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Explanation: Rocks from space hit Earth every day. The larger the rock, though, the less often Earth is struck. Many kilograms of space dust pitter to Earth daily. Larger bits appear initially as a bright meteor. Baseball-sized rocks and ice-balls streak through our atmosphere daily, most evaporating quickly to nothing. Significant threats do exist for rocks near 100 meters in diameter, which strike the Earth roughly every 1000 years. An object this size could cause significant tsunamis were it to strike an ocean, potentially devastating even distant shores. A collision with a massive asteroid, over 1 km across, is more...

China's official news agency is reporting that the country's Chang'e 2 deep-space probe made an amazing flyby of the asteroid Toutatis this week, snapping a series of pictures as it passed just 2 miles away. The achievement signals China's entry into yet another exclusive space club. Only four of the world's space efforts have managed close encounters with asteroids: NASA (with NEAR Shoemaker and Dawn, for example), the European Space Agency (with Rosetta), Japan (with Hayabusa) — and now China with Toutatis

Scientists using data from NASA's Wide-field Infrared Survey Explorer, or WISE, have uncovered new clues in the ongoing mystery of the Jovian Trojans -- asteroids that orbit the sun on the same path as Jupiter. Like racehorses, the asteroids travel in packs, with one group leading the way in front of the gas giant, and a second group trailing behind. The observations are the first to get a detailed look at the Trojans' colors: both the leading and trailing packs are made up of predominantly dark, reddish rocks with a matte, non-reflecting surface. What's more, the data verify the previous...

Scientists on NASA's asteroid sample return mission, Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx), have measured the orbit of their destination asteroid, 1999 RQ36, with such accuracy they were able to directly measure the drift resulting from a subtle but important force called the Yarkovsky effect -- the slight push created when the asteroid absorbs sunlight and re-emits that energy as heat... Observations that Michael Nolan at Arecibo Observatory in Puerto Rico made in September 2011, along with Arecibo and Goldstone radar observations made in 1999 and 2005, when 1999 RQ36 passed much closer to Earth, show that...

NASA's WISE Telescope Detects 4,700 Possibly Hazardous AsteroidsBy Mark Whittington | Yahoo! Contributor Network – 10 hrs ago According to CNN, NASA has announced that there are potentially 4700 asteroids -- give or take 1,500 -- that are large enough and pass close enough to the Earth in their orbits around the sun to constitute a hazard. Hazardous asteroids A hazardous asteroid, as defined by NASA, is a body that is greater than 100 meters or 330 feet in diameter and approaches Earth within 5 million miles, about 20 times the distance from the Earth to the moon. Such an...

Explanation: What would it be like to fly over the asteroid Vesta? Animators from the German Aerospace Center recently took actual images and height data from NASA's Dawn mission currently visiting Vesta to generate such a virtual movie. The above video begins with a sequence above Divalia Fossa, an unusual pair of troughs running parallel over heavily cratered terrain. Next, the virtual spaceship explores Vesta's 60-km Marcia Crater, showing numerous vivid details. Last, Dawn images were digitally recast with exaggerated height to better reveal Vesta's 5-km high mountain Aricia Tholus. Currently, Dawn is rising away from Vesta after being close...

Gannett newspaper, link only: http://www.desmoinesregister.com/article/20120117/NEWS/301170042/0/mobile/?odyssey=nav|head

Explanation: Though the sizes are not to scale, the Sun and planets of the inner solar system are shown in this illustration, where each red dot represents an asteroid. New results from NEOWISE, the infrared asteroid hunting portion of the WISE mission, are shown on the left compared to old population projections of mid-size or larger near-Earth asteroids from surveys at visible wavelengths. And the good news is, NEOWISE observations estimate there are 40 percent fewer near-Earth asteroids that are larger than 100 meters (330 feet), than indicated by visible light searches. Based on infrared imaging, the NEOWISE results are...

Want to mine an asteroid? Rather than travel to it with all their mining equipment, three Chinese scientists have proposed a better way. In a paper published today on the Los Alamos astro-ph preprint website, they have calculated the energy required to shift the orbits of the six thousand near-Earth asteroids and place them in Earth orbit for later mining. Of these, they found 46 asteroids that had the potential for such an operation, and two likely candidates for a space mission. One 30-foot-wide asteroid, 2008EA9, will actually be in the right place for this technique in 2049.

In a paper published today on the Los Alamos astro-ph preprint website, two Chinese scientists have proposed using a solar sail for deflecting any asteroid that happens to be aimed at the earth. The diagram to the right is their simulated mission to impact the asteroid Apophis, which will pass close to the earth in 2029 and — depending on whether that flyby puts it through a very small 600 meter-wide mathematical “keyhole” — could then return in 2036 on a collision course.

It seemed far-fetched on the silver screen. But the European Space Agency is planning to launch a mission similar to the plot of Hollywood movie Armageddon, in which Bruce Willis and his intrepid team attempt to blow up a huge asteroid that’s hurtling towards Earth. [snip!]

A surprise meteor shower spotted in February was likely caused by cosmic "bread crumbs" dropped by an undiscovered comet that could potentially pose a threat to Earth, astronomers announced today (July 27). The tiny meteoroids that streaked through Earth's atmosphere for a few hours on Feb. 4 represent a previously unknown meteor shower, researchers said. The "shooting stars" arrived from the direction of the star Eta Draconis, so the shower is called the February Eta Draconids, or FEDs for short. The bits of debris appear to have been shed by a long-period comet. Long-period comets whiz by the sun very...

A new record was set on 29 January 2011 when the science team operating a new prototype telescope discovered not one Near-Earth Asteroid, not two, but nineteen in a single night! “This record number of discoveries shows that PS1 is the world’s most powerful telescope for this kind of study,” said Nick Kaiser, head of the Pan-STARRS project. One of the most difficult jobs astronomers have in outreach is encouraging spending in asteroid discovery programs, to give us sufficient warning of any potential asteroids that will collide with Earth, while avoiding the temptation to whip up false panic. The risk...

Astronomer Brian G. Marsden, a comet and asteroid tracker who stood sentinel to protect the Earth from collisions with interplanetary rocks and other remnants of the solar system's creation, died Thursday of cancer at Lahey Clinic Medical Center in Burlington, Mass. He was 73. Director emeritus of the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., Marsden was perhaps best known for his 1998 announcement that an asteroid known as 1997 XF11 might strike the Earth in 2028, causing untold damage. The announcement sparked additional studies which quickly showed that such an impact was unlikely. Marsden,...

MONTREAL — Great balls of fire have been reported swooping over Eastern Canada and several U.S. states. Even NASA's on the case. There are different theories about what was behind the sighting of those fireballs. A NASA spacecraft got a closer look at one of the possible sources today. The spacecraft flew past Hartley 2 -- taking closeup pictures after the comet made one of its closest passes by Earth this week. But one expert is skeptical of reports that any fireballs came from Hartley -- which is roughly 1.2 kilometres wide and spews deadly cyanide gas. Scientist Peter Brown...

A new report calls on NASA to establish a Planetary Defense Coordination Office to lead national and international efforts in protecting Earth against impacts by asteroids and comets. The final report of the Ad-Hoc Task Force on Planetary Defense of the NASA Advisory Council was delivered to the Council this month, proposing five recommendations that suggest how the space agency should organize, acquire, investigate, prepare, and lead national and international efforts in planetary defense against near-Earth objects.

Want to know what would happen if a 10km-wide asteroid came out of the sky and slammed down on your city? Scientists at Purdue University and Imperial College London have updated their popular impact effects calculator first produced in 2004. Users dial in details about the hypothetical impactor, like its diameter and density. The web program then estimates the scale of the ensuing disaster, such as the size of the crater left behind. It will also tell you how far away you need to be to avoid being buried by all the material thrown out by the blast, or set...

In separate 10-page letters to the House Committee on Science and Technology and the Senate Committee on Commerce, Science and Transportation, John Holdren, director of the White House Office of Science and Technology Policy, or OSTP, outlines plans for "(A) protecting the United States from a near-Earth object that is expected to collide with Earth; and (B) implementing a deflection campaign, in consultation with international bodies, should one be necessary." ... While Holdren indicates that no large asteroid or comet presents an immediate hazard to our planet, the fact that devastating impacts have occurred on Earth in the distant past...

Evidence that water came to Earth during its formation from cosmic dust, rather than following later in asteroids, has been shown by a group of international scientists. The origin of the abundant levels of water on Earth has long been debated with the main differences in the theories being the nature of the material that carries the water, and whether the water came during or after planet formation. Now, Nora de Leeuw at University College London, UK, and colleagues have used molecular-level calculations to prove that dissociative chemisorption of water onto the surface of olivine rich minerals, such as forsterite,...

A United Nations working group is currently looking into how the UN should respond to possible threats to the planet from near-earth objects, such as asteroids, Mazlan Othman, the Director of the UN Office for Outer Space Affairs (UNOOSA), told reporters at UN Headquarters in New York on October 14 2010, the UN News Service said. She said that the working group -- within the UN Committee on the Peaceful Uses of Outer Space -- is expected to come up with recommendations which would be presented to the General Assembly for UN member states to make a decision on response...