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Ultraviolet Andromeda
http://antwrp.gsfc.nasa.gov/apod/image/0909/UVAndromeda_swif...
Submitted by APOD
2 months, 1 week, 3 days, 8 hours ago
Taken by a telescope onboard
NASA's Swift satellite ,
this stunning vista represents the highest resolution image
ever made of the
Andromeda Galaxy (aka M31) - at ultraviolet
wavelengths .
The mosaic is composed of 330 individual images covering
a region 200,000 light-years wide.
It shows about 20,000 sources ,
dominated by hot, young stars
and dense star clusters that radiate strongly in
energetic
ultraviolet light.
Of course, the Andromeda Galaxy
is the closest large spiral galaxy
to our own Milky Way, at a distance of some 2.5 million light-years.
To compare this
gorgeous island universe's appearance
in optical light with its ultraviolet portrait, just slide your cursor over
the image.
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The Tarantula Zone
http://antwrp.gsfc.nasa.gov/apod/image/0909/tarantula_gleaso...
Submitted by APOD
2 months, 1 week, 4 days, 8 hours ago
The
Tarantula Nebula is more than 1,000 light-years in diameter --
a giant star forming region within our neighboring galaxy
the Large Magellanic Cloud (LMC).
That cosmic arachnid lies left of center
in this sharp, colorful telescopic image taken through
narrow-band filters .
It covers a part of the LMC
over 2,000 light-years across.
Within the Tarantula ( NGC 2070 ), intense radiation, stellar winds and
supernova shocks from the central young cluster of massive
stars, cataloged as R136 ,
energize the nebular glow and shape the spidery filaments.
Around the Tarantula are other violent star-forming regions with
young star clusters, filaments and
bubble-shaped clouds.
The rich field is about as wide
as the full Moon on the sky, located in the southern
constellation
Dorado .
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NGC 6888: The Crescent Nebula
http://antwrp.gsfc.nasa.gov/apod/image/0909/NGC6888_Lopez900...
Submitted by APOD
2 months, 1 week, 5 days, 8 hours ago
NGC 6888, also known as the Crescent Nebula, is a
cosmic bubble about 25 light-years across, blown by
winds from its central, bright, massive star.
This
beautiful portrait of the nebula is from the
Isaac Newton Telescope at
Roque de los Muchachos
Observatory in the Canary Islands.
It combines a composite color image
with narrow band data that isolates light from hydrogen
and oxygen atoms in the wind-blown nebula.
The oxygen atoms produce the blue-green hue that seems to enshroud
the detailed folds and filaments.
NGC 6888's central star is classified as a
Wolf-Rayet star
(WR 136).
The star is shedding its outer envelope in a strong
stellar
wind ,
ejecting the equivalent of the Sun's mass every 10,000 years.
The nebula's complex structures are likely the result of this
strong wind interacting with material ejected in an earlier phase.
Burning fuel at a prodigious rate and
near the
end
of its stellar life this star should ultimately go out with a bang in a
spectacular supernova explosion.
Found in the nebula rich
constellation Cygnus,
NGC 6888
is about 5,000 light-years away.
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The Center of Globular Cluster Omega Centauri
http://antwrp.gsfc.nasa.gov/apod/image/0909/omegacencenter_h...
Submitted by APOD
2 months, 1 week, 6 days, 8 hours ago
What is left over after stars collide?
To help answer this question,
astronomers have been studying the center of the
most massive ball of stars in our
Milky Way Galaxy .
In the center of
globular cluster
Omega Centauri, stars are packed in
10,000 times more densely than near our Sun.
Pictured above , the newly upgraded
Hubble Space Telescope
has resolved the very center of
Omega Centauri into individual stars.
Visible are many faint yellow-white stars that are smaller than our
Sun ,
several yellow-orange stars that are
Red Giants , and an occasional
blue star .
When two stars collide they likely either combine
to form one more massive star,
or they stick, forming a new
binary star system.
Close binary stars interact,
sometimes emitting
ultraviolet or
X-ray
light when gas falls from one star
onto the surface of a compact companion such as a
white dwarf or
neutron star .
Two such binaries have now been located in
Omega Centauri 's center.
The star cluster lies about 15,000
light-years
away and is visible toward the constellation of
Centaurus .
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The Holographic Principle
http://antwrp.gsfc.nasa.gov/apod/image/0909/teapotsirds_winf...
Submitted by APOD
2 months, 2 weeks, 8 hours ago
Is this picture worth a thousand words?
According to the Holographic Principle , the most
information you can get from this image is about
3 x 10 65 bits for a normal sized computer monitor.
The Holographic Principle , yet unproven, states that
there is a maximum amount of information content
held by regions adjacent to any surface.
Therefore, counter-intuitively , the information content
inside a room depends not on the volume of the room but
on the area of the bounding walls.
The principle derives from the idea that the
Planck length , the length scale where
quantum mechanics begins to dominate
classical gravity , is one side of an area
that can hold only about one bit of information.
The limit was first postulated by physicist
Gerard 't Hooft in 1993.
It can arise from generalizations from seemingly
distant speculation that the information held by a
black hole is determined not by its
enclosed volume but by the surface area of its
event horizon .
The term "holographic" arises from a
hologram analogy where three-dimension images are
created by projecting light though a flat screen.
Beware, other people looking at the
above image may not claim to see 3 x 10 65 bits --
they might claim to
see a
teapot .
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Summer Night in Astronomy Town
http://antwrp.gsfc.nasa.gov/apod/image/0909/SummerSky_tafres...
Submitted by APOD
2 months, 2 weeks, 1 day, 8 hours ago
This serene view records a late summer night sky
over the rolling, green hills of planet Earth.
It was taken near the rural village of
Saadat Shahr, Fars province, in southern Iran.
Saadat Shahr is also known as
Astronomy Town ,
as the inhabitants
have demonstrated a remarakble
passion for sky gazing .
Fittingly, this Astronomy Town sky view finds a lovely part
of the Milky Way near picture center.
The three brightest stars are the stars of the
Summer
Triangle ,
Deneb in Cygnus (top), Altair in Aquila (left), and Vega in Lyra (right).
The foreground landscape, illuminated by Astronomy Town lights,
includes a kind of wild pistachio tree common in the region.
To identify the stars and constellations, just slide your cursor
over the image.
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Stephan's Quintet
http://antwrp.gsfc.nasa.gov/apod/image/0909/stephansquintet_...
Submitted by APOD
2 months, 2 weeks, 2 days, 8 hours ago
The first identified compact galaxy group,
Stephan's Quintet is featured in
this stunning image from the
newly upgraded Hubble Space Telescope.
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 bluish galaxy at the upper left (NGC 7320)
is much closer than the others.
A mere 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 image, hinting that it is much closer than
the others.
Stephan's Quintet lies within the boundaries of the high flying
constellation
Pegasus .
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The Butterfly Nebula from Upgraded Hubble
http://antwrp.gsfc.nasa.gov/apod/image/0909/butterfly_hst.jp...
Submitted by APOD
2 months, 2 weeks, 3 days, 8 hours ago
The bright clusters and nebulae of planet Earth's night sky are often
named for
flowers or
insects , and
NGC 6302 is no exception.
With an estimated surface temperature of about 250,000 degrees C,
the central star of this particular
planetary nebula is exceptionally
hot though -- shining brightly in ultraviolet light but hidden from
direct view by a dense torus of dust.
Above is a
dramatically detailed close-up of the
dying
star's nebula recorded by the
newly upgraded Hubble Space Telescope .
Cutting across a bright cavity of ionized gas,
the dust torus surrounding the central star is in the upper
right corner of this view, nearly edge-on to the line-of-sight.
Molecular hydrogen
has recently been detected in this hot star's dusty cosmic shroud.
NGC 6302 lies about 4,000 light-years away in the
arachnologically correct constellation
Scorpius .
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Star Trails Over Oregon
http://antwrp.gsfc.nasa.gov/apod/image/0909/startrails_bury....
Submitted by APOD
2 months, 2 weeks, 4 days, 8 hours ago
As the Earth spins on its axis, the sky seems to rotate around us.
This motion, called
diurnal motion ,
produces the beautiful concentric
trails
traced by stars during time exposures.
Partial-circle star trails are
pictured above
over Grants Pass ,
Oregon ,
USA last month.
Near the middle of the circles is the North Celestial Pole (NCP), easily identified as the point in the sky at the center of all the star trail arcs.
The star Polaris ,
commonly known as the
North Star ,
made the very short bright circle near the NCP.
About 12,000 years ago, the bright star
Vega was the
North Star , and in about 14,000 years, as the
Earth's spin axis slowly continues to
precess , Vega will become the North Star again.
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Unexpected Impact on Jupiter
http://antwrp.gsfc.nasa.gov/apod/image/0909/jupiterimpact_al...
Submitted by APOD
2 months, 2 weeks, 5 days, 8 hours ago
Two months ago, something unexpected hit Jupiter.
First discovered by an amateur astronomer
Anthony Wesley on 2009 July 19,
the impact was quickly confirmed and even
imaged by the
Hubble Space Telescope the very next day.
Many of the
world's telescopes
then zoomed in on our Solar System's
largest planet to see the result.
Some of these images have been complied into the
above animation .
Over the course of the last month and a half, the
above time-lapse sequence shows the dark spot -- first created when
Jupiter was struck -- deforming and dissipating as
Jupiter 's clouds churned and
Jupiter rotated .
It is now thought that a small comet -- perhaps less than one kilometer across --
impacted Jupiter on or before 2009 July 19.
Although initially expected to be
visible for only a week, astronomers continue to track atmospheric remnants of the impact for new information about winds and currents in
Jupiter's thick atmosphere .
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