अन्तरिक्ष बिज्ञान र प्रबिधि (Astronomy Science and Technology)

A new study provides a possible explanation of mysterious X-ray flares detected by the Chandra K-ray Observatory for several years in the region of Sagittarius A*, or Sgr A*. The study suggests a cloud around Sgr A*, a supermassive black hole at the center of our Milky Way Galaxy, which contains hundreds of trillions of asteroids and comets that have been stripped from their parent stars. The flares occur when asteroids of six miles or larger in radius are consumed by the black hole. An asteroid that undergoes a close encounter with another object, such as a star or planet, can be thrown into an orbit headed towards Sgr A*. If the asteroid passes within about 100 million miles of the black hole, roughly the distance between the Earth and the sun, it is torn into pieces by the tidal forces from the black hole. These fragments would then be vaporized by friction as they pass through the hot, thin gas flowing onto Sgr A*, similar to a meteor heating up and glowing as it

On February 5, 2002, NASA launched what was then called the High Energy Solar Spectroscopic Imager (HESSI) into orbit. Renamed within months as the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) after Reuven Ramaty, a deceased NASA scientist who had long championed the mission, the spacecraft's job was to observe giant explosions on the sun called solar flares. During a solar flare, the gas soars to over 20 million degrees Fahrenheit, and emits X-rays that scientists can use as fingerprints to study these events on the sun. X-rays cannot penetrate Earth's atmosphere, however, so RHESSI observes them from space. Its goal is simple: to understand how the sun so efficiently shoots out such huge amounts of energy and particles. Ten years since its launch, RHESSI has observed more than 40,000 X-ray flares, helped craft and refine a model of how solar eruptions form, and fueled additional serendipitous science papers on such things as the shape of the

Young Stars at Home in Ancient Cluster Looking like a hoard of gems fit for an emperor's collection, this deep sky object called NGC 6752 is in fact far more worthy of admiration. It is a globular cluster, and at over 10 billion years old is one the most ancient collections of stars known. It has been blazing for well over twice as long as our solar system has existed. NGC 6752 contains a high number of "blue straggler'' stars, some of which are visible in this image. These stars display characteristics of stars younger than their neighbors, despite models suggesting that most of the stars within globular clusters should have formed at approximately the same time. Their origin is therefore something of a mystery. Studies of NGC 6752 may shed light on this situation. It appears that a very high number -- up to 38 percent -- of the stars within its core region are binary systems. Collisions between stars in this turbulent area could produce the

Near the lower left corner of this view is the three-petal lander platform that NASA's Mars Exploration Rover Spirit drove off in January 2004. The lander is still bright, but with a reddish color, probably due to accumulation of Martian dust. Image credit: NASA/JPL-Caltech/Univ. of Arizona This image, taken Jan. 26, 2012, shows NASA's no-longer-active Phoenix Mars Lander spacecraft after its second Martian arctic winter. Image credit: NASA/JPL-Caltech/Univ. of Arizona The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter recorded a scene on Jan. 29, 2012, that includes the first color image from orbit showing the three-petal lander of NASA's Mars Exploration Rover Spirit mission. Spirit drove off that lander platform in January 2004 and spent most of its six-year working life in a range of hills about two miles to the east. Another recent image from HiRISE, taken on Jan. 26

Supermassive black hole Sagittarius A* at the center of the Milky Way. (X-ray: NASA/CXC/MIT/F. Baganoff et al.; Illustrations: NASA/CXC/M.Weiss)   The giant black hole at the center of the Milky Way may be vaporizing and devouring asteroids, which could explain the frequent flares observed, according to astronomers using data from NASA's Chandra X-ray Observatory. For several years Chandra has detected X-ray flares about once a day from the supermassive black hole known as Sagittarius A*, or "Sgr A*" for short. The flares last a few hours with brightness ranging from a few times to nearly one hundred times that of the black hole's regular output. The flares also have been seen in infrared data from ESO's Very Large Telescope in Chile. "People have had doubts about whether asteroids could form at all in the harsh environment near a supermassive black hole," said Kastytis Zubovas of the University of Leicester in the United Kingd

The Galaxy Evolution Explorer was launched on April 28, 2003.  NASA's Galaxy Evolution Explorer, or Galex, was placed in standby mode today as engineers prepare to end mission operations, nearly nine years after the telescope's launch. The spacecraft is scheduled to be decommissioned -- taken out of service -- later this year. The mission extensively mapped large portions of the sky with sharp ultraviolet vision, cataloguing millions of galaxies spanning 10 billion years of cosmic time. The Galaxy Evolution Explorer launched into space from a Pegasus XL rocket in April of 2003. Since completing its prime mission in the fall of 2007, the mission was extended to continue its census of stars and galaxies. The mission's science highlights include the discovery of a gigantic comet-like tail behind a speeding star, rings of new stars around old galaxies, and "teenager" galaxies, which help to explain how galaxies evolve. The observatory also h

On Jan. 27, 2012, a large X-class flare erupted from an active region near the solar west limb. X-class flares are the most powerful of all solar events. Seen here is an image of the flare captured by the X-ray telescope on Hinode. This image shows an emission from plasma heated to greater than eight million degrees during the energy release process of the flare.     ( बड़े एक्स वर्ग चमक सूर्य पर गूँज उठता है 27 जनवरी , 2012 पर , एक बड़े वर्ग भड़कना एक्स सौर पश्चिम अंग के पास एक सक्रिय क्षेत्र से भड़क उठी . एक्स वर्ग flares के सभी सौर घटनाओं की सबसे शक्तिशाली हैं . यहाँ देखा Hinode पर एक्स - रे दूरबीन द्वारा कब्जा कर लिया चमक की एक छवि है . इस छवि को भड़क की ऊर्जा की रिहाई की प्रक्रिया के दौरान आठ लाख से अधिक डिग्री करने के लिए गर्म प्लाज्मा से उत्सर्जन से पता चलता है .)

Vital clues about the devastating ends to the lives of massive stars can be found by studying the aftermath of their explosions. In its more than twelve years of science operations, NASA's Chandra X-ray Observatory has studied many of these supernova remnants sprinkled across the galaxy. The latest example of this important investigation is Chandra's new image of the supernova remnant known as G350.1-0.3. This stellar debris field is located some 14,700 light years from the Earth toward the center of the Milky Way. Evidence from Chandra and from ESA's XMM-Newton telescope suggest that a compact object within G350.1+0.3 may be the dense core of the star that exploded. The position of this likely neutron star, seen by the arrow pointing to "neutron star" in the inset image, is well away from the center of the X-ray emission. If the supernova explosion occurred near the center of the X-ray emission then the neutron star must have received a po

This drawing of the Mars Science Laboratory mission's rover, Curiosity, indicates the location of science instruments and some other tools on the car-size rover. Clockwise from upper left: Mastcam is the Mast Camera instrument. ChemCam is the Chemistry and Camera instrument. RAD is the Radiation Assessment Detector instrument. CheMin is the Chemistry and Mineralogy instrument. SAM is the Sample Analysis at Mars instrument. DAN is the Dynamic Albedo of Neutrons instrument. MARDI is the Mars Descent Imager instrument. MAHLI is the Mars Hand Lens Imager instrument. APXS is the Alpha Particle X-ray Spectrometer instrument. The brush, drill, sieves and scoop are tools on the rover's robotic arm. REMS is the Rover Environmental Monitoring Station. The Mars Science Laboratory spacecraft is being prepared for launch during the period Nov. 25 to Dec. 18, 2011. In a prime mission lasting one Martian year -- nearly two Earth years -- after landing, resea

This oblique view of the mound in Gale Crater shows several different rock types of interest to the Mars Science Laboratory mission. The lower part of the mound consists of layers of rock in which orbiting instruments have detected the signatures of clay minerals and sulfate salts. Mars scientists have several important hypotheses about how these minerals reflect possible changes in the Martian environment, particularly changes in the amount of water on the surface of Mars. The Mars Science Laboratory rover, Curiosity, will use its full suite of instruments to study these minerals and how they formed to give us insights into these ancient Martian environments. These rocks are also a prime target in the search for organic molecules since these environments may have been habitable -- able to support microbial life. Scientists will study how organic molecules, if present, vary with mineralogical variations in the layers to understand how they formed and what infl