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Comet Between Fireworks and Lightning
Sometimes the sky itself is the best show in town.
Last January, people from
Perth,
Australia
gathered on a local beach to
watch a sky light up with delights near and far.
Nearby, fireworks exploded as part of
Australia Day celebrations.
On the far right,
lightning from a
thunderstorm
flashed in the distance.
Near the image center, though, seen through clouds, was the most unusual sight of all:
Comet McNaught.
The
photogenic comet was so bright that it even remained visible though the din of Earthly flashes.
Comet McNaught has now returned to the outer Solar System and is now
only visible
with a large telescope.
The
above image
is actually a three photograph panorama digitally processed to reduce
red reflections from the exploding
firework.
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SN 1006 Supernova Remnant
A new star, likely the brightest supernova
in recorded human
history, lit up
planet Earth's sky in the year 1006 AD.
The expanding debris cloud from the stellar explosion,
found in the southerly constellation
of Lupus,
still puts on a cosmic light show across the
electromagnetic spectrum.
In fact, this
composite view includes
X-ray data in blue from the
Chandra Observatory,
optical data in
yellowish hues, and radio image data in red.
Now known as the SN 1006
supernova remnant, the debris cloud
appears to be about 60 light-years across and is understood
to represent the remains of a white dwarf star.
Part of a binary star system,
the compact white dwarf gradually
captured material from its companion star.
The buildup in mass finally triggered a
thermonuclear
explosion that destroyed the dwarf star.
Because the distance to the supernova remnant is about 7,000
light-years, that explosion actually
happened 7,000 years before the light reached Earth in 1006.
Shockwaves in the remnant
accelerate
particles to extreme energies and are
thought to be a source of the mysterious
cosmic rays.
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Hoodoo Sky
http://antwrp.gsfc.nasa.gov/apod/image/0807/hoodooBC_pacholk...
Submitted by APOD
2 days, 21 hours ago
The strange-looking rock formations in the foreground of this skyscape
are called
hoodoos.
Towers of weathered, eroded sedimentary rock, hoodoos are
found in arid regions of planet Earth and are particularly abundant
in an area known as
Bryce Canyon National Park
in southern Utah, USA.
The more familiar night sky pictured here was recorded early
Monday morning
and includes bright star
Capella,
alpha star of the constellation
Auriga,
left of center.
On the far right, a very over exposed crescent Moon dominates the
sky in close conjunction with the
sister
stars of the
Pleiades cluster.
The curious shapes
of the two tall, illuminated hoodoos suggest their popular monikers;
Thor's Hammer (right) and The Temple of Osiris.
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Night Shinings
http://antwrp.gsfc.nasa.gov/apod/image/0807/MoonPleiadesNlc_...
Submitted by APOD
3 days, 21 hours ago
In the early morning hours of June 30th, ghostly clouds hovered in
the east in this view of
near dawn
skies over western France.
The noctilucent
or night-shining clouds lie near the
edge
of space,
reflecting sunlight from about 80 kilometers above Earth's surface.
Usually spotted above the poles in summer, they are now seen
with increasing frequency farther from the poles, in this case
extending to
the photographer's latitude of about 48 degrees north.
The trend could be a telltale sign of global
changes in the
atmosphere.
Another 400,000 kilometers away, the Moon's sunlit crescent
shines brightly, its night side illuminated
by Earthshine.
Of course, as a bonus for early risers
June's old crescent Moon
was followed closely
across the sky by the lovely
Pleiades star cluster, surrounded
by cosmic dust clouds and shining from a mere 400 light-years away.
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Pickering's Triangle from Kitt Peak
http://antwrp.gsfc.nasa.gov/apod/image/0807/pickeringstriang...
Submitted by APOD
4 days, 21 hours ago
Wisps like this are all that remain visible of a Milky Way star.
About 7,500 years ago that star exploded in a
supernova leaving the
Veil Nebula, also known as the Cygnus Loop.
At the time, the expanding cloud
was likely as bright as a crescent Moon, remaining
visible for weeks to people living at the dawn of
recorded history.
Today, the resulting supernova remnant
has faded and is now visible only through a small telescope directed toward the
constellation of
Cygnus.
The remaining Veil
Nebula is physically huge, however, and even though it lies about 1,400
light-years distant, it covers over five times the size of the
full Moon.
In images of the
complete Veil Nebula,
studious readers
should be able to identify the
Pickering's Triangle
component pictured above, a component named for a
famous astronomer and the wisp's
approximate shape.
The above image is a mosaic from the 4-meter
Mayall telescope at the
Kitt Peak National Observatory
located in Arizona,
USA.
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In the Center of the Trifid Nebula
http://antwrp.gsfc.nasa.gov/apod/image/0806/trifidcenter_lop...
Submitted by APOD
5 days, 21 hours ago
Clouds of glowing gas mingle with lanes of dark dust in the
Trifid Nebula, a star forming region toward the constellation of Sagittarius.
In the center, the three huge dark
dust lanes that give the
Trifid its name all come together.
Mountains of opaque dust
appear on the right, while filaments of
dust are visible threaded throughout the nebula.
A single massive star visible near the center causes much of the
Trifid's glow.
The Trifid, also known as
M20,
is only about 300,000 years old, making it among the youngest
emission nebula known.
The nebula lies about 9,000 light years away and part
pictured above spans about 10 light years.
The above image was created by the 0.8-meter
IAC80 telescope on the
Canary Islands of
Spain.
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Shadow of a Martian Robot
http://antwrp.gsfc.nasa.gov/apod/image/0806/shadow_opportuni...
Submitted by APOD
6 days, 21 hours ago
What if you saw your shadow on Mars and it wasn't
human?
Then you might be the
Opportunity rover
currently exploring Mars.
Opportunity and sister robot Spirit
have been probing the
red planet
since early 2004, finding
evidence of ancient water,
and sending breathtaking images across the inner
Solar System.
Pictured above, Opportunity looks opposite the Sun into
Endurance Crater and sees its own
shadow.
Two wheels are visible on the lower left and right,
while the floor and walls of the unusual crater are
visible in the background.
Opportunity and Spirit have now spent over
four years exploring the red world,
find new clues into the wet ancient past of our Solar System's second
most habitable planet.
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Fireball at Ayers Rock
http://antwrp.gsfc.nasa.gov/apod/image/0806/FireballAyersRoc...
Submitted by APOD
1 week, 21 hours ago
A weekend trip for astrophotography in central
Australia can
result in gorgeous skyscapes.
In this example recorded in March of 2006,
the center of our
Milky Way Galaxy rises over planet Earth's
horizon and the large sandstone formation called Uluru,
also known as Ayers Rock.
After setting up two cameras to automatically image this
celestial scene in a series of exposures,
one through a wide-angle and the other through a telephoto lens,
photographer Joseph Brimacombe briefly turned his back
to set up other equipment.
To his surprise, the ground around him suddenly lit up with
the brilliant flash of a
fireball meteor.
To his delight, both cameras captured the
bright meteor
streak.
Highlighted in the telephoto view (inset), the fireball trail
shines through cloud banks, just left of
Ayers Rock.
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M81: Feeding a Black Hole
http://antwrp.gsfc.nasa.gov/apod/image/0806/m81_composite_c8...
Submitted by APOD
1 week, 1 day, 21 hours ago
This impressive
color composite
shows spiral galaxy M81 across the
electromagnetic spectrum.
It combines X-ray data (blue) from the
Chandra
Observatory,
infrared data (pink) from the
Spitzer Space Telescope, and
an ultraviolet image (purple) from the
GALEX satellite,
with a visible light (green)
Hubble image.
The inset highlights X-rays from some of M81's black holes,
including
black
holes in binary star systems with about
10 times the mass of the sun, as well as the central,
supermassive black hole of over 70 million
solar masses.
Comparing computer models of the giant black hole's energy
output to the
multiwavelength data
suggests that feeding that
monster
is relatively simple -- energy and radiation is generated
as material in the central region swirls inwards forming an
accretion disk.
In fact, the process otherwise appears to be just like the
accretion process feeding M81's stellar mass black holes,
even though the central black hole is millions of times more massive.
M81 itself is about
70,000 light-years across and only 12 million
light-years away in the northern constellation
Ursa Major.
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M27: Not A Comet
http://antwrp.gsfc.nasa.gov/apod/image/0806/M27FTN_szymanek_...
Submitted by APOD
1 week, 2 days, 21 hours ago
Born on June 26th in 1730,
astronomer Charles Messier scanned 18th century French skies
for comets.
To avoid confusion and aid his comet hunting, he
diligently recorded this object as number 27 on
his
list of things which are definitely not comets.
In fact, 21st century astronomers would classify it as a
Planetary
Nebula, but it's not a planet either, even though it may
appear round
and planet-like in a small telescope.
Messier 27 (M27) is now
known to be an excellent example of a
gaseous emission nebula created
as a sun-like star runs out
of nuclear fuel in its core.
The nebula forms as the star's outer layers are expelled into
space, with a visible glow generated by atoms excited by the dying
star's intense but invisible
ultraviolet light.
Known by the popular name of the
Dumbbell
Nebula, the beautifully
symmetric interstellar gas cloud is over 2.5 light-years across and
about 1,200 light-years away in the
constellation
Vulpecula.
This impressive color composite highlights subtle jet
features in the nebula.
It was recorded with a robotic
telescope sited in Hawaii using narrow band
filters sensitive to emission from oxygen atoms (shown in
green) and hydrogen atoms.
The hydrogen
emission is
seen as red (H-alpha) and fainter
bluish hues (H-beta).
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