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Sonntag, 17. Februar 2013 - 14:45 Uhr

Astronomie - Asteroid 2012 DA14 Vorbeiflug an der Erde am 15.02.2013

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29.01.2013

Discovered by the LaSagra observatory in southern Spain, the small asteroid 2012 DA14 will pass within about 3.5 Earth radii of the Earth's surface on February 15, 2013. Although its size is not well determined, this near-Earth asteroid is thought to be about 45 meters in diameter. Asteroid 2012 DA14 will pass inside the geosynchronous satellite ring, located about 35,800 km above the equator. Its orbit about the sun can bring it no closer to the Earth's surface than 3.2 Earth radii on February 15, 2013. On this date, the asteroid will travel rapidly from the southern evening sky into the northern morning sky with its closest Earth approach occurring about 19:26 UTC when it will achieve a magnitude of less than seven, which is somewhat fainter than naked eye visibility. About 4 minutes after its Earth close approach, there is a good chance it will pass into the Earth's shadow for about 18 minutes or so before reappearing from the eclipse. When traveling rapidly into the northern morning sky, 2012 DA14 will quickly fade in brightness.

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Talk about a close shave. On Feb. 15th an asteroid about half the size of a football field will fly past Earth only 17,200 miles above our planet's surface. There's no danger of a collision, but the space rock, designated 2012 DA14, has NASA's attention.
"This is a record-setting close approach," says Don Yeomans of NASA's Near Earth Object Program at JPL. "Since regular sky surveys began in the 1990s, we've never seen an object this big get so close to Earth."
Earth's neighborhood is littered with asteroids of all shapes and sizes, ranging from fragments smaller than beach balls to mountainous rocks many kilometers wide. Many of these objects hail from the asteroid belt, while others may be corpses of long-dead, burnt out comets. NASA's Near-Earth Object Program helps find and keep track of them, especially the ones that come close to our planet.
2012 DA14 is a fairly typical near-Earth asteroid. It measures some 50 meters wide, neither very large nor very small, and is probably made of stone, as opposed to metal or ice.  Yeomans estimates that an asteroid like 2012 DA14 flies past Earth, on average, every 40 years, yet actually strikes our planet only every 1200 years or so.
The impact of a 50-meter asteroid is not cataclysmic--unless you happen to be underneath it. Yeomans points out that a similar-sized object formed the mile wide Meteor Crater in Arizona when it struck about 50,000 years ago. "That asteroid was made of iron," he says, "which made it an especially potent impactor." Also, in 1908, something about the size of 2012 DA14 exploded in the atmosphere above Siberia, leveling hundreds of square miles of forest. Researchers are still studying the "Tunguska Event" for clues to the impacting object.
"2012 DA14 will definitely not hit Earth," emphasizes Yeomans. "The orbit of the asteroid is known well enough to rule out an impact."
Even so, it will come interestingly close. NASA radars will be monitoring the space rock as it approaches Earth closer than many man-made satellites. Yeomans says the asteroid will thread the gap between low-Earth orbit, where the ISS and many Earth observation satellites are located, and the higher belt of geosynchronous satellites, which provide weather data and telecommunications.
"The odds of an impact with a satellite are extremely remote," he says. Almost nothing orbits where DA14 will pass the Earth.
NASA's Goldstone radar in the Mojave Desert is scheduled to ping 2012 DA14 almost every day from Feb. 16th through 20th. The echoes will not only pinpoint the orbit of the asteroid, allowing researchers to better predict future encounters, but also reveal physical characteristics such as size, spin, and reflectivity. A key outcome of the observing campaign will be a 3D radar map showing the space rock from all sides.
During the hours around closest approach, the asteroid will brighten until it resembles a star of 8th magnitude. Theoretically, that’s an easy target for backyard telescopes. The problem, points out Yeomans, is speed. “The asteroid will be racing across the sky, moving almost a full degree (or twice the width of a full Moon) every minute. That’s going to be hard to track.” Only the most experienced amateur astronomers are likely to succeed.
Those who do might experience a tiny chill when they look at their images. That really was a close shave.
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Update: 1.02.2013
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Talk about a close shave. On Feb. 15th an asteroid about half the size of a football field will fly past Earth only 17,200 miles above our planet's surface. There's no danger of a collision, but the space rock, designated 2012 DA14, has NASA's attention.
"This is a record-setting close approach," says Don Yeomans of NASA's Near Earth Object Program at JPL. "Since regular sky surveys began in the 1990s, we've never seen an object this big get so close to Earth."
Earth's neighborhood is littered with asteroids of all shapes and sizes, ranging from fragments smaller than beach balls to mountainous rocks many kilometers wide. Many of these objects hail from the asteroid belt, while others may be corpses of long-dead, burnt out comets. NASA's Near-Earth Object Program helps find and keep track of them, especially the ones that come close to our planet.
2012 DA14 is a fairly typical near-Earth asteroid. It measures some 50 meters wide, neither very large nor very small, and is probably made of stone, as opposed to metal or ice. Yeomans estimates that an asteroid like 2012 DA14 flies past Earth, on average, every 40 years, yet actually strikes our planet only every 1200 years or so.
The impact of a 50-meter asteroid is not cataclysmic--unless you happen to be underneath it. Yeomans points out that a similar-sized object formed the mile wide Meteor Crater in Arizona when it struck about 50,000 years ago. "That asteroid was made of iron," he says, "which made it an especially potent impactor." Also, in 1908, something about the size of 2012 DA14 exploded in the atmosphere above Siberia, leveling hundreds of square miles of forest. Researchers are still studying the "Tunguska Event" for clues to the impacting object.
"2012 DA14 will definitely not hit Earth," emphasizes Yeomans. "The orbit of the asteroid is known well enough to rule out an impact."
Even so, it will come interestingly close. NASA radars will be monitoring the space rock as it approaches Earth closer than many man-made satellites. Yeomans says the asteroid will thread the gap between low-Earth orbit, where the ISS and many Earth observation satellites are located, and the higher belt of geosynchronous satellites, which provide weather data and telecommunications.
"The odds of an impact with a satellite are extremely remote," he says. Almost nothing orbits where DA14 will pass the Earth.
NASA's Goldstone radar in the Mojave Desert is scheduled to ping 2012 DA14 almost every day from Feb. 16th through 20th. The echoes will not only pinpoint the orbit of the asteroid, allowing researchers to better predict future encounters, but also reveal physical characteristics such as size, spin, and reflectivity. A key outcome of the observing campaign will be a 3D radar map showing the space rock from all sides.
During the hours around closest approach, the asteroid will brighten until it resembles a star of 8th magnitude. Theoretically, that's an easy target for backyard telescopes. The problem, points out Yeomans, is speed. "The asteroid will be racing across the sky, moving almost a full degree (or twice the width of a full Moon) every minute. That's going to be hard to track." Only the most experienced amateur astronomers are likely to succeed.
Those who do might experience a tiny chill when they look at their images. That really was a close shave.
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Quelle:NASA
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Update 5.02.2013
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Asteroid 2012 DA14 – Earth Flyby Reality Check02.04.13
 
Small near-Earth asteroid 2012 DA14 will pass very close to Earth on February 15, so close that it will pass inside the ring of geosynchronous weather and communications satellites. NASA's Near-Earth Object Program Office can accurately predict the asteroid's path with the observations obtained, and it is therefore known that there is no chance that the asteroid might be on a collision course with Earth. Nevertheless, the flyby will provide a unique opportunity for researchers to study a near-Earth object up close. Here are the facts about the safe flyby of Earth of asteroid 2012 DA14 -- a record close approach for a known object of this size. 
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Graphic depicts the trajectory of asteroid 2012 DA14 on Feb 15, 2013. In this view, we are looking down from above Earth's north pole. Image credit: NASA/JPL-Caltech
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Graphic depicts the trajectory of asteroid 2012 DA14 during its close approach, as seen edge-on to Earth's equatorial plane. The graphic demonstrates why the asteroid is invisible to northern hemisphere observers until just before close approach: it is approaching from "underneath" our planet. On the other hand, after close approach it will be favorably placed for observers in the northern hemisphere. Image credit: NASA/JPL-Caltech
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Quelle: NASA.    
Update: 14.02.2013 
NASA to Chronicle Close Earth Flyby of Asteroid
 
 
PASADENA, Calif. -- NASA Television will provide commentary starting at 2 p.m. EST (11 a.m. PST) on Friday, Feb. 15, during the close, but safe, flyby of a small near-Earth asteroid named 2012 DA14. NASA places a high priority on tracking asteroids and protecting our home planet from them. This flyby will provide a unique opportunity for researchers to study a near-Earth object up close. 
The half-hour broadcast from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., will incorporate real-time animation to show the location of the asteroid in relation to Earth, along with live or near real-time views of the asteroid from observatories in Australia, weather permitting. 
At the time of its closest approach to Earth at approximately 2:25 p.m. EST (11:25 a.m. PST/ 19:25 UTC), the asteroid will be about 17,150 miles (27,600 kilometers) above Earth's surface. 
The commentary will be available via NASA TV and streamed live of NASA-TV. 
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Update: 15.02.2013
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An asteroid as large as an Olympic swimming pool will race past the Earth on Friday at a distance of just 27,700km (17,200mi) - the closest ever predicted for an object of that size.
It will pass closer even than the geosynchronous satellites that orbit the Earth, but there is no risk of impacts or collisions.
Its closest approach will be 19:25 GMT.
For regions in darkness around that time, it will be visible using good binoculars or a telescope.
The asteroid's arrival was preceded by damaging meteor event in Russia on Friday - but indications from the meteor's path suggest that the two events are entirely unrelated - just a cosmic coincidence.
The asteroid orbits the Sun in 368 days - a period similar to Earth's year - but it does not orbit in the same plane as the Earth.
As it passes - at 7.8km/s (17,450 mi/hr) - it will come from "under" the Earth and return back toward the Sun from "above".
It will pass over directly over the eastern Indian Ocean, making for the best viewing in Eastern Europe, Asia and Australia.
But keen viewers anywhere can find one of several live streams of the event on the internet, including a feed from the Jet Propulsion Laboratory at Nasa, available from 19:00 GMT.
2012 DA14 was first spotted in February 2012 by astronomers at the La Sagra Sky Survey in Spain - once a fairly small-scale, amateur effort to discover and track asteroids that has in recent years become a significant contributor to our knowledge of these "near-Earth objects".
They caught sight of the asteroid after its last pass, at a far greater distance.
From their observations, they were able to calculate the asteroid's future and past paths and predict Friday's near-miss - which will be the closest the object comes for at least 30 years.
Alan Fitzsimmons of Queens University Belfast said that it is a scientific opportunity not to be missed.
"When asteroids come this close, it's very important to try to learn about them - it's become so bright, so it's so easy to study," he told BBC News.
"We get an additional insight into these small objects, which are the most likely impactors on Earth."
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Quelle: BBC-News
    
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Like trailers for the coming attraction, new images show asteroid 2012 DA14 on its way to a record-close approach to Earth on Feb. 15. One image, taken by amateur astronomer Dave Herald of Murrumbateman, Australia, on Feb. 13, shows the asteroid as a tiny white dot in the field of view. Another set of animated images, obtained by the Faulkes Telescope South in Siding Springs, Australia, on Feb. 14, and animated by the Remanzacco Observatory in Italy, shows the asteroid as a bright spot moving across the night sky.

These are some of many images that may be taken of the asteroid during its close - but safe - encounter with Earth. It will be observed by numerous optical observatories worldwide in an attempt to determine its rough shape, spin rate and composition. NASA scientists will use NASA's Goldstone Solar System Radar, located in California's Mojave Desert, to take radar images of the asteroid to determine its precise size and shape on Feb. 16, 18, 19 and 20. The NASA Near Earth Object Observation (NEOO) Program will continue to track the asteroid and predict its future orbit.

Asteroid 2012 DA14 is about 150 feet (45 meters) in diameter. It is expected to fly about 17,200 miles (27,000 kilometers) above Earth's surface at the time of closest approach, which is about 11:25 a.m. PST (2:25 p.m. EST) on Feb. 15. This distance is well away from Earth and the swarm of low Earth-orbiting satellites, including the International Space Station, but it is inside the belt of satellites in geostationary orbit (about 22,200 miles, or 35,800 kilometers, above Earth's surface.) The flyby of 2012 DA14 is the closest-ever predicted approach to Earth for an object this large.

The NASA Near Earth Object Observation (NEOO) Program detects and tracks asteroids and comets passing close to Earth using ground- and space-based telescopes. The network of projects supported by this program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them and plots their orbits to determine if any could be potentially hazardous to our planet.

The Near-Earth Object Program Office at JPL manages the technical and scientific activities for NASA's Near-Earth Object Observation Program of the Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena. The NEOO Program Office performs more precise orbit determination on the objects, and predicts whether any will become an impact hazard to the Earth, or any other planet in the solar system.

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Asteroid 2012 DA14 in View

This image from D. Herald of Murrumbateman, Australia, shows the asteroid 2012 DA14 as a tiny speck in the center of the field of view. It was taken just past midnight on Feb. 13, 2013 in Australia (the morning of Feb. 12 in the U.S.), as it headed towards its closest approach to Earth on Feb. 15. The image is an overlay of 12 one-minute exposures. The asteroid is the small dot at the center, indicated by the red arrows. The white streaks are images of stars, trailed because the telescope was tracking the motion of the asteroid. At the time the image was taken, the asteroid was passing nearly in front of the globular cluster 47 Tucanae, located 17,000 light years away. The asteroid itself was only 770,000 miles (1.2 million kilometers) away, and closing in fast for its dramatic close approach on Feb. 15. At its closest, 2012 DA14 is expected to fly safely by the Earth at about 17,200 miles (27,700 kilometers) above the surface.

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This animated set of three images depicts asteroid 2012 DA14 as it was seen on Feb. 14, 2013, at a distance of 465,000 miles (748,000 kilometers). Image credit: LCOGT/Faulkes

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Quelle: NASA

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Update: 16.02.2013

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Update: 17.02.2013

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Farewell to a rocky visitor: asteroid 2012DA14 (the near-horizontal streak in the image) seen departing Earth around 23:45 CET after making closest approach at 20:27 CET on 15 February 2013. This image was acquired at ESA's Optical Ground Station (OGS) located on Tenerife, Spain. 

Credits: ESA/Instituto de Astrofísica de Canarias/Iciar Montilla, Julio Castro, Alfred Rosenberg
 
 

3008 Views

Sonntag, 17. Februar 2013 - 12:15 Uhr

Mars-Curiosity-Chroniken - Sol 182-185

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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 182 (2013-02-09 03:43:57 UTC) .

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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 182 (2013-02-09 07:14:11 UTC) .

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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 182 (2013-02-09 07:14:50 UTC) .

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This image was taken by Mars Hand Lens Imager (MAHLI) onboard NASA's Mars rover Curiosity on Sol 182 (2013-02-09 04:03:01 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 182 (2013-02-09 02:58:17 UTC) .

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This image was taken by Navcam: Left A (NAV_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 182 (2013-02-09 02:58:17 UTC) .

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This image was taken by Front Hazcam: Left A (FHAZ_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 182 (2013-02-09 02:07:10 UTC) .

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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 183 (2013-02-10 03:46:22 UTC) .

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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 183 (2013-02-10 03:53:54 UTC) .

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This image was taken by ChemCam: Remote Micro-Imager (CHEMCAM_RMI) onboard NASA's Mars rover Curiosity on Sol 183 (2013-02-10 07:12:01 UTC) .

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This image was taken by Front Hazcam: Left A (FHAZ_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 183 (2013-02-10 00:36:17 UTC) .

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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 184 (2013-02-10 23:20:10 UTC) .

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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 184 (2013-02-11 00:32:26 UTC) .

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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 184 (2013-02-11 01:00:09 UTC) .

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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 184 (2013-02-11 06:34:08 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 184 (2013-02-11 06:40:08 UTC) .

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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 185 (2013-02-12 04:33:30 UTC) .

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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 185 (2013-02-12 04:49:45 UTC) .

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This image was taken by Front Hazcam: Left A (FHAZ_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 185 (2013-02-12 01:55:30 UTC) .

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Fotos: NASA


3151 Views

Sonntag, 17. Februar 2013 - 11:00 Uhr

Mars-Curiosity-Chroniken - Curiosity-News Sol 183

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Laser Hits on Martian Drill Tailings

A day after NASA's Mars rover Curiosity drilled the first sample-collection hole into a rock on Mars, the rover's Chemistry and Camera (ChemCam) instrument shot laser pulses into the fresh rock powder that the drilling generated. This scene shows a line of pits left by laser hits on the drill tailings. The view is an annotated mosaic of images taken by the remote micro-imager in ChemCam, with color information from Curiosity's Mast Camera.

The drilled hole, at lower center, is about 0.6 inch (1.6 centimeters) in diameter. Curiosity drilled the hole 2.5 inches (6.4 centimeters) deep during the 182nd Martian day, or sol, of the rover's work on Mars (Feb. 8, 2013). ChemCam repeatedly zapped several points near the hole on Sol 183 (Feb. 9, 2013) to obtain spectra providing information about composition, and then on the same sol took the images that have been combined to create this view. Arrows at 10 locations indicate the marks from the laser hits.

The site is on a patch of flat rock called "John Klein" in the "Yellowknife Bay" area of Mars' Gale Crater.

Quelle: NASA


3260 Views

Samstag, 16. Februar 2013 - 18:30 Uhr

Astronomie - Bolide auch über USA und Kuba am 15.02.2013

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Did you see it?

On a day that had a lot of people talking about meteorites and asteroids, a fireball of some sort was seen streaking across the Bay Area skies.

The fireball was seen around 7:45 p.m.

There were reports into the newsroom from people as far north as Fairfield and as far south as Gilroy. It was also seen in Sacramento, Newark, Walnut Creek, and St. Helena.

It was bluish in color and appeared to be heading straight to the ground, according to one viewer in Santa Clara. 

Meteors are pieces of rock and metal from space that fall to Earth. They burn up as they go through our atmosphere. The burning is what causes the bright flash of light.

"I saw that meteor/fireball over Solano County after spending the day reporting on asteroids and fireballs," said NBC Bay Area reporter Jodi Hernandez.

Candice Guruwaiya told us on Facebook she saw it in San Jose. "I was leaving Safeway on Branham and Snell when I saw it. It looked like it was headed for the Capital Auto Mall area. It was a bright green when it first appeared, then it went to a bright yellow. It was awesome!" Guruwaiya posted.

Gina Johnson also saw it in San Jose. She also posted on our Facebook page that she had just walked out of a Fresh and Easy in San Jose's Willow Glen neighborhood. "It looked just like the one I saw back in October except it was a little smaller. It was greenish in color just like the one on October. Everyone in the parking lot stopped and looked at it," Johnson posted

It comes on the same night a 150-foot-wide asteroid was due to come within 17,200 miles of Earth. It was not immediately clear if the fireball had any connection to the asteroid.

Chabot astronomers in Oakland said the meteor was not related to the asteroid passing near Earth.

Astronomer Gerald McKeegan said based on accounts he thinks it was a "sporadic meteor," which can happen several times a day.  He told Bay City News that sporadic meteors bring as much as 15,000 tons of space debris to Earth each year.

He said it was likely smaller than another meteor that landed in the Bay  Area in October, which caused a loud sonic boom as it fell in the North Bay.

It also happened about 24 hours after a huge meteorite fell from the skies over Russia's Chelyabinsk region, resulting in a powerful blast that injured nearly 1,000 people and shattered windows across the area.

Chelyabinsk health chief Marina Moskvicheva told the Russian news agency Interfax that 985 people in her city asked for medical help and 43 were hospitalized.

Many of the injuries were reportedly from broken windows as a result of a sonic boom that followed the initial impact of the meteorite.

Someone posted the following on YouTube within an hour of the fireball sighting.

The video was titled "Shooting Star across San Francisco 2/15/2013 7:44PM."  The person who posted it said he was driving south on I-280 toward the peninsula.

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Suspected meteor explosion reported in central Cuba
 
   

HAVANA, Feb. 15 (Xinhua) -- An object fell from the sky over central Cuba on Thursday night and turned into a fireball "bigger than the sun" before it exploded, a Cuban TV channel reported Friday, citing eyewitnesses.

Some residents in the central province of Cienfuegos were quoted as saying that at around 8 p.m. local time Thursday (0100 GMT Friday) they saw a bright spot in the sky comparable to a bus in size.

The object then turned into a fireball "bigger than the sun," said the witnesses, adding that several minutes later they heard a loud explosion.

One resident told the TV station that his house shook slightly in the blast.

Cuban experts have been dispatched to the area to look for possible remains of the meteor-like object, said the report.

It remains unknown whether the reported phenomenon in Cuba is related to Friday's meteor strike in central Russia, which set off a shockwave that shattered windows and left some 1,000 people injured.

Quelle: NBC


3347 Views

Samstag, 16. Februar 2013 - 11:00 Uhr

Raumfahrt - Saturn-Mond Titan im Focus von Cassini

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Outline of an Ancient Sea on Titan

This image from NASA's Cassini spacecraft shows an ancient southern sea that used to sprawl out near the south pole of Saturn's moon Titan. In an annotated version, the red outline traces the ancient shoreline. Within this basin is the largest present-day lake in Titan's southern hemisphere, Ontario Lacus. Ontario Lacus appears black, indicating it is filled with liquid.

This image was obtained by Cassini's radar instrument on July 2009 and January 2010. Several images have been stitched together. By analyzing these images, scientists estimate the ancient sea was possibly as large as 300 by 170 miles (475 by 280 kilometers) across and likely less than a few hundred feet (meters) deep. Ontario Lacus is about 80 by 235 kilometers across, and probably at least 30 feet (10 meters) deep at its center. Seas may have covered large parts of the southern hemisphere less than 50,000 years ago.

Titan, Saturn's largest moon, is the only place besides Earth in our solar system that hosts large open bodies of liquid. At the cold temperatures of Titan, about minus 290 degrees Fahrenheit (94 kelvins), that liquid is not water, but methane and ethane. Over one hundred lakes and three seas are seen at the north pole of Titan, while the south pole only has a few small lakes. Scientists have suggested that cycles analogous to Croll-Milankovich cycles on Earth cause long-term cyclic transfer of liquid hydrocarbons from pole to pole, with the north pole now containing the bulk of the liquids. Less than 50,000 years ago, the cycle would have been reversed, suggesting that the south polar region should contain remnants of southern seas.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, DC. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

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Titan's Lake District, One Season Later

These images obtained by NASA's Cassini spacecraft show Titan's stable northern lake district. Cassini's radar instrument obtained the recent images on May 22, 2012. It observed some previously unseen regions but also some regions containing lakes that were last observed about six years-nearly one Titan season--ago. This marks the longest time interval between lake observations in the northern hemisphere.

The top image here shows part of the radar swath from May 22, 2012, centered near 79 degrees north latitude, 58 degrees west longitude, and about 220 by 47 miles (350 by 75 kilometers) in dimension. At the bottom, parts of this image are compared with those obtained in 2006. (The images appear slightly different from previous releases because they use a new filtering technique). In 2006, it was winter in the northern hemisphere and the lakes were in the dark. Although Titan spring began in 2009 and the sun has now risen over the lakes, there is no apparent change in lake levels since the 2006 flybys, consistent with climate models that predict stability of liquid lakes over several years. This shows that the northern lakes are not transient weather events, in contrast to the temporary darkening of parts of the equator after a rainstorm in 2010 (PIA 12819).

Changes in lake levels may still be detected later in the mission as Cassini continues to observe these high northern latitudes into the beginning of summer in 2017. At that point, the sun may cause evaporation. However, the lack of significant change over six years sets important constraints for climate models and the stability of liquids on Titan. Illumination is coming from the bottom.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, DC. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

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Titan's Hot Cross Bun

NASA's Cassini spacecraft obtained this image of a feature shaped like a hot cross bun in the northern region of Titan (left) that bears a striking resemblance to a similar feature on Venus (right). The Titan image was obtained by Cassini's radar instrument on May 22, 2012. The bun is located at about 38.5 degrees north latitude and 203 degrees west longitude. This image is taken from a longer radar swath, which is about 3,200 miles (5,200 kilometers) long and about 400 miles (600 kilometers) at its widest.

The circular feature shown, which looks like a giant hot cross bun, is about 43 miles (70 kilometers) in diameter with near-perpendicular markings about 37 miles (60 kilometers) wide, meeting at its center. The illumination for this synthetic aperture radar image is from the right. Similar features are seen on other planets. In a synthetic aperture radar image of Venus by NASA's Magellan spacecraft, this radar-bright circular-shaped region of 20 miles (30 kilometers) across lies at the summit of a large volcano called Kunapipi Mons (at about 33.3 degrees south latitude and 85.5 degrees west longitude on Venus). This comparison leads to the interpretation that the Titan crosses are also fractures caused by uplift from below. Steam often causes the top of bread to lift and stretch, but on Titan some other force, such as rising cryomagma, may have uplifted the surface, leading to the crossed cracks.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, DC. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

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Quelle: NASA


3312 Views

Samstag, 16. Februar 2013 - 10:48 Uhr

Raumfahrt - ISS-News

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Canadian Space Agency astronaut Chris Hadfield performed the Education Payload Operation-Space Sports 2-Demonstrations (EPO-Demos) with NASA astronaut Thomas Marshburn onboard the International Space Station. EPO Demos are educational videos; the Space Sports2 video is intended for grades 5-8 students and educators. Objectives include demonstrating how crew members play games and sports in a microgravity environment and how Isaac Newton's Laws of Motion are applied to games in space.

Hadfield exchanged the Material Science Laboratory sample cartridge assembly. A Columnar-to-Equiaxed Transition in Solidification Processing (CETSOL) was successfully installed and processed. The CETSOL investigation aims to deepen the understanding of the physical principles that govern solidification processes in metal alloys. The patterns of the crystals resulting from transitions of liquids to solids are of great importance to processes in producing materials such as metal alloys.

Hadfield reviewed the Japanese Aerospace and Exploration Agency Payload Observation 10 (JAXA EPO10) Blue Earth Gazing materials, set up the hardware and performed two Blue Earth Gazing experiment video takes. He performed closeout activities at the end of the operation. Blue Earth Gazing is an onboard artistic effort that allows people to see the Earth through reflected images on the surface of the water. This new way of Earth viewing enlightens the general public about microgravity and human spaceflight. The crew member performs in-orbit demonstrations that show microgravity provides a unique environment useful not only for exploration by scientists and engineers, but also for writers, poets, teachers, artists, etc.

NASA astronaut Kevin Ford, Expedition 34 commander, loaded the Rack Interface Controller, or RIC, Release 8 Software on EXpedite the PRocessing of Experiments for Space Station Racks (EXPRESS Racks) 3 and 5. EXPRESS Racks are multipurpose payload rack systems that store and support research aboard the space station. The racks can support science experiments in any discipline by providing structural interfaces, power, data, cooling, water and other items needed to operate science experiments in space.

Hadfield performed nine Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions-3 (InSPACE-3) runs. To date, 41 of the 47 runs are complete. InSPACE-3 studies the fundamental behavior of magnetic colloidal fluids under the influence of various magnetic fields. This technology has promise to improve the ability to design structures, such as bridges and buildings, to better withstand earthquake forces.

Other human research investigations continued for various crew members including Neurospat, Nutrition, Repository and Reaction Self Test.

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Canadian Space Agency astronaut Chris Hadfield holds two Material Science Laboratory Solidification and Quench Furnace (MSL SQF) Sample Cartridge Mechanical Protection Containers (MPCs) during the cartridge exchange in the Destiny laboratory of the International Space Station. (NASA)

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Blue Earth Gazing was inspired by Otsukimi, which is a Japanese traditional custom to see the moon. Blue Earth Gazing is an onboard artistic effort that allows people to see the Earth through reflected images on the surface of the water. This new way of Earth viewing enlightens the general public about microgravity and human spaceflight. (JAXA/Takahiro Ando)

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EXPRESS Rack 3 (NASA)


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The six-person Expedition 34 crew of the International Space Station wrapped up the workweek Friday with robotics and preparations for a commercial cargo craft set to arrive in early March.

Commander Kevin Ford and Flight Engineers Tom Marshburn and Chris Hadfield began their morning with the Reaction self test, a short reaction time task that allows the crew to track the effects of fatigue on performance. Marshburn and Hadfield also participated in a urine pH test for the Pro K study as nutritionists monitor how dietary changes affect the bone loss that occurs during spaceflight.

Ford spent the bulk of his morning disassembling components of the Aquatic Habitat, which was most recently home to some spacefaring Medaka fish. When the preserved specimens from the Medaka Osteoclast experiment are returned to Earth, Japanese researchers hope to understand more about the causes of bone density loss during long-duration spaceflight.

Marshburn meanwhile conducted the annual inspection of the two food warmers aboard the station – one in the Zvezda service module and the other in the Destiny lab.

Marshburn also packed various items into stowage bags for return to Earth aboard the SpaceX Dragon cargo ship, now scheduled to launch to the station March 1. When the Dragon capsule carrying about 1,200 pounds of supplies rendezvous with the station, the crew will use the 57.7-foot Canadarm2 to reach out and grapple the spacecraft. The robotics officer in Houston’s Mission Control will then remotely command the arm to berth Dragon to the Earth-facing port of the Harmony node while the onboard crew monitors the Common Berthing Mechanism operations that fasten the capsule to its port.

To prepare for the arrival of Dragon, Ford and Marshburn used the robotics workstation in the cupola Friday to practice the procedures for an offset grapple of the commercial cargo craft. Afterward the two NASA astronauts participated in a debrief with flight controllers to review the training.

Marshburn rounded out his day inspecting the seals of the open hatches throughout the U.S. segment of the station.

Hadfield, a Canadian Space Agency astronaut, spent part of his morning setting up Robonaut 2 for some remote testing for the first humanoid robot in space. The ground teams used Robonaut’s vision processing system to collect data from a task panel and assessed its finger sensors. After these operations were completed, Hadfield disassembled and stowed Robonaut as it awaits its next round of tests. Robonaut was designed with the intention of eventually taking over tasks deemed too dangerous or mundane for astronauts, perhaps even venturing outside the complex to assist spacewalkers.

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Clouds form the backdrop for this scene photographed by one of the Expedition 34 crew members aboard the International Space Station, with the Soyuz TMA-07M docked to the Rassvet module. The Permanent Multipurpose Module is visible top right. Credit: NASA

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Hadfield also wrapped up some spacewalk equipment battery maintenance before taking time out to talk with students at the University of Waterloo in Ontario, Canada.

On the Russian side of the station, Flight Engineers Evgeny Tarelkin and Roman Romanenko worked on the BAR experiment, studying methods and instruments for detecting the location of an air leak from one of the station’s modules. Their fellow cosmonaut Flight Engineer Oleg Novitskiy spent much of his day replacing condensate lines in the Zvezda service module.

Tarelkin also unloaded some of the 2.9 tons of cargo that arrived Monday when the ISS Progress 50 cargo craft docked with the station less than six hours after its launch from the Baikonur Cosmodrome in Kazakhstan.


Over the weekend, the space station’s residents will enjoy some off-duty time, during which they’ll continue to monitor station systems and experiments, perform their daily exercise regimen and talk with their families back on Earth.

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3247 Views

Freitag, 15. Februar 2013 - 14:10 Uhr

UFO-Forschung - Re-Entry von M-18M-Progress-Treibstufe über Deutschland löst Ufo-Melde-Flap bei CENAP aus.

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13.02.2013 / 8.45 MEZ

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Video-Aufnahmen von Re-Entry, auch wenn dies als Komet und Asteroid bezeichnet wurde:

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Mehr darüber auch auf unserem ufo-meldestelle.blog.de

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Update: 14.02.2013 / 15.15 MEZ

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Quelle: Heilbronner Stimme Online

 

  

Quelle: Mannheimer Morgen Online

 

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Quelle: Rhein-Neckar-Zeitung 

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Update: 23.15 MEZ

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Quelle: Stuttgarter Zeitung Online

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Re-Entry auch über Belgien, Frankreich und England gesehen:

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Quelle: CNES

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Quelle: G7IZU-RRD

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Update: 15.02.2013 

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Tags: Re-Entry von M-18M-Progress 

3383 Views

Freitag, 15. Februar 2013 - 11:30 Uhr

Astronomie - Neue Hinweise auf den geheimnisvollen Ursprung der kosmischen Strahlung

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Detaillierte Beobachtungen der Überbleibsel einer Supernova, die vor eintausend Jahren stattgefunden hat, mit dem Very Large Telescope (VLT) der ESO haben neue Hinweise auf den Ursprung der kosmischen Strahlung geliefert. Erstmals wurden Anzeichen von schnellen Teilchen gefunden, die so etwas wie die Vorläufer der kosmischen Strahlung sein könnten. Die Ergebnisse der Studie erscheint am 14. Februar 2013 in der Fachzeitschrift Science.
Im Jahr 1006 n Chr. leuchtete am Südhimmel ein neuer Stern auf, der heller als der Planet Venus wurde und vielleicht sogar die Helligkeit des Mondes erreichte. Dieses Ereignis wurde an vielen Orten auf der Welt beobachtet, zumal der neue Stern im Maximum seiner Helligkeit nachts Schatten warf und sogar am Taghimmel sichtbar blieb. Viel später wurde der genaue Ort dieser Supernova, die von den Astronomen die Bezeichnung SN 1006 erhielt, im südlichen Sternbild Lupus (der Wolf) identifiziert. An dieser Stelle wurde eine leuchtende Schale aus expandierender Materie entdeckt, die den Überrest der gewaltigen Explosion darstellt.
Schon seit langem vermutet man, dass solche Supernovaüberreste die Orte sind, an denen ein Teil der sogenannten kosmischen Strahlung erzeugt wird– hochenergetische Teilchen, die von außerhalb des Sonnensystems stammen und sich beinahe mit Lichtgeschwindigkeit bewegen. Die Details dieses Prozesses sind jedoch immer noch rätselhaft.
Ein von Sladjana Nikolić vom Max-Planck-Institut für Astronomie in Heidelberg [1] geleitetes Astronomenteam hat mit dem Instrument VIMOS am VLT den tausend Jahre alten Supernova-Überrest SN 1006 genauer als je zuvor unter die Lupe genommen. Das Ziel der Forscher war es, herauszufinden, was genau an der Stelle geschieht, an der das bei der Supernova mit hoher Geschwindigkeit herausgeschleuderte Material auf die im Vergleich dazu nahezu stillstehende interstellare Materie trifft. An dieser Stelle bildet sich eine sogenannte Schockfront aus, die sich mit hoher Geschwindigkeit ausdehnt und Ähnlichkeit mit dem Überschallknall eines Düsenflugzeugs hat. Sie könnte als kosmischer Teilchenbeschleuniger an der Erzeugung der kosmischen Strahlung beteiligt sein.
Dem Team gelang es, erstmals Informationen zur Materie im Schock zu sammeln, und dabei nicht nur an eine Stelle der Schockfront zu vermessen, sondern eine ganze Karte der Eigenschaften des Gases und ihrer räumlichen Variationen zu erstellen. Daraus ergaben sich wichtige Hinweise auf eine mögliche Lösung des Rätsels der kosmischen Strahlung.
Zur Überraschung der beteiligten Wissenschaftler gibt es Anzeichen für eine große Zahl von schnellen Protonen im Gas der Schockregion [2]. Bei diesen Protonen handelt es sich noch nicht um die kosmische Strahlung selbst, sondern um Vorläuferteilchen (engl. „seed particles“), die anschließend durch Wechselwirkung mit der Schockfront auf die erforderlichen hohen Energien beschleunigt werden und als Teilchenstrahlung hinaus in den Raum fliegen können.
Nikolić erklärt: „Dies ist das erste Mal, dass wir die physikalischen Prozesse in und um die Schockregion genauer untersuchen konnten. Wir haben dabei Hinweise auf die Existenz einer Region gefunden, die offenbar auf genau jene Weise erwärmt wird, wie man es erwarten würde, wenn dort Protonen existieren, welche die Energie aus direkt hinter der Schockfront gelegenen Regionen in die Bereiche direkt vor dem Schock transportieren.“
Bei der Studie wurde erstmals ein Integralfeld-Spektrograf [3] verwendet, um die Eigenschaften einer Supernova-Schockfront derart detailliert zu untersuchen. Das Team plant nun, die Methode auch bei anderen Supernovaüberresten anzuwenden.
Ko-Autor Glenn van de Ven vom Max-Planck-Institut für Astronomie fügt hinzu: „Diese neuartige Beobachtungstechnik könnte sich als Schlüssel erweisen um herauszufinden, wie Supernova-Überreste kosmische Strahlung erzeugen.“
Endnoten
[1] Die neuen Hinweise ergaben sich während der Analyse der Beobachtungsdaten durch Sladjana Nikolić vom Max-Planck-Institut für Astronomie im Rahmen ihrer laufenden Promotionsarbeit an der Universität Heidelberg.
[2] Diese Protonen bezeichnet man als suprathermisch, da sie sich viel schneller bewegen als man allein an Hand der Temperatur der Materie erwarten würde.
[3] Möglich wurde dies durch ein Bauteil von VIMOS, die sogenannte Integral Field Unit. Dort wird das Licht, das auf jeden Pixel fällt, in seine Spektralfarben zerlegt. Jedes dieser Spektren wird dann registriert. Bei der anschließenden Analyse können so zum Beispiel räumlich aufgelöste Karten der Geschwindigkeitsverteilung oder der chemischen Zusammensetzung des beobachteten Objekts gewonnen werden.
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Dieses eindrucksvolle Bild wurde aus Einzelaufnahmen verschiedener Teleskope im Weltall und auf dem Erdboden erstellt. Es zeigt den Supernovaüberrest SN 1006 im Radiobereich (Rot), im Röntgenlicht (Blau) und im sichtbaren Licht (Gelb).
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Komposit aus Beobachtungen im Licht des Wasserstoffs mit der Advanced Camera for Surveys vom Februar 2006 und Aufnahmen der Wide Field Planetary Camera 2 im April 2008 im blauen, gelb-grünen und nahinfraroten Licht. Der Supernovaüberrest ist nur im Licht des Wasserstoffs zu sehen, das in diesem Bild rötlich dargestellt ist.
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Quelle: ESO

3105 Views

Freitag, 15. Februar 2013 - 10:48 Uhr

Raumfahrt - Erfolgreicher Start von Landsat auf Vandenberg-AFB

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Frams von NASA-TV LIVE:

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Quelle: NASA

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Updat: 15.02.2013

Frams von Abtrenn-Manöver von Landsat im Orbit und als Zugabe "bei Sonnenaufgang":

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Quelle: NASA


3135 Views

Donnerstag, 14. Februar 2013 - 14:40 Uhr

Raumfahrt - NASA's next Small Explorer (SMEX) Mission IRIS

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19.01.2013

The fully integrated spacecraft and science instrument for NASA's Interface Region Imaging Spectrograph (IRIS) mission is seen in a clean room at the Lockheed Martin Space Systems Sunnyvale, Calif. facility. The solar arrays are deployed in the configuration they will assume when in orbit. Credit: Lockheed Martin

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NASA's next Small Explorer (SMEX) mission to study the little-understood lower levels of the sun's atmosphere has been fully integrated and final testing is underway.

Scheduled to launch in April 2013, the Interface Region Imaging Spectrograph (IRIS) will make use of high-resolution images, data and advanced computer models to unravel how matter, light, and energy move from the sun’s 6,000 K (10,240 F / 5,727 C) surface to its million K (1.8 million F / 999,700 C) outer atmosphere, the corona. Such movement ultimately heats the sun's atmosphere to temperatures much hotter than the surface, and also powers solar flares and coronal mass ejections, which can have societal and economic impacts on Earth.

"This is the first time we'll be directly observing this region since the 1970s," says Joe Davila, IRIS project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "We're excited to bring this new set of observations to bear on the continued question of how the corona gets so hot."

A fundamentally mysterious region that helps drive heat into the corona, the lower levels of the atmosphere -- namely two layers called the chromosphere and the transition region -- have been notoriously hard to study. IRIS will be able to tease apart what's happening there better than ever before by providing observations to pinpoint physical forces at work near the surface of the sun.

The mission carries a single instrument: an ultraviolet telescope combined with an imaging spectrograph that will both focus on the chromosphere and the transition region. The telescope will see about one percent of the sun at a time and resolve that image to show features on the sun as small as 150 miles (241.4 km) across. The instrument will capture a new image every five to ten seconds, and spectra about every one to two seconds. Spectra will cover temperatures from 4,500 K to 10,000,000 K (7,640 F/4,227 C to 18 million F/10 million C), with images covering temperatures from 4,500 K to 65,000 K (116,500 F/64,730 C).

These unique capabilities will be coupled with state of the art 3-D numerical modeling on supercomputers, such as Pleiades, housed at NASA’s Ames Research Center in Moffett Field, Calif. Indeed, recent improvements in computer power to analyze the large amount of data is crucial to why IRIS will provide better information about the region than ever seen before.

“The interpretation of the IRIS spectra is a major effort coordinated by the IRIS science team that will utilize the full extent of the power of the most advanced computational resources in the world. It is this new capability, along with development of state of the art codes and numerical models by the University of Oslo that captures the complexities of this region, which make the IRIS mission possible. Without these important elements we would be unable to fully interpret the IRIS spectra,” said Alan Title, the IRIS principal investigator at the Advanced Technology Center (ATC) Solar and Astrophysics Laboratory in Palo Alto, Calif.

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Lockheed Martin Space Systems engineer Cathy Chou, integration and test lead for NASA's Interface Region Imaging Spectrograph (IRIS) observatory, inspects the IRIS solar telescope in a clean room at the company's Advanced Technology Center in Palo Alto, Calif. Credit: Lockheed Martin

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“NASA Ames is pleased to partner with Lockheed Martin on this exciting mission,” said John Marmie, assistant project manager at Ames. “The Mission Operations Center testing with the Observatory and Space/Ground Networks are progressing well, as we prepare to support launch and flight operations. Our daily interface with the IRIS observatory will enable our scientists a means to better understand the solar atmosphere.”

The IRIS observatory will launch from Vandenberg Air Force Base, Calif., and will fly in a sun-synchronous polar orbit for continuous solar observations during a two-year mission.

IRIS was designed and built at the Lockheed Martin Space Systems ATC in Palo Alto, Calif., with support from the company’s Civil Space line of business and major partners Smithsonian Astrophysical Observatory and Montana State University. Ames is responsible for mission operations and the ground data system. The Norwegian Space Agency will provide the primary ground station at Svalbard, Norway, inside the Arctic Circle. The science data will be managed by the Joint Science Operations Center, run by Stanford and Lockheed Martin. Goddard oversees the SMEX program.

The NASA SMEX Program is designed to provide frequent, low-cost access to space for heliophysics and astrophysics missions using small to mid-sized spacecraft. The program also seeks to raise public awareness of NASA's space science missions through educational and public outreach activities.

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Mission Overview

The Interface Region Imaging Spectrograph (IRIS) is a NASA Small Explorer Mission to observe how solar material moves, gathers energy, and heats up as it travels through a little-understood region in the sun's lower atmosphere. Tracking how material and energy move through this region is a crucial part of understanding the dynamics of the sun. Such information can help explain what causes the ejection of solar material -- from the steady stream of the solar wind to larger, explosive eruptions such as coronal mass ejections (CMEs) -- that travels toward Earth and causes space weather that can disrupt human technology.

Visible in ultraviolet light, the two regions closest to the sun are called the chromosphere and the transition region. They form a violently dynamic interface region in which hot and cold plasma are mixed over a range of heights, stretching from the sun's surface to several thousand miles up. This location is where one of the most mysterious occurrences on the sun takes place. Usually the closer you get to a heat source, such as a fire, the hotter it gets -- but the solar atmosphere doesn't do that. The solar atmosphere gets hotter as it gets further away from the sun, and scientists don't yet have enough information to distinguish between various theories on why this happens. The atmosphere changes from 6,000 K at the surface to about a million K at the top of the transition region. The temperatures continue to increase up to millions of degrees in the sun's upper atmosphere, the corona, but since the lowermost layers contain more material, the strongest heating is believed to occur there.

This image of a sunspot, taken by NASA's Transition Region and Coronal Explorer (TRACE) in Sept. 2000, showing the bright emission of the gas at about 1 million degrees, with the cooler material around 10,000 degrees showing up as dark, absorbing structures. Credit: NASA/TRACE This image of a sunspot, taken by NASA's Transition Region and Coronal Explorer (TRACE) in Sept. 2000, showing the bright emission of the gas at about 1 million degrees, with the cooler material around 10,000 degrees showing up as dark, absorbing structures. Credit: NASA/TRACE

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Tracking the complex processes within these layers of the solar atmosphere requires instrument and modeling capabilities that are within technological reach for the first time. IRIS is the first mission designed to simultaneously observe the range of temperatures specific to the chromosphere and transition region at very high spatial and temporal resolution -- going beyond earlier missions that were lower resolution or did not cover a wide range of temperatures.

IRIS also draws on state of the art computer modeling sophisticated enough to deal with the complexity of this area. In combination, IRIS's resolution, wide temperature coverage and computer modeling will enable scientists to map plumes of solar material as they move throughout the region and to pinpoint where in their travels they gain energy and heat.

The mission's general science objectives are to answer the following questions:

  1. Which types of non-thermal energy dominate in the chromosphere and beyond?
  2. How does the chromosphere regulate mass and energy supply to the corona and heliosphere?
  3. How do magnetic flux and matter rise through the lower atmosphere and what role does flux emergence play in flares and mass ejections?

The IRIS satellite design is derived from several previous NASA/LMSAL spacecraft. By re-using prior designs Lockheed Martin was able to reduce technical, scheduling and cost risks. Solar arrays omitted for clarity. Credit: LMSAL

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IRIS is NASA's Interface Region Imaging Spectrograph. Its primary goal is to understand how heat and energy move through the lower levels of the solar atmosphere.

IRIS is a class of spacecraft called a Small Explorer, which NASA defines as costing less than $120 million. Lockheed Martin (LM) Solar and Astrophysics Laboratory in LM’s Advanced Technology Center is the principle investigator institution and has overall responsibility for the mission, with major contributions from Lockheed Martin Civil Space, NASA Ames, Smithsonian Astrophysical Laboratory, Montana State University, Stanford University and the University of Oslo.

IRIS weighs 440 pounds. It is approximately 7 feet (2.1 meters) long and, with its solar panels extended, is a little over 12 feet (3.7 meters) across.

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Diagram of spectrograph and slit-jaw imager with part of the internal structure and baffling. Credit: NASA/LMSAL

The spectrograph will observe material at temperatures from 5,000 K to 10 million K. Spectra provide information on exactly how much light is visible from any specific wavelength. This, in turn, corresponds to how much material is present at specific velocities, temperatures and densities.

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The Science of IRIS

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IRIS will make use of high-resolution images, data and advanced computer models to unravel how matter, light, and energy move from the sun’s 6000 K surface to its million K outer atmosphere or corona. A fundamentally mysterious region that helps drive heat into the corona, this area has been notoriously hard to study. IRIS will be able to tease apart what's happening there better than has ever been done before.

IRIS will study the Chromosphere and Transition Region of the sun. Credit: National Solar Observatory

To do this, IRIS will observe the lowest part of the sun's atmosphere: the chromosphere, an expanse of ionized gas or plasma lying just above the sun's surface, and the transition region, where the chromosphere transitions into the even hotter corona above. This interface region lies at the core of many outstanding questions about the sun's atmosphere, such as how the sun creates giant explosions like solar flares or coronal mass ejections (CMEs), or how solar material in the corona reaches millions of degrees, several thousand times hotter than the surface of the sun itself.

Much of this coronal heating begins in the chromosphere and transition region. These highly dynamic regions are constantly in motion, so it isn't simple to profile temperatures with respect to position. Indeed, a wide range of temperatures can occur at similar heights, with different swaths of material propelled upward and downward in response to the release of magnetic energy, as well as various types of plasma waves. This moving interface region covers a wide range of heights above the sun’s surface, extending over several thousand miles. Throughout this height range, not only do the temperatures vary dramatically from 5000 Kelvin to almost a million degrees, but there are also enormous density contrasts, with certain areas up to a million times more dense than others.

This turbulent interface region contains more mass than does all the rest of the corona and heliosphere, which extends to the very edge of the solar system. Given how much material is there, the chromosphere requires a heating rate at least ten times greater than that of the corona itself.

One of IRIS's main science objectives will be to study how this foundational region of the heliosphere contributes mass and energy to the atmosphere above it, depositing so much heat into the corona. IRIS observations will mesh with those from NASA's Solar Dynamics Observatory (SDO), which launched in 2010. SDO observes the sun's surface and the corona, while IRIS will observe the crucial region in between the photosphere and corona at much higher resolution than ever before captured. IRIS is what's called an imaging spectrograph, which means it will provide both images and what are called spectra, which splits light into its various colors. Each line of light carries information about different materials o the sun and how they move, thus they can be used to probe physical characteristics in the solar atmosphere such as density, temperature and velocity.

IRIS will attempt to distinguish between two mechanisms that may be responsible for powering this region: magnetic field reconnection and dissipation of waves that travel through the solar atmosphere. Both these phenomena can add to the turbulence of the region and IRIS’s high-resolution spectra and images will be able to tease apart just which forms of energy cause which effects.

Such information will also help scientists examine how the solar material and its attendant magnetic fields contribute to eruptions on the sun such as solar flares and CMEs. This may increase our ability to forecast such space weather, which can disable satellites, cause power grid failures, and disrupt GPS services.

Lastly, understanding our own star better will help deepen our insight into atmospheres at distant stars as well.

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