitrogen-red, hydrogen-green, and oxygen-blue) outline the tenuous walls of the hourglass. The unprecedented sharpness of the HST images has revealed surprising details of the nebula ejection process that are helping to resolve the outstanding mysteries of the complex shapes and symmetries of planetary nebulas.
The Greatest Stars- Aleksandr Solzhenitsyn, George Mason, Max Born, Kennedy, Santana, Baez, Gaye, Trungpa, & Zinn
The small open star cluster Pismis 24 lies in the core of the NGC 6357 nebula in Scorpius, about 8,000 light-years away from Earth. The brightest object in the center of this image is designated Pismis 24-1 and was once thought to weigh as much as 200 to 300 solar masses. This would not only have made it by far the most massive known star in the galaxy, but would have put it considerably above the currently believed upper mass limit of about 150 solar masses for individual stars.
However, Hubble Space Telescope high-resolution images of the star show that it is really two stars orbiting one another that are each estimated to be 100 solar masses.
In addition, spectroscopic observations with ground-based telescopes further reveal that one of the stars is actually a tight binary that is too compact to be resolved even by Hubble. This divides the estimated mass for Pismis 24-1 among the three stars. Although the stars are still among the heaviest known, the mass limit has not been broken due to the multiplicity of the system.
The images of NGC 6357 were taken with Hubble’s Wide Field and Planetary Camera 2 in April 2002.
ImageCredit: NASA, ESA, and J. Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain) Read more at www.nasa.gov |
Too Close To A Black Hole- Willa Cather, Chomsky, Einstein, Paulo Coelho, Nietzsche, Rumi, Hafiz, Gaiman, Kundera
Hartley 2 Star Cluster Tour - Helen Keller, Ivan Illich, Benazir Bhutto, Maria Callas, & William Wordsworth #arts
Explanation:
Early in November, small
but active
Comet Hartley 2 (103/P Hartley) became the
fifth comet
imaged close-up by a
spacecraft
from planet Earth.
Continuing its own
tour
of the solar system with a 6 year
orbital period, Hartley 2 is
now appearing in the
nautical
constellation Puppis.
Still a target for binoculars or small telescopes from dark sky
locations, the comet is captured in this composite image
from November 27, sharing the rich 2.5 degree wide
field of view
with some star clusters well known
to earthbound skygazers.
Below and right of the comet’s alluring green coma lies
bright M47,
a young open star cluster some 80 milion years old,
about 1,600 light-years away.
Below and left open cluster
M46 is older,
around 300 million years of age, and 5,400 light-years distant.
Hartley 2’s short, faint tail even extends
up and right
toward another fainter star cluster in the scene, NGC 2423.
On November 27, Comet Hartley 2 was about 2.25
light-minutes from Earth.
Sweeping toward
the bottom of this field, by November 28 the
comet’s path had carried it between M46 and M47.
Read more at apod.nasa.gov |
Anticrepuscular Rays Over Colorado - William Blake (Birthday), Helen Keller, George Washington, & Heinrich Heine
Anticrepuscular Rays Over Colorado Credit & Copyright:
John Britton
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Star Streams Of NGC 4216 - Daily Muse - Robyn Hitchcock - Bruce Lee (Born November 27, 1940) - Meister Eckhart <3
Explanation:
Some 40 million light-years distant,
edge-on spiral galaxy NGC 4216
is nearly 100,000 light-years across, about the size of our
own Milky Way.
Found in the dense
Virgo Galaxy Cluster, NGC 4216 is centered in
this deep telescopic portrait
flanked by fellow
Virgo cluster members NGC 4206 (right) and NGC 4222.
Like other large spirals, including the Milky Way, NGC 4216 has
grown by cannibalizing
smaller satellite galaxies.
In fact, this view has caught it in the act, with still distinct satellite
galaxies showing faint
star streams extending
for thousands of light-years into the halo of NGC 4216.
Taken as part of a survey
hunting for star
streams in nearby spirals,
the image was recorded with a small telescope and camera able to
convincingly detect faint, extended features.
Having trouble spotting the star streams?
Slide your cursor over the image to see a composite
negative view.
The streams should more easily stand out as dark swaths
against a white background.
Read more at apod.nasa.gov |
Flame Nebula Close-Up - William Cowper (Poet), Eugène Ionesco (Playwright), Ellen G. White, & F. Scott Fitzgerald
Explanation:
Of course, the Flame Nebula is not on fire.
Also known as
NGC 2024,
the nebula’s suggestive
reddish color is due to the glow
of
hydrogen
atoms at the edge of the giant Orion
molecular cloud complex some 1,500 light-years away.
The hydrogen atoms have been
ionized, or stripped of their
electrons, and glow as the atoms and electrons recombine.
But what ionizes the
hydrogen
atoms?
In this
close-up view,
the central dark lane of absorbing interstellar dust stands out
in silhouette against the
hydrogen glow
and actually hides
the true source of the Flame Nebula’s energy from optical
telescopes.
Behind the dark lane lies a cluster of hot, young stars, seen
at infrared
wavelengths through the obscuring dust.
A young, massive star in that cluster is
the likely source
of energetic ultraviolet radiation that ionizes the
hydrogen gas in the Flame Nebula.
Read more at apod.nasa.gov |
Stardust In Aries - Albert Camus On The Purpose Of Writers - Ba Jin (Born November 25, 1904) - Tecumseh On Wisdom
Explanation:
This composition in
stardust
covers almost 2 degrees
on the sky, close to the border of the zodiacal
constellation
Aries and the plane of our Milky Way Galaxy.
At the lower right of the gorgeous skyscape is a dusty blue
reflection nebula surrounding a bright star
cataloged as
van den Bergh 13 (vdB 13), about 1,000 light-years away.
At that estimated distance, the
cosmic canvas is over 30 light-years across.
Also surrounded by scattered blue starlight, vdB 16 lies
toward the upper left, while
dark dusty nebulae sprawl across the
scene.
Near the edge of a large
molecular
cloud, they can hide newly
formed stars and young stellar objects
or protostars from prying optical telescopes.
Collapsing due to
self-gravity, the
protostars
form around dense cores embedded in the molecular cloud.
Read more at apod.nasa.gov |
Stephan’s Quintet - Robert F. Kennedy, Benoit Mandelbrot, & Nadine Gordimer - Martin Luther King Jr.’s Dream <3
Explanation:
The first identified compact galaxy group,
Stephan’s Quintet is featured in
this
eye-catching image constructed with data drawn from
the extensive Hubble Legacy Archive.
About 300 million light-years away, only four galaxies of the group
are actually locked in a cosmic dance of repeated close encounters.
The odd man out is
easy to spot, though.
The four
interacting galaxies
(NGC 7319, 7318A, 7318B, and 7317)
have an overall yellowish cast
and tend to have distorted
loops and tails, grown under the
influence of disruptive gravitational tides.
But the larger bluish galaxy, NGC 7320,
is much closer than the others.
Just 40 million light-years distant, it isn’t part of the
interacting group.
In fact, individual stars in the foreground galaxy can be seen in
the sharp Hubble view, hinting that it is much closer than
the others.
Stephan’s Quintet lies within the boundaries of the high flying
constellation
Pegasus.
Read more at apod.nasa.gov |
Frosted Leaf Orion - Martin Scorsese, Henry David Thoreau, & Frank Herbert’s Dune - Beginnings, Good, & Peace <3
Explanation:
Sometimes, you can put some night sky in your art.
Captured above
Japan earlier this month, a picturesque night sky was photographed behind a picturesque frosted leaf.
The reflecting ice crystals on the leaf coolly mimic the shining stars far in the background.
The particular background sky on
this 48-second wide angle exposure,
however, might appear quite interesting and familiar.
On the far left, although hard to find, appears a
streaking meteor.
Below and to the right of the meteor appears a longer and brighter streak of an airplane.
The bright star on the left is the dog-star
Sirius, the brightest star on the night sky.
To Sirius’ right appears the
constellation of Orion, including the three linear belt stars below the red giant
Betelgeuse.
The bright patch of light further to the right is the
Pleiades
open star cluster.
Similar views including the constellation
Orion can be seen above much of the northern hemisphere for the next several months,
although you might have to provide your own leaf.
Read more at apod.nasa.gov |
Sisters Of The Dusty Sky - Pleiades / Seven Sisters - Alan Moore (Born November 18, 1953) - What Is Reality?
Explanation:
Hurtling through a cosmic dust cloud some 400 light-years away,
the lovely Pleiades or
Seven Sisters
star cluster is well-known for its striking blue
reflection nebulae.
In the dusty sky toward the constellation Taurus and the
Orion Arm
of our Milky Way Galaxy, this
remarkable image shows the famous
star cluster at the upper left.
But lesser known dusty nebulae lie along the region’s fertile
molecular cloud,
within the 10 degree wide field,
including the bird-like visage of
LBN 777
near center.
Small bluish reflection nebula VdB 27 at the lower right is
associated with the young, variable star
RY Tau.
At the distance of the Pleiades,
the 5 panel mosaic
spans nearly 70 light-years.
Read more at apod.nasa.gov |
Atoms-For-Peace Galaxy Collision - Marie De France On Stories & Beginnings - Astronomy Picture Of The Day Nov. 16
Atoms-for-Peace Galaxy Collision Credit:
ESO
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