Thursday, December 31, 2009

Dust and the Helix Nebula

Thursday, December 31, 2009
http://www.wikio.com 0 comments

Dust makes this cosmic eye look red. The eerie Spitzer Space Telescope image shows infrared radiation from the well-studied Helix Nebula (NGC 7293) a mere 700 light-years away in the constellation Aquarius. The two light-year diameter shroud of dust and gas around a central white dwarf has long been considered an excellent example of a planetary nebula, representing the final stages in the evolution of a sun-like star. But the Spitzer data show the nebula's central star itself is immersed in a surprisingly bright infrared glow. Models suggest the glow is produced by a dust debris disk. Even though the nebular material was ejected from the star many thousands of years ago, the close-in dust could be generated by collisions in a reservoir of objects analogous to our own solar system's Kuiper Belt or cometary Oort cloud. Formed in the distant planetary system, the comet-like bodies would have otherwise survived even the dramatic late stages of the star's evolution.

read more

Wednesday, December 30, 2009

Suzaku Finds "Fossil" Fireballs from Supernovae

Wednesday, December 30, 2009
http://www.wikio.com 0 comments
Studies of two supernova remnants using the Japan-U.S. Suzaku observatory have revealed never-before-seen embers of the high-temperature fireballs that immediately followed the explosions. Even after thousands of years, gas within these stellar wrecks retain the imprint of temperatures 10,000 times hotter than the sun's surface.

"This is the first evidence of a new type of supernova remnant -- one that was heated right after the explosion," said Hiroya Yamaguchi at the Institute of Physical and Chemical Research in Japan.

A supernova remnant usually cools quickly due to rapid expansion following the explosion. Then, as it sweeps up tenuous interstellar gas over thousands of years, the remnant gradually heats up again.

Capitalizing on the sensitivity of the Suzaku satellite, a team led by Yamaguchi and Midori Ozawa, a graduate student at Kyoto University, detected unusual features in the X-ray spectrum of IC 443, better known to amateur astronomers as the Jellyfish Nebula.

The remnant, which lies some 5,000 light-years away in the constellation Gemini, formed about 4,000 years ago. The X-ray emission forms a roughly circular patch in the northern part of the visible nebulosity.

Suzaku's X-ray Imaging Spectrometers (XISs) separate X-rays by energy in much the same way as a prism separates light into a rainbow of colors. This allows astronomers to tease out the types of processes responsible for the radiation.

Some of the X-ray emission in the Jellyfish Nebula arises as fast-moving free electrons sweep near the nuclei of atoms. Their mutual attraction deflects the electrons, which then emit X-rays as they change course. The electrons have energies corresponding to a temperature of about 12 million degrees Fahrenheit (7 million degrees Celsius).

Several bumps in the Suzaku spectrum were more puzzling. "These structures indicate the presence of a large amount of silicon and sulfur atoms from which all electrons have been stripped away," Yamaguchi said. These "naked" nuclei produce X-rays as they recapture their lost electrons.

But removing all electrons from a silicon atom requires temperatures higher than about 30 million degrees F (17 million C); hotter still for sulfur atoms. "These ions cannot form in the present-day remnant," Yamaguchi explained. "Instead, we're seeing ions created by the enormous temperatures that immediately followed the supernova."

The team suggests that the supernova occurred in a relatively dense environment, perhaps in a cocoon of the star's own making. As a massive star ages, it sheds material in the form of an outflow called a stellar wind and creates a cocoon of gas and dust. When the star explodes, the blast wave traverses the dense cocoon and heats it to temperatures as high as 100 million degrees F (55 million C), or 10,000 times hotter than the sun's surface.

Eventually, the shock wave breaks out into true interstellar space, where the gas density can be as low as a single atom per cubic centimeter -- about the volume of a sugar cube. Once in this low-density environment, the young supernova remnant rapidly expands.

The expansion cools the electrons, but it also thins the remnant's gas so much that collisions between particles become rare events. Because an atom may take thousands of years to recapture an electron, the Jellyfish Nebula's hottest ions remain even today, the astronomers reported in the Nov. 1 issue of The Astrophysical Journal.

"Suzaku sees the Jellyfish's hot heart," Ozawa said.

The team has already identified another fossil fireball in the supernova remnant known as W49B, which lies 35,000 light-years away in the constellation Aquila. In the Nov. 20 edition of The Astrophysical Journal, Ozawa, Yamaguchi and colleagues report X-ray emission from iron atoms that are almost completely stripped of electrons. Forming these ions requires temperatures in excess of 55 million degrees F (30 million C)-- nearly twice the observed temperature of the remnant's electrons.

Launched on July 10, 2005, Suzaku was developed at the Japanese Institute of Space and Astronautical Science (ISAS), which is part of the Japan Aerospace Exploration Agency (JAXA), in collaboration with NASA and other Japanese and U.S. institutions.

read more

Spitzer's M101

http://www.wikio.com 0 comments

Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way Galaxy. M101 was also one of the original spiral nebulae observed by Lord Rosse's large 19th century telescope, the Leviathan of Parsontown. Recorded at infrared wavelengths by the Spitzer Space telescope, this 21st century view shows starlight in blue hues while the galaxy's dust clouds are in red. Examining the dust features in the outer rim of the galaxy, astronomers have found that organic molecules present throughout the rest of M101 are lacking. The organic molecules tracked by Spitzer's instruments are called polycyclic aromatic hydrocarbons (PAHs). Of course, PAHs are common components of dust in the Milky Way and on planet Earth are found in soot. PAHs are likely destroyed near the outer edges of M101 by energetic radiation in intense star forming regions. Also known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major, about 25 million light-years away.

read more

Tuesday, December 29, 2009

Rigel and the Witch Head Nebula

Tuesday, December 29, 2009
http://www.wikio.com 0 comments

Double, double toil and trouble; Fire burn, and cauldron bubble -- maybe Macbeth should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula on the lower left is associated with the bright star Rigel, to its right, in the constellation Orion. More formally known as IC 2118, the Witch Head Nebula glows primarily by light reflected from Rigel. Fine dust in the nebula reflects the light. Pictured above, the blue color of the Witch Head Nebula and of the dust surrounding Rigel is caused not only by Rigel's blue color but because the dust grains reflect blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in Earth's atmosphere are molecules of nitrogen and oxygen. Rigel, the Witch Head Nebula, and gas and dust that surrounds them lie about 800 light-years away.

read more

Tuesday, December 22, 2009

Planetary Systems Now Forming in Orion

Tuesday, December 22, 2009
http://www.wikio.com 0 comments

How do planets form? To help find out, the Hubble Space Telescope was tasked to take a detailed look at one of the more interesting of all astronomical nebulae, the Great Nebula in Orion. The Orion nebula, visible with the unaided eye near the belt in the constellation of Orion, is an immense nearby starbirth region and probably the most famous of all astronomical nebulas. Insets to the above mosaic show numerous proplyds, many of which are stellar nurseries likely harboring planetary systems in formation. Some proplyds glow as close disks surrounding bright stars light up, while other proplyds contain disks further from their host star, contain cooler dust, and hence appear as dark silhouettes against brighter gas. Studying this dust, in particular, is giving insight for how planets are forming. Many proplyd images also show arcs that are shock waves - fronts where fast moving material encounters slow moving gas. The Orion Nebula lies about 1,500 light years distant and is located in the same spiral arm of our Galaxy as our Sun.

read more

Monday, December 21, 2009

Star Cluster R136 Bursts Out

Monday, December 21, 2009
http://www.wikio.com 0 comments

In the center of star-forming region 30 Doradus lies a huge cluster of the largest, hottest, most massive stars known. These stars, known collectively as star cluster R136, were captured above in visible light by the newly installed Wide Field Camera peering though the recently refurbished Hubble Space Telescope. Gas and dust clouds in 30 Doradus, also known as the Tarantula Nebula, have been sculpted into elongated shapes by powerful winds and ultraviolet radiation from these hot cluster stars. The 30 Doradus Nebula lies within a neighboring galaxy known as the Large Magellanic Cloud and is located a mere 170,000 light-years away.

read more

Sunday, December 20, 2009

Tutulemma: Solar Eclipse Analemma

Sunday, December 20, 2009
http://www.wikio.com 0 comments

If you went outside at exactly the same time every day and took a picture that included the Sun, how would the Sun appear to move? With great planning and effort, such a series of images can be taken. The figure-8 path the Sun follows over the course of a year is called an analemma. This coming Tuesday, the Winter Solstice day in Earth's northern hemisphere, the Sun will be at the bottom of the analemma. Analemmas created from different latitudes would appear at least slightly different, as well as analemmas created at a different time each day. With even greater planning and effort, the series can include a total eclipse of the Sun as one of the images. Pictured is such a total solar eclipse analemma or Tutulemma - a term coined by the photographers based on the Turkish word for eclipse. The composite image sequence was recorded from Turkey starting in 2005. The base image for the sequence is from the total phase of a solar eclipse as viewed from Side, Turkey on 2006 March 29. Venus was also visible during totality, toward the lower right.

read more

Friday, December 18, 2009

Update on Last Night's DNS Disruption

Friday, December 18, 2009
http://www.wikio.com 0 comments
Domain Name System or DNS is an Internet protocol used to translate IP addresses into domain names so instead of typing in a long string of numbers we can enter urls like www.twitter.com into a browser to visit our favorite web sites. Last night, DNS settings for the Twitter web site were hijacked. From 9:46pm to 11pm PST, approximately 80% of Traffic to Twitter.com was redirected to other web sites. We tweeted, blogged, and updated our status page last night.

During the attack, we were in direct contact with our DNS provider, Dynect. We worked closely to reset our DNS as quickly as possible. The motive for this attack appears to have been focused on defacing our site, not aimed at users—we don't believe any accounts were compromised. If you're concerned that your account could have been affected in some way, feel free to contact us, accountsafe [at] twitter.com.

read more

Aurora Shimmer, Meteor Flash

http://www.wikio.com 0 comments

Northern Lights, or aurora borealis, haunted skies over the island of Kvaløya, near Tromsø Norway on December 13. This 30 second long exposure records their shimmering glow gently lighting the wintery coastal scene. A study in contrasts, it also captures the sudden flash of a fireball meteor from December's excellent Geminid meteor shower. Streaking past familiar stars in the handle of the Big Dipper, the trail points back toward the constellation Gemini, off the top of the view. Both aurora and meteors occur in Earth's upper atmosphere at altitudes of 100 kilometers or so, but aurora are caused by energetic charged particles from the magnetosphere, while meteors are trails of cosmic dust.

read more

Southern Geminids

http://www.wikio.com 0 comments

At least 34 meteors are included in this composite image as they rain through Australian skies during the annual Geminid Meteor shower. Dust particles strung out along the orbit of extinct comet Phaethon vaporize when they plow through planet Earth's atmosphere causing the impressive display. Although the particles are traveling parallel to each other, the resulting streaks clearly seem to radiate from a single point on the sky near Gemini's twin stars Castor and Pollux at the lower right. The radiant effect is due to perspective, as the parallel tracks appear to converge at a distance. Taken over a period of 2 hours on the morning of December 14, short exposures recording individual meteor streaks were combined with a single long exposure to show the background stars, with Sirius at the top, and the constellation Orion at left. Faint stars and nebulae of the Milky Way track through the center of the frame. Near the radiant point, an extra star in Gemini is actually the flash of a meteor seen almost head-on.

read more

Thursday, December 17, 2009

Mojave Desert Fireball

Thursday, December 17, 2009
http://www.wikio.com 0 comments

Monstrously bright, this fireball meteor lit up the Mojave Desert sky Monday morning, part of this year's impressive Geminid meteor shower. Seen toward the southwest over rock formations near Victorville, California, a more familiar celestial background was momentarily washed out by the meteor's flash. The background includes bright star Sirius at the left, and Aldebaran and the Pleaides star cluster at the right side of the image. The meteor itself blazes through the constellation Orion. Its greenish trail begins just left of a yellow-tinted Betelgeuse and points back to the shower's radiant in Gemini, just off the top of the frame. A rewarding catch for photographer Wally Pacholka, the spectacular image is one of over 1500 frames that he reports captured 48, mostly faint, Geminid meteors.

read more

Wednesday, December 16, 2009

Comet Hyakutake Passes the Earth

Wednesday, December 16, 2009
http://www.wikio.com 0 comments

In 1996, an unexpectedly bright comet passed by planet Earth. Discovered less than two months before, Comet C/1996 B2 Hyakutake came within only 1/10th of the Earth-Sun distance from the Earth in late March. At that time, Comet Hyakutake, dubbed the Great Comet of 1996, became the brightest comet to grace the skies of Earth in 20 years. During its previous visit, Comet Hyakutake may well have been seen by the stone age Magdalenian culture, who 17,000 years ago were possibly among the first humans to live in tents as well as caves. Pictured above near closest approach as it appeared on 1996 March 26, the long ion and dust tails of Comet Hyakutake are visible flowing off to the left in front of a distant star field that includes both the Big and Little Dippers. On the far left, the blue ion tail appears to have recently undergone a magnetic disconnection event. On the far right, the comet's green-tinted coma obscures a dense nucleus of melting dirty ice estimated to be about 5 kilometers across. A few months later, Comet Hyakutake began its long trek back to the outer Solar System. Because of being gravitationally deflected by massive planets, Comet Hyakutake is not expected back for about 100,000 years.

read more

Tuesday, December 15, 2009

A Fading Moonset Over Hong Kong

Tuesday, December 15, 2009
http://www.wikio.com 0 comments

Do stars appear dimmer when nearer the horizon? Yes -- atmospheric air absorbs and reradiates light, so that the greater the airmass through which one peers, the fainter an object will appear. Pictured above in a multi-frame image, stars, the planet Jupiter, and even the Moon show the horizon-dimming effects of Earth's nearly-transparent atmosphere. The image was taken in the evening about three weeks ago over Hong Kong, China. The brightest streak near the center is the setting Moon, while intermittent thin clouds sometimes dispersed moonlight into a larger halo. Jupiter sets just to the Moon's right. The dim steaks cutting across the image horizontally were caused by passing airplanes. The bright strange multi-pronged streak over the house is a helicopter taking off. An astute observer will also notice faint rays emanating from near the horizon. Their cause is unknown, but may be crepuscular rays caused by the Sun shining through gaps in thick clouds.

read more

Wednesday, December 9, 2009

HUDF Infrared: Dawn of the Galaxies

Wednesday, December 9, 2009
http://www.wikio.com 0 comments

When did galaxies form? To help find out, the deepest near-infrared image of the sky ever has been taken of the same field as the optical-light Hubble Ultra Deep Field (HUDF) in 2004. The new image was taken this summer by the newly installed Wide Field Camera 3 on the refurbished Hubble Space Telescope. Faint red smudges identified on the above image likely surpass redshift 8 in distance. These galaxies therefore likely existed when the universe was only a few percent of its present age, and may well be members of the first class of galaxies. Some large modern galaxies make a colorful foreground to the distant galaxies. Analyses by the HUDF09 team indicate that at least some of these early galaxies had very little interstellar dust. This early class of low luminosity galaxies likely contained energetic stars emitting light that transformed much of the remaining normal matter in the universe from a cold gas to a hot ionized plasma.

read more

Tuesday, December 8, 2009

Ice Moon Tethys from Saturn-Orbiting Cassini

Tuesday, December 8, 2009
http://www.wikio.com 0 comments

What processes formed the unusual surface of Saturn's moon Tethys? To help find out, NASA sent the robotic Cassini spacecraft right past the enigmatic ice moon in 2005. Pictured above is one of the highest resolution images of an entire face of Tethys yet created. The pervasive white color of Tethys is thought to be created by fresh ice particles continually falling onto the moon from Saturn's diffuse E-ring -- particles expelled by Saturn's moon Enceladus. Some of the unusual cratering patterns on Tethys remain less well understood, however. Close inspection of the above image of Tethys' south pole will reveal a great rift running diagonally down from the middle: Ithaca Chasma. A leading theory for the creation of this great canyon is anchored in the tremendous moon-wide surface cracking that likely occurred when Tethys' internal oceans froze. If so, Tethys may once have harbored internal oceans, possibly similar to the underground oceans some hypothesize to exist under the surface of Enceladus today. Might ancient life be frozen down there?

read more

Monday, December 7, 2009

The International Space Station Over the Horizon

Monday, December 7, 2009
http://www.wikio.com 0 comments

This was home. Just over a week ago, the STS-129 crew of the Space Shuttle Atlantis undocked from the International Space Station (ISS) and returned to Earth. As the shuttle departed the space station, they took the above image. Visible on the ISS are numerous modules, trusses, and long wing-like solar panels. The space shuttle crew spent almost 12 days calling the space station home. The shuttle crew resupplied the space station and delivered valuable spare parts. The ISS continues to be home for five astronauts of Expedition 21. The ISS's crew now includes astronauts representing NASA, the European Space Agency, the Russian Federal Space Agency, and the Canadian Space Agency.

read more

Sunday, December 6, 2009

The Magnificent Tail of Comet McNaught

Sunday, December 6, 2009
http://www.wikio.com 0 comments

Comet McNaught, the Great Comet of 2007, was the brightest comet of the last 40 years. Its spectacular tail spread across the sky and was breathtaking to behold from dark locations for many Southern Hemisphere observers. The head of the comet remained quite bright and was easily visible to even city observers without any optical aide. Part of the spectacular tail was visible just above the horizon after sunset for many northern observers as well. Comet C/2006 P1 (McNaught), which reached an estimated peak brightness of magnitude -6 (minus six), was caught by the comet's discoverer in the above image soon after sunset in 2007 January from Siding Spring Observatory in Australia. The robotic Ulysses spacecraft fortuitously flew through Comet McNaught's tail and found, unexpectedly, that the speed of the solar wind dropped significantly.

read more

Saturday, December 5, 2009

Himalayan Skyscape

Saturday, December 5, 2009
http://www.wikio.com 0 comments

Capella, alpha star of the constellation Auriga, rises over Mt. Everest in this panoramic view of the top of the world at night. The scene was recorded in late November near Namche Bazar, Nepal, gateway to the Himalayan mountain range. Moonlight illuminates the famous peaks of Everest (8840 meters) and Lhotse (8516 meters) at the far left, and a stupa (a Buddhist religious monument) in the foreground, along the main trail to the Everest Base Camp. The light in the valley is from the Tengboche Monastery, also along the trail at about 4000 meters. From left to right above the moonlit peaks, the stars of Auriga give way to bright giant star Aldebaran eye of the Taurus the Bull, the Pleiades star cluster, alpha Ceti, and finally alpha Phoenicis of the Phoenix. Peaks and stars can be identified by placing your cursor over the image.

read more

Friday, December 4, 2009

STS-130 Mission Information

Friday, December 4, 2009
http://www.wikio.com 0 comments
Image above: (From left) Mission Specialist Nicholas Patrick, Pilot Terry Virts, Mission Specialists Robert Behnken and Kathryn Hire, Commander George Zamka and Mission Specialist Stephen Robinson. Image credit: NASA

Launch Target:
Feb. 4, 2010

Orbiter:
Endeavour

Mission Number:
STS-130
(130th space shuttle flight)


Launch Window:
10 minutes

Launch Pad:
39A

Mission Duration:
13 days

Landing Site:
KSC

Inclination/Altitude:
51.6 degrees/122 nautical miles

Primary Payload:
32nd station flight (20A), Tranquility Node 3, Cupola


STS-130 Crew Profiles

Commander George Zamka will lead the STS-130 mission to the International Space Station aboard space shuttle Endeavour. Terry Virts Jr. will serve as the pilot. Mission specialists are Nicholas Patrick, Robert Behnken, Stephen Robinson and Kathryn Hire. Virts will be making his first trip to space.

Endeavour will deliver a third connecting module - the Tranquility node - to the station and a seven-windowed cupola to be used as a control room for robotics. The mission will feature three spacewalks.

STS-130 is the 32nd shuttle mission to the station.

read more

STS-130 Crew Profiles

http://www.wikio.com 0 comments
Crew Profiles

George D. Zamka
Commander

View biography




Terry W. Virts Jr.
Pilot

View biography




Nicholas J. M. Patrick
Mission Specialist

View biography




Robert L. Behnken
Mission Specialist

View biography




Stephen K. Robinson
Mission Specialist

View biography




Kathryn P. Hire
Mission Specialist

View biography

read more

Space Shuttle Mission: STS-130

http://www.wikio.com 0 comments
In Orbiter Processing Facility-2 at NASA's Kennedy Space Center in Florida, technicians are halfway complete with a three-day leak test on space shuttle Endeavour's environmental control and life support system, as well as structural leak tests.

The shuttle's move, also known as rollover, to the Vehicle Assembly Building is scheduled for Dec. 12. Once inside, the Endeavour will be hoisted and then lowered onto the waiting mobile launcher platform where the massive external fuel tank and solid rocket boosters stand ready.

Today, the six STS-130 astronauts are studying flight procedures at NASA's Johnson Space Center in Houston.

Shuttle Endeavour, with its payload of the Tranquility node and the seven-windowed Cupola module, is targeted to launch Feb. 4, 2010.

Endeavour's STS-130 Mission

Commander George Zamka will lead the STS-130 mission to the International Space Station aboard space shuttle Endeavour. Terry Virts will serve as the pilot. Mission specialists are Nicholas Patrick, Robert Behnken, Stephen Robinson and Kathryn Hire. Virts will be making his first trip to space.

Endeavour will deliver a third connecting module, the Tranquility node, to the station in addition to the seven-windowed Cupola module, which will be used as a control room for robotics. The mission will feature three spacewalks.

Liftoff from NASA's Kennedy Space Center in Florida is targeted for February 4, 2010 at 5:52 a.m. EST.

Additional Resources
› STS-129 Mission Information

read more

The Double Cluster

http://www.wikio.com 0 comments
A lovely starfield in the heroic northern constellation Perseus holds this famous pair of open or galactic star clusters, h and Chi Perseii. Also cataloged as NGC 869 (right) and NGC 884, both clusters are about 7,000 light-years away and contain stars much younger and hotter than the Sun. Separated by only a few hundred light-years, the clusters' ages based on their individual stars are similar - evidence that they were likely a product of the same star-forming region. Always a rewarding sight in binoculars, the Double Cluster is even visible to the unaided eye from dark locations. Star colors (and spikes) are enhanced in this beautiful, wide field, telescopic image.

read more

Thursday, December 3, 2009

Honoring Apollo 13's Fred Haise

Thursday, December 3, 2009
http://www.wikio.com 0 comments
At a 1 p.m. ceremony on Dec 2, 2009, Administrator Charles Bolden presented NASA's Ambassador of Exploration Award to Apollo 13 astronaut Fred Haise, a Biloxi, Miss., native.

The ceremony took place at Biloxi's Gorenflo Elementary School.

Pictured from left to right are school principal Tina Thompson, Administrator Bolden, Fred Haise, Biloxi Public School District Superintendent Paul Tisdale and Stennis Space Center Director Gene Goldman.

read more

Daphnis' Disturbances

http://www.wikio.com 0 comments

This Cassini image, which at first appears to show a serene scene, in fact reveals dramatic disturbances created in Saturn's A ring by its moon Daphnis.

Near the center of the image, tiny Daphnis (8 kilometers, 5 miles across) appears as a bright dot in the Keeler Gap near the edge waves it has created in the A ring. The moon has an inclined orbit and its gravitational pull perturbs the orbits of the particles of the A ring forming the Keeler Gap's edge and sculpts the edge into waves having both horizontal (radial) and out-of-plane components. Material on the inner edge of the gap orbits faster than the moon so that the waves there lead the moon in its orbit. Material on the outer edge moves slower than the moon, so waves there trail the moon. See PIA11656 to learn more about this process.

Epimetheus (113 kilometers, 70 miles across) orbits beyond the F ring at the bottom of the image. Bright specks in the image are background stars.

This view looks toward the northern, sunlit side of the rings from about 11 degrees above the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 24, 2009. The view was obtained at a distance of approximately 1.8 million kilometers (1.1 million miles) from Daphnis. Image scale is 11 kilometers (7 miles) per pixel.

The Cassini Equinox Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

read more

Polar Ring Galaxy NGC 660

http://www.wikio.com 0 comments

NGC 660 lies near the center of this intriguing field of galaxies swimming within the boundaries of the constellation Pisces. Over 20 million light-years away, its peculiar appearance marks it as a polar ring galaxy. A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of a flat galactic disk. The bizarre configuration could have been caused by the chance capture of material from a passing galaxy by the disk galaxy, with the captured debris strung out in a rotating ring. Polar Ring galaxies can be used to explore the shape of the galaxy's otherwise unseen dark matter halo by calculating the dark matter's gravitational influence on the rotation of the ring and disk. Broader than the disk, NGC 660's ring spans about 40,000 light-years.

read more

Wednesday, December 2, 2009

Scientists Explain Puzzling Lake Asymmetry on Titan

Wednesday, December 2, 2009
http://www.wikio.com 0 comments
Researchers at the California Institute of Technology, NASA's Jet Propulsion Laboratory, and other institutions suggest that the eccentricity of Saturn's orbit around the sun may be responsible for the unusually uneven distribution of lakes over the northern and southern polar regions of the planet's largest moon, Titan. A paper describing the theory appears in the Nov. 29 advance online edition of Nature Geoscience.

Saturn's oblong orbit around the sun exposes different parts of Titan to different amounts of sunlight, which affect cycles of precipitation and evaporation in those areas. Similar variations in Earth's orbit also drive long-term ice-age cycles on our planet.

As revealed by Synthetic Aperture Radar imaging data from NASA's Cassini spacecraft, liquid methane and ethane lakes in Titan's northern high latitudes cover 20 times more area than lakes in the southern high latitudes. The Cassini data also show there are significantly more partially filled and now-empty lakes in the north. (In the radar data, smooth features -- like the surfaces of lakes -- appear as dark areas, while rougher features -- such as the bottom of an empty lake-appear bright.) The asymmetry is not likely to be a statistical fluke because of the large amount of data collected by Cassini in its five years surveying Saturn and its moons.

Scientists initially considered the idea that "there is something inherently different about the northern polar region versus the south in terms of topography, such that liquid rains, drains or infiltrates the ground more in one hemisphere," said Oded Aharonson of Caltech, lead author of the Nature Geoscience paper.

However, Aharonson notes that there are no substantial known differences between the north and south regions to support this possibility. Alternatively, the mechanism responsible for this regional dichotomy may be seasonal. One year on Titan lasts 29.5 Earth years. Every 15 Earth years, the seasons of Titan reverse, so that it becomes summer in one hemisphere and winter in the other. According to this seasonal variation hypothesis, methane rainfall and evaporation vary in different seasons -- recently filling lakes in the north while drying lakes in the south.

The problem with this idea, Aharonson said, is that it accounts for decreases of about one meter per year in the depths of lakes in the summer hemisphere. But Titan's lakes are a few hundred meters deep on average, and wouldn't drain (or fill) in just 15 years. In addition, seasonal variation can't account for the disparity between the hemispheres in the number of empty lakes. The north polar region has roughly three times as many dried-up lake basins as the south and seven times as many partially filled ones.

"How do you move the hole in the ground?" Aharonson asked. "The seasonal mechanism may be responsible for part of the global transport of liquid methane, but it's not the whole story." A more plausible explanation, say Aharonson and his colleagues, is related to the eccentricity of the orbit of Saturn -- and hence of Titan, its satellite -- around the sun.

Like Earth and other planets, Saturn's orbit is not perfectly circular, but is instead somewhat elliptical and oblique. Because of this, during its southern summer, Titan is about 12 percent closer to the sun than during the northern summer. As a result, northern summers are long and subdued; southern summers are short and intense.

"We propose that, in this orbital configuration, the difference between evaporation and precipitation is not equal in opposite seasons, which means there is a net transport of methane from south to north," said Aharonson. This imbalance would lead to an accumulation of methane -- and hence the formation of many more lakes -- in the northern hemisphere.

This situation is only true right now, however. Over very long time scales of tens of thousands of years, Saturn's orbital parameters vary, at times causing Titan to be closer to the sun during its northern summer and farther away in southern summers, and producing a reverse in the net transport of methane. This should lead to a buildup of hydrocarbon -- and an abundance of lakes -- in the southern hemisphere.

"Like Earth, Titan has tens-of-thousands-of-year variations in climate driven by orbital motions," Aharonson said. On Earth, these variations, known as Milankovitch cycles, are linked to changes in solar radiation, which affect global redistribution of water in the form of glaciers, and are believed to be responsible for ice-age cycles. "On Titan, there are long-term climate cycles in the global movement of methane that make lakes and carve lake basins. In both cases we find a record of the process embedded in the geology," he added.

"We may have found an example of long-term climate change, analogous to Milankovitch climate cycles on Earth, on another object in the solar system," he said.

The paper's co-authors are Caltech graduate student Alexander G. Hayes; Jonathan I. Lunine, Lunar and Planetary Laboratory, Tucson, Ariz.; Ralph D. Lorenz, Applied Physics Laboratory at the Johns Hopkins University, Laurel, Md.; Michael D. Allison, NASA Goddard Institute for Space Studies, New York; and Charles Elachi, director of JPL. The work was partially funded by the Cassini Project.

For more information about the Cassini-Huygens mission, visit: http://www.nasa.gov/cassini or http://saturn.jpl.nasa.gov/index.cfm . The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington, D.C.


read more

Atlantis and the STS-129 Profile

http://www.wikio.com 0 comments
Surrounded by the blackness of space, this profile view of the space shuttle Atlantis was photographed by the Expedition 21 crew on the International Space Station soon after the shuttle and station began their post-undocking relative separation.

Undocking of the two spacecraft occurred at 3:53 a.m. CST on Nov. 25, 2009.

Atlantis and the STS-129 crew landed safely at Kennedy Space Center on Nov. 27

read more

Details of Dark Senkyo

http://www.wikio.com 0 comments

The low albedo feature known as Senkyo is visible through the haze of Titan's atmosphere.

To learn about this area that appears dark near the moon's equator. This view looks toward Saturn-facing side of Titan (5150 kilometers, 3200 miles across) and is centered on terrain at 1 degree south latitude, 345 degrees west longitude. North on Titan is up and rotated 10 degrees to the right.

The image was taken with the Cassini spacecraft narrow-angle camera on Oct. 12, 2009 using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers. The view was acquired at a distance of approximately 296,000 kilometers (184,000 miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 11 degrees. Image scale is 2 kilometers (1 mile) per pixel.

The Cassini Equinox Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

read more

Dust Sculptures in the Rosette Nebula

http://www.wikio.com 0 comments

What creates the cosmic dust sculptures in the Rosette Nebula? Noted for the common beauty of its overall shape, parts of the Rosette Nebula, also known as NGC 2237, show beauty even when viewed up close. Visible above are globules of dark dust and gas that are slowly being eroded away by the energetic light and winds by nearby massive stars. Left alone long enough, the molecular-cloud globules would likely form stars and planets. The above image was taken in very specific colors of Sulfur (shaded red), Hydrogen (green), and Oxygen (blue). The Rosette Nebula spans about 50 light-years across, lies about 4,500 light-years away, and can be seen with a small telescope towards the constellation of the Unicorn (Monoceros).

read more

Tuesday, December 1, 2009

Another Stall of Right-Rear Wheel Ends Drive

Tuesday, December 1, 2009
http://www.wikio.com 0 comments
Spirit's right-rear wheel stalled again on Sol 2099 (Nov. 28, 2009) during the first step of a two-step extrication maneuver. This stall is different in some characteristics from the stall on Sol 2092 (Nov. 21). The Sol 2099 stall occurred more quickly and the inferred rotor resistance was elevated at the end of the stall. Investigation of past stall events along with these characteristics suggest that this stall might not be result of the terrain, but might be internal to the right-rear wheel actuator. Rover project engineers are developing a series of diagnostics to explore the actuator health and to isolate potential terrain interactions. These diagnostics are not likely to be ready before Wednesday. Plans for future driving will depend on the results of the diagnostic tests.

Before the Sol 2099 drive ended, Spirit completed 1.4 meters of wheel spin and the rover's center moved 0.5 millimeters (0.02 inch) forward, 0.25 millimeters (0.01 inch) to the left and 0.5 millimeters (0.02 inch) downward. Since Spirit began extrication on Sol 2088, the rover has performed 9.5 meters (31 feet) of wheel spin and the rover's center, in total, has moved 16 millimeters (0.63 inch) forward, 10 millimeters (0.39 inch) to the left and 5 millimeters (0.20 inch) downward.


read more

Expedition 21 Crew Lands in Kazakhstan

http://www.wikio.com 0 comments
Expedition 21 Flight Engineer and Soyuz Commander Roman Romanenko, European Space Agency Flight Engineer Frank De Winne and Canadian Space Agency Flight Engineer Robert Thirsk have returned to Earth, landing on the steppes of Kazakhstan in their Soyuz TMA-15 spacecraft. Landing occurred at 2:15 a.m. EST Tuesday, 1:15 p.m. Kazakhstan time.

All three crew members were reported to be in good condition. Due to icy conditions at the landing site, the landing support team recalled its helicopters to their bases in Kustanai and Arkalyk, Kazakhstan. Instead the team arrived in all-terrain vehicles from nearby Arkalyk to extract the Expedition 21 crew members from the Soyuz crew module.

Romanenko, De Winne and Thirsk spent 188 days in space, 186 of those aboard the orbiting International Space Station. The three arrived at the station in May as part of Expedition 20, which marked the start of six-person crew operations aboard the station. With their arrival, all five of the international partner agencies – NASA, the Russian Federal Space Agency (Roscosmos), the Japan Aerospace Exploration Agency (JAXA), the European Space Agency (ESA) and the Canadian Space Agency (CSA) – were represented on orbit for the first time.

Romanenko, a cosmonaut with Roscosmos, served as a flight engineer for Expeditions 20 and 21. He was selected as a test-cosmonaut candidate of the Gagarin Cosmonaut Training Center Cosmonaut Office in December 1997. The son of veteran Cosmonaut Yuri Romanenko, he qualified as a test cosmonaut in November 1999.

De Winne, an ESA astronaut, served as a flight engineer for Expeditions 20 and 21 and commander for Expedition 21. He spent nine days aboard the station in 2002 as a member of the Odissea mission arriving on a new spacecraft, the Soyuz TMA-1, then leaving on an older Soyuz TM-34.

Thirsk, a CSA astronaut, served as a flight engineer for Expeditions 20 and 21. In 1996, Thirsk flew as a payload specialist astronaut aboard space shuttle mission STS-78, the Life and Microgravity Spacelab mission.

After traveling back to the Gagarin Cosmonaut Training Center in Star City, Russia, the crew members will be reunited with their families and start their reorientation to a gravity environment after a half year off the planet.

Commander Jeff Williams and Flight Engineer Maxim Suraev remain on the station, comprising the Expedition 22 crew as a two-man contingent for three weeks until the arrival Dec. 23 of Russian cosmonaut Oleg Kotov, NASA’s T.J. Creamer, and Soichi Noguchi of the Japan Aerospace Exploration Agency, who will launch to the station Dec. 20 on the Soyuz TMA-17 craft.

read more

NGC 6992: Filaments of the Veil Nebula

http://www.wikio.com 0 comments

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 the Swan (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 above filaments on the lower left. The above image is a mosaic from the 2.5-meter Isaac Newton Telescope at Roque de los Muchachos Observatory in the Canary Islands.

read more

Slicing the Arc

http://www.wikio.com 0 comments

The bright arc within Saturn's G ring is shown truncated by the shadow of the planet at the bottom of this image.

Although it can't be seen here, the tiny moonlet Aegaeon (formerly known as S/2008 S 1) orbits within the bright arc. See PIA11148 to learn more. This view looks toward the northern, sunlit side of the rings from about 4 degrees above the ringplane. Many background stars are visible elongated by the motion of the spacecraft during the image's exposure.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Oct. 9, 2009. The view was obtained at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn. Image scale is 12 kilometers (8 miles) per pixel.

The Cassini Equinox Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini Equinox Mission visit http://ciclops.org

read more

Monday, November 30, 2009

WISE Snug in Its Nose Cone

Monday, November 30, 2009
http://www.wikio.com 0 comments
NASA's Wide-field Infrared Survey Explorer has been wrapped in the outer nose cone, or "fairing," that will protect it during its scheduled Dec. 9 launch from Vandenberg Air Force Base, Calif.

The fairing will split open like a clamshell about five minutes after launch. The spacecraft will circle Earth over the poles, scanning the entire sky one-and-a-half times in nine months. The mission will uncover hidden cosmic objects, including the coolest stars, dark asteroids and the most luminous galaxies.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages WISE for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu .

read more

Shadow and Spokes

http://www.wikio.com 0 comments

A moon's shadow strikes Saturn's rings near bright spokes on the B ring near the center of this Cassini image taken about one month after the planet's August 2009 equinox.

Mimas, the moon casting the shadow, is not shown. To learn more about the ghostly radial markings called spokes, see PIA11144 and PIA08288. Spokes appear bright when they are viewed at phase, or Sun-Saturn-spacecraft, angles higher than about 45 degrees. The phase angle in this image is 106 degrees.

The novel illumination geometry that accompanies equinox lowers the sun's angle to the ringplane, significantly darkens the rings, and causes out-of-plane structures to look anomalously bright and cast shadows across the rings. These scenes are possible only during the few months before and after Saturn's equinox which occurs only once in about 15 Earth years. Before and after equinox, Cassini's cameras have spotted not only the predictable shadows of some of Saturn's moons (see PIA11657), but also the shadows of newly revealed vertical structures in the rings themselves (see PIA11665).

This view looks toward the northern, sunlit side of the rings from about 8 degrees above the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 9, 2009. The view was obtained at a distance of approximately 2.9 million kilometers (1.8 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 106 degrees. Image scale is 17 kilometers (11 miles) per pixel.

The Cassini Equinox Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

read more

Bright Sun and Crescent Earth from the Space Station

http://www.wikio.com 0 comments

This was just one more breathtaking view from the International Space Station. The Sun, a crescent Earth, and the long arm of a solar panel were all visible outside a window when the Space Shuttle Atlantis visited the orbiting outpost last week. Reflections from the window and hexagonal lens flares from the camera are superposed. The space shuttle landed Friday after a successful 10 day mission to expand and resupply the ISS. Numbered STS-129, the space shuttle mission returned astronaut Nicole Stott to Earth from her stay on the ISS as a Flight Engineer in the Expedition 20 and21 crews.

read more

Sunday, November 29, 2009

Tour NASA's New Climate Reel

Sunday, November 29, 2009
http://www.wikio.com 0 comments
We’re less than two weeks away from the United Nation’s long awaited Copenhagen Climate Change Conference. In anticipation of the event, NASA has compiled a climate resource reel that highlights ten of its most compelling climate videos and visualizations.

Video topics range from a 3-D tour of the Earth’s rapidly changing cryosphere, and the unexpected role that honey bees can play as climate data collectors, to NASA’s efforts to understand the ozone layer.

Two of the videos offer details about NASA's new climate satellite Glory. One of them discusses Glory's Total Irradiance Monitor, a sensor that will help monitor the sun's fluctuations. The other -- titled Hello Crud -- delves into the perplexing world of airborne particles called aerosols.

You can see all ten of the top picks at NASA’s Global Climate Change website. Additional climate-related videos and animations are available through NASA’s Scientific Visualization Studio.

read more

Winter Frosted Mars Dunes : Big Pic

http://www.wikio.com 0 comments
NASA's High Resolution Science Imaging Experiment (HiRISE) on board the Mars Reconnaissance Orbiter has changed our view of the Red Planet. With mind-blowing clarity, this hi-tech instrument can even keep an eye on the Mars rovers as they roll across the regolith.

The HiRISE image gallery has become one of the most comprehensive and visually stunning chronicles of planetary exploration available online and it is continually updated with freshly-processed images of various Martian landscapes. Although the mission is currently recovering after a glitch in August, forcing controllers to switch the satellite into "safe mode," new HiRISE images are always being processed.

In this example, dunes within a Mars crater are detailed (to a resolution of 50 cm/pixel). The image was taken when the southern hemisphere was in the depths of winter in November 2006. The ripples in the dunes are caused by winds shaping the lose dust and sand. The bright areas are either water or carbon dioxide ice frosting the east-facing slopes of the dunes (in the shade from the sun). The darker areas are where sunlight has heated the surface, melting the ice.

For context, a full-resolution overview of the region is available.


read more

Ancient Layered Hills on Mars

http://www.wikio.com 0 comments

Is this a picture of Mars or Earth? Oddly enough, it is a picture of Mars. What may appear to some as a terrestrial coastline is in fact a formation of ancient layered hills and wind-blown sand on Mars. The above-pictured region spans about three kilometers in Schiaparelli Crater. What created the layers of sediment is still a topic of research. Viable hypotheses include ancient epochs of deposit either from running water or wind-blown sand. Winds and sandstorms have smoothed and eroded the structures more recently. The "water" that appears near the bottom is actually dark colored sand. The image was taken with the Mars Global Surveyor spacecraft that operated around Mars from 1996-2006 and returned over 200,000 images.

read more

Saturday, November 28, 2009

Annapurna Star Trails

Saturday, November 28, 2009
http://www.wikio.com 0 comments

In myth, Atlas holds up the heavens. But in this moonlit mountainscape, peaks of the Himalayan Annapurna Range appear to prop up the sky as seen from Ghandruk, Nepal. From left to right the three main peaks are Annapurna South (7,219 meters), Hiunchuli (6,441 metes), and Machapuchare (6,995 meters). Of course the mountains are moving not the stars, the Earth's rotation about its axis causing the concentric star trails recorded in the time exposure. Positioned above Annapurna South, the North Celestial Pole is easily identified as the point at the center of all the star trail arcs. The star Polaris, also known as the North Star, made the very short and bright arc closest to the North Celestial Pole.

read more

Friday, November 27, 2009

Shadows Above and Below

Friday, November 27, 2009
http://www.wikio.com 0 comments

The shadows of two moons appear on Saturn, above and below the plane of the planet's rings.

North on Saturn is up in this image, and the shadow of Dione (1123 kilometers, 698 miles across) can be seen south of the planet's equator. The smaller shadow of Mimas (396 kilometers, 246 miles across) is north of the equator. Dione and Mimas both have orbits that are slightly inclined in relation to the planet's equatorial plane, so, depending upon the orientation of their orbits, their shadows may appear north or south of Saturn's equator. The moons themselves do not appear in this image.

This view looks toward the northern, sunlit side of the rings from about 1 degree above the ringplane. Scale in the original image was 100 kilometers (62 miles) per pixel. The image has been magnified by a factor of 1.5 and contrast-enhanced to aid visibility.

The image was taken with the Cassini spacecraft wide-angle camera on Oct. 15, 2009 using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers. The view was acquired at a distance of approximately 899,000 kilometers (558,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 65 degrees.

The Cassini Equinox Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

read more