Your Account
Community
More |
Everyone - Upcoming stories
Solstice to Solstice Solargraph
http://antwrp.gsfc.nasa.gov/apod/image/0906/solsolargraph_za...
Submitted by APOD
5 months, 3 days, 8 hours ago
This six month long exposure compresses the
time
from solstice to solstice
(~ December 21, 2008 to June 20, 2009) into a single
point of view.
Dubbed a solargraph, the
unconventional
picture was recorded with a pinhole camera
made from an aluminum can lined
with a piece of photographic paper.
Fixed to a
single spot
for the entire exposure, the simple camera continuously
records the Sun's daily path as a glowing trail
burned into the photosensitive paper.
Breaks and gaps in the trails are caused by cloud cover.
In this case, the spot was chosen to look out
from inside a
radio telescope
at the
Ondrejov Observatory
in the Czech Republic.
At the end of the exposure, the paper was removed from the
can and immediately scanned digitally.
Contrasts and colors were then enhanced and added to the
digital image.
Of course, in December, the Sun trails
begin lower down
at the northern hemisphere's winter solstice.
The trails climb higher in the sky as the
June 21st summer solstice approaches.
Join discussion... (0 comments)
Sarychev Peak Volcano in Stereo
http://antwrp.gsfc.nasa.gov/apod/image/0906/ISS020-E-9050_52...
Submitted by APOD
5 months, 4 days, 8 hours ago
From 400 kilometers
above
planet Earth , the Expedition 20 Crew
onboard the International Space Station
( ISS ) was able to witness a
remarkable event from a remarkable vantage point --
the June 12 eruption of the
Sarychev Peak Volcano .
The active volcano is located in Russia's
Kuril Island chain ,
stretching to the northeast of Japan.
Emphasizing the orbital perspective, this stunning color
stereo view
was made by combining two
images from the ISS and is
intended to be viewed with
red/blue
glasses (red for the left eye).
Punching upwards into the atmosphere at an early stage of the eruption,
the volcanic plume features a brown column of ash topped with a smooth,
bubble-like, white cloud that is likely water condensation.
Below, a cloud of denser grey ash slides down the volcanic slope.
About 1.5 kilometers of the island coastline is visible at ground
level.
The evolving
ash plume posed no danger to the Expedition 20 crew,
but commercial airline flights were diverted away
from the region to minimize the danger of engine failures from ash intake.
Join discussion... (0 comments)
Noctilucent Clouds Over Germany
http://antwrp.gsfc.nasa.gov/apod/image/0906/noctilucent_roll...
Submitted by APOD
5 months, 5 days, 8 hours ago
Sometimes it's night on the ground but day in the air.
As the Earth rotates to eclipse the Sun,
sunset rises up from the ground.
Therefore, at sunset on the ground,
sunlight still shines on clouds above.
Under usual circumstances, a
pretty sunset
might be visible, but unusual
noctilucent clouds float so high up they
can be seen well after dark.
Pictured above last week, a network of
noctilucent
clouds cast an eerie white glow after dusk, beyond a local field near
Potsdam ,
Germany .
Although
noctilucent clouds are thought to be composed of
small ice-coated particles,
much remains unknown about them.
Satellites launched to help study these clouds includes Sweden's
Odin and NASA's
AIM .
Recent evidence indicates that at least some
noctilucent clouds result from freezing water exhaust from
Space Shuttle s.
Join discussion... (0 comments)
Molecular Cloud Barnard 68
http://antwrp.gsfc.nasa.gov/apod/image/0906/barnard68v2_vlt....
Submitted by APOD
5 months, 6 days, 8 hours ago
Where did all the stars go?
What used to be considered a hole in the sky
is now known to astronomers as a dark molecular cloud .
Here, a high concentration of
dust and
molecular gas
absorb practically all the visible light
emitted from background stars.
The eerily dark surroundings help make the interiors of
molecular clouds some of the coldest
and most isolated places in the universe.
One of the most notable of these
dark absorption nebulae
is a cloud toward the constellation
Ophiuchus known as
Barnard 68 ,
pictured above .
That no stars are visible in the center indicates that
Barnard
68 is relatively nearby, with measurements placing it about
500 light-years away and half a light-year across.
It is not known exactly how
molecular clouds like
Barnard 68 form, but it is known that these clouds are themselves
likely places
for new stars to form .
In fact, Barnard 68 itself has
recently been found likely to collapse and form a new star system.
It is possible to
look right through the cloud in infrared light.
Join discussion... (0 comments)
Atlas 5 Rocket Launches to the Moon
http://antwrp.gsfc.nasa.gov/apod/image/0906/lrolaunch_nasa.j...
Submitted by APOD
5 months, 1 week, 8 hours ago
This rocket is headed for the Moon.
Pictured above , a huge
Altas V rocket
roared off the
launch pad last week to start NASA's
first missions to Earth's
Moon in 10 years.
The rocket is carrying two robotic spacecraft.
The Lunar Reconnaissance Orbiter
( LRO )
is scheduled to orbit and better map the Moon, search for buried and hidden ice, and return many high resolution images.
Some images will be below one-meter in resolution and include images of historic
Apollo landing site s.
Exploratory data and images should allow a more informed choice of possible future astronaut landing sites.
The Lunar CRater Observation and Sensing Satellite (LCROSS) is scheduled to
monitor the controlled
impact of the rocket's
upper stage into a permanently shadowed crater near the
Moon's south pole .
This impact, which should occur in about three months, might be visible on Earth through small telescopes .
Join discussion... (0 comments)
Sunrise over the Parthenon
http://antwrp.gsfc.nasa.gov/apod/image/0906/parthenon_ayioma...
Submitted by APOD
5 months, 1 week, 1 day, 8 hours ago
Today, the sun will stay in the sky longer than any other day of the year, as seen from the northern hemisphere of Earth.
Named the Summer Solstice, today's
maximum daylight is indicative of the high amount of sunlight this time of year that is primarily responsible for the heat of the
summer season .
At the north pole and for all places above the
arctic circle ,
there will be no night -- the entire day today will be lit by sunlight.
The situation is reversed in Earth's southern hemisphere, where today has the least sunlight of any day.
Today's solstice is commemorated above by a
well-planned picture of our five billion year old Sun rising behind the 2,500 year old
Parthenon in
Greece .
Trees and birds occupy the foreground, while a modern
crane
is shown restoring parts of this historic symbol of a cultural
civilization .
Join discussion... (1 comments)
Seaside Moon Mirage
http://antwrp.gsfc.nasa.gov/apod/image/0906/Navires013_audri...
Submitted by APOD
5 months, 1 week, 2 days, 8 hours ago
This surprising view of the Full Moon
rising on
June 7 was captured
with a telephoto lens from a seaside balcony near Nice, France.
The orange Moon's
dark markings and odd shape put the photographer
in mind of an alien creature's face staring down at the passing ship.
Of course, the Moon's distorted appearance is due to the unusual bending
( refraction ) of light rays
creating multiple images or
mirages , similar to
sunset and
sunrise mirages .
The effects are most pronounced when
temperature
layers in the atmosphere produce sharp changes in air density and
refractive index.
Acting over long sight-lines to the rising and setting Sun or Moon,
the refraction significantly alters the
path of
light rays creating merged, distorted images.
Such mirages are also associated with the
Green Flash .
Join discussion... (0 comments)
Dunhuang Star Atlas
http://antwrp.gsfc.nasa.gov/apod/image/0906/dunhuang_npole_c...
Submitted by APOD
5 months, 1 week, 3 days, 8 hours ago
This ancient Chinese map of planet Earth's northern sky is part
of the Dunhuang Star Atlas, one of the most impressive
documents in the history of astronomy .
The oldest complete star atlas known, it dates to the years 649 to
684, discovered at the
Silk Road town of Dunhuang in 1907.
A recent analysis
that examines the accuracy and projections
used to make it notes the atlas marks positions of over
1,300 stars and outlines 257 Chinese
star groups or asterisms .
The star positions in the hand drawn atlas were found to be
accurate to within a few degrees.
In this example showing the north polar region, a very
recognizable Big Dipper , part of the modern
constellation Ursa Major, lies along the bottom of the chart.
An additional 12 charts depict equatorial regions in 30 degree
sections and also include a grouping resembling the modern
constellation Orion .
The atlas is on display
at the British Library in London to celebrate the
International Year of Astronomy .
Join discussion... (2 comments)
NGC 6240: Merging Galaxies
http://antwrp.gsfc.nasa.gov/apod/image/0906/ngc6240_spitzerh...
Submitted by APOD
5 months, 1 week, 4 days, 8 hours ago
NGC 6240 offers a rare glimpse of a cosmic catastrophe in its
final throes.
The titanic galaxy-galaxy
collision
is located a mere 400 million light-years away in the constellation
Ophiuchus .
One of the brightest sources in the
infrared sky , the merging galaxies
spew distorted tidal tails
of stars, gas, and dust and undergo frantic bursts of star
formation.
The two supermassive
black holes in the original galactic cores
will also coalesce into a single, even more massive black hole.
Soon, only one large galaxy will remain.
This dramatic image of the scene is a
multiwavelength composite;
red colors trace infrared emission from dust recorded by the
Spitzer Space Telescope , with Hubble visible light
images of stars and gas in green and blue hues.
The view spans over 300,000 light-years at the estimated distance
of NGC 6240 .
Join discussion... (0 comments)
M13: A Great Globular Cluster of Stars
http://antwrp.gsfc.nasa.gov/apod/image/0906/m13_russell.jpg
Submitted by APOD
5 months, 1 week, 5 days, 8 hours ago
M13
is one of the most prominent and best known
globular clusters .
Visible with binoculars in the constellation of Hercules , M13 is frequently one of the first objects found by
curious sky gazers seeking
celestials wonders
beyond
normal human vision.
M13 is a colossal home to over 100,000 stars, spans over 150
light years across,
lies over 20,000 light years distant,
and is over 12 billion years old.
At the 1974 dedication of
Arecibo Observatory , a
radio message
about Earth was sent in the direction of
M13 .
The reason for the low abundance of unusual
blue straggler stars
in M13 remains unknown .
Join discussion... (0 comments)
|