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Meteorite Shockwaves Trigger Dust Avalanches on Mars

December 15, 2011 Leave a comment

Dust avalanches around impact craters on Mars appear to be the result of the shock wave preceding the actual impact, according to a study led by an undergraduate student at the UA.

When a meteorite careens toward the dusty surface of the Red Planet, it kicks up dust and can cause avalanching even before the rock from outer space hits the ground, a research team led by an undergraduate student at the University of Arizona has discovered.

“We expected that some of the streaks of dust that we see on slopes are caused by seismic shaking during impact,” said Kaylan Burleigh, who led the research project. “We were surprised to find that it rather looks like shockwaves in the air trigger the avalanches even before the impact.”

Full Story: http://uanews.org/node/43798

A Galaxy Blooming with New Stars

December 15, 2011 2 comments

Credit:  ESO/INAF-VST Acknowledgement: A. Grado/L. Limatola/INAF-Capodimonte Observatory

Credit: ESO/INAF-VST Acknowledgement: A. Grado/L. Limatola/INAF-Capodimonte Observatory

The VLT Survey Telescope (VST) has captured the beauty of the nearby spiral galaxy NGC 253. The new portrait is probably the most detailed wide-field view of this object and its surroundings ever taken. It demonstrates that the VST, the newest telescope at ESO’s Paranal Observatory, provides broad views of the sky while also offering impressive image sharpness.

NGC 253 gleams about eleven and a half million light-years away in the southern constellation of Sculptor. It is often just called the Sculptor Galaxy, although other descriptive names include the Silver Coin or Silver Dollar Galaxy. It is easy to get a good look at NGC 253 through binoculars as it is one of the brightest galaxies in the sky after the Milky Way’s closest, big galactic neighbour, the Andromeda Galaxy.

Astronomers have noted the widespread active star formation in NGC 253 and labelled it a “starburst” galaxy [1]. The many bright clumps dotting the galaxy are stellar nurseries where hot young stars have just ignited. The radiation streaming from these giant blue-white babies makes the surrounding hydrogen gas clouds glow brightly (green in this image).

Full Story: http://www.eso.org/public/news/eso1152/

NASA Takes Next Step in Developing Commercial Crew Program

December 15, 2011 Leave a comment

NASA announced today a modified competitive procurement strategy to keep on track the agency’s plan to have U.S. companies transport American astronauts into space instead of outsourcing this work to foreign governments.

Instead of awarding contracts for the next phase of the Commercial Crew Program, the agency plans to use multiple, competitively awarded Space Act Agreements. Using competitive Space Act Agreements instead of contracts will allow NASA to maintain a larger number of partners during this phase of the program, with the flexibility to adjust technical direction, milestones and funding.

This flexibility is important during a period of high budget uncertainty when NASA is receiving less funding than President Obama requested for the agency’s commercial space program.

Full Story: http://www.nasa.gov/home/hqnews/2011/dec/HQ_11-419_RXTE_Black_Hole282689.html

NASA’s RXTE Detects ‘Heartbeat’ of Smallest Black Hole Candidate

December 15, 2011 Leave a comment

An international team of astronomers has identified a candidate for the smallest-known black hole using data from NASA’s Rossi X-ray Timing Explorer (RXTE). The evidence comes from a specific type of X-ray pattern, nicknamed a “heartbeat” because of its resemblance to an electrocardiogram. The pattern until now has been recorded in only one other black hole system.

Named IGR J17091-3624 after the astronomical coordinates of its sky position, the binary system combines a normal star with a black hole that may weigh less than three times the sun’s mass. That is near the theoretical mass boundary where black holes become possible.

Gas from the normal star streams toward the black hole and forms a disk around it. Friction within the disk heats the gas to millions of degrees, which is hot enough to emit X-rays. Cyclical variations in the intensity of the X-rays observed reflect processes taking place within the gas disk. Scientists think that the most rapid changes occur near the black hole’s event horizon, the point beyond which nothing, not even light, can escape.

Astronomers first became aware of the binary system during an outburst in 2003. Archival data from various space missions show it becomes active every few years. Its most recent outburst started in February and is ongoing. The system is located in the direction of the constellation Scorpius, but its distance is not well established. It could be as close as 16,000 light-years or more than 65,000 light-years away.

Full Story: http://www.nasa.gov/topics/universe/features/black-hole-heartbeat.html

Hubble Serves Up a Holiday Snow Angel

December 15, 2011 Leave a comment

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

NASA’s Hubble Space Telescope presents a festive holiday greeting that’s out of this world. The bipolar star-forming region, called Sharpless 2-106, looks like a soaring, celestial snow angel. The outstretched “wings” of the nebula record the contrasting imprint of heat and motion against the backdrop of a colder medium.

Sharpless 2-106, Sh2-106 or S106 for short, lies nearly 2,000 light-years from us. The nebula measures several light-years in length. It appears in a relatively isolated region of the Milky Way galaxy.

A massive, young star, IRS 4 (Infrared Source 4), is responsible for the furious activity we see in the nebula. Twin lobes of super-hot gas, glowing blue in this image, stretch outward from the central star. This hot gas creates the “wings” of our angel.

A ring of dust and gas orbiting the star acts like a belt, cinching the expanding nebula into an “hourglass” shape. Hubble’s sharp resolution reveals ripples and ridges in the gas as it interacts with the cooler interstellar medium.

Full Story: http://www.nasa.gov/mission_pages/hubble/science/snow-angel.html

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