अन्तरिक्ष बिज्ञान र प्रबिधि (Astronomy Science and Technology)

PASADENA, Calif. -- NASA's Voyager 2 has successfully switched to the backup set of thrusters that controls the roll of the spacecraft. Deep Space Network personnel sent commands to the spacecraft to make the change on Nov. 4 and received confirmation today that the switch has been made.  The change allows engineers to reduce the amount of power that the 34-year-old spacecraft needs to operate by turning off the heater that keeps the fuel to the primary thrusters warm. Although the rate of energy generated by Voyager 2's nuclear power source continues to decline, by reducing its power requirements, engineers expect the spacecraft can continue to operate for another decade. The switch also allows the spacecraft to use previously unused thrusters as it continues its journey toward interstellar space, beyond our solar system. Voyager 1 and Voyager 2 are each equipped with six sets, or pairs, of thrusters to control the pitch, yaw and roll motions of the spacecra

New data from the Herschel Space Observatory shows that galaxies with the most powerful, active, supermassive black holes at their cores produce fewer stars than galaxies with less ones. Supermassive black holes are believed to reside in the hearts of all large galaxies. When gas falls upon these monsters, the materials are accelerated and heated around the black hole, releasing great torrents of energy. In the process, active black holes often generate colossal jets that blast out twin streams of heated matter. Inflows of gas into a galaxy also fuel the formation of new stars. In a new study of distant galaxies, Herschel helped show that star formation and black hole activity increase together, but only up to a point. Astronomers think that if an active black hole flares up too much, it starts spewing radiation that prevents raw material from coalescing into new stars. This artist concept of the local galaxy Arp 220, captured by the Hubble Space Telescope, helps illustrate the

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 .)