Hello.
I want to put this post to talk about latest news around astronomy, Its a new astronomical news page......
I'll appreciate if u help me with this post........
Thank u All
Hello.
I want to put this post to talk about latest news around astronomy, Its a new astronomical news page......
I'll appreciate if u help me with this post........
Thank u All
ویرایش توسط planetstruck : 04-11-2011 در ساعت 09:36 AM دلیل: Adding words,Correcting Grammar points
On 15 April, the French space agency CNES rotated the Pleiades Earth observation satellite to capture this image of Envisat. At a distance of about 100 km, Envisat’s main body, solar panel and radar antenna were visible.
CREDIT: CNES
View full size image
The European Space Agency declared the death of its massive Earth-observing satellite Envisat today (May 9) after a month of mysterious silence from the school bus-size spacecraft.
Envisat is the world's largest Earth-watching satellite for civilian use, with ESA officials touting its 10th anniversary in space earlier this year. The $2.9 billion satellite was originally designed to snap high-resolution photos of Earth for five years, but managed to last 10 years during its successful mission.
The troubles for Envisat began April 8, when the satellite abruptly stopped communicating with ground stations. Repeated attempts to restore contact failed week after week, with ESA officials calling off the recovery efforts today.
"Despite continuous commands sent from a widespread network of ground stations, there has been no reaction yet from the satellite," ESA officials explained in a statement.
An artist's illustration of the Envisat satellite in orbit.
CREDIT: ESA
There are several possible explanations for Envisat's unexpected demise.
The failure of a power regulator may be blocking the satellite's telemetry and telecommand systems, ESA officials said. There may have also been a short circuit on board that plunged Envisat into a protective "safe mode," then a second malfunction that left the satellite in an unknown state, incapable of receiving commands from Earth, they added. [Photos: Envisat Satellite & Earth Views]
"Although chances of recovering Envisat are extremely low, the investigation team will continue attempts to re-establish contact while considering failure scenarios for the next two months."
According to ground-based radar images of Envisat and photos of the craft from France's Pleiades Earth-observing satellite (which was called in during recovery efforts), the solar array on Envisat is properly deployed, officials have said.
Envisat is by all accounts a huge satellite. It is about 30 feet long (9 meters) and 16 feet wide (5 m). The spacecraft weighs 17,600 pounds (8,000 kilograms) and has a huge sail-like solar array that is 16 feet wide (5 m) and 46 feet long (14 m).
In 2010, space debris experts said that the satellite's immense size will make Envisat a major space junk risk for up to 150 years.
ESA launched the Envisat mission in 2001 to study the Earth from space in extreme detail. The satellite carries 10 sensors to study Earth's oceans, land, ice caps and atmosphere and has been a vital resource for about 2,500 scientific studies of our home planet.
Envisat’s Advanced Synthetic Aperture Radar (ASAR) captured this image on April 8, 2012 at 11:09 GMT. The image was transmitted in X-band to the Santa Maria station in the Azores, Portugal, operated by Edisoft. It shows Spain’s Canary Islands. It is the last Envisat data transmitted via X-band before the communication anomaly.
CREDIT: ESA/EdisoftView
The satellite has mapped the gradual decline of Arctic sea ice and tracked the regular opening of polar shipping routes in the summer months, in addition to its other discoveries, ESA officials said.
"The outstanding performance of Envisat over the last decade led many to believe that it would be active for years to come, at least until the launch of the follow-on Sentinel missions," ESA officials wrote. "However, Envisat had already operated for double its planned lifetime, making it well overdue for retirement."
The first launch of the new Sentinel Earth-observation satellites is slated for 2013.
source: space.com
“It's easier to run
Replacing this pain with something numb
It's so much easier to go
Than face all this pain here all alone.”
― Linkin Park
Huge Asteroid Vesta Actually an Ancient Protoplanet
by Mike Wall, SPACE.com Senior Writer
Date: 10 May 2012 Time: 02:00 PM ET
Global, colorized and hill-shaded digital terrain model of the ancient protoplanet Vesta, based on data gathered by NASA's Dawn spacecraft.
CREDIT: Science/AAAS
View full size image
This story was updated at 3:15 p.m. EDT.
New observations from a NASA spacecraft show that the huge asteroid Vesta is a battered protoplanet left over from the solar system's early days, with a unique mix of characteristics unknown from any other space rock.
Scientists had thought that Vesta, the second-largest body in the main asteroid belt between Mars and Jupiter, probably started down a planet-forming path shortly after the solar system's birth. Data gathered by NASA's Dawn probe have now confirmed that suspicion, researchers announced in a raft of studies that came out today (May 10) in the journal Science.
"We now know that Vesta is the only intact, layered planetary building block surviving from the very earliest days of the solar system," Dawn deputy principal investigator Carol Raymond, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., told reporters today.
The other objects like Vesta, researchers added, were probably incorporated into full-fledged planets or destroyed by collisions long ago. [Photos: Asteroid Vesta by Dawn Probe]
Some surprises
"Those studying meteorites that have fallen to Earth, many from Vesta, had produced a theory on the evolution of the solar system and what Vesta should be made of," said Dawn principal investigator Chris Russell of UCLA, lead author of one of the six new Science papers.
"They were very, very right," Russell told SPACE.com via email. "This is good, because we can now use that model to understand more about the solar system."
But Dawn has also delivered some surprising new results. The gigantic Rheasilvia basin at Vesta's south pole, for example, apparently was created by a massive impact just 1 billion years ago or so — long after the solar system's collision-filled "shooting gallery" stage is thought to have ended.
"An age of about 1 billion years for Rheasilvia is unexpectedly young," Simone Marchi of the Southwest Research Institute in Boulder, Colo., lead author of another of the new papers, said in a statement. "This result has important implications for our understanding of the evolution of Vesta, its asteroid family and the inner main asteroid belt in general."
"We have just started exploring Vesta’s secrets, and I’m sure other intriguing results will come along shortly," Marchi added.
Comparative imagery of nine asteroids. With a diameter of about 330 miles (530 kilometers), Vesta dwarfs all of these small bodies. Many scientists think it's a protoplanet left over from the solar system's first few million years.
CREDIT: NASA/JPL-Caltech/JAXA/ESA View full size image
The protoplanet Vesta
With a diameter of about 330 miles (530 kilometers), Vesta is roughly as wide as the U.S. state of Arizona. In the main asteroid belt, only the dwarf planet Ceres is bigger.
The $466 million Dawn spacecraft arrived at the huge asteroid in July 2011 to help unlock its many secrets. One of the probe's main missions, researchers said, is to determine if Vesta is indeed a long-surviving protoplanet — a body left over from the solar system's first few million years, many of which later coalesced to form rocky planets such as Earth and Mars.
Scientists got this idea mainly by examining fallen howardite-eucrite-diogenite (or HED) meteorites, which are thought to come from Vesta. The new Dawn results strongly support the protoplanet notion — by confirming that Vesta is indeed the HED meteorites' parent body, for starters.
Moreover, the huge asteroid isn't just some chunk of uniform rock. Rather, it's now known to be a differentiated object with an iron core about 137 miles (220 km) wide. That's big enough, perhaps, to have once sustained a dynamo like the one that generates Earth's magnetic field, researchers said.
The team figured out the dimensions of Vesta's core in part by carefully tracking Dawn's movements through space, then using this information to calculate Vesta's mass, density and gravitational pull with unprecedented precision. [Video: Vesta Flyover in 3D]
Other Dawn data also back Vesta's protoplanet status. For instance, its surface composition implies a complex geological history that's more similar to that of terrestrial planets than other asteroids, researchers said. And Vesta boasts color variations unlike anything seen on an asteroid before, further suggesting that the massive object is something special.
"We now know that Vesta is large enough to have had its own internal geologic evolution and is not just a battered lump of rock," said Paul Schenk of the Lunar and Planetary Institute in Houston, lead author of another of the new studies.
Cross sections of the central peak of Vesta's huge Rheasilvia impact basin, which measures 314 miles across. (A) shows color-contoured topography, while (B) is an orthorectified image mosaic.
CREDIT: Science/AAASView full size image
Two gigantic (and recent) impacts
Vesta's surface is pocked with craters from countless collisions over the eons. Dawn's observations have allowed scientists to reconstruct the protoplanet's impact history by counting these craters, and noting how many impact features overlie others.
Researchers found a huge difference between Vesta's northern and southern halves. The northern part retains a record of some of the asteroid's earliest impacts, while the south was "reset" by two enormous collisions far more recently.
One of these smashups occurred about 2 billion years ago, creating a 249-mile-wide (400-km) basin called Veneneia. But Veneneia was mostly obliterated about 1 billion years ago by another impact, which created the 314-mile (505-km) Rheasilvia crater.
"This basin erased at least half the surface and messed up a lot of the rest of it," Schenk told SPACE.com via email.
The Rheasilvia impact also created strange circular troughs around Vesta's equator and raised a central peak more than twice as high as Mount Everest, Russell said. And it excavated approximately 250,000 cubic miles (1.04 million cubic km) of material, much of which was blasted into space.
"Two hundred and fifty thousand cubic miles is enough to fill the Grand Canyon about a thousand times over," said David O'Brien, a Dawn scientist based at the Planetary Science Institute in Tucson, Ariz. "So this is a very large volume of material."
Both giant craters were likely caused by asteroids between 25 and 36 miles (40 to 60 km) wide, Schenk said. And both impacts seem to have occurred surprisingly late, several billion years after the presumed end of the so-called Late Heavy Bombardment that blasted many craters into Earth's moon and other solar system bodies.
More discoveries to come
The new results are based on data that Dawn gathered during the early stages of its stay at Vesta. The spacecraft will continue studying the protoplanet until Aug. 26, so we should expect more discoveries from the mission, researchers said.
"We have not yet reported on the high-resolution measurements made at low altitudes," Russell said. "We will be searching for water, just like there have been water searches on the moon."
Further, Vesta's far northern reaches have been in shadow thus far, so Dawn has been unable to study large chunks of the protoplanet. But that will change before too long.
"Sunlight is moving northward on Vesta, and we will soon see the north pole regions," Russell said. "What could be there to complement what we see in the south?"
When Dawn finishes up at Vesta, it will start the long trek to the dwarf planet Ceres, which is roughly as wide as Texas. The probe is scheduled to reach the "queen of the asteroid belt" in February 2015 and embark upon a whole new round of discoveries.
"We expect that Ceres is a much wetter world" than Vesta, Russell said. But, he added, "we have no meteorites to help us here. Everything will be a surprise."
“It's easier to run
Replacing this pain with something numb
It's so much easier to go
Than face all this pain here all alone.”
― Linkin Park
Giant Asteroid Vesta's Planetary Chances Killed by Jupiter
by Mike Wall, SPACE.com Senior Writer
Date: 10 May 2012 Time: 05:41 PM ET
![]()
NASA's Dawn spacecraft obtained this image of the giant asteroid Vesta with its framing camera on July 24, 2011.
CREDIT: NASA/JPL-Caltech/ UCLA/MPS/DLR/PSI
View full size image
Big, bad Jupiter likely squashed any chance the giant asteroid Vesta may have had of growing into a full-fledged planet long ago, researchers say.
Scientists analyzing observations from NASA's Dawn spacecraft announced today (May 10) that the enormous asteroid Vesta is actually an ancient protoplanet, a planetary building block left over from the solar system's earliest days.
Many other Vesta-like objects were incorporated into rocky worlds such as Earth, but Vesta's development along this path was halted.
Vesta's stunted growth is chiefly a product of its location, researchers said. The protoplanets that glommed together to form Mercury, Earth, Mars and Venus did so in the inner solar system, relatively far from the disruptive gravitational influence of a giant planet.
The 330-mile-wide (530-kilometer) Vesta, on the other hand, grew up in the main asteroid belt between Mars and Jupiter. And the solar system's largest planet made it tough for Vesta to hook up with others of its kind.
"In the asteroid belt, Jupiter basically stirred things up so much that they weren't able to easily accrete with one another," Dawn scientist David O'Brien, of the Planetary Science Institute in Tucson, Ariz., told reporters today.
"The velocities in the asteroid belt were really high, and the higher the velocity is, the harder it is for things to merge together under their own gravity," O'Brien added.
Those high velocities also set the stage for some incredibly violent collisions, which probably destroyed a fair number of Vesta-like bodies. Vesta itself was battered and bloodied by some huge impacts; one crater near its south pole is 314 miles (505 km) wide, and another underneath that one measures 250 miles (400 km) across.
So while Vesta — the second-largest denizen of the asteroid belt — was doomed to a life of solitude, it has had the toughness and luck to stick around for the last 4.5 billion years. And scientists are thankful that it did.
"Vesta is special, because it survived the intense collisional environment of the main asteroid belt for billions of years, allowing us to interrogate a key witness to the events at the very beginning of the solar system," said Dawn deputy principal investigator Carol Raymond, of NASA's Jet Propulsion Laboratory in Pasadena, Calif.
"We believe Vesta is the only intact member of a family of similar bodies that have since perished," she added.
“It's easier to run
Replacing this pain with something numb
It's so much easier to go
Than face all this pain here all alone.”
― Linkin Park
Endeavour Unplugged: NASA Powers Down its Last Space Shuttle
by Robert Z. Pearlman, collectSPACE.com Editor
Date: 11 May 2012 Time: 02:02 PM ET
![]()
A last look at a fully lit space shuttle. NASA shut down space shuttle Endeavour for the final
time on May 11, 2012, but not before giving collectSPACE.com the chance to photograph the retired spacecraft's powered-on flight deck.
CREDIT: collectSPACE.com/Robert Pearlman
NASA pulled the plug on its last powered space shuttle today (May 11), 20 years after it flew its first mission.
Space shuttle technicians working inside Orbiter Processing Facility-2 (OPF-2) at NASA's Kennedy Space Center in Florida powered down Endeavour, the youngest of the retired fleet's orbiters, at 9:58 a.m. EDT (1358 GMT) as they moved forward with preparations for the winged spacecraft's museum display.
This September, NASA will mount Endeavour on top of a modified Boeing 747 carrier aircraft and ferry it to Los Angeles for its exhibit at the California Science Center.
more information and source at http://www.space.com/15650-space-shu...unplugged.html
“It's easier to run
Replacing this pain with something numb
It's so much easier to go
Than face all this pain here all alone.”
― Linkin Park
Stellar Archaeology Traces Milky Way's History
Unfortunately, stars don't have birth certificates. So, astronomers have a tough time figuring out their ages. Knowing a star's age is critical for understanding how our Milky Way galaxy built itself up over billions of years from smaller galaxies. But Jason Kalirai of the Space Telescope Science Institute and The Johns Hopkins University's Center for Astrophysical Sciences, both in Baltimore, Md., has found the next best thing to a star's birth certificate. Using a new technique, Kalirai probed the burned-out relics of Sun-like stars, called white dwarfs, in the inner region of our Milky Way galaxy's halo. The halo is a spherical cloud of stars surrounding our galaxy's disk. Those stars, his study reveals, are 11.5 billion years old, younger than the first generation of Milky Way stars. They formed more than 2 billion years after the birth of the universe 13.7 billion years ago. Previous age estimates, based on analyzing normal stars in the inner halo, ranged from 10 billion to 14 billion years. Kalirai's study reinforces the emerging view that our galaxy's halo is composed of a layer-cake structure that formed in stages over billions of years.
More Information
Source
Web Chat: Hubble and Andromeda Galaxy: Astronomers Predict Next Cosmic Event
On Thursday, May 31, at 3:00 p.m. EDT NASA will host an informal discussion for the general public with astronomers about new Hubble Space Telescope observations that allow them to predict with certainty the next major cosmic event to affect our entire galaxy, sun, and solar system.
It has been known for a long time that the Andromeda galaxy is approaching us. Because of uncertainties in Andromeda's motion, it has not been possible to determine whether the Milky Way will have a head-on collision or glancing blow with the neighboring galaxy billions of years in the future. Hubble's precise observations will settle this question.
I think This chat for our time its about 3 hour later is started
The web chat panel members are:
Roeland van der Marel, astronomer, Space Telescope Science Institute, Baltimore
Sangmo Tony Sohn, astronomer, Space Telescope Science Institute, Baltimore
Gurtina Besla, astronomer, Columbia University, New York
Rosemary Wyse, professor, Physics and Astronomy, Johns Hopkins University, Baltimore
source : www.nasa.gove
It seems,this topic is a place to put the news and talk about them ,as Mr sadeghian told before. Tonight I recognize that you just copy the news and put them here!I wonder how useful it could be
ویرایش توسط gissoo : 06-01-2012 در ساعت 01:52 AM
مرگ اگر مرگ است آيد پيش من
تا كشم خوش در كنارش تنگ تنگ
من از او جانی برم بی رنگ و بو
او ز من دلقی ستاند رنگ رنگ
Yes dear gissoo, you're right & I really agree with you
Yes it's not according to this topic's goal & somehow just informing others from some news (the same as our farsi topic of astronomical news which members just copying news from somewhere else in it).The main goal of these topics is disscussing about news & specially learn new things from them
I hope we can reach to this topic's main aim with help of you & other friends
Thank you so much for your good comment & words![]()
برگ در انتهاي زوال مي افتد و ميوه در ابتداي کمال … بنگر که چگونه مي افتي ؟!
The Launch Readiness Review for the Pegasus XL rocket set to carry NASA's NuSTAR spacecraft was held on June 11, concluding with a "go" for launch on June 13 during a four-hour window that begins at 11:30 a.m. EDT. The review determined that there were no remaining open issues or concerns, and all action items were closed. Weather presents between a five and ten percent chance of violating the criteria due to of a slight chance of rain showers in the drop box area.
A launch countdown dress rehearsal was conducted on June 9, providing an opportunity for the launch team to work a combination of both simulated and actual problems. The team is scheduled to be off today to allow for sufficient rest before the countdown begins. On Wednesday, Orbital Sciences' L-1011 aircraft that will carry the Pegasus is scheduled to taxi out to the end of the runway at approximately 70 minutes before launch, and take off from Kwajalein Atoll ten minutes later. The drop location for the Pegasus is 117 nautical miles south of Kwajalein, at an altitude of 39,000 feet over the Pacific Ocean. This location is 6.75 degrees above the equator. Spacecraft separation occurs 13 minutes, 14 seconds after deployment from the L-1011.
Launch coverage begins at 10 a.m. EDT.
The NuSTAR Countdown Clock is on nasa.gov and you can see it online
http://www.nasa.gov/mission_pages/nu...ain/index.html
WASHINGTON -- Researchers anticipate that asteroid 2011 AG5, discovered in January 2011, will fly safely past and not impact Earth in 2040.
Observations to date indicate there is a slight chance that AG5 could impact Earth in 2040. Attendees expressed confidence that in the next four years, analysis of space and ground-based observations will show the likelihood of 2011 AG5 missing Earth to be greater than 99 percent.
Measuring approximately 460 feet (140 meters) in size, the space rock was discovered by the NASA-supported Catalina Sky Survey operated by the University of Arizona in Tucson. Several observatories monitored 2011 AG5 for nine months before it moved too far away and grew too faint to see.
"While there is general consensus there is only a very small chance that we could be dealing with a real impact scenario for this object, we will still be watchful and ready to take further action if additional observations indicate it is warranted," said Lindley Johnson, program executive for the Near-Earth Object (NEO) Observation Program at NASA Headquarters in Washington.
For More Information go to this link :http://www.nasa.gov/images/content/6...20615-full.jpg
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